Baixe Np - en - 196-2-2005 e outras Notas de estudo em PDF para Gestão Ambiental, somente na Docsity! EUROPEAN STANDARD EN 196-2 NORME EUROPÉENNE EUROPÁISCHE NORM February 2005 ICS 91.100.10 Supersedes EN 196-2:1994, EN 196-21:1989 English version Methods of testing cement - Part 2: Chemical analysis of cement Méthodes d'essais des ciments - Partie 2: Analyse Prúfverfahren fur Zement - Teil 2: Chemische Analyse von chimique des ciments Zement This European Standard was approved by CEN on 29 December 2004. CEN members are bound to comply with the CEN/CENELEC Intemal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. La EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPAISCHES KOMITEE FÚR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels O 2005 CEN | Allrights of exploitation in any form and by any means reserved Ref. No. EN 196-2:2005: E worldwide for CEN national Members. EN 196-2:2005 (E) Contents Page Foreword...... cod 1 Scope..... 6 2 Normative references...... 6 3 General requirements for testing 6 31 Number oftests. 6 3.2 Repeatability an: y 6 3.3 Expression of masses, volumes, factors and results 7 34 Ignitions. 7 3.5 Determination of constant mass. 7 3.6 Check for absence of chloride ions (silver nitrate test). 7 3.7 Blank determinations....... 7 4 Reagents.... 8 5 Apparatus ............. 6 Preparation of a test sample of cement .................. 7 Determination of loss on ignition. 74 Principle.. 7.2 73 . 74 for oxidation of sulfides. .25 7.5 Repeatability and reproducibility... 8 Determination of sulfat 8.1 Principle.. 8.2 Procedur: 83 Calculation and expression of results. 84 Repeatability and reproducibility... 9 Determination of residue insoluble in hydrochloric acid and sodium carbonate 9.1 Principle.. 9.2 Procedur: 9.3 Calculation and expression of results. 9.4 Repeatability and reproducibility... 10 Determination of residue insoluble in hydrochloric acid and potassium hydroxide 10.1 | Principle.. 10.2 Procedur: 10.3 Calculation and expression of results. 10.4 Repeatability and reproducibility... 1 Determination of sulfid 11.1 Principle. 11.2 | Procedur: 11.3 Calculation and expression of result 11.4 ' Repeatability and reproducibility... 12 Determination of manganese 12.1 Principle. 12.2 Procedur: 12.3 | Calculation of results 12.4 Repeat ty and reproducil 12.5 Expression of results..... 13 Determination of major elements....... EN 196-2:2005 (E) j) an ignition temperature of (950 + 25 ) ºC has been set for the determination of loss on ignition and the ignition of barium sulfate and insoluble residues; k) determination of sulfate before and after ignition in the determination of loss on ignition becomes the reference method when correcting for sulfide; |) determination of silica by the double evaporation method becomes the reference method; m in the determination of carbon dioxide by decomposition with sulfuric acid an additional, empty, gas washing bottle is included as a safety precaution against the reverse flow of sulfuric acid should pressure be lost; n) in the determination of alkali the influence of phosphoric acid on the potassium emission from the calibration solutions is suppressed by the addition of calcium to the calibration solutions. The procedure is adjusted accordingly. Analytical methods utilising x-ray fluorescence (XRF) were considered during this revision but no published, standardised method was considered sufficiently comprehensive to be included. A new work item has been established by CEN/TC51 in order to prepare a method based on XRF. XRF and other instrumental methods such as differential thermal analysis for determination of carbon dioxide, atomic absorption spectroscopy, etc. may be used as alternative methods provided they are calibrated against the reference methods, or against internationally accepted reference materials. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 196-2:2005 (E) 1 Scope This document specifies the methods for the chemical analysis of cement. This document describes the reference methods and, in certain cases, an alternative method which can be considered to be equivalent. In the case of a dispute, only the reference methods are used. Any other methods may be used provided they are calibrated, either against the reference methods or against internationally accepted reference materials, in order to demonstrate their equivalence. This document describes methods which apply principally to cements, but which can also be applied to their constituent materials. They can also be applied to other materials, the standards for which call up these methods. Standard specifications state which methods are used. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 196-7, Methods of testing cement — Part 7: Methods of taking and preparing samples of cement ISO 385-1, Laboratory glassware — Burettes — Part 1: General requirements ISO 835-1, Laboratory glassware — Graduated pipettes — Part 1: General requirements 3 General requirements for testing 3.1 Number of tests Analysis of a cement may require the determination of a number of its chemical properties. For each determination one or more tests shall be carried out in which the number of measurements to be taken shall be as specified in the relevant clause ofthis document. Where the analysis is one of a series subject to statistical control, determination of each chemical property by a single test shall be the minimum required. Where the analysis is not part of a series subject to statistical control, the number of tests for determination of each chemical property shall be two (see also 3.3). In the case of a dispute, the number of tests for determination of each chemical property shall be two (see also 3.3). 3.2 Repeatability and reproducibility Repeatability - Precision under repeatability conditions where independent test results are obtained with the same method on identical test items (material) in the same laboratory by the same operator using the same equipment within short intervals of time. Reproducibility - Precision under reproducibility conditions where test results are obtained with the same method on identical test items (material) in different laboratories with different operators using different equipment. EN 196-2:2005 (E) Repeatability and reproducibility in this document are expressed as repeatability standard deviation(s) and reproducibility standard deviation(s) in e.g. absolute percent, grams, etc., according to the property tested. 3.3 Expression of masses, volumes, factors and results Express masses in grams to the nearest 0,000 1 g and volumes from burettes in millilitres to the nearest 0,05 ml. Express the factors of solutions, given by the mean of three measurements, to three decimal places. Express the results, where a single test result has been obtained, as a percentage generally to two decimal places. Express the results, where two test results have been obtained, as the mean of the results, as a percentage generally to two decimal places. lfthe two test results differ by more than twice the standard deviation of repeatability, repeat the test and take the mean of the two closest test results. The results of all individual tests shall be recorded. 3.4 Ignitions Carry out ignitions as follows. Place the filter paper and its contents into a crucible which has been previously ignited and tared. Dry it, then incinerate slowly in an oxidising atmosphere in order to avoid immediate flaming, while ensuring complete combustion. Ignite the crucible and its contents at the stated temperature then allow to cool to the laboratory temperature in a desiccator. Weigh the crucible and its contents. 3.5 Determination of constant mass Determine constant mass by making successive 15 min ignitions followed each time by cooling and then weighing. Constant mass is reached when the difference between two successive weighings is less than 0,000 5 q. 3.6 Check for absence of chloride ions (silver nitrate test) After generally five to six washes of a precipitate, rinse the base of the filter stem with a few drops of water. Wash the filter paper and its contents with several millilitres of water and collect this in a test tube. Add several drops of silver nitrate solution (4.43). Check the absence of turbidity or precipitate in the solution. If present, continue washing while carrying out periodic checks until the silver nitrate test is negative. 3.7 Blank determinations Carry out a blank determination without a sample, where relevant, following the same procedure and using the same amounts of reagents. Correct the results obtained for the analytical determination accordingly. EN 196-2:2005 (E) 4.45 Sodium carbonate solution. Dissolve 50 g of anhydrous sodium carbonate (4.39) in water and make up to 1 000 ml. 4.46 Potassium hydroxide solution. Dissolve 250 g of potassium hydroxide (KOH) in water and make up to 1 000 ml. Store in a polyethylene container. 4.47 | Ammoniacal zinc sulfate solution. Dissolve 50 g of zinc sulfate (ZnSO,.7H>0) in 150 ml water and add 350 ml of concentrated ammonium hydroxide (4.25). Leave to stand for at least 24h and filter. 4.48 Lead acetate solution. Dissolve approximately 0,2 g of lead acetate (Pb(CH;COO)>.3H,0) in water and make up to 100 ml. 4.49 Starch solution. To 1 g of starch (water soluble), add 1g of potassium iodide (KI), dissolve in water and make up to 100 ml. Use within two weeks. 4.50 Polyethylene oxide solution. Dissolve 0,25 g of polyethylene oxide (-CH>-CH>0O-), of average molecular mass 200 000 to 600 000, in 100 ml water while stirring vigorously. Use within two weeks. 4.51 Boric acid solution, saturated. Dissolve approximately 50 g of boric acid (HsBOs) in water and make up to 1 000 ml. 4.52 Citric acid solution. Dissolve 10 g of citric acid (CeHs07.H>0) in water and make up to 100 ml. 4.53 Calcium carbonate (CaCO), dried to constant mass at (200 + 10) “C (of purity > 99,9 %). 4.54 Ammonium molybdate solution. Dissolve 10 g of ammonium molybdate (NH,)eMo;054.4H,0 in water and make up to 100 ml. Store the solution in a polyethylene flask. Use within one week. 4.55 Copper sulfate solution. Dissolve 0,45 g of copper sulfate (CuSO,.5H,0) in water and make up to 50 mlin a volumetric flask. 4.56 Ammonium acetate solution. Dissolve 250 g of ammonium acetate (CH;COONH,) in water and make up to 1 000 ml. 4.57 Triethanolamine N(CH>CH>0H); (>99 %) diluted to 1 + 4 solution. 4.58 Reducing solution. Dissolve 1 g of tin (Il) chloride (SnCl>.2H,0) (4.33) in water to which has been added 1 ml of concentrated hydrochloric acid (4.1). Make up to 100 ml with water. Use within one day. 4.59 Buffer solution of pH 1,40. Dissolve (7,505 + 0,001) g of amino-acetic acid (4.23) and (5,850 + 0,001) g of sodium chloride (NaCl) (4.37) in water and make up to 1 000 ml. Dilute 300 ml of this solution to 1 000 ml with hydrochloric acid 1 + 99 (4.8). 4.60 Standard potassium iodate solution, approximately 0,016 6 molÃ. Weigh, to + 0,000 5 9, (3,6 + 0,1) 9, of potassium iodate (KIOs) (4.34) (m,) and place in a 1000 ml volumetric flask. Add 0,2 g of sodium hydroxide (4.29), 25 g of potassium iodide (KI), dissolve all the solids in freshly boiled and cooled water and make up to the mark using the same water. Calculate the factor F of the potassium iodate solution from the following formula: m 35668 (1) where m« is the mass of the portion of potassium iodate, in grams. 4.61 Sodium thiosulfate solution approximately 0,1 mol/l 4.61.1 Preparation 10 EN 196-2:2005 (E) Dissolve (24,82 + 0,01) g of sodium thiosulfate (Na,S,05.5H,0) in water and make up to 1 000 ml. Before each test series, determine the factor f of this solution as described in 4.61.2. 4.61.2 Standardization 4.61.2.1 This standardization is carried out preferably using the standard potassium iodate solution (4.60). For this standardization, pipette 20 ml of the standard potassium iodate solution (4.60) into a 500 ml conical flask and dilute with approximately 150 ml of water. Acidify with 25 ml of hydrochioric acid 1+1 (4.2) and titrate with the approximately 0,1 mol/l sodium thiosulfate solution (4.61.1) to a pale yellow colour. Add 2 ml of the starch solution (4.49) and continue the titration until the colour changes from blue to colourless. Calculate the factor fof the sodium thiosulfate solution from the formula: 20 x 0,01667 x 21401 x F F f=[]000DD0DD00" 00 / = w0x— (2) 35668 x Vi V where F is the factor of the standard potassium iodate solution (4.60); V, is the volume of the approximately 0,1 mol/l sodium thiosulfate solution used for the titration, in millilitres; 3,5668 is the mass of potassium iodate corresponding to a solution with exactly 0,016 67 molll of potassium iodate, in grams; 214,01 | is the molecular mass of KIOs, in grams. 4.61.2.2 The standardization may alternatively be carried out using a known quantity of potassium iodate. For this standardization, weigh, to + 0,000 5 g, (0,070 + 0,005) g of potassium iodate (4.34) (m,) and place in a 500 ml conical flask. Dissolve in approximately 150 ml of water. Add about 1 g of potassium iodide, acidify with 25 ml of hydrochloric acid 1+1 (4.2) and titrate with the approximately 0,1 mol/l sodium thiosulfate solution (4.61.1) until a pale yellow colour is obtained. Then add 2 ml of the starch solution (4.49) and titrate until the colour changes from blue to colourless. Calculate the factor fof the sodium thiosulfate solution from the formula: f-= S5058 =280,3634 x m (3) where mo is the mass of potassium iodate, in grams; A is e volume of the approximately 0,1 mol/l sodium thiosulfate solution used for the titration, in millilitres; 3,5668 is the mass of potassium iodate corresponding to a solution with exactly 0,016 67 molll of potassium iodate, in grams. 4.62 Standard manganese solution 4.62.1 Anhydrous manganese sulfate Dry hydrated manganese sulfate (MnSO,.xH>0) to constant mass at (250 + 10) ºC. The composition of the product obtained corresponds to the formula MnSO.,. 1 EN 196-2:2005 (E) 4.62.2 Preparation Into a 1 000 ml volumetric flask, weigh, to + 0,000 5 g, (2,75 + 0,05) g of anhydrous manganese sulfate (ms); dissolve in water and make up to the mark. Calculate the content G of manganese (Il) ions of this solution, expressed in milligrams of Mn? per millilitre, from the formula: G = (4) 2,1485 where ms is the mass of anhydrous manganese sulfate, in grams. 4.62.3 Construction of the calibration curve Into each of two volumetric flasks, respectively 500 ml (No. 1) and 1 000 ml (No. 2), pipette 20 ml of the standard manganese solution. Make up to the mark with water. Into each of three volumetric flasks, respectively 200 ml (No. 3), 500 ml (No. 4) and 1 000 ml (No. 5) pipette 100 ml ofthe solution from flask No. 2 and make up to the mark with water. Take 100 ml of each solution from flasks 1 to 5 and pipette each portion into a 400 ml beaker. Add 20 ml of concentrated nitric acid (4.12), 1,5 g of potassium periodate (4.35) and 10 ml of phosphoric acid (4.19), heat to boiling and boil gently for 30 min. Allow to cool to room temperature and transfer the contents of each beaker to a 200 ml volumetric flask and make up to the mark with water. Measure the absorbance of the solutions using a photometer (5.10) at a wavelength of around 525 nm, against water (use one or more cells (5.11) of appropriate sizes). Record the absorbance values to three decimal places. For each cell optical length construct a separate curve of the absorbance of these calibration solutions E1 to E5 as a function of the corresponding manganese concentrations in milligrams of Mn per 200 ml. The corresponding manganese concentrations are given in Table 1. They can be used as given if the content G obtained in accordance with 4.62.2 has the value 1,000 O. Otherwise, multiply the manganese concentrations in Table 1 by the value of G calculated from equation (4). Table 1 — Concentrations of manganese calibration solutions Calibration solution E1 E2 E3 E4 Es Concentration of manganese in mg of 40 2,0 1,0 0,4 0,2 Mn per 200 ml 12 EN 196-2:2005 (E) 4.65.3 Standardization Pipette 50 ml of the standard calcium ion solution (4.64) into a beaker suitable for the measuring apparatus (5.12). Then dilute with water to a volume suitable for the operation ofthe apparatus. Using the pH meter (5.18.1), adjust the pH of this solution to (12,5 + 0,2) with either of the sodium hydroxide solutions (4.30 or 4.31). Determine the end-point using one of the following two methods. a) Photometric determination of the end-point (reference method) Add, without weighing, about 0,1 g of murexide (4.69) or of mixed calcein and methylthymol blue indicator (4.75). Place the beaker in the apparatus (5.12) set at 620 nm when using murexide or at 520 nm when using the mixed indicator and, while stirring continuously, titrate with the approximately 0,03 mol/l EDTA solution. In the vicinity of the indicator colour change, construct a curve giving the absorbance values as a function of the volume of EDTA added. The volume V; used is determined from the intersection of the line of greatest slope near the colour change and the line of almost constant absorbance after the colour change. Calculate the factor fp of the EDTA solution from the formula: — 80x m 6652 x 4 (5) 100,09 x 0,03x Vá Vs fo = where mg is the mass of calcium carbonate taken to prepare the standard calcium ion solution (4.64), in grams; V; is the volume of the EDTA solution used for the titration, in millilitres. b) Visual determination of the end-point (alternative method) Add, without weighing, about 0,1 g of either the calcon indicator (4.71) or the Patton and Reeders indicator (4.76). Stir and titrate with the approximately 0,03 mol/l EDTA solution (4.65) until the colour changes from pink to blue (calcon) or purple to blue (Patton and Reeders), volume Vs, and one drop in excess does not further increase the intensity of the blue colour. Calculate the standardization factor fp of the EDTA solution using equation (5). 4.66 Copper complexonate solution Pipette 25 ml ofthe copper sulfate solution (4.55) into a 400 ml beaker and add from a burette an equivalent volume Vs of the approximately 0,03 molA EDTA solution (4.65). Determine the required volume Vs of EDTA solution as follows. Pipette 10 ml of the copper sulfate solution (4.55) into a 600 ml beaker. Dilute to approximately 200 ml with water and add 10 ml of concentrated ammonium hydroxide (4.25) and, without weighing, about 0,1 g of murexide indicator (4.69). Titrate with the approximately 0,03 mol/l EDTA solution (4.65) until the colour changes from pink to violet (V,). Calculate the volume Vs of the approximately 0,03 mol/l EDTA solution to be added to 25 ml of the copper sulfate solution to obtain copper complexonate from the formula: Vs =25 x Va (6) where V, is the volume of the approximately 0,03 mol/l EDTA solution for the titration, in millilitres. 15 EN 196-2:2005 (E) 4.67 EGTA solution, approximately 0,03 mol/l 4.67.1 Ethyleneglycolbis (aminoethylether) tetra-acetic acid (EGTA) 4.67.2 Preparation Dissolve (11,4 + 0,01) g of EGTA in 400 ml of water and 30 ml of the sodium hydroxide solution (4.31) in a 600 ml beaker. Heat the mixture until the EGTA is completely dissolved. Allow to cool to room temperature. Using the pH meter (5.18.1), adjust the pH to (7,0 + 0,5), by adding, drop by drop, hydrochloric acid 1 + 2 (4.3). Transfer the solution quantitatively to a 1 000 ml volumetric flask and make up to the mark with water. Store the solution in a polyethylene container. 4.67.3 Standardization Pipette 50 ml of the standard calcium ion solution (4.64) into a beaker suitable for the measuring apparatus (5.12). Then dilute with water to a volume suitable for the correct operation of the apparatus. Add 25 ml ofthe triethanolamine 1 + 4 solution (4.57). Using the pH meter (5.18.1), adjust the pH of this solution to (12,5 + 0,2) with either of the sodium hydroxide solutions (4.30 or 4.31). Add, without weighing, about 0,1 g of murexide (4.69) or of calcein indicator (4.70). Place the beaker in the apparatus (5.12) set at 620 nm when using murexide or at 520 nm when using calcein and, while stirring continuously, titrate with the approximately 0,03 mol/l EGTA solution. In the vicinity of the indicator colour change, take note of the absorbance values and the correspondent volumes of EGTA added and construct a curve of absorbance versus volume of titrant. The volume Vg used is determined from the intersection of the line of greatest slope near the colour change and the line of almost constant absorbance after the colour change. Calculate the factor fs ofthe EGTA solution from the formula: 50 x ms = 16,652 x 75 (7) fe = to000 x 003 X Ve Ve where ms isthe mass of calcium carbonate taken to prepare the standard calcium ion solution (4.64), in grams; Vs isthe volume of the EGTA solution used for the titration, in millilitres. 16 EN 196-2:2005 (E) 4.68 DCTA solution, approximately 0,01 mol/l 4.68.1 1,2-diaminocyclohexane tetra-acetic (DCTA) 4.68.2 Preparation Dissolve (3,64 + 0,01) g of DCTA in about 400 ml of water and 10 ml of sodium hydroxide solution (4.31) in a 600 ml beaker. Heat the mixture until the DCTA is completely dissolved. Allow to cool to room temperature. Using the pH meter (5.18.1), adjust the pH to (7,0 + 0,5) by adding hydrochloric acid 1 + 2 (4.3), drop by drop. Transfer the solution quantitatively to a 1000 ml volumetric flask and make up to the mark with water. Store this solution in a polyethylene container. 4.68.3 Standardization Pipette 50 ml of the standard calcium ion solution (4.64) into a beaker appropriate for the measuring apparatus (5.12). Then dilute with water to a volume suitable for the correct operation of the apparatus. Using the pH meter (5.18.1), adjust the pH of this solution to (10,5 + 0,2) with concentrated ammonium hydroxide (4.25). Add, without weighing, about 0,1 g of murexide (4.69) or of calcein indicator (4.70). Place the beaker in the apparatus (5.12) set at 620 nm when using murexide or at 520 nm when using calcein and, while continuously stirring the solution, titrate with the approximately 0,01 molA DCTA solution. In the vicinity ofthe colour change of the indicator, take note of the absorbance values and the correspondent volumes of DCTA added and construct a curve of absorbance versus volume of titrant. The volume V; used is determined by the intersection of the line of greatest slope near the colour change and the line of almost constant absorbance after the colour change. Calculate the factor fo ofthe DCTA solution from the formula: fo = 50 x me = 49,955 x 16 (8) 100,09 x 0,01 x V7 v7 where me isthe mass of calcium carbonate taken to prepare the standard calcium ion solution (4.64), in grams; W isthe volume of the DCTA solution used for the titration, in millilitres. 4.69 Murexide indicator Prepare by grinding (1,0 + 0,1) g of murexide (ammonium purpurate, CsH4NsOs.NH4) with (100 + 1) g of sodium chloride (NaCl). 4.70 Calcein indicator Prepare by grinding (1,0 + 0,1) g of calcein (bis [(bis (carboxymethyl)-amino-methyl)] —2', 7-fluorescein, Fluoresceindi-(methylimino diacetic acid) sodium salt) with (100 + 1) g of potassium nitrate (KNOs). 4.71 | Calconindicator Prepare by grinding (1,0 + 0,1) g of calcon (sodium 2-hydroxy-4-(2-hydroxy-1-naphthylazo) naphthalene-1- sulfonate, EriochromeBlue-Black R) with (100 + 1) g of anhydrous sodium sulfate (Na,SO,). 17 EN 196-2:2005 (E) NOTE The methods specify where platinum crucibles are to be used. Unless platinum is specified porcelain crucibles may be used. 5.2.2 Lids, suitable lids to be fitted to crucibles (5.2.1) where required. 5.3 Fire proof ceramic support(s), for preventing overheating of the crucible. It shall be in thermal equilibrium with the furnace at the moment the crucible is introduced. 5.4 Porcelain evaporating dish, of approximately 200 ml. 5.5 Electric furnaces(s), naturally ventilated, capable of being set at the following temperatures: (500 + 10) ºC, (950 + 25) “C and (1 175 + 25) ºC. 5.6 Laboratory oven(s), capable of being set at the following temperatures: (110 +5) ºC; (120 + 5) ºC; (150 + 5) ºC; (200 + 10) ºC; and (250 + 10) ºC. 5.7 Desiccator(s), containing anhydrous magnesium perchlorate (Mg(CIO,)>) or silica gel. NOTE Where self-indicating silica gel is used a non-toxic indicator is recommended. 5.8 Bulb condenser 5.9 Apparatus for determining sulfide. A typical apparatus is shown in Figure 1. A Woolf bottle may be added to control the flow of gas. The connecting tubes shall be made of a material free from sulfur (polyvinyl chloride, polyethylene, etc.). Key 1 Lead acetate solution (4.48) 2 Air, nitrogen or argon 3 Ammoniacal solution of zinc sulfate (4.47) 4 Reaction flask 5 Dropping funnel Figure 1 — Typical apparatus for the determination of sulfide 20 EN 196-2:2005 (E) 5.10 Photometer(s), for measuring the absorbance of a solution in the vicinity of 525 nm and 815 nm. 5.11 Cells, for the photometer. 5.12 Apparatus for measuring the absorbance, at 520 nm and 620 nm of a solution contained in a titration beaker, while stirring. 5.13 Stirrer, e.g. magnetic stirrer, with inert, e.g. PTFE, covered bar. 5.14 Evaporation apparatus, controlled at (105 + 5) ºC e.g. water bath or hot plate. 5.15 Sand bath or hot plate, controlled at approximately 400ºC. 5.16 Filter papers. The filter papers used shall be ashless. NOTE Filter papers with a mean pore diameter of around 2 um are termed fine, those with a mean pore diameter of around 7 um are termed medium and those with a mean pore diameter of around 20 um are termed coarse. 5.17 Volumetric glassware. The volumetric glassware shall be of analytical accuracy, i.e. class A as defined in ISO 385-1 and ISO 835-1. 5.18 pH measuring equipment 5.18.1 pH meter, capable of measuring to an accuracy of + 0,05. 5.18.1 pH indicator paper(s), capable of measuring pH in the 0 — 14 range. 5.19 Apparatus for the determination of the carbon dioxide (reference method) Typical apparatus is shown in Figure 2 which can be fitted with either a cylindrical pressure container, a small electrical compressor or a suitable suction pump which will ensure an even flow of gas or air. The gas (air or nitrogen) entering the apparatus has previously had its carbon dioxide removed by first being passed through an absorbent tube or tower containing the carbon dioxide absorbent (4.86). The apparatus consists of a 100 ml distillation flask (14) fitted with a three neck adaptor. Neck (5) is connected to a dropping funnel (4), neck (6) to a connecting tube and neck (8) to a water cooled condenser. The funnel onto (5) and the connecting tube onto (6) are joined together by means of a Y-piece (1), so that the carbon dioxide-free air can flow either through the connecting tube or the funnel by means of a Mohr clip (2). After the condenser (9), the gas is passed through concentrated sulfuric acid (4.15) (10), then through absorption tubes containing the absorbent for hydrogen sulfide (4.84) (11) and for water (4.85) (12) and subsequently through two absorption tubes (13) which can be weighed and which are three-quarters filled with the absorbent for carbon dioxide (4.86) and a quarter with the absorbent for water (4.85). The absorbent for carbon dioxide (4.86) is placed upstream of the absorbent for water (4.85) with respect to the gas flow. Absorption tubes (13) are followed by an additional absorption tube (15), which also contains the absorbent for carbon dioxide and water, which is fitted in order to protect second absorption tube (13) against penetration by carbon dioxide and water from the air. 21 EN 196-2:2005 (E) Key No urna n 12 13 14 15 Y-piece Mohr clip Absorption tower containing carbon dioxide absorbent (4.86) Dropping funnel Dropping funnel connector Comnecting tube connector Three-armed still head Condensor connector Condensor Wash bottle with concentrated sulfuric acid (4.15) Absorption tube with absorbent for hydrogen sulfide (4.84) Absorption tube with absorbent for water (4.85) Absorption tubes with absorbents for carbon dioxide (4.86) and water (4.85) 100 ml distillation flask Absorption tubes with absorbents for carbon dioxide (4.86) and water (4.85) Figure 2 — Typical apparatus for the determination of carbon dioxide (reference method) The absorption tubes (13) which are to be weighed may have, for example, the following approximate sizes. 22 External distance between branches 45 mm Internal diameter 20 mm Distance between the lower part of the tube and the upper part of the ground section 75mm Tube wall thickness 1,5mm EN 196-2:2005 (E) ms is the mass ofthe ignited test portion, in grams. 7.4 Correction for oxidation of sulfides Calculate the correction for the extent of oxidation of sulfide that occurs during the determination of loss on ignition by determining the sulfate present before ignition, SO; (initial), and after ignition, SOs (final), from the following relationships: a) SO, (final) - SO; (initial) = SO, resulting from the oxidation of sulfides; b) Oxygen taken up = 0,8 x (SOs from oxidation of sulfide) = correction; c) Corrected loss on ignition = observed loss on ignition (L) + oxygen taken up; where in a), b) and c) all values are expressed in percent based on the initial mass(es) of unignited test portion(s). Any corrections applied shall be indicated in the test report. 7.5 Repeatability and reproducibility The standard deviation for repeatability is 0,04 %. The standard deviation for reproducibility is 0,08 %. 8 Determination of sulfate 8.1 Principle Sulfate ions, produced by the decomposition of cement with hydrochloric acid, are precipitated at a pH between 1,0 and 1,5 by a solution of barium chloride. The precipitation of barium sulfate is carried out at boiling point. The determination is then completed gravimetrically and sulfate expressed as SOs. 8.2 Procedure Weigh, to + 0,000 5 g, (1,00 + 0,05) g of cement (my), place in a 250 ml beaker, and add 90 ml of water. While stirring the mixture vigorously, add 10 ml of concentrated hydrochloric acid (4.1). Heat the solution gently and crush the sample with the flattened end of a glass stirring rod until decomposition is complete. Allow the solution to digest for 15 min at a temperature just below boiling. Filter the residue on a medium filter paper (5.16) into a 400 ml beaker. Wash thoroughly with hot water until free from chloride ions, tested by the silver nitrate test (3.6). Adjust the volume to about 250 ml; if necessary, adjust the pH of the solution to between 1,0 and 1,5 with hydrochloric acid 1 + 11 (4.6) or ammonium hydroxide 1 + 16 (4.28). Bring to the boil and boil for 5 min. Check that the solution is clear; if not, start the determination again using a new test portion. While stirring vigorously, maintain the solution at boiling point and add drop by drop 10 ml of the barium chloride solution (4.41) heated to just below boiling. Maintain the solution at just below boiling point for at least 30 min, ensuring that the volume is kept between 225 ml and 250 ml, and then allow the covered beaker to stand at room temperature for 12 hto 24h before filtration. Filter the precipitate on a fine filter paper (5.16) and wash with boiling water until free from chloride ions, tested by the silver nitrate test (3.6). 25 EN 196-2:2005 (E) Ignite (3.4) at (950 + 25) ºC to constant mass (3.5) (mo). NOTE In general, an ignition period of 15 min is sufficient to achieve constant mass. 8.3 Calculation and expression of results Calculate the sulfate content, expressed as SO, in percent from the formula: = mo X 0348 x 100 | 444, imo (10) mg mg so, where ms isthe mass of the test portion, in grams; mio is the mass of barium sulfate, in grams. 84 Repeatability and reproducibility The standard deviation for repeatability is 0,07 %. The standard deviation for reproducibility is 0,08 %. 9 Determination of residue insoluble in hydrochioric acid and sodium carbonate 9.1 Principle This is a method in which the insoluble residue in cement is obtained by treatment with dilute hydrochloric acid in order to minimise the precipitation of soluble silica. The residue from this treatment is treated with a boiling solution of sodium carbonate in order to re-dissolve traces of silica which may have been precipitated. After ignition the residue is determined gravimetrically. 9.2 Procedure Weigh, to + 0,000 5 g, (1,00 + 0,05) g of cement (m,.), place in a 250 ml beaker, add 90 ml of water and, while stirring the mixture vigorously, add 10 ml of concentrated hydrochloric acid (4.1). Heat the solution gently and crush the sample with the flattened end of a glass stirring rod until decomposition is complete. Allow the solution to digest for 15 min at a temperature just below boiling. Filter the residue on a medium filter paper (5.16) and wash thoroughly with almost boiling water. Transfer the filter paper and its contents back to the reaction beaker and add 100 ml of the sodium carbonate solution (4.45). Boil for approximately 30 min. Filter on a medium filter paper and wash with almost boiling water, then four times with hot hydrochloric acid 1 + 19 (4.7) until pH < 2 by indicator paper (5.18.2) is obtained and with almost boiling water until free from chloride ions, tested by the silver nitrate test (3.6). Ignite (3.4) at (950 + 25) ºC to constant mass (3.5) (m,5). NOTE 1 In general, an ignition period of 30 min is sufficient to achieve constant mass. NOTE 2 fa cloudy filtrate is observed, filter again on a fine filter paper, wash thoroughly with hot water and combine the two residues on their filter papers to ignite them. Ifin spite of this operation the filtrate remains cloudy, its effect on the insoluble residue may be neglected. 26 EN 196-2:2005 (E) 9.3 Calculation and expression of results Calculate the insoluble residue in percent from the formula: Insolubleresidue = 2212 x 100 (11) mm where mm is the mass ofthe test portion, in grams; mp is the mass ofthe ignited insoluble residue, in grams. 9.4 Repeatability and reproducibility The standard deviation for repeatability is 0,04 %. The standard deviation for reproducibility is 0,06 %. 10 Determination of residue insoluble in hydrochioric acid and potassium hydroxide 10.1 Principle This is a method in which the insoluble residue in cement is obtained initially by treatment with a hydrochloric acid solution. The residue from this treatment is then treated with a boiling solution of potassium hydroxide. After ignition the residue is determined gravimetrically. 10.2 Procedure Weigh, to + 0,000 5 g, (1,00 + 0,05) g of cement (ms), place in a porcelain dish (5.4), add 25 ml of water and disperse using a glass stirring rod. Add 40 ml of concentrated hydrochloric acid (4.1). Heat the solution gently and crush the sample with the flattened end of a glass stirring rod until decomposition is complete. Evaporate to dryness on a water bath (5.14). Repeat the operation twice more with 20 ml concentrated hydrochloric acid (4.1). Treat the residue from the third evaporation with 100 ml of hydrochloric acid 1 + 3 (4.4). Re-heat, filter on a medium filter paper (5.16) and wash with almost boiling water until free from chloride ions, tested by the silver nitrate test (3.6). Transfer the filter paper and its contents to a 250 ml conical flask fitted with a bulb condenser (5.8) and add 100 ml of the potassium hydroxide solution (4.46). Leave to stand for 16 h at room temperature and then boil the solution under reflux for 4h. Filter on a medium filter paper (5.16) and wash with water then with 100 ml of hydrochloric acid 1 + 9 (4.5) and finally with almost boiling water until free from chloride ions, tested by the silver nitrate test (3.6). Ignite (3.4) at (950 + 25) “C to constant mass (3.5) (m,4). NOTE | In general, an ignition period of 30 min is sufficient to achieve constant mass. 27 EN 196-2:2005 (E) where C isthe manganese (Mn) concentration of the solution, in milligrams per 200 ml; me is the mass of the test portion, in grams. 12.4 Repeatability and reproducibility The standard deviation for repeatability is 0,003 %. The standard deviation for reproducibility is 0,03 %. 12.5 Expression of results The manganese content is normally expressed as MnO or Mn,05. The following formulae are used in their calculation: MnO = 1,29 x Mn ,in percent; (15) Mn203 = 144 x Mn, in percent. (16) 13 Determination of major elements 13.1 Principle The analysis is carried out after the cement is completely dissolved. The decomposition with hydrochloric acid and ammonium chloride (alternative method) may be used for cement with an insoluble residue (as determined in accordance with Clause 9) not exceeding 1,5 %. The cement is decomposed by sintering with sodium peroxide or by treatment with hydrochloric acid in the presence of ammonium chloride. In the first case, after dissolution of the sintered solid in hydrochloric acid, the major part of the silica is precipitated either by double evaporation or by hydrochloric acid with coagulation by polyethylene oxide; in the second case, the major part of the silica is separated by the treatment. The impure silica precipitated is treated with hydrofluoric acid and sulfuric acid to volatilize silica; the residue, treated with a mixture of sodium carbonate and sodium chloride, is dissolved in hydrochloric acid and added to the silica filtrate. In the case of the treatment with hydrochloric acid in the presence of ammonium chloride, if the residue obtained after volatilization of impure silica by means of hydrofluoric acid and sulfuric acid is greater than 0,5 %, the method is not applicable. In this case it is necessary to decompose the cement by sodium peroxide. In the final solution, the soluble (residual) silica is determined by photometric determination, and iron (III) oxide, aluminium oxide, calcium oxide and magnesium oxide are determined by complexometric methods. The schematic diagram of the chemical analysis is shown in Figure 4. The relative amounts of impure, pure and soluble (residual) silica may vary depending on the procedure used, but the same result for the total silica is obtained whichever path in Figure 4 is chosen. 13.2 Decomposition with sodium peroxide Weigh, to + 0,000 5 g, (1,00 + 0,05) g of cement (m+7) and place, with about 2 g of sodium peroxide (4.36), into a platinum crucible (5.2.1); mix thoroughly with a spatula. Brush back into the mixture any particles adhering to the spatula. Cover the mixture with about 1 g of sodium peroxide. Carefully preheat the crucible fitted with a lid (5.2.2) for about 2 min at the opening of the furnace (5.5) before placing it on its support (5.3) in the heated zone controlled at a uniform temperature of (500 + 10) ºC. 30 EN 196-2:2005 (E) After 30 min, remove the crucible from the furnace and allow it to cool to room temperature. The sintered solid mass should not stick to the sides of the crucible. If it does, then repeat the decomposition at a temperature 10 ºC lower than was first used. Transfer the sintered solid mass to a 400 ml beaker and rinse the crucible with 150 ml of cold water. 31 EN 196-2:2005 (E) Direct treatment of 1 g ” Decomposition of 1 g with Na,0,> or (13.2) with HCI + NH.CI (13.5) Precipitation by or Precipitation by HClin double evaporation the presence of polyethylene by HCl (13.3) oxide (13.4) Impure SiO> Volatilization of pure SiO», (1)? Filtrate by HF + HoSO, (13.6) Fusion of residue with NasCOs + NaCl and dissolution (13.7) Final solution 500 ml or 20 ml 100 ml 25 ml 50 ml 50ml 50ml Soluble SiO, by Fe,05 Cao Mgo Cao CaO + MgO photometry EDTA EGTA DCTA EDTA EDTA (11) (13.8) (1310) (13.12) (13.13) (13.14) (13.15) (1+ 1) AbOs MgO Total SiO, EDTA by difference (13.9) (1311) 1) Ifthe residue insoluble in hydrochloric acid and sodium carbonate (see Clause 9) is greater than 1,5 %, it is necessary to use the method of decomposition by sodium peroxide. 2) When the ammonium chloride method is used, ifthe residue after volatilization with hydrofluoric acid and sulfuric acid exceeds 0,5 %, itis necessary to recommence the analysis using the decomposition by sodium peroxide. Figure 4 — Schematic diagram for analysis of the major elements 32 EN 196-2:2005 (E) This is used, together with the evaporation residue decomposed as described in 13.7, for the photometric determination of soluble silica (i.e. residual silica in solution) in accordance with 13.8. Ignite (3.4) the filter and the precipitate, to constant mass (3.5) (m>), in a platinum crucible at (1 175 + 25) ºC. NOTE In general, an ignition period of 60 min is sufficient to obtain constant mass. Volatilize the ignited precipitate as described in 13.6. 13.5.2 Calculation and expression of results Calculate the impure silica in percent from the formula: Impure SiO, = 2! x 100 (19) mzo where Ma is the mass ofthe test portion used in 13.5.1, in grams; my is the mass determined in accordance with 13.5.1, in grams. 13.6 Determination of pure silica 13.6.1 Procedure Moisten the precipitate, obtained in accordance with 13.3.1 (ms) or 13.4.1 (ms) or 13.5.1 (m»), with about 0,5 ml to 1 ml of water, add approximately 10 ml of hydrofluoric acid (4.10) then two drops of sulfuric acid (4.15). Evaporate in a fume cupboard over a sand bath or hot plate (5.15), then continue to heat until free from white sulfuric acid fumes. Ignite the crucible with the evaporation residue in an electric furnace (5.5) at (1 175 + 25) ºC for 10 min, leave to cool to room temperature in a desiccator and weigh (>>). Decompose the evaporation residue as described in 13.7. If the residue obtained by this method exceeds 0,5 %, restart the analysis using the method of decomposition with sodium peroxide (13.2). 13.6.2 Calculation and expression of results Calculate the pure silica content in percent from the formula: Pure SiO, = "24" m22 400 (20) mz3 where m>> isthe mass determined in accordance with 13.6.1, in grams; m>3 isthe mass of the test portion used in 13.2 (m+7) or in 13.5.1 (mo), in grams; mo>s isthe mass determined in accordance with 13.3.1 (ms), 13.4.1 (ms9) or 13.5.1 (m»), in grams. 13.7 Decomposition of the evaporation residue To the evaporation residue, obtained in accordance with 13.6.1, add about 2 g of the sodium carbonate and sodium chloride mixture (4.40) and fuse to a bright red heat e.g. using a gas burner. Swirl the melt frequently until the residue is completely dissolved. 35 EN 196-2:2005 (E) Check visually that no part of the residue remains at the base of the crucible. Allow the crucible and its contents to cool, transfer to a 250 ml beaker, add about 100 ml water and acidify with a few millilitres of concentrated hydrochloric acid (4.1). When the decomposed mass is completely dissolved, remove the platinum crucible from the solution and rinse it with water. Check that the solution is clear. If not, filter through a medium filter paper (5.16), wash, burn off the paper, ignite and then repeat the decomposition as above. Transfer the solution to the 500 ml volumetric flask containing the filtrate and washings from the precipitation of silica in accordance with 13.3.1 or 13.4.1 or 13.5.1; make up to the mark with water. After shaking the flask vigorously, this solution is ready to be used in the photometric determination of the soluble silica (13.8) and also in the complexometric determinations of iron (III) oxide (13.10), aluminium oxide (13.11), calcium oxide (13.12 or 13.14) and magnesium oxide (13.13 or 13.15). 13.8 Determination of soluble silica 13.8.1 Procedure Pipette 20 ml of the solution prepared in accordance with 13.7 from the 500 ml volumetric flask into a polyethylene beaker already containing a magnetic stirrer bar (5.13) and add 20 ml water. While stirring with the magnetic stirrer (5.13), add 15 drops of hydrofluoric acid 1 + 3 (4.11). Stir again for at least 1 min. Then pipette 15 ml of the boric acid solution (4.51). Add from a pipette 5 ml of the ammonium molybdate solution (4.54) to the solution. Adjust the pH of the solution to (1,60 + 0,05) by adding, drop by drop, sodium hydroxide (4.30) or hydrochloric acid 1 + 2 (4.3), using a pH meter (5.18.1) calibrated with a buffer solution of similar pH value (e.g. 1,40 see 4.59). Transfer the solution to a 100 ml volumetric flask and rinse the beaker with hydrochloric acid of pH 1,60 (4.9). After 20 min, add from a pipette 5 ml of the citric acid solution (4.52), stir and leave to stand for 5 min. Then add from a pipette 2 ml of the reducing solution (4.58). (Time 0). Make up to volume with dilute hydrochloric acid of pH 1,60 (4.9) and mix. At time (0 + 30) min measure the absorbance with the photometer (5.10) against a blank solution prepared in a similar way and using the same wavelength and a cell (5.11) of the same optical length as used for the construction of the calibration curve (4.63.5). The silica concentration (m>s) in mg SiO>/100 ml is read from the calibration curve. 13.8.2 Calculation and expression of results Calculate the soluble silica content in percent from the formula: Soluble SiO, = 500 x mos x 100 | 25 x ME (21) 20 x 1000 x mos mos where m> isthe mass of the test portion used in 13.2 (m+7) or 13.5.1 (m>o), in grams; m> isthe silica concentration of the solution in accordance with 13.8.1, in milligrams of SiO> in 100 ml. 13.9 Determination of total silica 13.9.1 Calculation and expression of results The total silica content, in percent, is the sum of the pure silica content (13.6) and the soluble silica content (13.8). 13.9.2 Repeatability and reproducibility The standard deviation for repeatability is 0,10 %. 36 EN 196-2:2005 (E) The standard deviation for reproducibility is 0,25 %. 13.10 Determination of iron (Ill) oxide NOTE 1 The presence cf titanium affects the speed of the titration of iron by EDTA. This cause of error can be overcome by proceeding slowly, for example with the help of an automatic burette. It is equally possible to mask the titanium by adding 2 ml of sulfuric acid 1 + 1 (4.16) to the solution before titration. NOTE 2 | This method uses photometric determination of the end-point. It is also possible to make visual observation of the titration although with less precision. Sulfosalicylic acid (4.72) is a suitable indicator (colour changes from violet to clear yellow). 13.10.1 Procedure Pipette 100 ml of the solution prepared in accordance with 13.7 from the 500 ml volumetric flask into a beaker compatible with the measuring apparatus (5.12). Then make up with water to a volume suitable for the correct operation of the equipment. Add 0,5 g amino-acetic acid (4.23) and 0,3 g to 0,4 g of sulfosalicylic acid indicator (4.72). Using a pH meter (5.18.1), adjust the pH of this solution to (1,5 + 0,1) with the ammonium hydroxide 1 + 1 (4.26) and 1 + 10 (4.27). Heat to (47,5 + 2,5) ºC. Place the beaker in the apparatus (5.12) set at 520 nm and, while stirring the solution, titrate with the approximately 0,03 mol/l EDTA solution (4.65). In the vicinity of the indicator colour change, construct a curve of the readings from the measuring apparatus as a function of the volume of EDTA solution added. Record the total volume Viy of EDTA solution added. The volume at the end point Vi is determined from the intersection of the line of greatest slope in the region of the colour change and the line of almost constant absorbance after the colour change. The excess volume Vs, of EDTA solution added is determined as volume Vi less volume V;o. During the titration, the temperature of the solution shall not exceed 50 “C. Otherwise the determination shall be repeated. This titrated solution is retained for the determination of aluminium oxide content in accordance with 13.11.1. 13.10.2 Calculation and expression of results Calculate the iron (III) oxide content in percent from the formula: 0,03 x 159,692 x 500 Fe;0; = 0,03 x 159,692 x 500 x Mo x fp x 100 = 11977 x Vo Xfp 2 x 1000 x 100 x 3 mos where Vio is the volume of the approximately 0,03 molà EDTA solution used for the titration, in millilitres; fb isthe factor of the approximately 0,03 mol/l EDTA solution determined in accordance with 4.65; ma isthe mass of the test portion used in 13.2 (m:,7) or 13.5.1 (mo), in grams. 13.10.3 Repeatability and reproducibility The standard deviation for repeatability is 0,08 %. The standard deviation for reproducibility is 0,15 %. 37 EN 196-2:2005 (E) 13.13.2 Calculation and expression of results Calculate the magnesium oxide content in percent from the formula: 0,01 x 40,311 x 500 x Viy x fo x 100 = 04031 x Vu X fe MgO = 1000 x 50 x ma mas (26) where Vis is the volume of the approximately 0,01 mol/l DCTA solution used for the titration, in millilitres; fe isthe factor of the approximately 0,01 mol/l DCTA solution determined in accordance with 4.68.3; ma is the mass of the test portion used in 13.2 (m+7) or 13.5.1 (m>o), in grams. 13.13.3 Repeatability and reproducibility The standard deviation for repeatability is 0,15 %. The standard deviation for reproducibility is 0,15 %. 13.14 Determination of calcium oxide by EDTA (alternative method) NOTE 1 | This method uses photometric determination of the end-point. It is possible to determine the end-point of the titration visually. In this case Calcon (4.71) (colour change from pink to blue), mixed calcein and methylthymol blue indicator (4.75) (colour change pink to yellow) or Patton and Reeders reagent (4.76) (colour change from purple to clear blue) are suitable indicators. NOTE 2 In this method any strontium oxide is determined and expressed as calcium oxide. 13.14.1 Restriction on the method This method can be used for determination of calcium oxide in the presence of manganese. Where the method is to be used in conjunction with the method of determination of magnesium oxide by EDTA (see 13.15), it shall be preceded by the determination of manganese content (see Clause 12) for comparison with the limit given in 13.15.1 for manganese oxide. 13.14.22 Procedure Pipette 50 ml of the solution prepared in accordance with 13.7 from the 500 ml volumetric flask into a beaker compatible with the measuring apparatus (5.12). Then dilute with water to a volume suitable for the correct operation of the equipment. Add 50 ml of the triethanolamine solution 1 + 4 (4.57). Using the pH meter (5.18.1), adjust the pH of this solution to (12,5 + 0,5) with sodium hydroxide solution (4.30). Add, without weighing, about 0,1 g of murexide (4.69), calcein indicator (4.70) or mixed calcein and methylthymol blue indicator (4.75). Place the beaker in the apparatus (5.12) set at 620 nm when using murexide or at 520 nm when using calcein and, while stirring the solution, titrate with the approximately 0,03 mol/l EDTA solution (4.65). In the vicinity of the colour change of the indicator, construct a curve of the absorbance values as a function of the volume of EDTA added. The volume V;s used is determined from the intersection of the line of greatest slope in the region of the colour change and the line of almost constant absorbance after the colour change. 40 EN 196-2:2005 (E) 13.14.3 Calculation and expression of results Calculate the calcium oxide content in percent from the formula: = 0,03 x 56,08 x 500 X Vis X fo x 100= 16824 x Vis X fo (27) 1000 x 50 x ma mas Cao where Vis is the volume of the approximately 0,03 molà EDTA solution used for the titration, in millilitres; fb isthe factor of the approximately 0,03 mol/l EDTA solution determined in accordance with 4.65.3; ma isthe mass of the test portion used in 13.2 (m:,7) or 13.5.1 (mo), in grams. NOTE Strontium oxide is determined and expressed as calcium oxide. 13.144 Repeatability and reproducibility The standard deviation for repeatability is 0,15 %. The standard deviation for reproducibility is 0,43 %. 13.15 Determination of magnesium oxide by EDTA (alternative method) NOTE This method uses photometric determination of the end-point. It is possible to determine the end-point of the titration visually. In this case mixed calcein and methylthymol blue indicator (4.75) (colour change from pink to colourless) or mixed indicator (4.77) (colour change from pink to colourless) or a dispersion of 1 g of phthalein purple in 100 g of solid NaCl (colour change from violet to pale pink) are suitable indicators. 13.15.1 Restriction on the method In the rare case where a cement has a manganese oxide (Mn>03) content greater than 0,5 %, only the method of determination of magnesium oxide by DCTA (13.13) is applicable. 13.15.2 Procedure Pipette 50 ml of the solution prepared in accordance with 13.7 from the 500 ml volumetric flask into a beaker compatible with the measuring apparatus (5.12). Then dilute with water to a volume suitable for the correct operation of the equipment. Add 50 ml of the triethanolamine solution 1 + 4 (4.57). Using the pH meter (5.18.1), adjust the pH of this solution to (10,5 + 0,5) with ammonium hydroxide 1 + 1 (4.26). Using a burette, add the volume Vis of EDTA solution (4.65) required for the titration of calcium oxide previously determined in 13.14.2. Then add, without weighing, about 0,1 g of methylthymol blue (4.74), mixed calcein and methylthymol blue indicator (4.75) or mixed indicator (4.77). Place the beaker in the apparatus (5.12) set at 620 nm and, while stirring the solution, titrate with the approximately 0,03 molA EDTA solution (4.65). In the vicinity of the colour change of the indicator, construct a curve of the absorbance values as a function of the volume of EDTA solution added. The volume Vig Used is determined from the intersection of the line of greatest slope in the region of the colour change and the line of almost constant absorbance after the colour change. 41 EN 196-2:2005 (E) 13.15.3 Calculation and expression of results Calculate the magnesium oxide content in percent from the formula: = 003 x 40311 x 500 x (Vis Vis) fo jog — 13093x (Vis = Vis) fo (og MgO 1000 x 50 x mos mos where Vis is the volume of EDTA solution required for the determination of calcium oxide as in 13.14.2, in millilitres; Vi is the volume of EDTA solution required for the determination of calcium oxide and magnesium oxide determined in 13.15.2, in millilitres; fo is the factor of the approximately 0,03 mol/l EDTA solution determined in accordance with 4.65.3; m> isthe mass of the test portion used in 13.2 (m+7) or 13.5.1 (m>o), in grams. 13.15.4 Repeatability and reproducibility The standard deviation for repeatability is 0,21 %. The standard deviation for reproducibility is 0,25 %. 14 Determination of chloride 14.1 Principle This method gives the total chloride plus bromide content and expresses the result as chloride ion (CI). Cement is treated with boiling dilute nitric acid to decompose it and to remove sulfides. The dissolved chloride is precipitated using a known volume of a standard silver nitrate solution. After boiling, the precipitate is washed with dilute nitric acid and discarded. The filtrate and washings are cooled to below 25 ºC and the residual silver nitrate is titrated with a standardised ammonium thiocyanate solution using an iron (Ill) salt as indicator. 14.2 Procedure Weigh, to + 0,000 5 g, (5,00 + 0,05) g of cement (me) and place in a 400 ml tall form beaker, add 50 ml of water and, while stirring with a glass rod, 50 ml of nitric acid 1 + 2 (4.13). Heat the mixture to boiling (in a fume cupboard for samples containing sulfide), stirring occasionally, and boil for 1 to 2 min avoiding loss of liquid. Remove from the source of heat and add 5 ml of silver nitrate solution (4.44) by pipette (5.17) into the solution. Then boil for not less than 1 min and not more than 2 min and filter through a coarse filter paper (5.16), washed before use with nitric acid 1 + 100 (4.14), into a 500 ml conical flask. Wash the beaker, glass rod and filter paper with nitric acid 1 + 100 until the volume of the filtrate and the washings is approximately 200 ml. Cool the filtrate and washings to below 25 “ºC in subdued light or in the dark. Add up to 5 ml indicator solution (4.81) and titrate with the ammonium thiocyanate solution (4.79) shaking vigorously until a drop of this solution produces a faint pink colouration which does not disappear on shaking. Record the volume V17 of ammonium thiocyanate used in the titration. If Vs is less than 0,5 ml, repeat the procedure with half the sample mass. Carry out the same procedure with no cement sample and record the volume, Vis, of ammonium thiocyanate solution used in the blank titration. 42 EN 196-2:2005 (E) 16.3 Procedure Weigh, to + 0,000 5 g, (1,00 + 0,05) g of cement (mo) into the 100 ml distillation flask (7) of the apparatus (5.20). Mix this cement with a small (about 50 mg) amount of mercuric (Il) chloride (4.87) using a spatula and then add enough water to form a slurry. Connect the flask to the ground joint of the dropping funnel (1). Then draw air for 15 min through the apparatus, passing the air through an absorption tower (8) filled with absorbent (4.86) to remove the carbon dioxide before the air passes into the flask. Condition the closed absorption tubes (4) for 15 min in the balance case in order to achieve temperature equilibrium. Then weigh each tube separately. Shut off the flow of gas and attach the tubes to the apparatus as shown in Figure 3. NOTE Care should be taken when handling the tubes to avoid affecting their weight, causing damage or sustaining injury. tis advisable to wear protective gloves when carrying out this operation. Add 25 mito 30 ml of sulfuric acid 1 + 4 (4.17) from the dropping funnel (1) into the flask. Take care to ensure that some of the acid remains in the dropping funnel as a seal. Turn the vacuum pump on again, so that the current of air carries the liberated carbon dioxide through the condenser (2) and the first two absorption tubes (3), filled with magnesium perchlorate (4.85) for the purposes of drying the air, to the two previously weighed absorption tubes (4) filled with absorbents (4.85 and 4.86). An absorption tube (5) filled with magnesium perchlorate (4.85) and absorbent (4.86) is fitted after these tubes in order to prevent penetration by the ambient air. Gas washing bottle (9) empty and (10), filled with concentrated sulfuric acid (4.15) or paraffin, as a bubble counter are connected. After about 10 min heat the contents of the flask to boiling and boil gently for 5 min. Maintain the air flow through the apparatus until the flask has cooled to room temperature. Close the taps and remove the absorption tubes (4), place them in the balance case for 15 min in order to achieve temperature equilibrium and then weigh them. 16.4 Calculation and expression of results Calculate the carbon dioxide content in percent from the formula: co; = 1X 100 em mao where Mag is the mass of the test portion, in grams; ma is the increase in mass of the absorption tubes (4) after absorption, in grams. H the carbon dioxide content calculated from equation (31) is less than 0,5 %, repeat the determination with (2,00 + 0,05) g of cement, weighed to + 0,000 5 g. Alternatively, where the cement contains a high proportion of carbonate the size of the sample should be decreased appropriately. 16.5 Repeatability and reproducibility The standard deviation of repeatability is 0,07 %. The standard deviation of reproducibility is 0,10 %. 45 EN 196-2:2005 (E) 17 Determination of alkali (reference method) 17.1 Principle A butane, propane or acetylene flame is used to excite the alkali metals to emit their characteristic spectrum in the visible range. The emission is proportional to the alkali content at low concentrations. The influence of large quantities of calcium in the sample on the sodium determination is suppressed by means of phosphoric acid. The influence of phosphoric acid on the potassium emission from the calibration solutions is suppressed by adding calcium to the calibration solutions. 17.2 Reagents Whenever a new batch of any reagent is used determine the alkali content by means of this method. If the alkali content of a reagent exceeds 0,01 %, either replace the batch with a new one, which shall be verified in the same way, or prepare new calibration solutions. 17.3 Preparation of calibration solutions and calibration curves Prepare the calibration solutions using the volumes of alkali stock solution, acid stock solution and calcium stock solution listed in Table 4. Make up the volumes listed in lines 1 to 7 to 1 000 ml with water and mix thoroughly. Store these calibration solutions in polyethylene bottles. Spray the calibration solutions into the flame of the flame photometer (5.21). Spray the blank solution (Table 4, S1) first and set the indication on the apparatus to zero. Spray the solution of greatest concentration (S7) and set the indication on the apparatus to maximum intensity. Spray the other calibration solutions in the order of increasing concentration (S2 to S6). Measure the intensities for Na,O at 589 nm and for K,O at 768 nm. Construct curves of the measured intensities against the corresponding concentrations of Na;O and KO in the calibration solutions. Table 4 — Volumes of solutions for the preparation of calibration solutions and their sodium oxide and potassium oxide concentrations Calibration Alkali stock Acid stock Calcium stock Na,0 and K,0 solution solution (4.88) solution (4.89) solution (4.90) concentrations ml ml ml mgi s1 - 100 100 0,0 s2 5 100 100 1,5 s3 10 100 100 30 s4 20 100 100 60 s5 30 100 100 9,0 s6 40 100 100 12,0 s7 50 100 100 15,0 17.4 Dissolution of the test portion 17.4.1 Cements with an insoluble residue not exceeding 3 % NOTE This method is applicable to cements which have an insoluble residue content, determined in accordance with Clause 9, not exceeding 3 %. Weigh (0,500 O + 0,000 5) g of cement into a 250 ml beaker, make into a slurry with 50 ml of water and add 50 ml of hydrochloric acid 1 + 19 (4.7). Warm the mixture until the cement has decomposed, crushing any lumps with a glass rod. Then allow the suspension to cool to ambient temperature. Transfer the contents of the beaker, rinsing the beaker with water, into a 500 ml volumetric flask. Add 50 ml of phosphoric acid 1 + 19 46 EN 196-2:2005 (E) (4.20), make up to the mark with water and mix thoroughly. Filter, without washing, sufficient solution through the filter paper (5.23) into a clean, dry beaker, before spraying solution into the flame. 17.4.2 Cements with an insoluble residue exceeding 3 % WARNING 1 Carry out the following evaporation procedures in an appropriate fume cupboard (see WARNING 2) because the vapours from nitric acid (4.12), perchloric acid (4.18) and hydrofluoric acid (4.10) are hazardous. In addition wear eye protection and suitable rubber or plastics gloves when handling or agitating these acids or their mixtures. NOTE Where the content of insoluble residue, determined in accordance with Clause 9, exceeds 3 %, the method described below should be used. Weigh (0,5000 + 0,0005) g of cement into a platinum dish (5.22) and add 15 ml of nitric acid (4.12). Heat the mixture, e.g. on a hot-plate, and evaporate to dryness. Disperse the residue from evaporation in 15 ml of water, add 5 ml of perchloric acid (4.18) and then add 25 ml of hydrofluoric acid (4.10). WARNING 2 Perchloric acid vapours form explosive mixtures with organic materials, it is therefore necessary to take special precautionary measures when working with perchloric acid, e.g. the use of fume cupboards flushed with water and a general ban on the use of organic substances in the same fume cupboard. Heat the mixture and evaporate to dryness. Prevent overheating by frequent agitation by means of the HF resistant stirrer (5.24). Add 10 ml of water and 50 ml of hydrochloric acid 1 + 19 (4.7) to the residue from evaporation and heat until the residue has dissolved. Allow the suspension to cool to room temperature. Transfer the contents of the platinum dish, rinsing the dish with water, into a 500 ml volumetric flask. Add 50 ml of phosphoric acid 1 + 19 (4.20) to the solution, make up to the mark with water and mix thoroughly. Filter, without washing, sufficient solution through the filter paper (5.23) into a clean, dry beaker, before spraying solution into the flame. 17.5 Procedure Spray the sample solution produced as described in 17.4.1 or 17.4.2 into the flame of the flame photometer (5.21). Measure the intensity of the sodium line at 589 nm and the potassium line at 768 nm. Obtain the sodium oxide or potassium oxide concentration in the solution respectively by means of a linear interpolation from the intensities and the associated concentrations of the calibration solutions measured as described in 173. Use the curves constructed in accordance with 17.3 to obtain the sodium oxide and potassium oxide concentrations of the solution in mg/l or use the intensities and the associated concentrations of the calibration solutions with the next higher and the next lower intensity for the calculation as follows. Calculate the sodium oxide Cnazo potassium oxide Curso concentration of the sample from the intensities Inazo Of Ik,o respectively using the following formulae: 1 -1 Cnaso = Cen + (Can - Con) x Me cn (32) IBh — IBn - Ko * lBn Ckso = Cen + (Cen - Can) x (33) lh — IBn where Cen is the concentration of the sodium oxide or potassium oxide respectively in the calibration solution having a lower concentration than the sample solution, in milligrams per litre; Cen is the concentration of the sodium oxide or potassium oxide respectively in the calibration solution having a higher concentration than the sample solution in milligrams per litre; ln -isthe intensity of the calibration solution having a lower concentration than the sample solution; 47