BS ISO 2599-2003 Iron ores - Determination of phosphorus content - Titrimetric method《铁矿石 磷含量的测定 滴定法》.pdf

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1、BRITISH STANDARD BS ISO 2599:2003 Iron ores Determination of phosphorus content Titrimetric method ICS 73.060.10 BS ISO 2599:2003 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 20 June 2003 BSI 20 June 2003 ISBN 0 580 42085 X National forewo

2、rd This British Standard reproduces verbatim ISO 2599:2003 and implements it as the UK national standard. It supersedes BS 7020-6.1:1988 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee ISE/58, Iron ores, which has the responsibility to: A list of orga

3、nizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Ind

4、ex”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself con

5、fer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulg

6、ate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the ISO title page, pages ii to iv, pages 1 to 12, an inside back cover and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. Amendments issue

7、d since publication Amd. No. Date Comments Reference number ISO 2599:2003(E)INTERNATIONAL STANDARD ISO 2599 Third edition 2003-02-15 Iron ores Determination of phosphorus content Titrimetric method Minerais de fer Dosage du phosphore Mthode titrimtrique BSISO2599:2003ii BSISO2599:2003 iiiContents Pa

8、ge Foreword iv 1 Scope 1 2 Normative references . 1 3 Principle . 1 4 Reagents 2 5 Apparatus. 3 6 Sampling and samples . 3 6.1 Laboratory sample 3 6.2 Preparation of predried test samples . 4 7 Procedure. 4 7.1 Number of determinations . 4 7.2 Test portion . 4 7.3 Blank test and check test. 4 7.4 De

9、termination 5 8 Expression of results 7 8.1 Calculation of phosphorus content 7 8.2 General treatment of results 7 8.3 Oxide factor . 9 9 Test report 9 Annex A (normative) Flowsheet of the procedure for the acceptance of analytical values for test samples 10 Annex B (informative) Derivation of repea

10、tability and permissible tolerance equations . 11 Annex C (informative) Precision data obtained by international analytical trials 12 BSISO2599:2003iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The wor

11、k of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governme

12、ntal, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The m

13、ain task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. A

14、ttention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 2599 was prepared by Technical Committee ISO/TC 102, Iron ore and direct reduced iron, Subcommitte

15、e SC 2, Chemical analysis. This third edition cancels and replaces the second edition (ISO 2599:1983), which has been editorially revised. BSISO2599:2003INTENRATIONAL TSANDADR IS:9952 O3002(E)1Iron ores Determination of phosphorus content Titrimetric method WARNING This International Standard may in

16、volve hazardous materials, operations and equipment. This International Standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this International Standard to establish appropriate health and safety practices and determine the

17、applicability of regulatory limitations prior to use. 1 Scope This International Standard specifies a titrimetric method for the determination of the phosphorus content of iron ores, using hexaammonium heptamolybdate (ammonium molybdate). This method is applicable to a concentration range of 0,10 %

18、(m/m) to 5,0 % (m/m) 1)of phosphorus in natural iron ores, and iron ore concentrates and agglomerates including sinter products. This International Standard provides a quality control method for the determination of phosphorus by titration, however, the method cannot be used for referee purposes. 2

19、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. ISO 648:1977, Laboratory gla

20、ssware One-mark pipettes ISO 1042:1998, Laboratory glassware One-mark volumetric flasks ISO 3082:2000, Iron ores Sampling and sample preparation procedures ISO 3696:1987, Water for analytical laboratory use Specification and test methods ISO 7764:1985, Iron ores Preparation of predried test samples

21、for chemical analysis 3 Principle The test portion is decomposed by treatment with hydrochloric, nitric and perchloric acids. The insoluble residue is filtered and the filtrate is reserved as the main solution. The residue is ignited, treated with sulfuric and hydrofluoric acids to remove silicon di

22、oxide, fused with sodium carbonate and the melt is leached with water. The alkaline solution is filtered and the residue is discarded. 1) This method has been tested internationally on samples containing phosphorus contents ranging from 0,03 % (m/m) to 1,50 % (m/m). BSISO2599:20032 The filtrate from

23、 residue treatment is acidified using hydrochloric acid, iron(III) chloride is added and the phosphorus is collected by precipitation with ammonia solution. The precipitate is dissolved in hydrochloric acid and combined with the main solution. Hydrobromic acid is added and evaporated to fumes of per

24、chloric acid to expel arsenic. The salts are dissolved in water and the solution, or an aliquot, is neutralized with ammonia solution and the acidity is adjusted using nitric acid. The solution is cooled to 20 C and vanadium is reduced by iron(II) sulfate. Ammonium molybdate is added to the cold sol

25、ution and the yellow precipitate of ammonium molybdophosphate is collected by filtration. The precipitate is washed free of acid and dissolved in a slight excess of sodium hydroxide, the excess being titrated with nitric acid. For test portions containing more than 18 mg of titanium, a modified proc

26、edure is used (see 7.4.1.2). 4 Reagents During the analysis, use only reagents of recognized analytical grade, and only water that conforms to grade 2 of ISO 3696:1987. 4.1 Ammonium nitrate (NH 4 NO 3 ). 4.2 Sodium carbonate (Na 2 CO 3 ), anhydrous. 4.3 Hydrochloric acid, 1,16 g/ml to 1,19 g/ml 4.4

27、Hydrochloric acid, 1,16 g/ml to 1,19 g/ml diluted 1 + 1. 4.5 Nitric acid, 1,42 g/ml. 4.6 Nitric acid, 1,42 g/ml diluted 1 + 50. 4.7 Nitric acid, 1,42 g/ml diluted 1 + 5 000. 4.8 Sulfuric acid, 1,84 g/ml. 4.9 Sulfuric acid, 1,84 g/ml diluted 1 + 1. 4.10 Perchloric acid, 1,54 g/ml, 60 % (m/m) solution

28、, or 1,67 g/ml, 70 % (m/m) solution. 4.11 Hydrofluoric acid, 1,13 g/ml, 40 % (m/m) solution. 4.12 Hydrobromic acid, 1,38 g/ml, 40 % (m/m) solution or 1,48 g/ml, 47 % (m/m) solution. 4.13 Ammonia solution, 0,9 g/ml. 4.14 Hydrogen peroxide, 30 % (m/m) solution, free from phosphate stabilizer. 4.15 Pot

29、assium nitrate, 10 g/l solution. 4.16 Ammonium molybdate, solution. Dissolve 40 g of finely pulverized crystalline ammonium molybdate tetrahydrate (NH 4 ) 6 Mo 7 O 24 4H 2 O in 300 ml of warm water and 80 ml of ammonia solution (4.13). Allow the solution to cool and add this solution in small portio

30、ns to 600 ml of nitric acid (1 + 1), while stirring. Add a few milligrams of sodium hydrogen phosphate or ammonium hydrogen phosphate and allow to stand for at least 2 d. Filter before use. BSISO2599:2003 34.17 Iron(III) chloride solution, containing 3 g of Fe/l. Dissolve 0,3 g of pure iron, with as

31、 small a content of phosphorus as possible, by treatment with hydrochloric acid (4.3), add a few drops of nitric acid (4.5) to oxidize the iron, and boil the mixture to remove chlorine. Allow the solution to cool and dilute with water to 100 ml. 4.18 Iron(III) sulfate solution, 100 g/l. Dissolve 100

32、 g of iron(II) sulfate heptahydrate (FeSO 4 7H 2 O) in 1 l of sulfuric acid (1 + 19). 4.19 Water, free of CO 2 . Heat distilled or deionized water to boiling point in a conical flask for 5 min to expel carbon dioxide. Cool, protecting the water in an appropriate way against any pickup of carbon diox

33、ide. 4.20 Sodium hydroxide, standard volumetric solution, c(NaOH) = 0,2 mol/l approximately. Dissolve 8 g of sodium hydroxide in 1 l of freshly boiled and cooled water (4.19). Standardize this solution using either amidosulfuric acid (sulfamic acid) or potassium hydrogen phthalate. Dry either potass

34、ium hydrogen phthalate or sulfamic acid at 105 C for 1 h and weigh, to the nearest 0,001 g, either approximately 1 g of potassium hydrogen phthalate or approximately 0,5 g of sulfamic acid. Dissolve either material in 50 ml of water free of CO 2(4.19) and titrate with sodium hydroxide solution (4.20

35、) using phenolphthalein solution (4.22) as indicator. 4.21 Nitric acid, standard volumetric solution c(HNO 3 ) = 0,2 mol/l approximately. Dilute 13 ml of nitric acid (4.5) with water, to 1 l. Standardize the solution as follows: accurately measure 25 ml of sodium hydroxide standard volumetric soluti

36、on (4.20) and titrate with nitric acid solution, using phenolphthalein solution (4.22) as indicator. 4.22 3,3-Bis(4-hydroxyphenyl)phthalide (phenolphthalein) solution, 0,1 g/100 ml. Dissolve 0,10 g of powdered phenolphthalein in 90 ml of ethanol, 95 % (V/V), and dilute with water, to 100 ml. 5 Appar

37、atus Ordinary laboratory apparatus, including one-mark pipettes and one-mark volumetric flasks in accordance with ISO 648 and ISO 1042. 6 Sampling and samples 6.1 Laboratory sample For analysis, use a laboratory sample of 100 m particle size which has been taken and prepared in accordance with ISO 3

38、082. In the case of ores having significant contents of combined water or oxidizable compounds, use a particle size of 160 m. NOTE A guideline on significant contents of combined water and oxidizable compounds is incorporated in ISO 7764. BSISO2599:20034 6.2 Preparation of predried test samples Thor

39、oughly mix the laboratory sample and, taking multiple increments, extract a test sample in such a manner that it is representative of the whole contents of the container. Dry the test sample at 105 C 2 C as specified in ISO 7764. (This is the predried test sample.) 7 Procedure 7.1 Number of determin

40、ations Carry out the analysis at least in duplicate in accordance with the flowsheet in Annex A, independently, on one predried test sample. NOTE The expression “independently” means that the second and any subsequent result is not affected by the previous result(s). For this particular analytical m

41、ethod, this condition implies that the repetition of the procedure be carried out either by the same operator at a different time or by a different operator including, in either case, appropriate recalibration. 7.2 Test portion Taking several increments, weigh, to the nearest 0,000 2 g, the amount o

42、f the predried test sample (6.2) specified in Table 1. NOTE The test portion should be taken and weighed quickly, in order to avoid reabsorption of moisture. Table 1 Mass of test portion Phosphorus content Mass of test portion Volume of aliquot portion Volume of ammonium molybdate solution (4.16) %

43、g ml ml 0,1 to 0,5 0,5 to 2,5 2,5 to 5,0 1,0 0,5 0,5 total total 100/250 50 100 100 7.3 Blank test and check test In each run, one blank test and one analysis of a certified material of the same type of ore shall be carried out in parallel with the analysis of the ore sample(s) under the same condit

44、ions. A predried test sample of the certified reference material shall be prepared as specified in 6.2. NOTE The certified reference material should be of the same type as the sample to be analysed and the properties of the two materials should be sufficiently similar to ensure that in either case n

45、o significant changes in the analytical procedure would become necessary. Where a certified reference material is not available, a reference material may be used (see 8.2.4). Where the analysis is carried out on several samples at the same time, the blank value may be represented by one test, provid

46、ed that the procedure is the same and the reagents used are from the same reagent bottles. Where the analysis is carried out on several samples of the same type of ore at the same time, the analytical value of one certified reference material may be used. BSISO2599:2003 57.4 Determination 7.4.1 Deco

47、mposition of the test portion 7.4.1.1 Test portions containing less than 18 mg titanium 7.4.1.1.1 Initial decomposition Place the test portion (7.2) in a 300 ml beaker, add 25 ml of hydrochloric acid (4.3), cover the beaker with a watch-glass and heat gently to decompose the ore. For decomposition o

48、f the test portion, place the beaker in a low temperature zone (60 C to 100 C) of the hot- plate to digest the sample for about 1 h, then transfer to a higher temperature zone and heat for about 10 min just below boiling. Add 5 ml of nitric acid (4.5) and 15 ml of perchloric acid (4.10), cover the b

49、eaker and heat to dense white fumes of perchloric acid. Maintain a steady refluxing of the acid on the walls of the beaker for about 10 min. Allow the beaker to cool, add about 50 ml of warm water and heat to dissolve soluble salts. Filter the solution through a close-texture paper and wash the residue three to five times with nitric acid (4.6) and finally with hot water until free from acid, receiving the filtrate and washing