1、BRITISH STANDARD CONFIRMED SEPTEMBER1989 BS1016-10: 1977 Methods for Analysis and testing of coal and coke Part 10: Arsenic in coal and coke UDC 662.66+662.74:543.847:546.19BS1016-10:1977 This British Standard, having been prepared under the directionof the Solid Fuel Standards Committee, waspublish
2、ed under the authorityof the Executive Boardon 29 April1977 BSI10-1999 First published March1942 First revision December1960 Second revision April1977 The following BSI references relate to the work on this standard: Committee references SFC/45 andSFC/45/8 Draft for comment73/42191DC ISBN 0 580 0937
3、3 5 Cooperating organizations The Solid Fuel Standards Committee, under whose supervision this BritishStandard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: Association of Consulting Engineers British Carbonization Re
4、search Association* British Cast Iron Research Association British Ironfounders Association British Mechanical Engineering Confederation Central Electricity Generating Board* Chamber of Coal Traders Coke Oven Managers Association* Combustion Engineering Association* Council of Ironfoundry Associatio
5、ns Department of Energy Domestic Solid Fuel Appliances Approval Scheme Greater London Council Health and Safety Executive Heating and Ventilating Contractors Association Institute of British Foundrymen* Institute of Fuel Institution of Heating and Ventilating Engineers Low Temperature Coal Distiller
6、s Association of Great Britain Ltd. National Coal Board* Society of British Gas Industries Solid Fuel Advisory Service Water-tube Boilermakers Association Womens Solid Fuel Council The organizations marked with an asterisk in the above list, together with the following, were directly represented on
7、the committee entrusted with the preparation of this British Standard: British Coal Exporters Federation British Gas Corporation British Steel Corporation Cement Makers Federation Chemical Industries Association Electricity Supply Industry in England and Wales Institute of Trading Standards Administ
8、ration London Coal Exporters Association Scientific Instruments Manufacturers Association of Great Britain Society of Chemical Industry Solid Smokeless Fuels Federation Independent experts Amendments issued since publication Amd. No. Date of issue CommentsBS1016-10:1977 BSI 10-1999 i Contents Page C
9、ooperating organizations Inside front cover Foreword ii 1 Scope 1 2 References 1 3 Definitions 1 4 Introduction 1 5 Sample 1 6 Wet oxidation method 1 7 Dry oxidation method 4 8 Reporting of result 6 9 Precision of the determination 6 Figure 1 Apparatus for the wet oxidation of the sample 2 Figure 2
10、Evolution apparatus 3 Figure 3 Combustion tube 6 Publications referred to Inside back coverBS1016-10:1977 ii BSI 10-1999 Foreword This British Standard is Part10 of a series issued under the same number, BS1016, dealing with methods for the analysis and testing of coal and coke; the other Parts are
11、as follows. Part1: Total moisture of coal; Part2: Total moisture of coke; Part3: Proximate analysis of coal; Part4: Moisture, volatile matter and ash in the analysis sample of coke; Part5: Gross calorific value of coal and coke; Part6: Ultimate analysis of coal; Part7: Ultimate analysis of coke; Par
12、t8: Chlorine in coal and coke; Part9: Phosphorus in coal and coke; Part11: Forms of sulphur in coal; Part12: Caking and swelling properties in coal; Part13: Tests special to coke; Part14: Analysis of coal ash and coke ash; Part15: Fusibility of coal ash and coke ash; Part16: Reporting of results. Th
13、e methods given in BS1016 are specified for the analysis of coal or of coke or, in some instances, for the analysis of both coal and coke. It is expected that the methods given in this Part would also be applicable to the determination of arsenic in manufactured smokeless fuels (other than coke) mad
14、e by a conventional process, although no systematic survey has been made. The revision of Part10 has been undertaken to complete the introduction of metric units and to adopt a uniform presentation. No technical changes have been made to the procedures retained from the previous edition of this stan
15、dard, but the “paper stain” method has now been omitted. The wet oxidation procedure and the subsequent procedure for the colorimetric determination of the arsenic are technically equivalent to those specified in ISO/R601; however, the dry oxidation procedure differs from that in the ISO standard in
16、 the nature of the oxidants and in the maximum temperature reached. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immuni
17、ty from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to6, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amend
18、ment table on the inside front cover.BS1016-10:1977 BSI 10-1999 1 1 Scope This Part of BS1016 describes two methods for determining the amount of arsenic in coal and coke. 2 References The titles of the publications referred to in this standard are listed on the inside back cover. 3 Definitions For
19、the purposes of this Part of BS1016 the following definitions apply. 3.1 coke the solid residue of the distillation of coal at high temperature (above800 C) 3.2 repeatability the maximum acceptable difference between duplicate determinations carried out at different times in the same laboratory on t
20、he same analysis sample by the same operator using the same apparatus 3.3 reproducibility the maximum acceptable difference between the mean or duplicate determinations carried out in one laboratory and the mean of duplicate determinations carried out in any other laboratory on representative sample
21、s taken from the same gross sample after the last stage of the reduction process 4 Introduction Two procedures are given for taking the sample into solution, after which the same procedure is followed in each case for the determination of the arsenic. 5 Sample The coal or coke used for the determina
22、tion of arsenic shall be the analysis sample having a top size not greater than0.2mm (ground to pass a2124m test sieve complying with the requirements of BS410), taken and prepared according to BS1017-1 or BS1017-2 as appropriate. The sample shall be thoroughly mixed, preferably by mechanical means,
23、 immediately before the determination. 6 Wet oxidation method 6.1 Principle. The carbonaceous material is removed from a known mass of the sample and the arsenic is taken into solution by repeated oxidation with nitric acid in the presence of sulphuric acid. The arsenic in solution is reduced to the
24、 trivalent state and evolved as arsine by the action of zinc, the arsine being absorbed and oxidized to arsenic acid in a dilute iodine solution. Treatment with ammonium molybdate solution and reduction with hydrazinium sulphate produces a molybdenum blue coloration, of which the absorbance is propo
25、rtional to the amount of arsenic present in the sample. The absorbance is measured by means of a suitable instrument and the arsenic content determined by reference to a calibration graph. 6.2 Special reagents. All reagents, unless otherwise specified, shall be of analytical reagent quality or AsT g
26、rade 1)(arsenic test grade), as appropriate. Distilled or deionized water complying with the requirements of BS3978 shall be used throughout. 6.2.1 Hydrochloric acid, d =1.18. 6.2.2 Nitric acid, d =1.42 (AsT grade). 6.2.3 Sulphuric acid, d =1.84 (AsT grade). 6.2.4 Sulphuric acid, 7N approximately. C
27、arefully add10ml of the sulphuric acid (see6.2.3) to50ml of water. 6.2.5 Sulphuric acid, 5.0N. Carefully add14ml of the sulphuric acid (see6.2.3) to80ml of water, cool and dilute to100ml. Standardize the solution against sodium carbonate and adjust to5.0N. 6.2.6 Potassium iodide solution. Dissolve15
28、g of potassium iodide (AsT grade) in100ml of water. Prepare a fresh solution each day. 6.2.7 Tin (II) chloride solution. Dissolve40g of tin (II) chloride dihydrate, SnCl 2 .2H 2 O, in100ml of the hydrochloric acid (see6.2.1). 6.2.8 Iodine solution (stock solution, approximately0.02N). Dissolve2.54g
29、of iodine in25ml of water containing8g of potassium iodide (AsT grade). Dilute to1litre and store in a dark glass bottle. 6.2.9 Iodine solution, approximately0.001N. Prepare a fresh solution daily by dilution of a suitable volume of the stock iodine solution (see6.2.8) with distilled water. 1) AsT g
30、rades complying with the British Pharmacopoeia are suitable.BS1016-10:1977 2 BSI 10-1999 6.2.10 Lead acetate solution, saturated. Add approximately4.5g of lead acetate trihydrate, (CH 3 COO) 2 Pb.3H 2 O, to10ml of water and shake well. Prepare a fresh solution daily. 6.2.11 Zinc, granulated, arsenic
31、 content lessthan0.02mg/kg. 6.2.12 Ammonium molybdate solution. Dissolve10g of ammonium molybdate tetrahydrate, (NH 4 ) 6 Mo 7 O 24 .4H 2 O, in1litre of the sulphuric acid (see6.2.5). 6.2.13 Hydrazinium sulphate solution. Dissolve0.15g of hydrazinium sulphate in100ml of water. 6.2.14 Arsenic solutio
32、n. Dissolve exactly0.1000g of arsenic (II) oxide, previously dried at110 C for2h, in50ml of water containing0.5ml of a700g/l aqueous solution of sodium hydroxide. Add2.0ml ofthe sulphuric acid5.0N (see6.2.5) and dilute to100ml with water. This solution contains1mg/ml of As 2 O 3 . 6.3 Special appara
33、tus 6.3.1 Oxidation apparatus. A suitable apparatus, constructed of borosilicate glass, is shown in Figure 1. It consists of the following items. 6.3.1.1 Flask. A Kjeldahl flask of300ml capacity fitted with a24/29 ground glass socket complying with the requirements of BS572. 6.3.1.2 Fume duct. A fum
34、e duct of approximately28mm outside diameter, fitted with a dropping funnel of at least15ml capacity and a24/29 ground glass cone complying with the requirements of BS572. The fume duct may be of one piece or assembled from separate units by means of ground glass joints. 6.3.1.3 Fume extractor. A gl
35、ass tube of approximately40mm diameter, sealed at one end and drawn out at the other end to form a connection to the water pump. The tube is fitted with a drain stopcock and a series of lipped holes to accommodate a number of fume ducts. 6.3.1.4 Digestion rack. A rack to hold several Kjeldahl flasks
36、 at an angle of45 over bunsen burners, with a holder for the fume extractor. 6.3.1.5 Glass water jet pump or other suction device. 6.3.2 Arsenic evolution apparatus. A suitable apparatus is shown in Figure 2. It consists of the following items. 6.3.2.1 Evolution flask (A). A80ml conical flask fitted
37、 with a19/26 ground glass socket complying with the requirements of BS572. 6.3.2.2 Delivery tube (B). A thick-walled glass tube of4mm internal diameter, fitted with a19/26 ground glass cone at one end and a7/16 ground glass cone at the other, both complying with the requirements of BS572. Glass hook
38、s are fitted just above the7/16 cone. 6.3.2.3 Delivery tube extension (C). A thick-walled glass tube of the shape and dimensions shown in Figure 2, fitted with a7/16 ground glass socket complying with the requirements of BS572 and glass hooks. 6.3.2.4 Absorption tube (D). A glass tube,15mm internal
39、diameter by approximately150mm long, fitted with a14/15socket and having a corresponding ground glass stopper complying with the requirements of BS572. The lower80mm of the tube is drawn out to approximately11mm internal diameter and the end sealed. Figure 1 Apparatus for the wet oxidation of the sa
40、mpleBS1016-10:1977 BSI 10-1999 3 6.3.2.5 Helix (E). A helix,80mm long and of5mm pitch, of glass or inert plastics material 2)of circular section. The helix has an outside diameter such that it fits the lower half of the absorption tube freely but not loosely and an internal diameter slightly larger
41、than the narrow end of the delivery tube. A correctly fitted helix allows gas bubbles to follow a spiral course freely and without bypass. 6.3.2.6 Springs. Small metal springs to ensure a gas-tight joint between the delivery tube and its extension. 6.3.3 Other apparatus. The following are also requi
42、red. 6.3.3.1 Pipettes. 1ml,5ml and10ml pipettes, classA, complying with the requirements of BS1583. 6.3.3.2 Burettes. Two5ml burettes, graduated to0.02ml, complying with the requirements of BS846. 6.3.3.3 Spectrophotometer. An absorptiometer of the required sensitivity 3) . 6.4 Procedure 6.4.1 Diges
43、tion of sample. Weigh accurately about1g of the coal or coke and transfer to the clean, dry Kjeldahl flask. Assemble the apparatus, as shown in Figure 1, in a well ventilated fume cupboard. Add7ml of the sulphuric acid (see6.2.3) and3.5ml of the nitric acid by means of the dropping funnel, rotating
44、the flask so as to wash down any sample remaining in the neck. After the initial reaction has subsided (see note1), heat the flask carefully so that the reaction proceeds smoothly and without frothing. Continue heating the flask under the same conditions until only fumes of sulphuric acid are evolve
45、d. Add0.2ml to0.4ml of the nitric acid to the dropping funnel and run the acid drop by drop into the flask. Heat for2min to3min until no more dense brown fumes are evolved. Add, in a similar manner, a further0.2ml to0.4ml of the nitric acid and heat again until brown fumes cease to be evolved. Conti
46、nue such additions of nitric acid, heating in the same way after each addition, until all visible carbonaceous matter has been oxidized, rotating the flask periodically to wash down any carbonaceous matter adhering to the sides of the flask. After about1“ h to2h the reaction mixture should be a pale
47、 greenish-yellow colour (see note2) with no visible carbonaceous matter present. Heat the flask more strongly until white fumes appear and allow to fume for5min (see note3). Cool the flask to approximately room temperature, remove the dropping funnel and fume duct assembly and add a few glass beads
48、to the contents of the flask. Add cautiously10ml of water, heat until white fumes appear and then allow to fume gently for10min. Cool the flask until the evolution of the white fumes ceases, add0.2ml of the nitric acid, reheat the flask and allow to fume for a further10min. To ensure complete oxidat
49、ion, cool the flask to approximately room temperature and repeat the procedure described in the preceding paragraph. 2) Unplasticized polyvinyl chloride is suitable. Figure 2 Evolution apparatus 3) A Unicam SP600 spectrophotometer or similar instruments is suitable.BS1016-10:1977 4 BSI 10-1999 Cool the flask to approximately room temperature, add10ml of water, heat to fuming and allow to fume for20min. Finally, add10ml of water, heat to fuming, allow to fume for10min and cool. Add10ml of water and transfer the solution to t
