1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN 12124:2012Chemicals used for treatmentof water intended for humanconsumption Sodium sulfiteBS EN 12124:2012 BRITISH STANDARDNational forewordThis British Standard is the UK
2、 implementation of EN 12124:2012. It supersedes BS EN 12124:2005 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee CII/59, Chemicals for drinking water treatment.A list of organizations represented on this committee can be obtained on request to its secr
3、etary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2013. Published by BSI Standards Limited 2013ISBN 978 0 580 77781 3 ICS 71.100.80 Compliance with a British Standard can
4、not confer immunity from legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 28 February 2013.Amendments issued since publicationDate T e x t a f f e c t e dBS EN 12124:2012EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 12
5、124 November 2012 ICS 71.100.80 Supersedes EN 12124:2005English Version Chemicals used for treatment of water intended for human consumption - Sodium sulfite Produits chimiques utiliss pour le traitement de leau destine la consommation humaine - Sulfite de sodium Produkte zur Aufbereitung von Wasser
6、 fr den menschlichen Gebrauch - Natriumsulfit This European Standard was approved by CEN on 23 September 2012. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alte
7、ration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language mad
8、e by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Eston
9、ia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STAND
10、ARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2012 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 12124:2012: EBS EN 12124:2012EN 12124:2012 (E) 2 Con
11、tents Page Foreword 3Introduction .41 Scope 52 Normative references 53 Description .54 Purity criteria 75 Test methods 86 Labelling Transportation Storage . 14Annex A (informative) General information on sodium sulfite 15Bibliography . 17BS EN 12124:2012EN 12124:2012 (E) 3 Foreword This document (EN
12、 12124:2012) has been prepared by Technical Committee CEN/TC 164 “Water supply”, the secretariat of which is held by AFNOR. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by May 2013, and conflictin
13、g national standards shall be withdrawn at the latest by May 2013. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document super
14、sedes EN 12124:2005. Significant technical differences between this edition and EN 12124:2005 are as follows: Modification of 6.2 on labelling, deletion of the reference to EU Directive 80/778/EEC of 15 July 1980 in order to take account of the latest Directive in force. According to the CEN/CENELEC
15、 Internal Regulations, the national standards organisations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Icela
16、nd, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. BS EN 12124:2012EN 12124:2012 (E) 4 Introduction In respect of potential adverse effects on the quality of water in
17、tended for human consumption caused by the product covered by this European Standard: a) this European Standard provides no information as to whether the product may be used without restriction in any of the Member States of the EU or EFTA; b) it should be noted that, while awaiting the adoption of
18、verifiable European criteria, existing national regulations concerning the use and/or the characteristics of this product remain in force. NOTE Conformity with this European Standard does not confer or imply acceptance or approval of the product in any of the Member States of the EU or EFTA. The use
19、 of the product covered by this European Standard is subject to regulation or control by National Authorities. BS EN 12124:2012EN 12124:2012 (E) 5 1 Scope This European Standard is applicable to sodium used for treatment of water intended for human consumption .It describes the characteristics and s
20、pecifies the requirements of sodium sulfite and refers to the corresponding analytical methods. It gives information for its use in water treatment. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its applicat
21、ion. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN ISO 3696, Water for analytical laboratory use Specification and test methods (ISO 3696) ISO 418, Photography Processing chemicals Sp
22、ecifications for anhydrous sodium sulfite ISO 3165, Sampling of chemical products for industrial use Safety in sampling ISO 5993, Sodium hydroxide for industrial use Determination of mercury content Flameless atomic absorption spectrometric method ISO 6206, Chemical products for industrial use Sampl
23、ing Vocabulary ISO 6332, Water quality Determination of iron Spectrometric method using 1,10-phenanthroline ISO 6353-1, Reagents for chemical analysis Part 1: General test methods ISO 8213, Chemical products for industrial use Sampling techniques Solid chemical products in the form of particles vary
24、ing from powders to coarse lumps ISO 22743, Water quality Determination of sulfates Method by continuous flow analysis (CFA) 3 Description 3.1 Identification 3.1.1 Chemical name Sodium sulfite. 3.1.2 Synonym or common name Sodium sulfite. 3.1.3 Relative molecular mass 126,04. 3.1.4 Empirical formula
25、 Na2SO3.BS EN 12124:2012EN 12124:2012 (E) 6 3.1.5 Chemical formula Na2SO3.3.1.6 CAS-Registry Number 1)7757-83-7. 3.1.7 EINECS reference 2)231-821-4. 3.2 Commercial form The product is a crystalline powder. 3.3 Physical properties 3.3.1 Appearance and odour The product is a white, fine crystalline, o
26、dourless powder. 3.3.2 Density The density of the product is 2,63 g/cm at 20 C. The bulk density is 1,2 g/cm to 1,5 g/cm at 20 C. 3.3.3 Solubility in water The solubility of the product in water is 250 g/l at 20 C. 3.3.4 Vapour pressure Not applicable. 3.3.5 Boiling point at 100 kPa 3)The product de
27、composes above 230 C. 3.3.6 Crystallisation point See 3.3.5. 3.3.7 Specific heat Not known. 1) Chemical Abstracts Service Registry Number. 2) European Inventory of Existing Commercial Chemical Substances. 3) 100 kPa = 1 bar. BS EN 12124:2012EN 12124:2012 (E) 7 3.3.8 Viscosity, dynamic Not applicable
28、. 3.3.9 Critical temperature Not applicable. 3.3.10 Critical pressure Not applicable. 3.3.11 Physical hardness Not applicable. 3.4 Chemical properties The pH value of a saturated aqueous solution of sodium sulfite is in the range of 9,7 to 10,2. At elevated temperatures ( 100 C) sulfur dioxide is ge
29、nerated. On contact with air, small amounts of sodium sulfate are formed. Sodium sulfite releases sulfur dioxide when mixed with acids. Sodium sulfite reacts violently with oxidising agents; e.g. with sodium hypochlorite or hydrogen peroxide. 4 Purity criteria 4.1 General This European Standard spec
30、ifies the minimum purity requirements for sodium sulfite used for the treatment of water intended for human consumption. Limits are given for impurities commonly present in the product. Depending on the raw material and the manufacturing process other impurities may be present and, if so, this shall
31、 be notified to the user and when necessary, to relevant authorities. Users of this product should check the national regulations in order to clarify whether it is of appropriate purity for treatment of water intended for human consumption, taking into account raw water quality, required dosage, con
32、tents of other impurities and additives used in the product not stated in this product standard. Limits have been given for impurities and chemical parameters where these are likely to be present in significant quantities from the current production process and raw materials. If the production proce
33、ss or raw materials leads to significant quantities of impurities, by-products or additives being present, this shall be notified to the user. 4.2 Composition of commercial product The content of sodium sulfite shall not be less than a mass fraction of 95 %. 4.3 Impurities and main by-products The c
34、ontent of sodium sulfate shall not exceed a mass fraction of 5 %. The content of iron (Fe) shall not exceed 25 mg/kg. BS EN 12124:2012EN 12124:2012 (E) 8 4.4 Chemical parameters The product shall conform to the requirements specified in Table 1. Table 1 Chemical parameters Parameter Limit mg/kg of c
35、ommercial product Antimony (Sb) max 2 Arsenic (As) max 1 Cadmium (Cd) max 1 Chromium (Cr) max 1 Lead (Pb) max 2 Mercury (Hg) max 0,5 Nickel (Ni) max 1 Selenium (Se) max 1 NOTE Pesticides and polycyclic aromatic hydrocarbons and cyanides ( CN-) are not relevant in sodium sulfite because the raw mater
36、ials used in the manufacturing are free of them. For parametric values of sodium sulfite on trace metal content in drinking water, see 1. 5 Test methods 5.1 Sampling Observe the general recommendations of ISO 3165 and take account of ISO 6206. Prepare the laboratory sample(s) required by the relevan
37、t procedure described in ISO 8213. 5.2 Analyses 5.2.1 Main product The sodium sulfite content shall be determined in accordance with ISO 418. NOTE Both methods, direct titration and back titration, can be used. 5.2.2 Impurities 5.2.2.1 Sulfate The content of sodium sulfate (Na2SO4) shall be determin
38、ed in accordance with ISO 22743. BS EN 12124:2012EN 12124:2012 (E) 9 5.2.2.2 Iron (Fe) The content of iron (Fe) shall be determined in accordance with ISO 6332 (spectrometric method). 5.2.3 Chemical parameters 5.2.3.1 General The content of chemical parameters shall be determined using the procedure
39、s specified in Table 2: Table 2 Procedures for the determination of chemical parameters Element Reference Method Wavelength (nm) Flame As see 5.2.3.3 Hydride AAS 193,7 n.a.Sb see 5.2.3.3 Hydride AAS 217,6 n.a. Cd ISO 6353-1 GM 29see 5.2.3.2 AAS 228,8 air-acetylene Cr ISO 6353-1 GM 29see 5.2.3.2 AAS
40、357,8 air-acetylene Pb ISO 6353-1 GM 29see 5.2.3.2 AAS 217,0 or 283,3 air-acetylene Ni ISO 6353-1 GM 29see 5.2.3.2 AAS 232,0 oxidising acetylene-air Se see 5.2.3.3 Hydride AAS 196,0 n.a.Hg in accordance withISO 5993 flameless AAS 253,6 n.a. AAS = Atomic Absorption Spectroscopy. n.a. = not applicable
41、. 5.2.3.2 Determination of cadmium (Cd), chromium (Cr), lead (Pb) and nickel (Ni) 5.2.3.2.1 Principle The elements cadmium (Cd), chromium (Cr), lead (Pb) and nickel (Ni) are determined using atomic absorption spectrometry with the standard additions technique. 5.2.3.2.2 Reagents All reagents shall b
42、e of a recognised analytical grade and the water used shall conform to the grade 3 specified in EN ISO 3696. BS EN 12124:2012EN 12124:2012 (E) 10 5.2.3.2.2.1 Standard solution (100 g/l Cd, Cr ,Pb or Ni). The standard solution shall be freshly prepared on the day of use by individual dilution of a st
43、ock solution. This stock solution with a Cd, Cr, Pb or Ni content of at least 1 mg/l shall be made by dilution of standard solutions of Cd, Cr, Pb and Ni which are available from all major suppliers of laboratory chemicals. This stock solution shall be kept in containers of tetrafluoroethylene-hexaf
44、luoropropylene copolymer (FEP), polytetrafluoroethylene (PTFE) or polyethylene (PE). The stock solution should not be kept for longer than four weeks. 5.2.3.2.3 Apparatus Ordinary laboratory apparatus and the following: 5.2.3.2.3.1 Atomic absorption spectrometer with the measurement parameters speci
45、fied in Table 2. 5.2.3.2.4 Procedure 5.2.3.2.4.1 Test portion Weigh 1 g (m) to the nearest 0,01 mg of the laboratory sample into a 100 ml one-mark volumetric flask and make up to the mark at 20 C with water. 5.2.3.2.4.2 Determination The reference solutions shall be made by spiking the sample with t
46、he standard solutions, which contain stepwise increasing contents of the elements to be determined. NOTE The amount of internal standard to be added can be estimated from a preliminary investigation, determining roughly the element content of the test sample from simple calibration. The steps in whi
47、ch internal standards have to be added shall be at least as high as the estimated content of the test sample. With the spectrometer (5.2.3.2.3.1), carry out the measurement with the parameters specified in Table 2 in accordance with the manufacturers instructions. Repeat the procedure with all reage
48、nts and the same volume of standard solution to be added using water in place of the sample as a blank determination. 5.2.3.2.5 Expression of results Prepare a calibration curve using the measured absorbencies of the spiked measurement solutions. Read the concentration of each element in the test so
49、lution by extrapolation of the correlation line to absorbance A = 0 (see Figure 1). Similarly determine the element concentration of the blank solution (see Figure 2) and subtract from the result obtained for the test solution. Alternatively, the evaluation can be carried out by linear regression. Additional dilution steps shall be compensated in the calculation. The interim result (y) expressed in micrograms per litre is converted to give the final concentration according to 5.2.3.2.6. BS
