1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationChemicals used for treatment of water intended for human consumption Sodium hydroxideBS EN 896:2012National forewordThis British Standard is the UK implementation of EN 896:2012.
2、 It supersedesBS EN 896:2005 which is withdrawn.The UK participation in its preparation was entrusted to Technical CommitteeCII/59, Chemicals for drinking water treatment.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purpor
3、t to include all the necessary provisions of acontract. Users are responsible for its correct application. The British Standards Institution 2013Published by BSI Standards Limited 2013ISBN 978 0 580 77697 7ICS 13.060.20; 71.100.80Compliance with a British Standard cannot confer immunity fromlegal ob
4、ligations.This British Standard was published under the authority of the StandardsPolicy and Strategy Committee on 28 February 2013.Amendments issued since publicationAmd. No. Date Text affectedBRITISH STANDARDBS EN 896:2012EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 896 November 2012 ICS 7
5、1.100.80 Supersedes EN 896:2005English Version Chemicals used for treatment of water intended for human consumption - Sodium hydroxide Produits chimiques utiliss pour le traitement de leau destine la consommation humaine - Hydroxyde de sodium Produkte zur Aufbereitung von Wasser fr den menschlichen
6、Gebrauch - Natriumhydroxid This European Standard was approved by CEN on 16 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 alteration. Up-to-date
7、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 made by translation un
8、der 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, Estonia, Finland, Former
9、 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 STANDARDIZATION COMIT EU
10、ROPEN 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 896:2012: EBS EN 896:2012EN 896:2012 (E) 2 Contents Page Foreword 3Intr
11、oduction .41 Scope 52 Normative references 53 Description .54 Purity criteria 85 Test methods . 106 Labelling Transportation Storage . 12Annex A (informative) General information on sodium hydroxide . 15Annex B (normative) Analytical methods 16Annex C (normative) General rules relating to safety . 2
12、6Bibliography . 27BS EN 896:2012EN 896:2012 (E) 3 Foreword This document (EN 896:2012) 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 i
13、dentical text or by endorsement, at the latest by May 2013, and conflicting 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 resp
14、onsible for identifying any or all such patent rights. This document supersedes EN 896:2005. Significant technical differences between this edition and EN 896:2005 are as follows: a) Modification of 6.2 on labelling, deletion of the reference to EU Directive 80/778/EEC of 15 July 1980 in order to ta
15、ke account of the latest Directive in force. According to the CEN/CENELEC 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, Forme
16、r 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 the United Kingdom. BS EN 896:2012EN 896:2012 (E) 4 Introducti
17、on In respect of potential adverse effects on the quality of water intended 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 E
18、U or EFTA; b) it should be noted that, while awaiting the adoption of 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
19、 of the product in any of the Member States of the EU or EFTA. The use of the product covered by this European Standard is subject to regulation or control by National Authorities. BS EN 896:2012EN 896:2012 (E) 5 1 Scope This European Standard is applicable to sodium hydroxide used for treatment of
20、water intended for human consumption. It describes the characteristics and specifies the requirements and the corresponding test methods for sodium hydroxide. It gives information on its use in water treatment. It also determines the rules relating to safe handling and use (see Annex C). 2 Normative
21、 references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) appl
22、ies. EN ISO 3696, Water for analytical laboratory use Specification and test methods (ISO 3696) EN ISO 12846:2012, Water quality Determination of mercury Method using atomic absorption spectrometry (AAS) with and without enrichment (ISO 12846:2012) ISO 979, Sodium hydroxide for industrial use Method
23、 of assay ISO 3165, Sampling of chemical products for industrial use Safety in sampling ISO 3196; Sodium hydroxide for industrial use Determination of carbonates content Titrimetric method ISO 6206, Chemical products for industrial use Sampling Vocabulary ISO 8213, Chemical products for industrial u
24、se Sampling techniques Solid chemical products in the form of particles varying from powders to coarse lumps 3 Description 3.1 Identification 3.1.1 Chemical name Sodium hydroxide. 3.1.2 Synonym or common name Caustic soda. 3.1.3 Relative molecular mass 40,0. 3.1.4 Empirical formula NaOH. 3.1.5 Chemi
25、cal formula NaOH. BS EN 896:2012EN 896:2012 (E) 6 3.1.6 CAS Registry Number1)1310-73-2. 3.1.7 EINECS reference2)215-185-5. 3.2 Commercial forms The product is available as flakes, pearls, solid, or as an aqueous solution of different concentrations. 3.3 Physical properties 3.3.1 Appearance Solid: th
26、e product is white, deliquescent. Liquid: the product is a clear solution, slightly turbid colourless solution, slightly viscous. 3.3.2 Density Solid : the density of this product is 2,1 g/cm3. The bulk density of pearls is 1,2 kg/dm3.Liquid : the density of solution is 1,52 g/ml for a product conce
27、ntration of mass fraction of 50 % at 20 C. 3.3.3 Solubility in water The product is highly soluble at all temperatures above 20 C (partial crystallization occurs above concentration of mass fraction of 55 %, (see Figure 1). 1) Chemical Abstracts Service Registry Number. 2) European Inventory of Exis
28、ting Commercial Chemical Substances. BS EN 896:2012EN 896:2012 (E) 7 Key 1 temperature in C. 2 NaOH concentration in mass fraction in % Figure 1 Solubility of sodium hydroxide 3.3.4 Vapour pressure Solution of concentration of mass fraction of 50 % - 120 Pa at 20 C; - 450 Pa at 40 C; - 5 000 Pa at 8
29、0 C. BS EN 896:2012EN 896:2012 (E) 8 3.3.5 Boiling point at 100 kPa3)145 C for a solution of concentration of mass fraction of 50 %. 3.3.6 Crystallization point + 12 C for a solution of concentration of mass fraction of 50 % (see Figure 1). 3.3.7 Specific heat 3 220 J/(kg K) at 20 C for a solution o
30、f concentration of mass fraction of 50 %. 3.3.8 Viscosity (dynamic) For a solution of concentration of mass fraction of 50 %: - 100 Pa.s at 20 C; - 25 Pa.s at 40 C; - 5 Pa.s at 80 C. 3.3.9 Critical temperature Not applicable. 3.3.10 Critical pressure Not applicable. 3.3.11 Physical hardness Not appl
31、icable. 3.4 Chemical properties The solutions of sodium hydroxide are strongly alkaline. Dilution of sodium hydroxide is very exothermic. 4 Purity criteria 4.1 General This European Standard specifies the minimum purity requirements for sodium hydroxide used for the treatment of water intended for h
32、uman 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 be notified to the user and when necessary to relevant authorities. 3) 100 kPa = 1 bar. BS EN 896:2012
33、EN 896:2012 (E) 9 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, contents of other impurities and additives used in the
34、products 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 process or raw materials leads to significant quantities
35、 of impurities, by-products or additives being present, this shall be notified to the user. 4.2 Composition of commercial product The product shall contain not less than a mass fraction of 96 % of NaOHfor the solid form. Typical concentration for solutions of sodium hydroxide is either a mass fracti
36、on of 50 % or 30 % , and shall be in any case within the manufacturers stated tolerance. 4.3 Impurities and main by-products The product shall conform to the requirements specified in Table 1. The concentration limits refer to pure NaOH mass fraction of 100 %. Table 1 Impurities Impurity Limit in ma
37、ss fraction in % of NaOH Sodium chloride (NaCl)a)max. 2,4Sodium carbonate (Na2CO3)b)max. 0,4 Sodium chlorate (NaClO3)c)max. 0,7a) Too high concentrations can cause problems with some ion exchange resins. b) Sodium carbonate is formed in contact with atmospheric carbon dioxide. c) The presence of any
38、 oxidizing agent in sodium hydroxide is to be avoided. 4.4 Chemical parameters The product shall conform to the requirements specified in Table 2. BS EN 896:2012EN 896:2012 (E) 10 Table 2 Chemical parameters Parameter Limit in mg/kg of NaOH Type 1 Type 2 Arsenic (As) max. 2 10 Cadmium (Cd) max. 1 5
39、Chromium (Cr) max. 1 10 Mercury (Hg) max. 0,1 1 Nickel (Ni) max. 2 10 Lead (Pb) max. 5 20 Antimony (Sb) max. 5 5 Selenium (Se) max. 5 5 NOTE Cyanides, pesticides and polycyclic aromatic hydrocarbons are not relevant in sodium hydroxide. For parametric values of sodium hydroxide on trace metal conten
40、t in drinking water, see 1. 5 Test methods 5.1 Sampling Prepare the laboratory sample(s) required by the relevant procedure described in ISO 8213, observe the recommendations of ISO 3165 and also take into account ISO 6206. The nature of caustic alkalis requires special care at all points of samplin
41、g and preparation for analysis. Sampling techniques shall be such as to limit or prevent atmospheric exposure since sodium hydroxides, either as aqueous solutions or as anhydrous products, rapidly absorb moisture and carbon dioxide (and other acid gases) from the atmosphere. Additional precautions a
42、re necessary if trace constituents are to be determined. NOTE For sampling liquids see 2. BS EN 896:2012EN 896:2012 (E) 11 5.2 Analyses 5.2.1 Main product 5.2.1.1 Total alkalinity The total alkalinity shall be determined by titration with an acid standard volumetric solution in accordance with ISO 9
43、79. 5.2.1.2 Caustic alkalinity The caustic alkalinity equals the total alkalinity as NaOH (see 5.2.1.1) minus the alkalinity as Na2CO3multiplied by 0,755 determined in accordance with ISO 3196. 5.2.2 Impurities 5.2.2.1 Sodium chloride The sodium chloride content shall be determined by potentiometric
44、 titration with silver nitrate solution (see B.1). 5.2.2.2 Sodium carbonate The sodium carbonate content shall be determined by the titrimetric method, in accordance with ISO 3196. 5.2.2.3 Sodium chlorate The sodium chlorate content shall be determined by ionic chromatography (see B.2). 5.2.3 Chemic
45、al parameters 5.2.3.1 Principle The elements antimony, arsenic, cadmium, chromium, lead, nickel and selenium are determined by inductively coupled plasma optical emission spectrometry. Mercury is determined by cold vapour atomic absorption spectrometry. 5.2.3.2 Arsenic The arsenic content shall be d
46、etermined by inductively coupled plasma optical emission spectrometry (ICP/OES) (see B.3). 5.2.3.3 Cadmium The cadmium content shall be determined by inductively coupled plasma optical emission spectrometry (ICP/OES) (see B.3). 5.2.3.4 Chromium The chromium content shall be determined by inductively
47、 coupled plasma optical emission spectrometry (ICP/OES) (see B.3). BS EN 896:2012EN 896:2012 (E) 12 5.2.3.5 Nickel The nickel content shall be determined by inductively coupled plasma optical emission spectrometry (ICP/OES) (see B.3). 5.2.3.6 Lead The lead content shall be determined by inductively
48、coupled plasma optical emission spectrometry (ICP/OES) (see B.3). 5.2.3.7 Antimony The antimony content shall be determined by inductively coupled plasma optical emission spectrometry (ICP/OES) (see B.3). 5.2.3.8 Selenium The selenium content shall be determined by inductively coupled plasma optical
49、 emission spectrometry (ICP/OES) (see B.3). 5.2.3.9 Mercury The mercury content shall be determined by cold vapour atomic absorption spectrometry in accordance with EN ISO 12846 (see B.4). 6 Labelling Transportation Storage 6.1 Means of delivery Sodium hydroxide can be delivered in rail or road tankers, in containers, in drums or in plastics bags. In order that the purity of the products is not affected, the means of delivery shall not have been used previously for any
