BS EN 897:2012 pdf download – Chemicals used for treatment of water intended for human consumption — Sodium carbonate
1 Scope
This European Standard is applicable to sodium carbonate used for treatment of water intended for humanconsumption. t describes the characteristics and specifies the requirements and the corresponding test methodsfor sodium carbonate. It gives information on its use in water treatment. It also determines the rules relating to safehandling and use (see Annex C).
2Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable forits application.For dated references, only the edition cited applies. For undated references, the latest edition of thereferenced document (including any amendments) applies.
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 (lsO 12846:2012)
ISo 740,Sodium carbonate for industrial use —Determination of total soluble alkalinity —Titrimetric method
ISO 746,Sodium carbonate for industrial use —Determination of matter insoluble in water at 50 degrees c
ISO 2460，Sodium hydrogen carbonate for industrial use — Determination of iron content —1,10-Phenanthrolinephotometric method
ISO 3165,Sampling of chemical products for industrial use — Safety in sampling
ISO 6206,Chemical products for industrial use — Sampling — Vocabulary
ISO 8213,Chemical products for industrial use — Sampling techniques — Solid chemical products in the form ofparticles varying from powders to coarse lumps
3 Description
3.1 Identification
3.1.1 Chemical name
Sodium carbonate.
3.1.2 Synonym or common name
Soda ash, anhydrous sodium carbonate, light soda ash, heavy soda ash.
3.1.3 Relative molecular mass
105,99.
3.1.4 Empirical formula
Na 2 CO 3
3.1.5 Chemical formula
Na 2 CO 3 .
3.1.6 CAS Registry Number 1)
497-19-8.
3.1.7 EINECS reference 2)
207-838-8.
3.2 Commercial forms
The product is available as dry powder or fine granules and is described as light soda ash or heavy soda ash according to bulk density (see 3.3.2).
3.3 Physical properties
3.3.1 Appearance
The product is a white powder or crystals, slightly hygroscopic.
3.3.2 Density
The density of this product is 2,53 g/cm 3 .
The bulk density is:
ranging from 0,5 kg/dm 3 to 0,65 kg/dm 3 (light soda ash);
ranging from 0,8 kg/dm 3 to 1,2 kg/dm 3 (heavy soda ash).
3.3.3 Solubility in water
The product is soluble at 212 g/l at 20 °C.
3.3.4 Vapour pressure
Not applicable.
3.3.5 Boiling point at 100 kPa 3)
Not applicable.
3.3.6 Melting point
851 °C.
3.3.7 Specific heat
1,043 J/(kg K).
3.3.8 Viscosity (dynamic)
Not applicable.
3.3.9 Critical temperature
Not applicable.
3.3.10 Critical pressure
Not applicable.
3.3.11 Physical hardness
The hardness of solid sodium carbonate is given as 1 to 2 on the Mohs’ scale of hardness.
3.4 Chemical properties
Sodium carbonate reacts exothermically with acids with the formation of carbon dioxide.
Sodium carbonate is slightly hygroscopic and dissolution in water is an exothermic reaction.
4 Purity criteria
4.1 General
This European Standard specifies the minimum purity requirements for sodium carbonate 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 be notified to the user and when necessary to relevant authorities. NOTE 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 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 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 99 % of Na 2 CO 3 .
4.3 Impurities and main by-products
The product shall conform to the requirements specified in Table 1.
The concentration limits refer to pure Na 2 CO 3