Standard No.:	GB/T 9776-2022
English Name:	Calcined gypsum
Chinese Name:	建筑石膏
Chinese Classification:	Q62    Gypsum product
Professional Classification:	GB    National Standard
ICS Classification:	91.100.10 91.100.10    Cement. Gypsum. Lime. Mortar 91.100.10
Issued by:	SAMR; SAC
Issued on:	2022-12-30
Implemented on:	2023-7-1
Status:	valid
Superseding:	GB/T 9776-2008 Calcined gypsum
Language:	English
File Format:	PDF
Word Count:	6000 words
Price(USD):	180.0
Delivery:	via email in 1 business day

Calcined gypsum 1 Scope This standard specifies classification and designation, raw materials, technical requirements, test method, inspection rules as well as packaging, marking, transportation and storage of the calcined gypsum. This document is applicable to calcined gypsum made from natural gypsum, flue gas desulfurization gypsum and phosphogypsum, and can also be used as a reference by calcined gypsum made from other industrial by-product gypsum. 2 Normative references The following documents contain provisions which, through reference in this text, constitute provisions 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. GB/T 5483-2008 Natural gypsum GB/T 5484-2012 Methods for chemical analysis of gypsum GB 6566 Limits of radionuclides in building materials GB/T 6682 Water for analytical laboratory use - Specification and test methods GB/T 17669.1-1999 General test conditions for gypsum plasters GB/T 17669.3-1999 Gypsum plasters - Determination of mechanical properties GB/T 17669.4-1999 Gypsum plasters - Determination of physical properties of pure paste GB/T 23456-2018 Phosphogypsum GB/T 36141 Methods for phase composition analysis of calcined gypsum GB/T 37785 Flue gas desulfurization gypsum JC/T 2073 Determination of phosphorus and fluorine content in phosphogypsum 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 calcined gypsum powdered cementing materials for building which are made from natural gypsum or industrial by-product gypsum after calcination and dehydration at a certain temperature, with β-calcium sulfate hemihydrate (β-CaSO4·1/2H2O) as main constituent, without adding any admixture or additives 3.2 calcined natural gypsum calcined gypsum made from natural gypsum (3.1) 3.3 industrial by-product gypsum by-products produced from industrial production, of which calcium sulphate dihydrate (CaSO4·2H2O) is the main constituent 3.4 calcined gypsum from flue gas desulfurization calcined gypsum (3.1) made from by-products which are obtained by desulfurization of sulfur dioxide by wet process using lime, calcium hydroxide or limestone and of which calcium sulphate dihydrate (CaSO4·2H2O) is the main constituent 3.5 calcined gypsum from phosphogypsum calcined gypsum (3.1) made from by-products which are obtained by preparing phosphoric acid by wet process using phosphate ore and of which calcium sulphate dihydrate (CaSO4·2H2O) is the main constituent 3.6 limited constituent constituent in calcined gypsum (3.1) that have adverse effects on the production and application of gypsum products and thus need to be limited 4 Classification and designation 4.1 Classification 4.1.1 Calcined gypsum is classified into three categories by types of raw materials, as shown in Table 1.

Foreword i 1 Scope 2 Normative references 3 Terms and definitions 4 Classification and designation 5 Raw materials Foreword i 1 Scope 2 Normative references 3 Terms and definitions 4 Classification and designation 5 Raw materials 6 Technical requirements 7 Test condition 8 Test method 9 Inspection rules 10 Packaging, marking, transportation and storage Annex A (Normative) Method for determination of water-soluble chloride ion content in calcined gypsum ts 7 Test condition 8 Test method 9 Inspection rules 10 Packaging, marking, transportation and storage Annex A (Normative) Method for determination of water-soluble chloride ion content in calcined gypsum