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The **standard GB/T9776-2008 for Building Gypsum** was issued on June 30, 2008, by the **General Administration of Quality Supervision, Inspection and Quarantine** and the **Standardization Administration Committee**, and came into effect on April 1, 2009. This standard was drafted by the Henan Building Materials Research and Design Institute, Wengfu (Group) Co., Ltd., and Yuntianhua International Chemical Co., Ltd., and is under the jurisdiction of the National Technical Committee for Standardization of Lightweight and Decorative Building Materials. This standard replaces the GB/T9776-1988 standard for \"Building Gypsum\". Compared with GB/T9776-1988 (hereinafter referred to as the “1988 standard”), the revised GB/T9776-2008 standard (hereinafter referred to as the new standard) has the following main changes: first, the scope of application has been expanded. “The “88 standard” applies only to building gypsum made from natural gypsum ； The new standard applies to building gypsum produced from natural gypsum, flue gas desulfurization gypsum, and phosphogypsum; other industrial by-product building gypsums may also follow this standard. Second, normative reference documents have been added. The new standard adopts the current standards in terms of methods for chemical analysis of gypsum, limits on radioactive nuclides in building materials, as well as testing methods for general properties, mechanical properties, and physical properties of construction gypsum. Third, it adds content on terms, definitions, and classifications. \"Construction gypsum\" is redefined as: a powdered cementing material obtained by dehydrating natural gypsum or gypsum produced as a by-product of industrial processes, with β-hemihydrate calcium sulfate (β-CaSO4·1/2H2O) as its main component, without any pre-added admixtures or additives” ； Definitions have also been established separately for industrial by-product gypsum and industrial by-product building gypsum ； Building gypsum is divided into 3 categories based on the type of raw material, with corresponding codes assigned: “natural building gypsum” is coded as “N”, “desulfurized building gypsum” is coded as “S”, and “phosphorus-based building gypsum” is coded as “P”. Fourth, significant changes have been made to the technical requirements. It is specified that the content (mass fraction) of β-hydrated calcium sulfate (β-CaSO4·1/2H2O) in the composition of building gypsum shall be not less than 60.0% ； The physical and mechanical properties of building gypsum shall meet the requirements specified in the table below ； The limits for radionuclides in building gypsum produced as an industrial by-product shall comply with the requirements of GB6566 ； It is also specified that the levels of the restricted components in industrial by-product building gypsum—potassium oxide (K2O), sodium oxide (Na2O), magnesium oxide (MgO), phosphorus pentoxide (P2O5), and fluorine (F)—shall be determined through agreement between the supply and demand parties. Fifthly, the new standard also introduces significant changes in terms of testing methods, inspection rules, as well as packaging, labeling, and storage. Physical and mechanical properties of building gypsum: Grade, fineness (% residual on a 0.2 mm square pore sieve), setting time/min, strength after 2 hours/Mpa, initial setting time, final setting time, flexural strength, compressive strength – 3.0 ≤10 ≥3 ≤30 ≥3.0 ≥6.0; 2.0 ≥2.0 ≥4.0; 1.6 ≥1.6 ≥3.0. Building gypsum is obtained by calcining phosphogypsum, and using it to produce various gypsum-based construction products represents one effective way of making comprehensive use of this material. The upcoming GB/T 9776-2008** standard for \"Construction Gypsum\" includes phosphorus-containing construction gypsum within its scope of application. Therefore, it is hoped that relevant phosphate fertilizer manufacturers will act swiftly to disseminate this information thoroughly and organize production in accordance with the requirements of these standards, so as to take the resource utilization of phosphogypsum to a new level.