SGT method α high-strength gypsum
The "SGT method" for the growth and crystallization of α - gypsum crystals involves dehydrating dihydrate gypsum in a closed container through the action of steam pressure and a crystallization agent to form α - hemihydrate gypsum.
The SGT method is jointly developed by Hubei Zhengxianda Environmental Protection Technology Co., Ltd. and Hubei ZhiMeiTang Gypsum New Technology Co., Ltd. Zhengxianda is responsible for process technology design, equipment development and manufacturing, and quality control, while ZhiMeiTang is responsible for process, testing, and application technology.
The SGT method results in coarse α - hemihydrate gypsum crystals with clear short columnar contours (see left figure). Its gel hardening body has high strength, with a 2-hour flexural and drying compressive strength that meets the strength grade of α 40 to α 50 in the building materials industry standard JC/T 2038-2010 (technical parameters are shown in Table 1 below).
Testing Items | Standard Requirements | Detection Result | |
Powder state | Uniform and without lumps | Light yellow, uniform, without lumps | |
whiteness | Actual measurement value | 46.6 | |
fineness | 0.3mm sieve residue<1.0% | 0.1% | |
0.15mm sieve residue<10% | 0.2% | ||
Odor (wet basis) | no smell | not have | |
pH | ≥5 | 6 | |
requirement of normal consistency | <65% | 35%(180mm) | |
setting time | Initial setting | ≥3min | 11min |
Final set | ≤30min | 15min | |
2-hour intensity | flexural | ≥3.5MPa | 5.6MPa |
Compression resistance | 20.9MPa | ||
Absolute dry strength | flexural | 12.0MPa | |
Compression resistance | ≥25MPa | 49.6MPa | |
expansivity | 0.367% |