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Slaughter plant waste proteins contain animal hair, bones, nails etc. Improper treatment will pollute the environment and result in waste of resources. A process is proposed to prepare gypsum retarder from such waste, firstly through hydrolysis at acidic condition, and then neutralized with alkalis. The optimal conditions for acid hydrolysis are obtained: concentration of HCL 4.8 mol/L, reaction temperature 98 °C, reaction time 7 h. After neutralization (to pH=7), the product can be used as gypsum retarder (retarder A). Compared with commonly used retarder, citric acid, the mechanical strength loss of gypsum paste containing retarder A is much lower. It is a cost-effective approach for safe utilization of slaughter plant waste proteins.

Gypsum block possesses good performances such as volume stability, lightweight and thermal insulation, is recognized as typical eco-friendly building material. However, its poor water resistance characteristics restrict the application. The semi-hydrated desulphurization gypsum is modified with steel slag, granulated blast-furnace and carbide slag (SGC) composite powder as well as waste glass-reinforced plastic (GFRP) fiber, aiming at producing water-resistant gypsum block. The proper mass proportioning of the modified gypsum block is obtained: semi-hydrated desulphurization gypsum 75%, SGC 25% and waste GFRP fiber 1.0%. The product is of softening coefficient of 0.84 and thermal flexural strength of 8.6 MPa. Phase change energy storage material (PCM) is used to increase the energy saving characteristics of the block. Compared with ordinary gypsum walls, the modified gypsum block with CA-SA exhibits good energy storage property.