Utilization of slaughter plant waste proteins in gypsum retarder: A case study

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.