China Nonferrous Metallurgy

In order to improve the traditional carbothermal reduction preparation of boron carbide for direct high temperature (1800~2000℃), severe dehydration cause boric acid raw material volatilized and low product purity and poor crystal defects. In this paper, with boric acid and petroleum coke as raw materials, the raw material forms (pellets and powder), dehydration temperature, heating time and heating rate on the slow-release effects of dehydration process were studied, the optimum parameters of slow release dehydration were determined and the kinetics of slow-release dehydration was studied. The results showed that the optimal slow release dehydration parameters were as follows: pressing into pellets of raw material, dehydration temperature of 300℃, dehydration time of 40min, and heating rate of 5℃/min.In addition, XRD and chemical composition analysis showed that the purity of B4C was increased by 9.01% and the free carbon content was reduced by 7.95% after slow release dehydration.It can be concluded that the slow release dehydration of raw materials is conducive to maintaining the balance of raw material proportion, so as to improve the reaction degree of carbothermal reduction.