Chemical treatment of simulated solution of evaporator concentrate for immobilization in bitumen

Studies on the preparation of leach-resistant insoluble boron compound from simulated solution of evaporator concentrate are reported in this work. The insoluble compound CaB6O10•4H2O has been prepared from simulated solution of evaporator concentrate by chemical treatment with calcium chloride solution. Other insoluble compounds CaB2O4•6H2O/Ca3B4O9•9H2O/Ca[B(OH)4]2•2H2O and NaCaB5O6•8H2O/NaCaB5O6•(OH)6•5H2O/Ca2B6O11•13H2O have been prepared from simulated solution of evaporator concentrate with calcium hydroxide under controlled conditions of temperature and time. Identification and characterization of these compounds have been done by X-ray diffraction, optical microscopy and differential thermal and thermogravimetric analysis. For low-level radioactive waste treatment, immobilization of insoluble borate compounds in bitumen will produce leach-resistant suitable waste product for safe disposal.