Study On Analysis Of Impurities In Titanium Gypsum And Titanium Gypsum As Building Material

Titanium gypsum is a solid waste generated in the manufacture of white titanic powder by adding lime or calcium carbide into acidic wastewater. Its basis is CaSO4·2H2O. About 20 tons of titanium gypsum is produced every day in Chongqing yutaibai company, and about 16～24 million tons of titanium gypsum is produced every year in China. Hardly any is used. Accumulation of titanium gypsum occupies land and pollutes the environment, which cause the manufacturer a great burden. Normally titanium gypsum contains about 60% CaSO4·2H2O which is a mat-erial for building industry. At present, nobody have studied titanium gypsum about the impurities, it is important to identify the characteristics and to study the effect on various properties of the material.By a combination of techniques of X-ray diffraction spectra (XRD), sca-nning electron microscope and physicochemical tests, the chemical composit-ion and form of impurities are studied systematically. Results show: the main-ly impurities of titanium gypsum contain Fe(OH)3,FeSO4 and Al(OH)3.Hydrate titanium gypsum is used to produce different types of building materials, the relevant factors are also studied systematically including preparation progress, the material properties, the mixing proportions, curing conditions and the hydration mechanism of different system.The effects of impurities were introduced when titanium gypsum was used as a set retarder of different kinds of cement. Experimental results show: the impurities may do little effect to cement. Compared cement used of natural gypsum with titani- um gypsum, the properties may be similar. Calcined gypsum produced by titanium gypsum is studied preparatorily. The transformation and the effect to building material of impurities is studied after titanium gypsum is heated. Results show: titanium building gypsum can't be used as building material without pretreatment.