Titanium Hydroxide as a Precursor for Production of Functional Materials

摘要

It in has been found in the course of studying the phase transformations of X-ray amorphous titaniumhydroxide during its mechanical activation in the presence of additives in the form of zinc compoundsthat finely ground powders can polymorphically transform into other nonequilibrium crystalline phases.Judging by the increase in the intensity of the peaks in the diffraction patterns, one can state that the amorphousphase crystallizes in the form of anatase and brookite as a result of high-energy exposure. It is shownthat the lower the degree of hydration of titanium hydroxide, the higher the efficiency of the mechanical effectof the additive on the phase transformations. The following trend in the effect of the introduced modifier isobserved: ZnSO_4?7H_2O > Zn(NO_3)_2?6H_2O > ZnO. This dependence is determined by the combination of physicaland chemical transformations of the material located in the field of intense mechanical influence, confirmedby the calculated data on the crystallite size and microstrains. The conversion of excess mechanical energy intothermal energy initiates chemical processes resulting in the formation of solid titanium-zinc solutions that acceleratethe restructuring of the crystal structure upon calcination of the modified titanium hydroxide according to thescheme anatase–brookite–rutile. The obtained results can find practical applications in the production of the socalled“rutile” nuclei used in the industrial production of multipurpose titanium dioxide.