Red Mud as an Additional Source of Titanium Raw Materials

In this study the extraction of titanium from bauxite residue (red mud) with 2 step acid leaching was proposed. In the first step red mud was leached with diluted hydrochloric acid under stirring to remove the soluble Ca, Na, Al, Si and K at 25 0C and pH=3 for 1 hour. The content of iron and titanium in the solid residue increased to 57.7% and 6.4%, respectively. The factors influencing sulfuric acid leaching of the solid residue in the second stage were examined by factorial design. The optimal iron and titanium extraction efficiency was obtained after leaching at 50 oC and L:S ration 20:1 for 90 min when 80 g/L sulfuric acid was used. The titanium oxide content in the concentrate obtained under the optimum conditions amounted to 46.7%. The maximum recovery of titanium in the sulfuric acid solution has not exceeded 6%. Keywords: red mud, acid leaching, TiO2, iron extraction, precipitation, comprehensive utilizatio

Research of Polymetallic Sulfide Industrial Waste Nitric Acid Treatment

Thermodynamic and kinetic features studies of polymetallic sulfide industrial waste nitric acid leaching were carried out. Elemental and phase composition of investigated raw material were studied with X-ray diffraction and electron microscopy methods. Calculations of the Gibbs energy change for the likely reactions of sulfide minerals with nitric acid were performed. In order to determine the most probable conditions of the sulfide industrial waste leaching in nitric acid, as well as the mutual influence of the produced pulp components on the performance of the process, the kinetics evaluation of multicomponent sulfide industrial waste in a nitric medium was studied using mathematical methods. Keywords: nitric acid leaching, polymetallic sulfide industrial waste, Gibbs energy change, kinetic feature

Alkali Fusion-Leaching Method For Comprehensive Processing Of Fly Ash

Fly ash, composed of mullite, hematite, amorphous silica and quartz, is a promising source for the recovery of alumina and silica. Desilication with help of NaOH and alkali fusion-leaching method and utilization of alumina and silica in the fly ash for preparation of sodalite and silica white were explored in this research. The samples were characterized by using wet chemical analysis and X-ray diffraction. The optimal extraction of SiO2 from Reftinskaya power plant fly ash was 46.2% with leaching at 95 oC for 3 h. Sodalite was synthesized at 200 °C for 1 h followed water leaching at 95 °C for 1 h. Silica white with specific surface area 180-220 m2/g was prepared by carbonation of the Na2SiO3 solution at 40 oC for 90-120 min. The as-prepared silica has a purity of 98,8%. The proposed method is suitable for the comprehensive utilization of the fly ash. Keywords: fly ash, alkali fusion, desilication, sodalite, silica white, carbonization, comprehensive utilizatio