On alkaline opening of columbite and tantalite

Sintering of columbite and tantalite with K₂CO₃·1.5H₂O with subsequent leaching of the sinters with water was studied. The possibility of selective extraction of Nb(V) and Ta(V) into liquid phase was demonstrated.     

Preparation of alkaline solutions of niobium(V)

Alkaline niobium(V) solutions containing up to 190 g l⁻¹ of niobium oxide were prepared by sintering niobium(V) oxide with potassium carbonate and following leaching of the sinters with water.     

Extraction of Tantalum(V) Impurities from Niobium(V) Fluoride Solutions with Octanol

Fine purification of niobium(V) to remove tantalum(V) by extraction was studied at various compositions of solutions and ratios of phase volumes. Washing of tantalum(V) and niobium(V) extracts with aqueous solutions of their fluorides was considered.     

Study of conditions of vanadium(IV, V) leaching from ash

Leaching of vanadium(IV, V) with water and a NaOH solution from ash produced in black oil combustion was studied.     

Influence of fluoroelement acids on extraction of Group IV–VI element fluorides

Effect of titanium(IV) and silicon(IV) on extraction of Ti(IV), Nb(IV), Ta(V), and W(VI) with octanol and tributyl phosphate from fluoride solutions was studied.     

Processing of Precipitates of Hydrated Tantalum(V), Niobium(V), and Titanium(IV) Oxides in Loparite Technology

Conditions were studied for the dissolution in HF of hydrated tantalum(V), niobium(V), and titanium(IV) oxides, which are formed by acid decomposition of loparite, and also for the selective extraction of Ta(V) with octanol from the resulting fluotitanic solutions.     

Preparation of alkaline Nb(V) solutions using K(I) compounds

Leaching with water of products obtained by sintering of Nb₂O₅ with K₂CO₃·1.5H₂O, KHCO₃, and KOH was studied. Solutions containing up to 500 g l^?1Nb₂O₅ were obtained. These solutions can be recommended for use in production of welding and other functional materials.     

Ring expansion of 1-(chloromethyl)silatrane

Conclusions Reaction of alkali metal sucrates and alkoxides with 1-(chloromethyl)silatrane results in expansion of one of the atrane rings to give 2-carba-3-oxahomosilatranes.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1404–1408, June, 1986.     

Extraction Recovery of Tantalum(V) and Niobium(V) from Hydrofluoric and Hydrofluoric-Sulfuric Acid Aqueous Solutions with Octanol

Comparative study of extraction of tantalum(V) and niobium(V) with octanol and tributyl phosphate was made. The data on distribution of tantalum(V) and niobium(V) between octanol and hydrofluoric and hydrofluoric-sulfuric acid aqueous solutions were obtained. The flowsheet for preparation of pure tantalum and niobium oxides was developed.     

Extraction of phosphorus(V), molybdenum(VI), and tungsten(VI) from fluoride solutions

The influence of titanim(IV) and silicon(IV) on the extraction of phosphorus(V), molybdenum (VI), and tungsten(VI) fluoride complexes by tributyl phosphate was studied.