D. V. Maiorov

Causes of insufficient recovery of zirconium during acidic processing of lovozero eudialyte concentrate

The chemical and mineralogical compositions of insoluble residues of the acid decomposition of the eudialyte concentrate are investigated. It is established that one of the causes of insufficient recovery of zirconium is the presence of acid-resistant zirconium minerals (vadeite and altered eudialyte) in the residue. It seems likely that these minerals are the products of natural hydrothermal alteration of usual eudialyte. Another cause may be the fact that coarse eudialyte grains are covered with a layer of silica precipitate preventing acid diffusion.

Joint effect of parameters of hydrochemical nepheline processing on alumina

A scheme of nepheline processing by a hydrochemical method was technically justified. In this process, silica is transformed into calcium hydrosilicate under autoclave conditions at a low concentration of caustic alkali. This allows the process at high heat regeneration and low steam flow for evaporation of a solution. A joint effect of temperature, leaching time, and concentration of caustic alkali solution was examined on an alumina recovery. Experiments were designed using a combined rotatable design of a second order.

Effect of the sodium hydrocarboaluminate preparation method on the properties of the products of its hydrolysis

Sodium hydrocarboaluminate samples are prepared using various methods. The temperature conditions of synthesis have a significant effect on the susceptibility of sodium hydrocarboaluminate to hydrolysis and the phase composition of hydrolysis products. The chemical reactivity of the hydrolysis products depends on the redox properties of their surface.

Study of physicochemical properties of aluminum hydroxides produced by solid-phase hydrolysis of its salts

Results obtained in a study of the physicochemical properties (porosity and acid-base properties of the surface) of aluminum hydroxides produced by solid-phase hydrolysis of aluminum salts are presented. A conclusion is made on the basis of the data obtained that these hydroxides have a higher adsorption capacity and reactivity as compared with the industrially manufactured aluminum hydroxide, which predetermines the promise of using these products in manufacture of catalysts, sorbents, ceramics, binders, and other materials.

Investigation of an effect exerted by methods of production of chromium(III) oxides-hydroxides on their physicochemical properties

Results of a research of physical and chemical properties of chromium(III) oxides-hydroxides are reported produced from chromo-potassium alum by solid-phase hydrolysis and sol-gel method. Comparative assessment of structural properties of chromium oxides-hydroxides obtained by various techniques was suggested and the morphology was studied.

Preparation and application of silica sol-gels based on nepheline

This paper reports on the results of investigations into the development of the methods employed for acid treatment of nepheline and the search for new directions in the use of products obtained in the nepheline processing, which have made it possible to design and implement technologies for producing the aluminum-silicon coagulant/flocculant for water purification, as well as technologies for fabrication and application of nepheline-based silicon-containing thickening agents intended for the simplest water-containing explosives of the “Akvatol” type and others.

Improvement of the technology for the synthesis of an alumosilicate coagulant-flocculant based on nepheline

The state of silicic acid in solutions obtained from the decomposition of nepheline by sulfuric acid of different concentrations has been studied. It has been established that the polymerized β- and γ-forms of silicic acid have the best flocculating properties. An improved technology, which allows a desired degree of polymerization of silicic acid to be attained directly in the process of decomposition, has been proposed for the synthesis of an aluminosilicate coagulant-flocculant based on nepheline.

Research of some physicochemical properties of basic aluminum sulfates

Properties of hydroxoaluminum sulfates produced by autoclave hydrolysis of aluminum containing sulfuric acid solutions in the absence and presence of ammonium sulfates.