Syberian Institute “State Academy of Occupational Retraining and Training of High-level Personnel and Specialists of Investment Sphere” (GASIS)

N. V. Golovnykh, Assistant Professor of a Chair of regional economics and ecological safety, e-mail: golovnykh@igc.irk.ru

“Ecological Engineering Centre” LLC

I. I. Shepelev, Chief Executive Officer

“RUSAL-Achinsk” OJSC

A. G. Pihtovnikov, Chief Management Officer

“RUSAL-Engineering and Technical Center” LLC

S. N. Gorbachev, Head of Department of Aluminous Production Engineering

To minimize the consumption and continue processing of nepheline ores from Kiya-Shaltyrskiy mine at the Achinsk Alumina Plant (AGK-plant) within more long time, it was proposed to use the man-made wastes together with natural raw, which provide measures on the reduction of tailing, and solution of environmental problems. Waste of fireclay refractory bricks. According to the analysis of the major phases, which present in the refractories are mullite — 3Al₂O3·2SiO₂, silica — SiO₂ (tridymite, α-quartz). At the stage of technological research components of the alumina charge was ground to a particle size of 0.08 mm. The prepared charge was sintered at 1250–1270°C. Leaching cakes served by the method of standard leaching, calculation of alumina and alkali extraction was performed on the chemical composition of sintered products and sludge. In the course of industrial tests of fireclay brick, end of life, delivered at the reception site and download the material, then through the nutrient tank was fed to the joint crushing with ore. Dosage refractory waste was carried out in an amount up to 15% by weight of nepheline ore. The results of research and testing has shown that during the sintering of the charge with the addition of alumina refractory brick removal is at the same level as that without additives — 91.0–91.5%. The fireclay additives introduced in alumina charge reduce from 3.6 to 2.8 tons of the specific consumption of nepheline ore per ton of alumina, as well as reduce the amount of waste in the 0.5–0.6 ton/ton Al₂O₃. The cost of production of alumina can be reduced by 2%. Increasing addition of fireclay brick wastes more than 11% by weight of the ore leads to an increase in silica content and lower content of alkalis, which requires a greater consumption of limestone for the binding of silicon oxide, and to compensate for the lack of alkali, additional soda solution is introduced. By increasing the melting temperature of the charge, respectively, increases fuel consumption. Slag of ferrous-titanium production. For chemicalmineralogical structure of the slag is a complex spinel — [CaFeTiAl]AlO₇. In the course of industrial tests that were conducted on the AGK-plant, it was selected period without (period number 1) and with the introduction of slag (the period number 2) in charge of alumina production. The slag, unloaded from the cars, with the help of the slag conveyors transported to the department of crushing the ore, where it was carried out the grounding of slag in cone crushers. Crushed slag is fed into the mill, which was carried out jointly with the grinding of nepheline ore on the revolving soda solution. Crushed slag-nepheline slurry delivered to the mixer, and then sent for processing to the redistribution of sintering. In the course of industrial tests it is established that the introduction of the slag in an amount of 2.1 wt% in the dry ore mixture increases the amount of Al₂O₃ in the sintering material of 0.4 wt%. Negative impact on the quality of the sintering product was not observed. In the period number 2, degree of the standard extraction Al₂O₃ from sintering product has not changed and remained at the same level as that at higher content of slag in the raw mix, as compared with the number 1, provides an additional output of alumina. This is confirmed by an increase in alumina production during the test at 2.6%. During this period, it was noted the presence in solutions of alumina and soda production of chromium and titanium ions. During industrial tests decline in the quality of products does not occur, however, at higher dosages of slag in the charge, pollution of products and wastes of these impurities may increase, and therefore, it is necessary to provide measures for their removal from process solutions. Thus, technological studies have shown the possibility of using slag of ferrous-titanium production and waste of fireclay lining upon receipt of alumina. The highest degree of extraction of aluminum oxide is achieved with a dosage of these wastes in a nepheline-limestone charge up to 10% by weight (~15–20% by weight of nepheline ore). The introduction of these quantities of fireclay waste in charge can be reduced ore by 0.75–0.85 ton/ton Al₂O₃ specific consumption of nepheline ore. When using the slag alumina output increased by 2.6%. Due to the involvement in the production of waste the tail maps are reduced, also decreases the harmful effects on the environment.

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