Improvement of a Preparation Process of Chromite Raw Material Used for Ferroalloys and Pigments Manufacture

K.T Zhantasov,E.N Kocherov,D.M Zhantasova,Zh.U Myrhalykov,B.B Turakulov,M.K Zhantasov

doi:10.18321/ectj251

Abstract

The given article contains the research results of carbon-containing chromite pellets’ production from off-grade raw material with application of internal coal-mining overburden rocks as flux. Besides, for the purpose of improvement of ecological situation in industrial regions and expansion of a raw-material base for ferrochrome and pigments manufacture we suppose to use in a charge composition the dust of aspiration units and electrostatic precipitators, which is formed at the preparation of raw materials and production of chromite pellets. The production technology of chromite pellets with use of a slime formed at the concentration of chrome ores as a binding substance was developed. Testing the suggested technology has been carried out in laboratory and trial conditions. The data of a chemical composition of initial components of a charge and calcined carbon-containing chromite pellets have shown economic and ecological efficiency of the developed technological process. Research results lead to the conclusion that the proposed granulation feedstock mixture pellets with a moisture content of 11–12% are obtained crude granules have a compressive strength of 2.3–3.2 kg/splashed. Increasing the content of Cr2O3 in the pellets to 7.6% occurs due to the increase in the extraction of chromium oxide and due to the charge of chromium oxides contained in the sludge, as well as removal of the batch formulation was heat treated carbonates, and volatile organic substances. It was established that during this mode, the temperature in the lower layers is about 1200 °C, and a reduction in natural gas consumption achieves 50% and the residual carbon content in the pellets is about 1.5%, which leads to improvement of technical and economic indices of production chromite pellets and ferrochrome.

Highlights

Environment protection, complex processing mineral raw materials and technogenic wastes, improvement of well-being of the humanity, flora and fauna – are actual problems of the modern Kazakhstan.Complex processing poor and off-grade chrome ores and concentration tails promotes ecological advancement and ipso facto raises significance of use of nonconventional raw materials at manufacture of chrome-containing products and pigments
According to the suggested technology of carbon-containing chromite pellets production we offer to use a bowl granulator instead of a drum pelletizer because a granulation process in it occurs more effectively
– at the granulation to use 2–2.5% of coke fines and up to 10% of internal coal-mining overburden rocks in a mixture with a chrome-containing material consisting from an off-grade chromite ore, concentration tails formed after water classification of slimes and aspiration dust;

Summary

Introduction

Environment protection, complex processing mineral raw materials and technogenic wastes, improvement of well-being of the humanity, flora and fauna – are actual problems of the modern Kazakhstan. In accordance with the developed technology the charge, mixed in the mixer, is fed in a bowl granulator by means of a conveyor, where there is a formation of crude pellets in diameter not less than 13 mm; a slime formed at the classification of chromite concentrates is used as a binding agent. – at the granulation to use 2–2.5% of coke fines and up to 10% of internal coal-mining overburden rocks in a mixture with a chrome-containing material consisting from an off-grade chromite ore, concentration tails formed after water classification of slimes and aspiration dust;. It is necessary to notice, that the process of carbon-containing roasted chromite pellets’ manufacture is a thermal process based on melting surfaces of the granules It consists of the following stages: batching and hashing of components of a charge, joint crushing, pelletizing, drying and high-temperature calcination, cooling and sorting of an end-product. For solving the above-stated actual problems connected with production of carbon-containing chromite pellets the experimental researches and trial tests have been carried out [26]

Technique of carrying out the research

Results and Discussion

Conclusions