Technology of direct reduction of nickel-iron particles from laterite-nickel ores in rotary kiln

Abstract

The invention discloses a technology of direct reduction of nickel-iron particles from laterite-nickel ores in a rotary kiln, comprising the steps of mixing the laterite-nickel ores, carbon reductant and limestone, then briquetting the mixtures into mixed pellets on a briquetting machine; sintering the mixed pellets through a preheating section and removing crystal water in the rotary kiln, reducing nickel elements at a transition section, and then entering into a sintering section to reduce iron elements and the nickel elements and metal particles grow up. Wherein, the temperature of the sintering section near the transition section is controlled within such scope that the materials are kept in solid state, and the kiln ringing can be prevented while keeping the metal reduction temperature; the temperature of the sintering section located at a kilneye is controlled within such scope that the materials are kept in half-molten state. Since the kilneye of the rotary kiln is in a throat structure, heat is uneasy to dissipate, in favor of reduction and enrichment of metal; even sometimes minor ringing occurs, the previous ringing can also be easily removed under the rolling effect of subsequent materials, so that the technology disclosed by the invention plays a foundation for continuous production of direct reduction, and the reduction efficiency of the rotary kiln is improved.

Description

technical field [0001] The invention relates to the technical field of metallurgical technology, in particular to a technology for directly reducing nickel-iron particles of laterite nickel ore in a rotary kiln. Background technique [0002] As a strategic element, nickel plays an extremely important role in the development of the national economy. About 2 / 3 of the world's nickel is used to produce stainless steel, and the cost of nickel raw materials accounts for about 70% of the production cost of austenitic stainless steel. In recent years, in order to reduce the production cost of stainless steel, stainless steel enterprises have begun to use a large amount of nickel-containing pig iron. [0003] At present, nickel-containing pig iron is smelted with laterite nickel ore containing 0.8-2.0% nickel as raw material. The smelting process of laterite nickel ore includes blast furnace, RKEF process, and rotary kiln direct reduction method. Among them, the rotary kiln direct ...

AI Technical Summary

Problems solved by technology

However, high temperature conditions have high requirements on the refractory materials of the rotary kiln, which shortens the life of the refractory kiln lining, and the temperature in the kiln is not easy to control, and the operability in production is poor. The caliber is large, and the molten iron solidifies under the rapid cooling of the cold air at the kiln mouth. As time goes by, the molten iron solidifies thicker and thicker, forming rings at the kiln mouth, making the material unable to be transported normally, and eventually causing the kiln to stop

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