Composite additive for strengthening middle-high magnesium-type laterite-nickel ore direct reduction and application of composite additive

Abstract

The invention provides a composite additive for strengthening high magnesium-type laterite-nickel ore direct reduction and an application of the composite additive. The composite additive comprises, by weight, 25-35% of desulphurization gypsum, 20-30% of sodium carbonate, 10-15% of sodium humate, 10-15% of polyacrylamide, 5-10% of coal powder, 5-10% of calcium oxide and 1-5% of iron powder. According to the composite additive for strengthening high magnesium-type laterite-nickel ore direct reduction, high-nickel concentrate can be prepared from high magnesium-type middle-low grade laterite-nickel ore and can be applied to direct reduction of high magnesium-type laterite-nickel ore. The application method of the composite additive comprises the steps that laterite-nickel ore and the composite additive are mixed, and a fresh pellet is obtained through pelletizing; the fresh pellet is dried, so that the fresh pellet is solidified to be a dried pellet, wherein the strength of the dried pellet exceeds 300 N; the dried pellet is placed into a rotary kiln, reduction coal is added into the rotary kiln to conduct segmented reduction, and a reduced product is obtained; and after water quenching and splat cooling are conducted on the reduced product, crushing ball-milling and wet magnetic separation are conducted, and high nickel iron ore concentrate is obtained.

Description

technical field [0001] The invention relates to the field of metallurgy and material science and technology, in particular to a composite additive for strengthening the direct reduction of high-magnesium type medium and low-grade laterite nickel ore and its application. Background technique [0002] The increasing consumption of stainless steel in the world makes people's demand for nickel deepen year by year. As the available resources of nickel sulfide ore are gradually exhausted, the effective utilization of laterite nickel ore, which accounts for about 72% of the world's total nickel resources, has become an urgent problem to be solved. Based on the existing theoretical research, lateritic nickel ore is mainly divided into two types of treatment processes according to the characteristics of raw materials. Because in low-grade limonite-type lateritic nickel ore (high iron, low magnesium, low nickel), nickel is mainly rich in goethite and has more crystal water, from the ...

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Problems solved by technology

However, with the deepening of the mining of laterite nickel resources, there are more and more low-grade laterite nickel ores with low iron, low nickel, and high magnesium. , fine embedded particle size, sparse and uneven distribution of ferronickel, etc., in the process of direct reduction-magnetic separation process of rotary kiln to treat this kind of laterite nickel ore, the reduction temperature is too high, the pellet pulverization rate is high, and the ring formation is serious , poor selective reduction effect, insufficient growth of ferronickel crystal grains leading to difficult magnetic separation and other problems need to be solved urgently, and the existing patented technology of compound additives is not enough to solve the above problems when dealing with high-magnesium type medium and low-grade laterite nickel ore , which also shows that additives still have selectivity to different types of laterite nickel ore raw materials in the process of strengthening the direct reduction process of laterite nickel ore

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