Method for recovering nickel, cobalt and iron from laterite-nickel ore

Abstract

The invention relates to the technical field of wet metallurgy of laterite-nickel ore, and concretely relates to a method for recovering nickel, cobalt and iron from laterite-nickel ore. The method comprises the following steps: adding enough concentrated sulfuric acid into a saprolite ore slurry, and reacting at a high temperature of 95-120DEG C to dissolve most soluble non-ferrous metals and soluble iron; carrying out solid-liquid separation to obtain normal pressure leached slag and normal pressure leachate; adding the normal pressure leachate and a limonite ore slurry into a pressure reactor in proportion, and carrying out pressure leaching at 195-240DEG C; carrying out solid-liquid separation to obtain pressure leached slag and pressure leachate; purifying the pressure leachate to recover nickel and cobalt; washing the pressure leached slag, and drying to obtain a fine iron powder product; and processing the normal pressure leached slag to obtain a high grade silica product and building sand. The method has the advantages of simultaneous treatment of saprolite and limonite, high nickel and cobalt recovery rate, realization of small size, short time and high efficiency of a normal pressure leaching device, and realization of small amount and effective utilization of waste slag.

Description

technical field [0001] The present invention relates to the hydrometallurgical process of lateritic nickel ore, in particular, it relates to carrying out sulfuric acid atmospheric pressure leaching of saprolite components of this ore and pressure leaching of limonite components with normal pressure leachate in the same process, While recovering nickel and cobalt, economically and effectively recover the main components of iron and part of the ore. Background technique [0002] Laterite ore is a nickel oxide ore formed by nickel-bearing peridotite after large-scale long-term weathering and leaching metamorphism in tropical or subtropical regions. Due to differences in geographical location, climatic conditions and weathering degrees, the types of laterite ore around the world are not completely the same People subjectively divide the laterite deposit into three layers from top to bottom, namely limonite layer, transitional layer and saprolite layer, in which limonite has fine...

AI Technical Summary

Problems solved by technology

But this method has the following disadvantages and deficiencies: First, the time for leaching limonite under normal pressure is longer, usually more than 4 hours, so the required normal pressure leaching equipment is huge; the second is that the acid consumption is higher, and the total acid / ore=0.6 / 1. Although this acid consumption index is far lower than atmospheric acid leaching, it is much higher than high-pressure acid leaching; third, the amount of saprolite ore used is twice that of limonite, which also contradicts the ore belt composition of laterite ore , it is well known that in lateritic nickel deposits, the amount of limonite: the amount of saprolite ≥ 2:1

[0019] In short, in the above-mentioned invention patents of lateritic nickel ore wet smelting, the disadvantages of the high-pressure acid leaching (HPAL) process and the improved high-pressure acid leaching process are: complex high-temperature, high-pressure autoclaves and related equipment are required, and their installation and Both are expensive to maintain; the HPAL process consumes more sulfuric acid than is required to stoichiometrically dissolve the non-ferrous components of the ore; the HPAL process is limited to processing mainly limonite-type feedstock; the HPAL process operates at high pressure The kettle is prone to fouling, and needs to be shut down regularly for cleaning, and the operating rate is low

The disadvantages of the atmospheric pressure acid leaching process and the improved atmospheric pressure acid leaching process are: high sulfuric acid consumption; low nickel and cobalt leaching rates; long reaction time and huge equipment required

The common disadvantage of high-pressure acid leaching including improved high-pressure acid leaching process and atmospheric pressure acid leaching process including improved atmospheric pressure acid leaching process is that the amount of leaching slag is large, and it is a mixed slag of silicon and iron, so that the main component of laterite ore, iron, cannot Economical and effective development and utilization

Although the invention patent of CN102206749A mentions the recycling of leaching slag, since the silicon dioxide, iron oxide, goethite, etc. Simple magnetic separation and other methods separate them, so the economic benefits of the development and utilization of the above-mentioned leaching slag are very poor, and they can only be treated as waste solids, and even the leaching slag with a low nickel leaching rate must be treated as hazardous waste.

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