Roasting-ammonia leaching processing method for brown iron type laterite nickel ore

Abstract

A roasting-ammonia leaching processing method for brown iron type laterite nickel ore includes the steps that firstly, suspension fluidized roasting is performed on ore powder of the brown iron type laterite nickel ore and reduction gas, nickel oxide and cobalt oxide in the ore powder are fast and dynamically reduced into metal nickel and metal cobalt within 20-120 s, brown iron is reduced into magnetic iron, roasted ore is obtained, and according to the technological condition of roasting, temperature is 600-900 DEG C, and the volume percentage of CO in reducing gas is 2-7%; secondly, magnetic separation is performed on the roasted ore, and magnetite concentrate containing metal nickel and metal cobalt is obtained through separation; and thirdly, ammonia leaching is performed on the magnetite concentrate, and nickel and cobalt leaching agents and magnetic iron leaching slag are obtained. The method achieves the purpose of extracting and purifying nickel and cobalt and comprehensively recovering iron.

Description

technical field [0001] The invention belongs to the field of extracting nickel and cobalt from laterite nickel ore, and in particular relates to a method for extracting nickel and cobalt through roasting-ammonia leaching of limonite-type laterite nickel ore and comprehensively recovering iron. Background technique [0002] Lateritic nickel ore is formed by long-term weathering and metamorphism of ultramafic rocks containing iron-magnesium silicate minerals (such as olivine, pyroxene, and hornblende). During the long-term weathering process, through uplift and erosion, the composition of the regolith changes, forming the following two types: one is the limonite-type laterite-nickel ore, which has high iron, low nickel, low silicon and magnesium, and low cobalt The other is the silicon-magnesium-nickel ore-type lateritic nickel ore, which has higher silicon and magnesium content, lower iron content, and lower cobalt content, but higher nickel content. The total resources of th...

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Problems solved by technology

However, reduction roasting generally uses a rotary kiln or multi-stage furnace for roasting. The reduction time is long, and the surface is prone to "overburning" and the interior is "impermeable". Partially reduced and over-reduced ferrous iron and metal iron are dissolved by the ammonia immersion solution during the ammonia leaching process. After the dissolution, the iron-ammonia complex ions are easily oxidized and hydrolyzed, and precipitate out as gel-state ferric hydroxide to adsorb nickel and cobalt ammonia. Complexes, in which cobalt is more easily adsorbed, which reduces the leaching rate of nickel and cobalt; at the same time, due to the over-reduction or non-reduction of some iron, it is not conducive to magnetic recovery of iron from the leaching residue

Moreover, there is no waste treatment before ammonia leaching in the process route, resulting in a large amount of gangue to be processed in the subsequent leaching process, low equipment output rate, and increased investment; The rate is low, or the recycling of iron is abandoned, resulting in a waste of iron resources; when the raw material ore is powder, it needs to be sintered or made into pellets, which increases the process steps and increases energy consumption.

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