Normal-pressure leaching method for simultaneously processing laterites with high iron content and high magnesium content

Abstract

The invention discloses a normal-pressure leaching method simultaneously processing laterites with high iron content and high magnesium content, comprising the following steps of: screening the laterites with high iron content and high magnesium content; adding sulfuric acid to the laterite with high iron content for leaching so as to obtain leaching residue A and a leaching solution B; adding the laterite with high magnesium content to the leaching solution B, leaching to obtain leaching residue C and a leaching solution D; carrying out magnetic separation on the leaching residue C, wherein a magnetic part E is recovered as an iron product, and a non-magnetic part F and the leaching residue A are mixed to be used for recovering silicon products; delivering a part of the leaching solutionD into a purifying and recovering process, and returning the other part of the leaching solution D into the leaching process of the laterite with high iron content, and carrying out a next leaching period; repeating the leaching period for 4-5 times, and completely delivering a leaching solution I obtained from a last leaching period into the recovering processes of nickel, cobalt, aluminum and magnesium. The normal-pressure leaching method has the advantages of low cost and acid consumption and high leaching efficiency of the nickel and the cobalt and realizes the efficient separation and the recycling of iron, silicon, the nickel and the cobalt and the discharge without acid liquor.

Description

technical field [0001] The invention relates to a nickel ore smelting method, in particular to an atmospheric pressure leaching method for simultaneously processing high-iron and high-magnesium content laterite 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 . Limonite-based laterite ores usually have higher iron content and lower magnesium content, and laterite ores mainly composed of silicate minerals have higher magnesium content and lower iron content. Laterite ore mainly composed of silicate minerals should be treated by pyrometallurgy, limonite-type ore deposits should be treated by hydrometallurgy, and intermediate transitional ores can be treated by pyr...

AI Technical Summary

Problems solved by technology

Heap leaching technology has a low leaching rate and is only suitable for processing laterite ores with high magnesium content; reduction roasting-ammonia leaching technology is rarely used due to high energy consumption and long process flow; pyrometallurgical technology can only produce ferronickel, Cobalt cannot be recovered and its application is limited

High-pressure acid leaching technology can effectively separate nickel, cobalt and iron, and is especially suitable for the treatment of high-iron and low-magnesium minerals. However, during the leaching process, silicon, aluminum and some iron will be deposited on the wall of the kettle to form scaling, resulting in a decrease in the processing capacity of the autoclave. Scaling must be cleaned regularly during the production process

Atmospheric pressure acid leaching technology is simple to operate and does not require the use of expensive autoclaves. However, it requires a large amount of acid to completely dissolve the minerals, and the leachate contains various metal ions, which complicates the subsequent leaching and separation process.

[0003] In order to develop laterite resources with high iron and high magnesium content at the same time, and to avoid the use of expensive autoclaves, some improved atmospheric pressure acid leaching techniques have been proposed, such as the invention patent with the publication number CN101273146A, which proposes the simultaneous extraction of limonite and saprolite or a two-step normal-pressure leaching method for leaching saprolite or first limonite and then leaching saprolite. This method has the advantage of not using an autoclave, but it is proposed in the flow process described in this application that the leaching solution is carried out When treating to remove Fe and / or Al, it is necessary to add a neutralizer to neutralize the residual acid in the leaching solution, so that most of the iron is deposited in the form of ferric hydroxide, which will cause the loss of valuable elements such as nickel and cobalt and slurry filtration difficulty

Another example is that the Chinese patent application whose publication number is CN101541985A proposes a method for leaching a mixture of limonite and saprolite at normal pressure, but its iron precipitation product is jarosite, which contains sulfate radicals, Therefore can increase the acid consumption of leaching process; And jarosite is a kind of thermodynamically unstable compound, can release sulfuric acid when stacking and depositing, thereby causes environmental pollution, in addition, jarosite is also difficult to recycle

Another example is the Chinese patent application whose publication number is CN101006190A, which proposes a method for treating the mixture of limonite and saprolite ore with concentrated acid and then leaching nickel and cobalt with water. The iron deposit produced by this method is other than jarosite Ferric oxide or hydroxide, but the leaching time of this application needs 12-48h, and the leaching time is longer, resulting in longer process cycle and higher production cost

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