Method for efficiently enriching gold and platinum group metals from complex low-grade rhodium iridium residues

Abstract

The invention relates to a method for efficiently enriching gold and platinum group metals from complex low-grade rhodium iridium residues and belongs to the field of wet metallurgy of rare and precious metals. The method comprises the following steps that: primary normal pressure leaching, secondary normal pressure leaching and pressurization leaching are performed by using a low-concentration pure sulfuric acid solution, wherein an oxidizing agent is not introduced or added into the primary normal pressure leaching, air in the secondary normal pressure leaching serves as an oxidizing and leaching agent, industrial oxygen serves as an oxidizing and leaching agent in the pressurization leaching; the high-grade high-quality rhodium iridium concentrate is obtained by employing a three-step impurity removal process. The method is simple in process and environment-friendly, toxic waste gas, waste residues and the like are not generated in the process, a toxic agent is not used, the enrichment ratio and recovery rate of rare and precious metals such as rhodium and iridium are high, the grade of the precious metals in the enriched residue is 15 percent, the recovery rate of the precious metals is over 98 percent, and the method is conveniently linked with rhodium and iridium separating and refining.

Description

technical field [0001] A method for efficiently enriching gold and platinum group metals from complex low-grade rhodium-iridium slag belongs to the field of rare and precious metal hydrometallurgy, that is, it belongs to the resource recycling industry solid waste synthesis in the energy-saving and environmental protection industry of the national strategic emerging industry development plan Utilization of new technology - high-efficiency dressing and smelting of low-grade co-associated mineral resources - key technology development field for separation and extraction of rare and precious metals. Background technique [0002] In the metallurgical process of extracting nickel and cobalt containing rare precious metals, especially copper-nickel sulfide ore, about 20g / t copper-nickel matte containing gold and platinum group metals is processed by crushing, grinding, grading, magnetic separation, flotation and other processes to obtain the particle size Coarse primary alloy with...

AI Technical Summary

Problems solved by technology

[0005] Because rhodium-iridium complex slag has complex mineral composition and many impurity elements, the complex and low-grade rhodium-iridium slag has poor control potential chlorination effect, and the leaching rate of base metals and non-metals is only 80-90%. Precious metals such as palladium and platinum are seriously dispersed and lost, and the concentration of various rare and precious metal elements in the solution reaches 0.2-0.6g / L; the grade of precious metals such as rhodium and iridium in the controlled potential chloride slag is low, while the content of base metals and non-metals is high. The content is as high as 45-75%. After the aqueous solution is chlorinated, a large number of base metals and non-metal elements and rare precious metals such as rhodium and iridium coexist in the chlorination solution, and the concentration ratio of base metals and non-metals to rare and precious metals such as rhodium and iridium reaches 5-10:1 or more, resulting in the above-mentioned separation of rare and precious metals and the separation of rare and precious metals from base metals, the effect is poor, and even the extraction process cannot be carried out normally, such as the third phase often appears, extraction section, washing section, stripping section, Unidentified sediments in the equilibrium section and regeneration section block the pores, and the water phase entrains the organic phase, etc., which seriously affect the extraction process.

In order to obtain qualified rhodium-iridium products, each process has to be carried out repeatedly, resulting in nearly 40 operations of the current rhodium-iridium extraction and separation refining production process, producing a large amount of intermediate products or waste and waste water in these processes, of which Gold and platinum group metals may be expensive to recycle or difficult to effectively recycle, or even permanently lost, resulting in waste and loss of expensive rare and precious metal resources such as rhodium and iridium, and the recovery rate of rare and precious metals such as rhodium and iridium is low

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