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CN-122012838-A - Process method for recovering iron from hydrogen reduction copper slag and application thereof

CN122012838ACN 122012838 ACN122012838 ACN 122012838ACN-122012838-A

Abstract

The invention belongs to the technical field of copper slag treatment, and discloses a process method for recovering iron from copper slag by hydrogen reduction and application thereof. The invention discloses a process for recovering iron from copper slag by hydrogen reduction, which comprises the steps of adding calcium oxide into copper slag, utilizing hydrogen to realize efficient reduction and directional polymerization of iron element, adopting hydrogen as a clean reducing agent, enabling reaction byproducts to be water vapor only, fundamentally avoiding carbon emission problems of a carbon-based reduction process, further carrying out primary pre-reduction through a gradient dissociation process of pre-reduction, grinding and secondary reduction, namely, carrying out primary polymerization on the iron element, then crushing and breaking the symbiotic structure of iron phases and gangue minerals through grinding a pre-reduction product, enabling the iron phases to be separated from other phases effectively, and finally carrying out secondary reduction, enabling the iron phases to be further aggregated and grown to form high-purity metal iron particles in a monomer form, thereby effectively solving the problem of insufficient iron phase dissociation in the traditional method.

Inventors

  • ZHANG XINGMING
  • LIANG SHANSHAN
  • WANG YONGJIAN
  • Yue Weihe
  • Cui Bang
  • LI ZHIRUI
  • DU JIANGUO
  • CHENG YIBING

Assignees

  • 白银华鑫九和再生资源有限公司
  • 佛山仙湖实验室

Dates

Publication Date
20260512
Application Date
20260120

Claims (10)

  1. 1. The process method for recovering iron by hydrogen reduction of copper slag is characterized by comprising the following steps of: S1, mixing copper slag and calcium oxide to obtain a mixture; s2, under the protection of nitrogen and/or inert gas, heating the mixture to a buffer temperature, and preserving heat, wherein the buffer temperature is 400-500 ℃; S3, after the heat preservation is completed, continuously heating to a reduction temperature, and replacing the nitrogen and/or inert gas with reducing gas to perform a reduction reaction, wherein the reduction temperature is 1000-1150 ℃; s4, after the step S3 is completed, replacing the reducing gas with nitrogen and/or inert gas, and cooling to obtain a pre-reduction product; S5, grinding the reduction product, and carrying out magnetic separation to obtain the metal iron.
  2. 2. The process according to claim 1, characterized in that it further comprises, before said step S3 is carried out, the steps of: a) Heating the mixture subjected to heat preservation in the step S2 to a pre-reduction temperature, and replacing the nitrogen and/or inert gas with reducing gas to perform a pre-reduction reaction, wherein the pre-reduction temperature is 900-1000 ℃; b) After the pre-reduction reaction of the step a) is completed, replacing the reducing gas with nitrogen and/or inert gas, and cooling to obtain a pre-reduction product; c) And grinding the pre-reduction product, heating to the buffer temperature under the protection of nitrogen and/or inert gas, and preserving heat.
  3. 3. The process according to claim 1, wherein the calcium oxide is present in an amount of 10-20% by mass of the mixture.
  4. 4. The process of claim 1, wherein the rate of temperature increase is from 5 to 10 ℃ per minute.
  5. 5. The process according to claim 1, wherein the incubation time in step S2 is 20-40min.
  6. 6. The process according to claim 1, wherein the time of the reduction reaction in step S3 is 0.25 to 1h.
  7. 7. The process of claim 1 wherein the reducing gas comprises hydrogen gas in an amount of 30 to 60 volume percent.
  8. 8. The process according to claim 1, wherein in step S5, the reduction product is ground to 1000-2000 mesh.
  9. 9. The process according to claim 1, wherein the metallic iron comprises >70wt% of the iron element in the copper slag.
  10. 10. Use of a process according to any one of claims 1 to 9 for the recovery of iron metal from copper slag.

Description

Process method for recovering iron from hydrogen reduction copper slag and application thereof Technical Field The invention belongs to the technical field of copper slag treatment, and particularly relates to a process method for recovering iron from copper slag by hydrogen reduction and application thereof. Background Copper is used as an important basic metal material and has an irreplaceable effect in the key fields of national economy such as construction, electric power, traffic and the like. A large amount of copper slag is generated in the copper smelting process, the content of iron element in the copper slag is high, and the copper slag has extremely high iron resource recovery potential. However, the iron element in the copper slag is mainly assigned to fayalite (Fe 2SiO4) and magnetite (Fe 3O4), and is tightly symbiotic with gangue minerals such as silicate and glass, and the embedded granularity is fine, so that the efficient enrichment and recovery of iron are difficult to realize by the traditional physical separation methods such as magnetic separation, floatation and the like. At present, a large amount of copper slag is still disposed in a piling or landfill mode, so that not only is land resources occupied, but also potential pollution is caused to soil and water due to heavy metal components, and ecological environment safety is threatened. In the prior art, although attempts have been made to treat copper slag by means of carbothermic reduction, smelting tempering and the like, the problems of high energy consumption, complex flow, low iron recovery rate, secondary pollution and the like are common. In particular to the realization of the efficient reduction of fayalite and the directional migration of iron phases, the traditional process still faces technical bottlenecks. Along with the improvement of the green low-carbon smelting requirement, the development of an efficient and clean copper slag iron recycling technology has become an urgent requirement of the industry. The hydrogen is used as a clean reducing agent, the metal oxide can be selectively reduced at high temperature, and the reaction product is only water, so that the carbon emission problem of the carbon-based reduction process is avoided. Therefore, based on the hydrogen reduction characteristic, a new process for efficiently activating and separating iron components in copper slag is designed, and the method has important significance for realizing high value-added utilization of the copper slag and promoting sustainable development of the metallurgical industry. Disclosure of Invention The present invention aims to solve at least one of the technical problems in the prior art described above. Therefore, the invention aims to provide a process method for recovering iron by reducing copper slag with hydrogen and application thereof, which radically solves the problem of carbon emission in the traditional carbon-based reduction process by adopting hydrogen to realize efficient reduction and directional polymerization of iron element, and further adopts a gradient dissociation process method of 'pre-reduction-grinding-secondary reduction', so that iron phases are further aggregated and grown to form high-purity metallic iron particles in a monomer form, and the problem of insufficient dissociation of the iron phases in the traditional method is effectively solved. In a first aspect of the invention, a process for recovering iron from copper slag by hydrogen reduction is provided, comprising the following steps: S1, mixing copper slag and calcium oxide to obtain a mixture; s2, under the protection of nitrogen and/or inert gas, heating the mixture to a buffer temperature, and preserving heat, wherein the buffer temperature is 400-500 ℃; S3, after the heat preservation is completed, continuously heating to a reduction temperature, and replacing the nitrogen and/or inert gas with reducing gas to perform a reduction reaction, wherein the reduction temperature is 1000-1150 ℃; s4, after the reduction reaction in the step S3 is completed, replacing the reducing gas with nitrogen and/or inert gas, and cooling to obtain a reduction product; S5, grinding the reduction product, and carrying out magnetic separation to obtain the metal iron. Specifically, a certain proportion of calcium oxide is added into the copper slag (the addition amount of the calcium oxide is calculated according to the elemental analysis of the copper slag, and the iron element in the fayalite or magnetite is guaranteed to be completely replaced), and the iron element in the copper slag is reduced by utilizing the reduction effect of hydrogen in a high-temperature environment, so that the iron resource in the copper slag can be recovered to the maximum extent. The method utilizes hydrogen reduction, only generates water vapor as a byproduct in the hydrogen reduction reaction, has clean and pollution-free whole reaction process, meets the green environment-frien