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A method for modifying and recovering iron by roasting copper slag

A technology for roasting modification and recycling iron, which is applied in the field of recycling iron from copper slag, which can solve the problems of environmental pollution, resource waste, land occupation, etc., and achieve the effects of short process flow, simple equipment and improved economic efficiency

Active Publication Date: 2020-04-07
JIANGXI UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, at present, the utilization rate of copper in copper slag in China is less than 12%, and the utilization rate of iron is even less than 1%. Most of the copper slag is piled up in the slag yard, which not only occupies land but also pollutes the environment, and is also a huge waste of resources. , has become an important factor hindering the sustainable development of copper smelting enterprises

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] Dry slaked lime and copper slag are roasted under nitrogen protection at a mass ratio of 1:10, kept at 900°C, and CO and CO are introduced during roasting 2 Mixed gas, CO and CO 2 The air intake flow rate is 10mL / min and 190mL / min respectively, and the CO is controlled between CO and CO 2 The proportion of the total gas composition is 5%, and it is baked for 1 hour.

[0041] After the roasting is finished, after grinding and classification, modified slag with a particle size of 38 μm is obtained, which is separated by magnetic separation under a weak magnetic field with a strength of 120 mT.

[0042] After the above process, the iron grade (iron grade, referring to the percentage of the iron metal content in the iron concentrate) of the recovered iron concentrate is 60%, the recovery rate is 98.5%, and the magnetic tailings (magnetic The recovery rate of separationtailing) is 1.5%, and the silicon content in the magnetic separation tailings is 29.36%, which realizes t...

Embodiment 2

[0044] The dry slaked lime and copper slag are roasted under the protection of argon at a mass ratio of 1:10, kept at 950°C, and CO and CO are introduced during the roasting. 2 Mixed gas, CO and CO 2 The air intake flow rate is 10mL / min and 190mL / min respectively, and the CO is controlled between CO and CO 2 The proportion of the total gas composition is 5%, and it is baked for 4 hours.

[0045] After the roasting is completed, the modified slag with a particle size of 38-50 μm is obtained through grinding and classification processes, and is separated by magnetic separation under a weak magnetic field with a strength of 110 mT.

[0046] Through the above process, the iron grade of the recovered iron concentrate is 62.5%, the recovery rate is 98.83%, the recovery rate of the magnetic separation tailings is 1.17%, the silicon content in the magnetic separation tailings is 30.05%, and the separation of iron and silicon is realized. and recycling of iron.

Embodiment 3

[0048] Dry slaked lime and copper slag are roasted under the protection of carbon dioxide at a mass ratio of 2:10, kept at 1000°C, and CO and CO are introduced during roasting 2 Mixed gas, CO and CO 2 The intake flow rate of the air intake is 5mL / min and 195mL / min respectively, and the CO is controlled between CO and CO 2 The proportion in the total gas composition is 2.5%, and it is baked for 8 hours.

[0049] After the roasting is finished, the modified slag with a particle size of 50-74 μm is obtained through grinding and classification processes, which are separated by magnetic separation under a weak magnetic field with a strength of 100 mT.

[0050] Through the above process, the iron grade of the recovered iron concentrate is 65.7%, the recovery rate is 99.25%, the recovery rate of the magnetic separation tailings is 0.75%, the silicon content in the magnetic separation tailings is 31.27%, and the separation of iron and silicon is realized. and recycling of iron.

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Abstract

A method for recovering iron by means of copper slag calcination and modification. The method comprises: (2) maintaining a calcination temperature and inert gas protection, communicating a calcination system with ambient air, simultaneously introducing CO and CO2 gases into the calcination system in step (1) with the volume percentage of CO in the total gas components of CO and CO2 being 0-5%, oxidizing free ferrous oxide into ferroferric oxide, and enabling crystals of ferroferric oxide to grow; and (3) performing cooling after calcination is finished, performing ore grinding and grading to obtain modified slag of different particle sizes, and performing magnetic separation under a magnetic field to obtain iron ore concentrate and magnetic separation tailings. According to the method, iron in copper slag can be efficiently recovered by using industrial waste gases CO and CO2, so as to obtain iron ore concentrate suitable for use as an iron melting raw material and magnetic separation tailings suitable for use as a raw material for building materials such as cement.

Description

technical field [0001] The invention relates to a process for recovering iron in copper slag, in particular to a method for roasting and modifying copper slag to recover iron. Background technique [0002] According to statistics, China's refined copper output reached 8.889 million tons in 2017. Copper slag is the slag produced in the copper smelting process, mainly produced in the matte smelting process of copper concentrate. According to the general slag-to-copper ratio of 2.2:1 To calculate, the amount of copper slag produced in my country in 2017 alone was as high as 17.778 million tons. The typical composition of copper slag is 30% to 40% of Fe, 0.2% to 5% of Cu, SiO 2 35% to 40%, Al 2 o 3 The content of copper and CaO is below 10%, and there are also a small amount of metal elements such as zinc, nickel, and cobalt. It can be seen that the content of iron in copper slag is very high. The coppermatte smelting process has complex physical and chemical reactions. The s...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22B1/02
CPCC22B1/02
Inventor 姜平国刘金生廖春发邱廷省曾颜亮
Owner JIANGXI UNIV OF SCI & TECH