Pulverized coal melt separation and recovery method for low-grade iron resources

A recycling method and low-grade technology, applied in fluidized bed furnaces and other directions, can solve the problems of low thermal conductivity of slag layer, no thermal conductivity of coke layer, and high energy consumption

Active Publication Date: 2015-09-23
CENT IRON & STEEL RES INST +1
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, this kind of non-ferrous metallurgy solid waste has a high recycling value. Discarding it will not only cause waste of resources, but also occupy a large amount of land and cause environmental pollution.
In addition, the grade of iron ore in my country is generally low, and it can only be put into the furnace after beneficiation and sintering into pellets. The process is long and the energy consumption is high. Non-blast furnace ironmaking is a reasonable way to deal with low-grade iron resource ores.
[0003] At present, there are various coal-based non-blast furnace ironmaking processes, the fundamental purpose of which is to avoid the utilization of coke, but due to the low thermal conductivity of the slag layer, there is no heat conduction effect of the coke layer, resulting in low thermal efficiency

Method used

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Examples

Experimental program
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Effect test

Embodiment 1

[0018] The water-quenched copper slag in Yunnan has a TFe content of 40.57% and a natural alkalinity of 0.15. Grinding the copper slag to a powder with a particle size of less than 0.125 mm, mixing it with lime and coal powder to prepare carbon-containing pellets with R=1. The dried pellets were placed in a corundum crucible with a grate on the bottom. The pellets are first reduced to metallized pellets with a metallization rate of 95% at a temperature of 1280°C, and then melted at 1450°C. The hot air rising from the bottom convects the pellets through the small holes of the grate, and the pellets are melted It drips through the small holes into the crucible below and forms a layer of slag and iron. In the melting stage, the amount of air introduced into the bottom of the tube furnace is controlled according to the carbon-to-oxygen ratio, the residual carbon content of the metallized pellets is controlled at about 10%, and the O / C ratio is controlled at 1.5, 1.0 and 0.8, resp...

Embodiment 2

[0020] Mix Yunnan water-quenched copper slag into flux and coal powder to prepare carbon-containing pellets with R=1, and reduce them to metallized pellets with metallization rates of 78%, 85%, and 95% at 1280°C, and then at 1450°C The melting is carried out in the temperature range of ℃. When the C / O ratio in the melting stage is controlled at 1.0, the yields of granular iron obtained by melting are 93%, 91% and 92%, respectively. The degree of reduction of metallized pellets has little effect on the melting stage, but considering To the influence of the melting zone of the melting furnace, the metallization rate should be controlled above 85%.

[0021] Case 3

[0022] Jiangxi copper slag has a TFe content of 42.94% and a natural alkalinity of 0.07; Jinchang low-nickel slag has a TFe content of 40.78% and a natural alkalinity of 0.05; Jinchang high-nickel slag has a TFe content of 32.97% and a natural alkalinity of 0.17. The slags above are ground and mixed with lime and c...

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Abstract

The invention relates to a pulverized coal melt separation and recovery method for low-grade iron resources and belongs to the technical field of ferrous metallurgy and environment protection. The pulverized coal melt separation and recovery method for low-grade iron resources comprises the steps that pulverized coal, raw materials containing iron and a fluxing agent are mixed to prepare carbon-containing pellets and are directly reduced rapidly; the metallized pellets are hot-charged in a melt separation furnace; heat required by melt separation is provided by hot air blown in from an air port and through combustion of hot coal left in the metallized pellets, and separation between slag and iron and recovery of iron are completed. The pulverized coal melt separation and recovery method for low-grade iron resources has the advantages that the heat utilization rate is increased, use amount of coke is reduced during melt separation, and energy consumption and production cost are reduced. Due to the fact that metallurgical solid waste and low-grade iron ore are high in slag content and low in iron grade, it is not economical if a traditional blast furnace technique is used for recovering iron; due to the fact that no coke layer exists in a traditional coal-based melt separation technique, molten iron carburization is not sufficient; in addition, due to the fact that the heat conductivity coefficient of a slag layer is low, iron melting is difficult. By the adoption of the technique, the high temperature and the high heat utilization rate which are required by molten iron melting are guaranteed; the technique is suitable for processing low-grade resources containing iron, and the current utilization situation of metallurgical solid waste and low-grade ore is greatly changed.

Description

technical field [0001] The invention belongs to the technical field of iron and steel metallurgy and environmental protection, and in particular relates to a coal powder melting recovery method for low-grade iron resources, which is suitable for recycling low-grade metallurgical solid waste and iron elements in iron ore. Background technique [0002] 97% of the domestic copper output is obtained through pyrometallurgy, and the copper slag output per ton of copper is about 2.2t, resulting in a huge copper slag output. The iron grade in copper slag is generally 30-40%, and contains 0.5-2% copper. About 6-16 tons of nickel slag is produced by flash furnace smelting 1 ton of nickel. Jinchuan Nonferrous Metals Company produces about 800,000 tons of nickel slag every year, most of which are accumulated. The iron content in nickel smelting waste slag is equivalent to that of copper slag, and the nickel content is about 0.2-0.7%. In addition, it also contains a certain amount of va...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21B13/00
Inventor 张俊齐渊洪严定鎏程相利
Owner CENT IRON & STEEL RES INST
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