Process for producing highly active steel slag powder and inert mineral products from steel slag

Abstract

The invention discloses a technology of producing high-activity steel slag powder and an inert mineral product by using steel slag. The technology comprises the six steps of dry process grinding, pneumatic separation, dry process magnetic separation, wet process grinding, wet process magnetic separation and dehydration. In the step of the dry process grinding, tailings after slag iron are recovered are ground into steel slag powder, and inert mineral dissociation is realized; in the step of the pneumatic separation, the steel slag powder is subjected to size grading by using a superfine powder concentrator, so that the enrichment of inert minerals in coarse powder is realized, and fine powder is a high-activity steel slag powder product; in the step of the dry process magnetic separation, the coarse powder is purified to be coarse concentrate by employing the magnetism of the inert minerals, and coarse tailings return back to the dry process grinding step; the coarse concentrate is made into fine pulp through the wet process grinding; the fine pulp is separated into a humid inert mineral raw material and a humid cement iron raw material through the wet process magnetic separation; and after the humid inert mineral raw material and the humid cement iron raw material are dehydrated separately, the inert mineral product and a cement iron raw material are obtained, and water returns to the wet process grinding step. According to the technology, the steel slag is processed into the high-activity steel slag powder, the high-iron-grade inert mineral product and the cement iron raw material, so that the full resource utilization of the steel slag is realized.

Description

technical field [0001] The invention belongs to the technical field of steel slag processing, and relates to the full resource utilization of steel slag, in particular to a process for producing high-activity steel slag powder and inert mineral products from steel slag. Background technique [0002] Steel slag is solid waste discharged from steelmaking, and its yield is generally 15% of crude steel output. According to the domestic monthly crude steel output of Oupu Steel Network, the total output of crude steel in my country in 2015 was 800.53 million tons, and about 120 million tons of steel slag was produced every year. The comprehensive utilization rate of steel slag announced by the Ministry of Industry and Information Technology in recent years has not exceeded 21%, and 95 million tons of waste steel slag has been added annually, which affects the smooth discharge of slag in steelmaking production, and also occupies valuable land and causes environmental pollution. The...

AI Technical Summary

Problems solved by technology

The technical defect of this invention: because its technical scheme is based on not realizing that the main inert mineral in the steel slag is the RO phase basis, so only pay attention to the extraction of metallic iron in the steel slag, do not realize that the dominant inert mineral (RO phase) in the steel slag ) sorting effect

The specific surface area of ​​the semi-product of steel slag powder produced by roller mill pre-grinding is less than 150m 2 / kg, the monomer comprehensive dissociation degree of RO phase mineral is less than 50%, the impurity of silicate mineral in the iron powder product (actually inert mineral product) obtained by magnetic separation is many, and the iron grade of product is low; Steel slag powder and magnetic separation tailings are made by ball milling. Due to the high content of inert minerals in the grinding material, even if the grinding fineness of steel slag powder is very high, its activity will not be significantly improved.

This invention has the following technical defects: (1) steel slag is dissociated and ground into -1.8mm powder, and the RO phase in steel slag generally has an average particle size of about 30 μm, which cannot reach the RO phase mineral monomer dissociation target; and When the particle size of the material minerals is not reached, the effect of the grinding process cannot clearly reflect the difference in the grinding resistance of the minerals, so that these inert minerals that are difficult to grind are enriched at the coarse-grained level

(2) Pneumatic separation of powder is classified by cutting particle size of 80 μm, which is much larger than the intrinsic particle size of the three inert minerals in steel slag, so there is little difference in the content of inert minerals in coarse powder and fine powder, and it is difficult to achieve mineral composition sorting requirements

After sorting, the content of inert minerals in the active powder slag in the two products is still relatively high, and its hydration activity has not been significantly improved; the inert minerals in the steel slag sand are not well enriched, and the purity is far lower than the design requirements

(3) To prepare the RO phase by taking out the sediment-enriched material from the mill, it is necessary to stop the mill, take out the material, and sort. Not only the process is complicated and the cost is high, but also the dissociation degree of the inert mineral monomer in the coarse particles is low, and the iron grade of the product is low. difficult to use

This technology still has the following deficiencies: the remaining material rich in inert minerals such as RO after sorting out high-activity steel slag powder, TFe<40%, far lower than YB / T 4267-2011 "Classification of Iron Ore Product Grades" The index of the lowest grade (fifth-class product) TFe≥54%; at the same time, the total amount of magnetic substances in it is less than 70%, which is also lower than the index of magnetic substance content ≥95% in MT / T 1017-2007 "Magnetite Powder for Coal Preparation"

Therefore, although the patent "a method for improving the hydration activity of steel slag" solves the problem of low activity of steel slag powder, the remaining materials rich in inert minerals, whether as iron ore or magnetite for coal preparation, are all It is difficult to use because it does not meet the product index, and it is easy to cause new industrial products to be discarded

[0008] To sum up, the existing steel slag tailings processing technology to produce steel slag powder, or the steel slag powder product has low activity and does not meet the market requirements, or the low grade of inert mineral products is difficult to use. Therefore, it is necessary to develop new technology to use Full resource utilization of steel slag

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