CN101264464B - Purification technique of steel scoria magnetic separation product - Google Patents

Abstract

The invention discloses a steel slag magnetic separation product purification process. The steel slag magnetic separation product is sent into a ball mill and water is added, and after being fully ground, it is naturally discharged from the discharge end of the ball mill, and then sieved into two products on the sieve and under the sieve by cylinder sieving. The products on the sieve are sorted by magnetic pulleys to get lump iron and tailings. After the lump iron is dried by the dryer, the water content is reduced to less than 2%; The size of the spray water is used to control the overflow grade of the classifier, and then control the sand return grade of the classifier. The returned sand is transported into the fine powder tank through the belt, the overflow of the classifier is pumped to the thickener, and the underflow of the thickener passes through the filter. After filtering, it enters the tail powder powder trough. The invention avoids the loss of non-magnetic or weakly magnetic materials, and makes the recovery of materials more complete and thorough. The iron content of granular iron is increased from 60% to 65% to more than 90%, and the grade of magnetic separation powder is increased from 40% to 50% to more than 60%, which comprehensively increases the iron content of steel slag products and improves the comprehensive utilization rate of steel slag .

Description

Steel slag magnetic separation product purification process

technical field

The invention relates to a steel slag treatment process, which is a process for deep processing steel slag magnetic separation products (granulated iron and magnetic separation powder).

Background technique

Steel slag is the waste residue removed during the steelmaking process. Steel slag mainly comes from the oxides formed after the oxidation of elements contained in molten iron and scrap steel, impurities brought by metal furnace charges, slagging agents added such as limestone, fluorite, silica, oxidants, desulfurization products, and eroded furnace lining materials. According to the different furnace types used in steelmaking, steel slag is divided into converter steel slag, open hearth furnace steel slag and electric furnace steel slag. At present, the domestic steel slag processing technology is single, and crushing-magnetic separation is generally used. For example, Anshan Iron and Steel currently has a 2.4 million tons/year magnetic separation processing line to process steel slag produced by converters. The production line adopts two stages of crushing and two stages of magnetic pulley separation, the separated concentrate products are reused, and the separated tailings products (steel slag magnetic separation products) are granular iron and magnetic separation powder. The annual output of the production line is about 100,000 tons of granular iron, and the iron content of granular iron is 60% to 65%. Because of the large fluctuations in alkalinity, it is difficult to return to the blast furnace for reuse; the annual output of the production line is about 40,000 tons of magnetic separation powder , The grade of magnetic separation powder is 40% to 50%. It cannot be directly used as raw material for blast furnace production. It can only be used as sintered pellets to add raw materials and return to sintering for reuse, but the recycling rate is low. Therefore, it is necessary to further process the steel slag magnetic separation products to improve the utilization rate of steel slag. Although the invention patent with the patent application No. 00123358.0 discloses a magnetic separation steel slag reprocessing process, since the separation method of this process only uses magnetic separation, the non-magnetic or weakly magnetic iron-containing materials cannot be separated in time , resulting in a certain amount of metal loss.

Contents of the invention

The purpose of the present invention is to provide a steel slag magnetic separation product (granulated iron and magnetic separation powder) purification process, to avoid the loss of non-magnetic or weak magnetic material, to make material recovery more fully and thoroughly, and to improve the utilization rate of steel slag.

The object of the present invention is achieved in this way, a steel slag magnetic separation product purification process is characterized in that the steel slag magnetic separation product is sent into a ball mill and water is added, and the metal iron in the material is separated from other substances after sufficient grinding, and the effect of water flow Down, it is naturally discharged through the discharge end of the ball mill, and the discharge of the ball mill is sieved by a cylinder into two products: the upper screen and the lower screen; the upper screen product is sorted by a magnetic pulley to produce lump iron and tailings, and the lump iron enters the lump iron intermediate warehouse. The tailings enter the tailings bin. After the lump iron is dried by the dryer, the water content is reduced to less than 2%, and then enters the lump iron finished product bin. The tailings return to the raw material bin because it contains a small amount of metallic iron; the products under the screen are classified by the spiral The machine sorts out the overflow and sand return, and spray water is installed above the spiral classifier. The overflow grade of the classifier is controlled by controlling the size of the spray water, and then the sand return grade of the classifier is controlled. The sand return of the classifier passes through The belt is transported into the powder trough for fine powder, the overflow of the classifier is pumped to the thickener, and the underflow of the thickener is filtered by the filter and then enters the powder trough for tailing powder.

Because the present invention adopts the method of combining gravity separation and magnetic separation, the loss of non-magnetic or weakly magnetic materials is avoided, the material recovery is more sufficient and thorough, and the iron content of granular iron is increased from 60% to 65% to 90%. Above, the grade of magnetic separation powder is increased from 40% to 50% to more than 60%. The iron content of steel slag products has been comprehensively improved, steel slag resources have been effectively utilized, the comprehensive utilization rate of steel slag has been improved, environmental pollution has been reduced, the problem of occupying a large amount of land has been solved, and great economic benefits have been created for the society.

Description of drawings

Figure 1 is an image connection diagram of process equipment.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

The invention relates to a purification process for steel slag magnetic separation products. The steel slag magnetic separation products with a particle size of 50-0mm (iron content of granular iron is 60%-65%, particle size is 50-0mm; magnetic separation powder grade is 40%- 50%, the particle size is 5-0mm) as raw materials, and after sorting, three products are finally produced, namely lump iron, refined powder and tail powder. This process can not only process granular iron and magnetic separation powder alone, but also process the mixture of granular iron and magnetic separation powder.

As shown in Figure 1, the raw materials are transported by car to the sorting workshop, and the pre-loading machine is used to load the raw material warehouse 1 before the slag grinding. Add water to make a material with a concentration of 70% to 80%. After the material is fully ground in the ball mill 2 with a ball medium filling rate of 30% to 40%, the metallic iron in the raw material is separated from other substances. Under the action of water flow, It is naturally discharged through the discharge end of the ball mill, and the discharge of the ball mill is divided into two products through the cylindrical sieve 3 with a sieve size of 1.5 mm, namely the over-sieve product and the under-sieve product. The products on the sieve and the products under the sieve are sorted by different processes.

The products on the sieve are selected through the magnetic field strength of 2000 Oersted magnetic pulley 5 to select lump iron (grade above 90%, water content above 10%) and tailings, and store them in lump iron intermediate bin 4 and tailings bin respectively within 6. After the lump iron is dried by the dryer 7, the water content is reduced to below 2%, which meets the technological requirements of the steelworks. The selected tailings return to the raw material bin 1 for re-selection because they contain a small amount of metallic iron.

The products under the sieve are classified into overflow and sand-returning (grade above 60%) two products by spiral classifier 9. The returned sand is transported by a belt into the fine powder powder trough 13, and the fine powder is transported to the sintering plant by car. The overflow of the classifier is pumped to the concentrator 10, and the underflow of the concentrator is filtered by the filter 11 and then enters the tailing powder tank 12, and is transported to the tailings yard by car.

The overflow water from each operation in the technological process enters the water treatment system for treatment and returns to the technological process for recycling.

Claims (4)

1. A steel slag magnetic separation product purification process is characterized in that the steel slag magnetic separation product is sent into the ball mill (2) and water is added, and the metallic iron in the material after sufficient grinding is separated from other substances, and under the action of water flow, the steel slag magnetic separation product is passed through the ball mill The discharge end is naturally discharged, and the discharge of the ball mill is divided into two products on the sieve and under the sieve by the cylindrical sieve (3); the product on the sieve is sorted by the magnetic pulley (5) to separate lump iron and tailings, and the lump iron enters the middle of the lump iron warehouse (4), the tailings enter the tailings warehouse (6), and after the lump iron is dried by the dryer (7), the water content is reduced to less than 2%, and enter the lump iron finished product warehouse (8), and the tailings are returned to the raw material Warehouse (1); the products under the screen are sorted by the spiral classifier (9) to sort out the overflow and sand return. There is spray water above the spiral classifier (9), and the classifier is controlled by controlling the size of the spray water. The overflow grade, and then control the sand return grade of the classifier, the sand returned by the classifier is transported by the belt into the fine powder powder tank (13), the overflow of the classifier is pumped to the thickener (10), and the underflow of the thickener passes through the filter ( 11) After filtering, it enters the tail powder powder trough (12); the concentration of the material in the ball mill is 70% to 80%, the ball medium filling rate of the ball mill is 30% to 40%, the sieve hole of the cylindrical sieve is ≥1.5mm, and the magnetic The magnetic field strength of the pulley is 2000-2500 Oersted. 2. The process for purifying steel slag magnetic separation products according to claim 1, characterized in that the steel slag magnetic separation products are granular iron with a particle size of ≤50 mm and an iron content of 60% to 65%. 3. The process for purifying steel slag magnetic separation products according to claim 1, characterized in that the steel slag magnetic separation products are magnetic separation powders with a particle size of ≤5 mm and a grade of 40% to 50%. 4. The purification process for steel slag magnetic separation products according to claim 1, characterized in that the steel slag magnetic separation products are granulated iron and magnetic separation powder, wherein the particle size of granulated iron is ≤50mm, the iron content is 60% to 65%, and the magnetic The particle size of the selected powder is ≤5mm, and the grade is 40% to 50%.

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