A method for wet treatment of magnetic separation powder of phosphorus-rich steel slag

Abstract

The present invention relates to a method for wet treatment of phosphorus-rich steel slag magnetic separation powder. The method is to perform two-stage screening on the pulp material after wet high-intensity volleyball milling. After two-stage screening, the undersize material is separated by magnetic separation to obtain steel slag concentrate powder. Compared with the prior art, the beneficial effects of the present invention are as follows: 1) Through two-stage separation, the present invention separates the granular steel mixed in the steel slag magnetic separation powder, and returns this part of granular steel directly to the steelmaking blast furnace for utilization, avoiding unnecessary sintering and ironmaking processes and energy waste. 2) The steel slag powder treated by the present invention using wet grinding combined with two-stage screening after grinding has finer particle size, can be further subjected to wet magnetic separation, discard useless tailings, improve the iron content of the steel slag powder added to the ironmaking sintering process, and reduce useless energy consumption. The TFe in the steel slag concentrate powder after magnetic separation is 50%-60%, and P is 0.2%-0.32%.

Description

Technical Field

[0001] The present invention belongs to the technical field of smelting, and relates to a process method for the deep treatment and reuse of steel slag, in particular to a method for wet treatment of phosphorus-rich steel slag magnetic separation powder. Background Art

[0002] Steel slag is a large amount of solid waste with a low comprehensive utilization rate in the iron and steel industry. At present, the comprehensive utilization rate of steel slag in China is only 30%. Due to the problem of cyclic accumulation of phosphorus in the recycling of steel slag, the internal recycling of steel slag in enterprises is severely restricted. Especially in recent years, with the increase of high-phosphorus hot metal, this problem has become more and more prominent.

[0003] At present, the dry crushing magnetic separation process is generally applied to steel slag treatment. After the steel slag is crushed, granular steel, steel slag magnetic separation powder and tail slag are dry-magnetically separated. The granular steel is used for steelmaking, and the magnetic separation powder is used for ironmaking sintering ore blending production (Su Xingwen, Development and utilization of converter steel slag in Angang [J]. Mining and Metallurgical Engineering. 2008(4): 58-60; Shi Lei. Discussion on the treatment and comprehensive utilization of steel slag [J]. China Resources Comprehensive Utilization. 2011(3): 29-32; Li Ke. Demonstration introduction of the production line construction of the steel slag resource utilization project in Benxi Steel [J]. Shanxi Metallurgy, 2010(5): 32-34).

[0004] Due to the high phosphorus content and low iron grade of the phosphorus-rich steel slag magnetic separation powder, adding this magnetic separation powder to the sintered ore will reduce the iron grade of the finished sintered ore and increase the phosphorus content of the subsequent product (pig iron), thus restricting the addition ratio of the phosphorus-rich steel slag magnetic separation powder in the sintered ore batching.

[0005] The characteristics of high phosphorus and low iron in the phosphorus-rich steel slag magnetic separation powder will have a very adverse impact on the subsequent ironmaking process. Therefore, the utilization amount in the sintering process is small or it cannot be used, resulting in overstocking and affecting the large balance of iron and steel production. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for wet treatment of phosphorus-rich steel slag magnetic separation powder. By using the process means of wet grinding combined with two-stage screening after grinding, finally, concentrated ore powder with low phosphorus content and high iron grade can be magnetically separated and produced, which can greatly increase its addition ratio in the sintered ore and promote the output and utilization balance of steel slag powder.

[0007] In order to achieve the above purpose, the present invention is realized by adopting the following technical solutions:

[0008] A method for wet treatment of phosphorus-rich steel slag magnetic separation powder, which is to perform two-stage screening on the pulp material after grinding by wet high-intensity volleyball mill. After two-stage screening, the undersize material is magnetically separated to select steel slag concentrated ore powder.

[0009] The feed material for the wet high-intensity volleyball mill grinding process is the phosphorus-rich steel slag magnetic separation powder obtained by dry magnetic separation.

[0010] The TFe in the phosphorus-rich steel slag magnetic separation powder is 20% - 40%, and the P is 0.36% - 0.80%.

[0011] The oversize material of the first-stage screening in the two-stage screening is mill scale or pure iron particles larger than 5 mm, and this part of mill scale or pure iron particles is directly sent to the steel plant for steelmaking. The first-stage screening sieve preferably uses a round cage sieve.

[0012] The oversize material of the second-stage screening in the two-stage screening is particles larger than 0.074 mm. The oversize material particles are returned to the wet high-intensity volleyball mill for regrinding, and the undersize material is fed into the magnetic separator for separation.

[0013] The TFe in the steel slag concentrate powder selected by magnetic separation is 50% - 60%, and the P is 0.2% - 0.32%.

[0014] The present invention performs wet grinding on the fine-grained products (steel slag magnetic separation powder) generated by the dry magnetic separation process of steel slag crushing. The granular steel mixed in the steel slag magnetic separation powder is mainly composed of pure iron or iron oxide. Due to its strong toughness, it will be flattened by the steel balls rather than broken, doubling its maximum particle size; while other materials are easily broken or ground in the ball mill. After the steel slag magnetic separation powder is forced out by the forced discharge device at the tail of the ball mill, it is fed into a round cage sieve for classification. Due to the large difference in particle size changes of granular steel and other materials in the ball mill, according to the granular steel particle size in the feed of the round cage sieve, a round cage sieve with a suitable aperture is selected for screening, and the granular steel mixed in the magnetic separation powder can be easily separated and directly sent to the steel plant for utilization, avoiding waste of energy. In addition, the steel slag powder separated by fine screening has a finer particle size. After further wet magnetic separation, the iron content grade of the steel slag powder added to the iron-making sintering process can be improved.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] 1) Through two-stage separation, the present invention separates the granular steel mixed in the steel slag magnetic separation powder, enabling this part of granular steel to be directly returned to the blast furnace for steelmaking, avoiding unnecessary sintering and iron-making processes and energy waste.

[0017] 2) The steel slag powder processed by the present invention using wet grinding combined with two-stage screening after grinding has a finer particle size, can be further subjected to wet magnetic separation, discard useless tailings, improve the iron content grade of the steel slag powder added to the iron-making sintering process, and reduce useless energy consumption. The TFe in the steel slag concentrate powder after magnetic separation is 50% - 60%, and the P is 0.2% - 0.32%. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is the process flow chart of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] The present invention will be described in more detail by way of examples, which are merely descriptions of the best embodiments of the present invention and do not limit the scope of the present invention in any way.

[0020] Example 1:

[0021] As Figure 1 shown, a method for wet processing of phosphorus-rich steel slag magnetic separation powder. In this method, the pulp material after wet high-intensity volleyball grinding is subjected to two-stage screening. After the two-stage screening, the undersize material is separated by magnetic separation to obtain steel slag concentrate powder. The tailings are discharged to the tailings pond by a sand pump.

[0022] The feedstock for the wet high-intensity volleyball grinding process is the phosphorus-rich steel slag magnetic separation powder obtained by dry magnetic separation. The phosphorus-rich steel slag magnetic separation powder from dry magnetic separation is sent to the ball mill for wet grinding by a disc feeder through a conveyor belt.

[0023] In the phosphorus-rich steel slag magnetic separation powder, TFe is 20% and P is 0.36%.

[0024] The oversize material in the first-stage screening of the two-stage screening is scale or pure iron particles larger than 5 mm. This part of the scale or pure iron particles is directly sent to the steel mill for steelmaking. The first-stage screening sieve preferably uses a circular cage sieve.

[0025] The oversize material in the second-stage screening of the two-stage screening is particles larger than 0.074 mm. The oversize material particles are returned to the wet high-intensity volleyball grinding mill for re-grinding, and the undersize material is fed into a magnetic separator for separation.

[0026] In the steel slag concentrate powder separated by magnetic separation, TFe is 50% and P is 0.2%.

[0027] The addition ratio of the steel slag concentrate powder in this example to the sintering material is: less than 3%.

[0028] Example 2:

[0029] As Figure 1 shown, a method for wet processing of phosphorus-rich steel slag magnetic separation powder. In this method, the pulp material after wet high-intensity volleyball grinding is subjected to two-stage screening. After the two-stage screening, the undersize material is separated by magnetic separation to obtain steel slag concentrate powder. The tailings are discharged to the tailings pond by a sand pump.

[0030] The feedstock for the wet high-intensity volleyball grinding process is the phosphorus-rich steel slag magnetic separation powder obtained by dry magnetic separation. The phosphorus-rich steel slag magnetic separation powder from dry magnetic separation is sent to the ball mill for wet grinding by a disc feeder through a conveyor belt.

[0031] In the phosphorus-rich steel slag magnetic separation powder, TFe is 30% and P is 0.50%.

[0032] The oversize material of the first-stage screening in the two-stage screening is scale or pure iron particles larger than 5 mm, and this part of scale or pure iron particles is directly sent to the steel plant for steelmaking. The first-stage screening sieve preferably uses a round cage sieve.

[0033] The oversize material of the second-stage screening in the two-stage screening is particles larger than 0.074 mm. The oversize material particles are returned to the wet high-intensity volleyball mill for re-grinding, and the undersize material is fed into a magnetic separator for separation.

[0034] The steel slag concentrate powder selected by magnetic separation contains 55% TFe and 0.25% P.

[0035] The addition ratio of the steel slag concentrate powder in this embodiment to the sintering material is: less than 3%.

[0036] Example 3:

[0037] As Figure 1 shown, a method for wet treatment of phosphorus-rich steel slag magnetic separation powder, which is to perform two-stage screening on the pulp material after wet high-intensity volleyball mill grinding. After the undersize material after two-stage screening is separated by magnetic separation, steel slag concentrate powder is selected. The tailings are discharged to the tailings pond by a sand pump.

[0038] The incoming material for the wet high-intensity volleyball mill grinding process is phosphorus-rich steel slag magnetic separation powder obtained by dry magnetic separation. The phosphorus-rich steel slag magnetic separation powder from dry magnetic separation is sent to the ball mill for wet grinding by a disc feeder through a conveyor belt.

[0039] The phosphorus-rich steel slag magnetic separation powder contains 35% - 40% TFe and 0.70% P.

[0040] The oversize material of the first-stage screening in the two-stage screening is scale or pure iron particles larger than 5 mm, and this part of scale or pure iron particles is directly sent to the steel plant for steelmaking. The first-stage screening sieve preferably uses a round cage sieve.

[0041] The oversize material of the second-stage screening in the two-stage screening is particles larger than 0.074 mm. The oversize material particles are returned to the wet high-intensity volleyball mill for re-grinding, and the undersize material is fed into a magnetic separator for separation.

[0042] The steel slag concentrate powder selected by magnetic separation contains 58% TFe and 0.28% P.

[0043] The addition ratio of the steel slag concentrate powder in this embodiment to the sintering material is: less than 4%.

[0044] Example 4:

[0045] As Figure 1As shown in the figure, a method for wet processing of phosphorus-rich steel slag magnetic separation powder. In this method, the pulp material after wet high-intensity volleyball mill grinding is subjected to two-stage screening. After the undersize material from the two-stage screening is separated by magnetic separation, steel slag concentrate powder is selected. The tailings are discharged to the tailings pond by a sand pump.

[0046] The feedstock for the wet high-intensity volleyball mill grinding process is the phosphorus-rich steel slag magnetic separation powder obtained by dry magnetic separation. The phosphorus-rich steel slag magnetic separation powder from dry magnetic separation is sent to the ball mill for wet grinding by a disc feeder through a conveyor belt.

[0047] In the described phosphorus-rich steel slag magnetic separation powder, TFe is 35% and P is 0.60%.

[0048] The oversize material from the first-stage screening in the two-stage screening is iron oxide scale or pure iron particles larger than 5 mm. This part of the iron oxide scale or pure iron particles is directly sent to the steel plant for steelmaking. The first-stage screening sieve preferably uses a circular cage sieve.

[0049] The oversize material from the second-stage screening in the two-stage screening is particles larger than 0.074 mm. The oversize material particles are returned to the wet high-intensity volleyball mill for re-grinding, and the undersize material is fed into the magnetic separator for separation.

[0050] In the steel slag concentrate powder selected by magnetic separation, TFe is 59% and P is 0.3%.

[0051] In this embodiment, the addition ratio of the steel slag concentrate powder in the sintering material is: less than 4%.

[0052] Example 5:

[0053] As Figure 1 As shown in the figure, a method for wet processing of phosphorus-rich steel slag magnetic separation powder. In this method, the pulp material after wet high-intensity volleyball mill grinding is subjected to two-stage screening. After the undersize material from the two-stage screening is separated by magnetic separation, steel slag concentrate powder is selected. The tailings are discharged to the tailings pond by a sand pump.

[0054] The feedstock for the wet high-intensity volleyball mill grinding process is the phosphorus-rich steel slag magnetic separation powder obtained by dry magnetic separation. The phosphorus-rich steel slag magnetic separation powder from dry magnetic separation is sent to the ball mill for wet grinding by a disc feeder through a conveyor belt.

[0055] In the described phosphorus-rich steel slag magnetic separation powder, TFe is 33% and P is 0.75%.

[0056] The oversize material from the first-stage screening in the two-stage screening is iron oxide scale or pure iron particles larger than 5 mm. This part of the iron oxide scale or pure iron particles is directly sent to the steel plant for steelmaking. The first-stage screening sieve preferably uses a circular cage sieve.

[0057] The oversize material from the second-stage screening in the two-stage screening is particles larger than 0.074 mm. The oversize material particles are returned to the wet high-intensity volleyball mill for re-grinding, and the undersize material is fed into the magnetic separator for separation.

[0058] The TFe in the steel slag concentrate powder separated by magnetic separation is 55%, and the P is 0.21%.

[0059] The addition ratio of the steel slag concentrate powder in this embodiment in the sintering material is: less than 3%.

Claims

1. A method for wet treatment of phosphorus-rich steel slag magnetic separation powder, characterized in that, in this method, the pulp material after wet high-intensity volleyball milling is subjected to two-stage screening. After the material passing through the two-stage screening is separated by magnetic separation, steel slag concentrate powder is selected; the feed material for the wet high-intensity volleyball milling process is the phosphorus-rich steel slag magnetic separation powder obtained by dry magnetic separation; in the said phosphorus-rich steel slag magnetic separation powder, TFe is 20% - 40%, and P is 0.36% - 0.80%; the oversize material in the first-stage screening of the two-stage screening is scale or pure iron particles larger than 5mm, and the scale or pure iron particles are directly sent to the steel plant for steelmaking; the oversize material in the second-stage screening of the two-stage screening is particles larger than 0.074mm. The oversize material particles are returned to the wet high-intensity volleyball milling machine for re-grinding, and the undersize material is fed into the magnetic separator for separation; in the steel slag concentrate powder selected by magnetic separation, TFe is 50% - 60%, and P is 0.2% - 0.32%.

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