Carbon etching-based micropore-rich metallurgical slag particle preparation technology and method

Abstract

In view to the technical problems of low recovery rate of metal elements in metallurgical slag and the problem of inefficient recovery of residual heat of metallurgical slag generated by traditional technology, the present application provides a technology and method for preparing microporous-rich metallurgical slag particles based on carbon etching and efficiently recovering residual heat of metallurgical slag in coal gasification, mainly including four parts of granulation system, etching powder adhesion system, etching gasification system and screening separation system which are sequentially connected, and mainly through four steps of molten metallurgical slag granulation, etching powder adhesion, etching gasification reaction, screening and separation, the efficient recovery and utilization of residual heat of metallurgical slag and the high value conversion of metallurgical slag particle products are realized. The utilization value of metallurgical slag particles is increased by 10-15 times through the system.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of metallurgy, energy and materials, and particularly relates to a technology and method for preparing microporous-rich metallurgical slag particles based on carbon etching. BACKGROUND

[0002] The metallurgical industry is the foundation industry of the national economy. China's metallurgical industry provides nearly half of the world's metallurgical products each year, while also producing hundreds of millions of tons of metallurgical slag. For example, blast furnace slag, steel slag, copper slag, nickel-iron slag, silicon-manganese slag, and chromium-iron slag. The tapping temperature of the above-mentioned metallurgical solid waste is all above 1300℃, which has high waste heat recovery value. At present, water quenching and slow cooling methods are mainly used to treat metallurgical slag. The water quenching method wastes a large amount of water and produces SO X and other harmful gases during the water quenching process; the slow cooling method is low in efficiency and has potential solid pollution, and both of the two treatment methods cannot effectively utilize the large amount of sensible heat rich in copper slag. In the process of realizing the "double carbon target", energy saving of high energy-consuming industries becomes particularly important, and efficient utilization of waste heat resources in industrial production becomes an important goal for the development of the industry. In recent years, dry granulation has gradually succeeded in experimental research. This technology can convert molten metallurgical slag into solid metallurgical slag without consuming water resources, while realizing waste heat recovery.

[0003] The final utilization channel of metallurgical slag after traditional treatment methods such as water quenching, slow cooling, and dry granulation is used in the cement, concrete, or road engineering industries. Metallurgical slag needs to be crushed and treated with additional energy during the use in these industries, and the metallurgical slag has unstable factors such as metamorphism when it comes into contact with water, which can easily lead to weakening of the strength of the project and safety problems. The traditional treatment method has low added value and insignificant economic benefits, so the technical transformation resistance is large. Therefore, a technology that can efficiently recover the waste heat of metallurgical slag and increase its added value is urgently needed to be developed. SUMMARY

[0004] In view of the problems existing in the prior art, the present application provides a technology and method for preparing microporous-rich metallurgical slag particles based on carbon etching and efficiently recovering waste heat of metallurgical slag by coal gasification, which solves the technical problems of low recovery rate of metal elements in metallurgical slag and inefficient recovery of waste heat of metallurgical slag. The technical solution of the present application is as follows:

[0005] The carbon etching-based micropore-rich metallurgical slag particle preparation technology and method mainly include the following steps:

[0006] The carbon etching-based micropore-rich metallurgical slag particle preparation technology and method mainly include the following steps:

[0007] (1) Granulation of molten metallurgical slag

[0008] The molten metallurgical slag at 1300-1500℃ enters the granulation system through the liquid slag inlet. In the granulation system, the liquid slag is converted into metallurgical slag initial particles of 0.5-5mm in size by the granulation device, and the temperature of the initial particles is 1100-1300℃. The outer surface of the initial metallurgical slag particles reaches the initial solidification state, and the center is still molten liquid. The heated air in the granulation system is drawn out of the outer cover by the induced draft fan. The initial metallurgical slag particles are collected and then enter the etching powder adhesion system.

[0009] (2) Etching powder adhesion

[0010] The initial metallurgical slag particles enter the etching powder adhesion system, and the heat of the initial metallurgical slag particles diffuses from the inner core to the outer surface, and the outer surface is in a softened state. The initial metallurgical slag particles roll and fall on the etching powder arrangement plate, and at the same time, the etching powder on the plate is adhered to the surface of the particles. The etching powder is automatically replenished through the automatic replenishment port to ensure a certain thickness of the etching powder. In the adhesion process of the etching powder, the initial metallurgical slag particles are reshaped by rolling, making the particle shape more regular.

[0011] (3) Etching gasification reaction

[0012] The metallurgical slag particles with adhered etching powder enter the etching gasification system, and the gasification agent is introduced into the system through the gasification agent inlet by the air blower. The etching powder is gasified under the heating of the residual heat of the metallurgical slag, producing coal gas which is collected through the coal gas collection port, and at the same time, the surface of the initial metallurgical slag particles is etched to produce microporous structures on the surface of the initial metallurgical slag particles, increasing the specific surface area of the metallurgical slag particles. Due to the etching gasification reaction of the etching powder and the cooling of the gasification agent, the copper slag is cooled to 70-140℃ in the etching gasification system.

[0013] (4) Screening and separation

[0014] The microporous-rich metallurgical slag particles with micro-porous structure on the surface after etching enter the separation system for screening and separation. The etching powder on the surface of the metallurgical slag not involved in the reaction is sent back to the circulating feeding device through the screening device for further recycling. The microporous-rich metallurgical slag particles are obtained after screening.

[0015] The metallurgical slag in steps (1)-(4) can be by-products such as blast furnace slag, steel slag, copper slag, nickel slag and the like generated in a metallurgical process.

[0016] The etching powder in steps (2)-(4) is carbon-containing substances such as coal powder, biomass powder, rubber, plastic, sludge and the like.

[0017] The main components of the coal gas generated in step (3) are CO and H2. The calorific value is 700-1000 kJ / m 3 After simple treatment, it can directly provide energy source for metallurgy.

[0018] The gasification agent introduced into the gasification system by the air blower in step (3) can be selected from one or more of air, water vapor, O2 and CO2.

[0019] The beneficial effects of the present application are:

[0020] (1) Efficient recycling of metallurgical slag waste heat: converting the waste heat of metallurgical slag particles into high-calorific-value coal gas, efficiently recycling the waste heat of metallurgical slag by chemical method, and the heat recovery rate is greater than 80%.

[0021] (2) High-value conversion of metallurgical slag particle products: converting metallurgical solid waste into microporous-rich metallurgical slag particles, changing the traditional utilization mode of metallurgical solid waste, and directly preparing metallurgical slag particles with rich micro-pores on the surface through the waste heat recovery process, which can be used as excellent catalyst substrate material, improving the economic value and utilization value of metallurgical solid waste. The utilization value of the metallurgical slag particles is increased by 10-15 times through the system. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 Preparation technology and method diagram of carbon etching microporous-rich metallurgical slag particles. Wherein:

[0023] 1-metallurgical slag granulation system, 1-1 liquid slag inlet, 1-2 granulation device, 1-3 induced draft fan, 1-4 outer cover;

[0024] 2-etching powder adhesion system, 2-1 flow guide cover, 2-2 etching powder feeding port, 2-3 etching powder arrangement plate, 2-4 etching powder accumulation layer;

[0025] 3-etching gasification system, 3-1 gasification agent inlet, 3-2 air blower, 3-3 etching reaction bed, 3-4 fuel gas collection port;

[0026] 4 separation and circulation system, 4-1 screening device, 4-2 circulating feeding device.

[0027] Figure 2 It is a schematic diagram of the process of etching of metallurgical slag with rich pores. Among them, A is the initial particle of metallurgical slag, B is the metallurgical slag particle with etching powder attached, C is the metallurgical slag particle with etching powder attached, D is the metallurgical slag particle in the etching reaction process, E is the metallurgical slag particle with rich micropores, and x is the etching powder.

[0028] Figure 3 It is a process flow chart of a preparation technology and method of metallurgical slag particles with rich micropores based on carbon etching.

[0029] Example 1

[0030] In this embodiment, the metallurgical slag is blast furnace slag, and the gasification agent is air.

[0031] A preparation technology and method of metallurgical slag particles with rich micropores based on carbon etching mainly includes a granulation system 1, an etching powder adhesion system 2, an etching gasification system 3, and a screening and separation system 4, which are sequentially connected. The granulation system 1 is composed of a liquid slag inlet 1-1, a granulation device 1-2, an induced draft fan 1-3, and an outer cover 1-4; the etching powder adhesion system is composed of a flow guide cover 2-1, an etching powder feeding port 2-2, and an etching powder arrangement plate 2-3; the etching gasification system is composed of a gasification agent inlet 3-1, a blower 3-2, an etching reaction bed 3-3, and a combustion gas collection port 3-4; the separation and circulation system is composed of a screening device 4-1 and a circulating feeding device 4-2.

[0032] A preparation technology and method of metallurgical slag particles with rich micropores based on carbon etching mainly includes the following steps.

[0033] (1) Granulation of molten metallurgical slag

[0034] 1300~1500℃ molten blast furnace slag enters the granulation system 1 through the liquid slag inlet 1-1. In the granulation system, the liquid slag is converted into 1mm~5mm blast furnace slag initial particles A by the granulation device, and the temperature of the blast furnace slag initial particles A is 1300℃(±50℃). The outer surface of the initial blast furnace slag particles reaches the initial solidification state, and the center is still molten liquid. The heated air in the granulation system is introduced out of the outer cover by the induced draft fan 1-3. The initial blast furnace slag particles are collected and then enter the etching powder adhesion system 2.

[0035] (2) Etching powder adhesion

[0036] The initial blast furnace slag particles A enter the etching powder adhesion system 2, in which the heat of the initial blast furnace slag particles A diffuses from the inner core to the outer surface, and the outer surface is in a softened state. The initial blast furnace slag particles roll and fall on the etching powder arrangement plate 2-3, and at the same time, the etching powder (carbon powder) on the etching powder arrangement plate is adhered to the surface of the particles. The etching powder is automatically replenished through the automatic replenishment port 2-2 to ensure a certain thickness of the etching powder. In the adhesion process of the etching powder, the initial blast furnace slag particles are reshaped again through rolling, so that the particle shape is more regular.

[0037] (3) Etching gasification reaction

[0038] The blast furnace slag particles with attached etching powder enter the etching gasification system, and at the same time, the air blower 3-2 blows the gasification agent (air) through the gasification agent inlet 3-1. The etching powder is heated by the blast furnace slag waste heat and undergoes a gasification reaction on the etching reaction bed 3-3, producing coal gas, which is collected through the coal gas collection port 3-4, and at the same time, the initial blast furnace slag surface is etched to produce a microporous structure on the surface of the initial blast furnace slag particles, increasing the specific surface area of the blast furnace slag particles. Due to the etching gasification reaction of the etching powder and the cooling of the gasification agent, the copper slag is cooled to 70~140℃ in the etching gasification system. The calorific value of the produced coal gas is 600~800kJ / m 3 It can directly provide energy for metallurgical production.

[0039] (4) Screening and separation

[0040] The microporous-rich blast furnace slag particles with etched surfaces enter the separation system 4 for screening and separation. The etching powder on the surface of the blast furnace slag that does not participate in the reaction is sent back to the circulating feeding device 4-2 for further recycling after passing through the screening device 4-1. The microporous-rich blast furnace slag particles are obtained after screening. Through this system, the utilization value of the blast furnace slag particles is increased by 10~15 times.

[0041] Example 2

[0042] In this embodiment, the metallurgical slag is copper slag, and the gasification agent is water vapor.

[0043] A microporous-rich metallurgical slag particle preparation technology and method based on carbon etching mainly includes the following steps.

[0044] (1) Granulation of molten metallurgical slag

[0045] 1250~1350℃ molten copper slag enters the granulation system 1 through the liquid slag inlet 1-1. In the granulation system, the liquid slag is converted into 0.5mm~3mm copper slag initial particles A by the granulation device. The temperature of the copper slag initial particles A is 1300℃(±50℃). The outer surface of the initial copper slag particles reaches the initial solidification state, and the center is still molten liquid. In the granulation system 1, the induced draft fan 1-3 induces the heated air in the granulation system out of the housing. The copper slag initial particles are collected and then enter the etching powder adhesion system 2.

[0046] (2) Etching powder adhesion

[0047] The copper slag initial particles A enter the etching powder adhesion system 2, where the heat of the copper slag initial particles A spreads from the inner core to the outer surface, and the outer surface is in a softened state. The copper slag initial particles roll down the etching powder arrangement plate 2-3 and simultaneously adhere the etching powder (carbon powder) on the etching powder arrangement plate to the surface of the particles. The etching powder is automatically replenished through the automatic replenishment port 2-2 to ensure a certain thickness of the etching powder. During the adhesion process of the etching powder, the particles are reshaped by rolling, making the particle shape more regular.

[0048] (3) Etching gasification reaction

[0049] The copper slag particles with attached etching powder enter the etching gasification system, and the air blower 3-2 blows in the gasification agent (water vapor) through the gasification agent inlet 3-1. The etching powder undergoes gasification reaction in the etching reaction bed 3-3 under the heating of the residual heat of the copper slag, producing coal gas, which is collected through the coal gas 3-4 collection port. At the same time, the surface of the initial copper slag is etched, producing a microporous structure on the surface of the initial copper slag particles, increasing the specific surface area of the copper slag particles. Due to the etching gasification reaction of the etching powder and the cooling of the gasification agent, the copper slag is cooled to 70~140℃ in the etching gasification system. The calorific value of the produced coal gas is 700~1000kJ / m 3 It can directly provide energy for metallurgical production.

[0050] (4) Screening and separation

[0051] The microporous-rich copper slag particles with a microporous structure on the surface after etching enter the separation system 4 for screening and separation. The etching powder on the surface of the copper slag that does not participate in the reaction is sent back to the circulating feeding device 4-2 for further recycling after passing through the screening device 4-1. The microporous-rich copper slag particles are obtained after screening. The value of the copper slag particles is increased by 10~15 times through this system.

Claims

1. A method for the preparation of microporous-rich metallurgical slag particles based on carbon etching, characterized by The granulation system, the etching powder adhesion system, the etching gasification system and the screening separation system are sequentially connected, wherein the granulation system comprises a liquid slag inlet, a granulation device, an air induction fan and an outer cover; the etching powder adhesion system comprises a flow guide cover, an etching powder feeding port and an etching powder arrangement plate; the etching gasification system comprises a gasification agent inlet, a blast fan, an etching reaction bed and a combustion gas collecting port; and the screening separation system comprises a screening device and a circulating feeding device. The granulation system, the etching powder adhesion system, the etching gasification system and the screening separation system are sequentially connected, wherein the granulation system comprises a liquid slag inlet, a granulation device, an air induction fan and an outer cover; the etching powder adhesion system comprises a flow guide cover, an etching powder feeding port and an etching powder arrangement plate; the etching gasification system comprises a gasification agent inlet, a blast fan, an etching reaction bed and a combustion gas collecting port; and the screening separation system comprises a screening device and a circulating feeding device. The metallurgical slag is one of blast furnace slag, steel slag, copper slag, nickel slag and lead slag. The etching powder is one or more of coal powder, biomass powder, rubber, plastic and sludge. The mass of the etching powder is 5-20% of the mass of the metallurgical slag particles. The etching powder is one or more of coal powder, biomass powder, rubber, plastic and sludge. The mass of the etching powder is 5-20% of the mass of the metallurgical slag particles. The etching powder is one or more of coal powder, biomass powder, rubber, plastic and sludge. The mass of the etching powder is 5-20% of the mass of the metallurgical slag particles.

2. A process for the preparation of microporous-rich metallurgical slag particles based on carbon etching according to claim 1, characterized by: The temperature of the molten metallurgical slag in step (1) is 1300-1500℃, the temperature of the initial metallurgical slag particles in step (1) is 1100-1200℃, the temperature of the initial metallurgical slag particles in step (2) is reduced to 1000-1100℃, the temperature of the metallurgical slag particles with micro-pore structure in step (3) is 400-1000℃, and the temperature of the metallurgical slag particles with micro-pore structure in step (4) is less than 400℃.

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