阅读说明：本技术 一种利用电炉熔分海绵铁渣直接制备的岩棉及其制备方法 (Rock wool directly prepared by melting sponge iron slag in electric furnace and preparation method thereof ) 是由 王习东 陈子威 王昊 陈为彬 刘丽丽 于 2019-10-29 设计创作，主要内容包括：本发明涉及资源综合利用领域和无机非金属材料制备领域,尤其涉及一种利用电炉熔分海绵铁渣直接制备的岩棉及其制备方法；利用电炉熔分海绵铁渣直接制备岩棉的方法,不需要添加任何改质剂,所述海绵铁渣的酸度系数大于1.5,所述海绵铁渣包含6～13％的FeO；优选所述海绵铁渣为以海绵铁为原料进行电炉炼钢的炉渣；本发明直接利用热态的海绵铁渣制备岩棉,将工艺利用热和回收热相结合,节省了熔体加热、离心成纤和岩棉固化环节的能量消耗,大幅度降低了岩棉的生产成本。本发明不仅实现了电炉炼钢的炉渣的高效率能质耦合利用,达到钢铁冶金行业节能减排的目的,而且创造性地将海绵铁渣不经调质直接用于岩棉的制备,具有显著的环境效益、经济效益和社会效益。(The invention relates to the field of comprehensive utilization of resources and the field of preparation of inorganic non-metallic materials, in particular to rock wool directly prepared by melting sponge iron slag by an electric furnace and a preparation method thereof; the method for directly preparing the rock wool by melting and separating the sponge iron slag by using the electric furnace does not need to add any modifier, the acidity coefficient of the sponge iron slag is more than 1.5, and the sponge iron slag contains 6-13% of FeO; preferably, the sponge iron slag is slag for electric furnace steelmaking by taking sponge iron as a raw material; the invention directly utilizes the hot sponge iron slag to prepare the rock wool, combines the process utilization heat and the recovery heat, saves the energy consumption of the links of melt heating, centrifugal fiber forming and rock wool solidification, and greatly reduces the production cost of the rock wool. The invention not only realizes the high-efficiency energy-quality coupling utilization of the slag of the electric furnace steelmaking, achieves the purposes of energy conservation and emission reduction in the ferrous metallurgy industry, but also creatively uses the sponge iron slag directly for the preparation of rock wool without tempering, and has obvious environmental benefit, economic benefit and social benefit.)

1. A method for directly preparing rock wool by melting sponge iron slag through an electric furnace is characterized in that the acidity coefficient of the sponge iron slag is more than 1.5 and contains 6-13% of FeO; preferably, the sponge iron slag is slag for electric furnace steelmaking by taking sponge iron as a raw material.

2. The method according to claim 1, wherein the sponge iron slag mainly comprises the following components in percentage by mass:

3. the method as claimed in claim 1, wherein the sponge iron has a total iron mass fraction of not less than 85%, a metallization rate of more than 70%, and a gangue content of 3.5-8.5%.

4. The method according to any one of claims 1 to 3, wherein the electric steelmaking is: putting the sponge iron into an electric furnace at a speed of 25-30 kg/(MW & min), and melting for 20-60 min at 1450-1800 ℃ to obtain molten iron and sponge iron slag; the temperature of the sponge iron slag is 1450-1750 ℃.

5. A method according to any one of claims 1 to 4, comprising the steps of:

(1) introducing sponge iron slag at 1450-1750 ℃ into a wire throwing device through a drainage device, and discretely stretching under the action of high-pressure energy-carrying gas and centrifugal force to obtain rock wool fibers;

(2) spraying a binder on the rock wool fibers while blowing the rock wool fibers into a cotton collecting chamber to form raw cotton;

(3) and (3) conveying the raw cotton into a curing furnace, and pressing and forming.

6. The method according to claim 5, wherein the body of the filament slinging device is a three-roll centrifuge having a rotational speed configured to: 8000-10000 r/min of distributing roller, 14000-20000 r/min of first-level accelerating roller and 17000-25000 r/min of second-level accelerating roller.

7. The method of claim 5, wherein the spinning device is provided with a high pressure energy-carrying gas inlet and outlet; the temperature of the rock wool fibers is controlled to be 500-900 ℃ by adjusting the temperature of the air flow and the air flow, and high-temperature air is discharged at the same time.

8. The method of claim 5, wherein the binder is polyvinyl alcohol and/or a water soluble phenolic resin.

9. The method according to any one of claims 5 to 8, wherein the rock wool fibers are heat-exchanged with air and then discharged as hot air; 30-80% of the hot air is supplied to the filament throwing device, and 20-70% of the hot air is supplied to the curing furnace.

10. Rock wool produced by the method according to any one of claims 1 to 9.

Technical Field

The invention relates to the field of comprehensive utilization of resources and the field of preparation of inorganic non-metallic materials, in particular to rock wool directly prepared by melting sponge iron slag in an electric furnace and a preparation method thereof.

Background

Sponge iron is a product obtained by reducing iron ore concentrate or high-quality iron ore below the melting temperature, and is also called direct reduced iron. The direct reduced iron process may be classified into a gas-based direct reduction and a coal-based direct reduction according to the type of the reducing agent. The gas-based direct reduction has the advantages compared with the coal-based direct reduction in the aspects of reduction speed, product quality, energy consumption, environmental benefits and the like. The gas-based direct reduction process mainly uses natural gas, coal gas and the like as reducing gas. The reduced iron ore or iron ore concentrate pellets are porous and loose, have low density and are similar to sponge, so the reduced iron ore or iron ore concentrate pellets are called sponge iron. The sponge iron is a high-quality electric furnace steelmaking raw material, and can be directly fed into an electric furnace or mixed with scrap steel to produce high-quality steel products. In an electric furnace, sponge iron undergoes two processes before and after steelmaking, slag iron is melted, separated and reduced in the early stage to produce slag and molten iron, and qualified molten steel is produced by deep melting and impurity removal in the later stage. Because sponge iron contains more gangue, a large amount of high-temperature slag is generated during the early stage of slag iron melting separation, and particularly, the sponge iron obtained by directly reducing refractory iron ore generates more slag in the early stage of electric furnace steelmaking. The slag components are mainly derived from the acidic gangue and the unreduced residual iron oxides in the sponge iron.

Rock wool is an inorganic fiber material and is widely applied to heat and cold insulation projects. The traditional raw materials are basalt and diabase; due to the gradual scarcity of natural resources and the environmental damage caused by mining activities, and in order to reduce the production cost, the production of rock wool by using industrial wastes as alternative raw materials becomes an important direction of research. Chinese patent document CN108129030A discloses a method for treating red mud slag, and specifically discloses a method for obtaining rock wool fibers by blowing and forming fibers from red mud slag, dolomite, silica and carbon-containing raw materials; chinese patent document CN104671657A discloses a method for producing alloy molten steel by combining rock wool melt through silicon oxidation, and particularly discloses a method for preparing rock wool melt with high acidity value for rock wool fibers by using a silicon raw material in waste silicon, a silicon element and a carbon element in silicon carbide; chinese patent document CN108585468A discloses a method for preparing rock wool by using silicon tailings as raw materials, and particularly discloses a method for preparing rock wool fibers by using silicon tailings, high-temperature ironmaking grain slag and other raw materials under the action of a centrifugal machine. However, when industrial waste is used as a raw material to prepare rock wool, a considerable proportion of cold modifier is usually added into high-temperature slag, which consumes a large amount of extra heat energy and has a complex tempering process; the acidity coefficient of traditional high-temperature slag, such as blast furnace slag, is too low, and even the components are difficult to control in a range suitable for preparing rock wool through thermal state tempering, so that the research on preparing the mineral wool with lower acidity coefficient by utilizing the traditional industrial slag is more. However, the performance of slag wool is far inferior to that of rock wool in terms of water resistance, heat resistance, corrosion resistance, and the like.

In view of the above, the present invention is particularly proposed.

Disclosure of Invention

In order to solve the technical problems, the invention provides a method for directly preparing rock wool by melting sponge iron slag by an electric furnace; the method for preparing the rock wool by directly fiberizing the sponge iron slag melted by the electric furnace has the advantages of no need of adding any modifier, simple process and simple and convenient operation, realizes the thermal mass coupling utilization of the sponge iron slag, and has important significance for the development strategy of energy conservation and emission reduction in the steel industry.

Specifically, the acidity coefficient of the sponge iron slag is greater than 1.5, and the sponge iron slag contains 6-13% of FeO; preferably, the sponge iron slag is slag for electric furnace steelmaking by taking sponge iron as a raw material.

The invention utilizes the slag (namely the hot sponge iron slag) of the electric furnace steelmaking to provide technical support for the clean production of the steel industry, greatly reduce the production cost of the rock wool, solve the problem of high energy consumption in the rock wool production and improve the greenness of rock wool products.

The main components in the sponge iron slag are derived from acid gangue and unreduced residual iron oxide in the sponge iron; further, the sponge iron slag mainly comprises the following components in percentage by mass:

wherein, the acidity coefficient of the sponge iron slag

Preferably, the sponge iron has the total iron mass fraction of not less than 85%, the metallization rate of more than 70% and the gangue content of 3.5-8.5%.

Preferably, the electric furnace steelmaking comprises the following steps: putting the sponge iron into an electric furnace at a speed of 25-30 kg/(MW & min), and melting for 20-60 min at 1450-1800 ℃ to obtain molten iron and sponge iron slag; the temperature of the sponge iron slag is 1450-1750 ℃.

Preferably, the method of the present invention comprises the steps of:

(1) introducing sponge iron slag at 1450-1750 ℃ into a wire throwing device through a drainage device, and discretely stretching under the action of high-pressure energy-carrying gas and centrifugal force to obtain rock wool fibers;

(2) spraying a binder on the rock wool fibers while blowing the rock wool fibers into a cotton collecting chamber to form raw cotton;

(3) and (3) conveying the raw cotton into a curing furnace, and pressing and forming.

According to the invention, the hot sponge iron slag is directly introduced into the wire throwing device through the drainage device, and no modifier or other auxiliary temperature control devices are needed; the sponge iron slag melted and separated by the electric furnace is directly thrown into filaments under the action of high-pressure energy-carrying gas and centrifugal force without tempering, and the rock wool fiber is obtained.

In order to further improve the performance of the rock wool, the process parameters are optimized (the optimized conditions are combined to obtain the better scheme of the invention); meanwhile, the heat energy released in the preparation method is considered, and then the heat energy is recycled; the method comprises the following specific steps:

preferably, the main body of the wire throwing device is a three-roll centrifuge, and the rotation speed of the three-roll centrifuge is configured as follows: 8000-10000 r/min of distributing roller, 14000-20000 r/min of first-level accelerating roller and 17000-25000 r/min of second-level accelerating roller.

Preferably, the throwing device is provided with a high-pressure energy-carrying gas inlet and outlet; controlling the temperature of the rock wool fibers to be 500-900 ℃ by adjusting the temperature of the air flow and the air flow, and simultaneously discharging high-temperature air; the temperature of the high-temperature air is 300-500 ℃, and the high-temperature air can be used as a heating source of steam required by power generation of a waste heat boiler.

Preferably, the binder is polyvinyl alcohol and/or a water-soluble phenolic resin.

Preferably, the rock wool fibers are subjected to heat exchange with air, and then hot air is discharged; 30-80% of the hot air is supplied to the filament throwing device, and 20-70% of the hot air is supplied to the curing oven; the rock wool fiber generates a large amount of heat energy after exchanging heat with normal temperature air, and the heat energy is supplied to a silk throwing device and a curing oven.

In order to enable the rock wool to be more compact, the height of the curing furnace is 3-6 mm lower than the thickness of the rock wool.

The invention also provides rock wool prepared by any one of the methods.

The invention directly utilizes the hot sponge iron slag to prepare the rock wool, greatly reduces the production cost of the rock wool and saves the energy consumption in the melt heating link.

The invention has the beneficial effects that:

the method for directly preparing the rock wool by melting and separating the sponge iron slag by the electric furnace has the advantages of conventional and common used equipment and short and easy-to-operate process flow; the method not only realizes the heat-mass coupling utilization of the slag obtained by electric furnace steelmaking to achieve the purposes of energy conservation and emission reduction in the ferrous metallurgy industry, but also creatively uses the sponge iron slag directly for the preparation of the rock wool without tempering, combines the process utilization heat and the recovery heat, realizes the self-sufficiency of heat energy in the production process, utilizes and recovers the waste heat of the high-temperature slag to the maximum extent, and simultaneously reduces the production cost of the rock wool as much as possible.

Drawings

FIG. 1 is a flow chart of a process for directly preparing rock wool by melting sponge iron slag in an electric furnace.

FIG. 2 is a pseudo-binary phase diagram of sponge iron slag; wherein (a) is the sponge iron slag composition of example 1; (b) the sponge iron slag composition of example 2.

FIG. 3 is a graph of the viscosity temperature curve of the sponge iron slag calculated by factSage; wherein (a) is a viscosity-temperature curve of the sponge iron slag of example 1; (b) the viscosity-temperature curve of the sponge iron slag of example 2.

Fig. 4 is rock wool fiber prepared in example 1.

Fig. 5 is rock wool prepared in example 2.

Detailed Description

The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.