阅读说明：本技术 一种利用工业废料原位制备高炉炉底炉缸用耐火浇注料的方法 (Method for in-situ preparation of refractory castable for blast furnace bottom and hearth by using industrial waste ) 是由 左亮珠 于 2020-06-18 设计创作，主要内容包括：本发明公开了一种利用工业废料原位制备高炉炉底炉缸用耐火浇注料的方法,主要原料包括工业废料(多晶硅切割废料和废电极),辅料为硅溶胶、沥青、α-Al<Sub>2</Sub>O<Sub>3</Sub>微粉和催化剂等,其中将多晶硅切割废料粉磨筛分成不同粒度级配,废电极磨成颗粒,混合浇注,低温硬化成型。本发明制备的浇注料硬度好,热导率高,机械性能强,相比于一般的碳砖材料和现有的浇注料,本发明利用高炉炉底炉缸的高温环境,将工业废料原位合成碳化硅,成本低、工艺简单、性能优良,适合应用于高炉炉底、炉缸等恶劣的工作环境中。(The invention discloses a method for preparing refractory castable for a blast furnace bottom hearth in situ by utilizing industrial waste, which comprises the main raw materials of industrial waste (polysilicon cutting waste and waste electrodes) and the auxiliary materials of silica sol, asphalt and α -Al 2 O 3 The polysilicon cutting waste is ground and sieved into different grain size distributions, the waste electrodes are ground into particles, and the particles are mixed, poured and hardened at low temperature to form the polysilicon cutting waste. The castable prepared by the invention has good hardness, high thermal conductivity and strong mechanical property, compared with common carbon brick materials and the existing castable, the castable utilizes the high-temperature environment of the furnace bottom and the furnace hearth of the blast furnace to synthesize silicon carbide in situ from industrial waste, has low cost, simple process and excellent performance, and is suitable for being applied to the severe working environments of the furnace bottom, the furnace hearth and the like of the blast furnace.)

1. A method for preparing a refractory castable for a blast furnace bottom hearth in situ by using industrial waste is characterized by comprising the following steps:

(1) selecting raw materials: cutting waste of polycrystalline siliconSilicon source, waste electrode as carbon source, silica sol, asphalt, α -Al₂O₃Micro powder and a catalyst are used as auxiliary materials;

(2) the castable is prepared from (by weight) polysilicon cutting waste 50-60%, waste electrode 15-25%, asphalt 10-15%, silica sol 3-8%, and α -Al₂O₃3-8% of micro powder and 1-3% of catalyst;

(3) grinding and screening the polycrystalline silicon cutting waste into different grain size distributions;

(4) grinding the waste electrode into particles;

(5) cutting the polycrystalline silicon into waste materials, waste electrode particles, asphalt, silica sol, α -Al₂O₃And (3) placing the micro powder and the catalyst into a stirrer to be mixed for 2 minutes at room temperature, pouring after the mixing is finished, and placing for 12-24 hours after the pouring is finished to finish the hardening and forming at low temperature.

2. The method of claim 1, wherein: in the step (3), the grain size distribution of the polycrystalline silicon cutting waste is 40% with the grain size of 0-48 μm; the granularity is 48-150 mu m and 30 percent; the particle size is 150-1000 μm, 30%.

3. The method of claim 1, wherein: the polycrystalline silicon cutting waste is photovoltaic industry processing waste, and the main components of the polycrystalline silicon cutting waste are metal silicon, silicon dioxide, silicon carbide and a small amount of iron oxide.

4. The method of claim 1, wherein: the raw materials are firstly mixed uniformly for 2 minutes at room temperature, then the mixture is cast, and the mixture is hardened and formed at low temperature for 12 to 24 hours after the casting, the gelling property of the asphalt is reflected above 300 ℃ in a furnace baking stage, and the strength of the casting material is further increased.

5. The method of claim 1, wherein: the in-situ synthesis is that graphite in a waste electrode is promoted to react with metal silicon or silicon dioxide in polycrystalline silicon cutting waste to produce silicon carbide crystals in the presence of a catalyst by utilizing the high-temperature environment (1500-1550 ℃) of a hearth position in the production process of a blast furnace, and the hearth silicon carbide refractory material is sintered in situ.

6. The method of claim 1, wherein: the waste electrode is an industrial waste graphite electrode, wherein the fixed carbon is more than 70%.

7. The method of claim 1, wherein: the silica sol and the asphalt belong to binders of systems at medium and low temperatures and can be used as sources of silicon elements and carbon elements respectively.

8. The method of claim 1, wherein: the catalyst is one or more of ferric oxide, borax, boron oxide, nickel sulfate and nickel oxide.

9. The method according to claim 1, wherein the reaction solution is α -Al₂O₃The particle size of the micro powder is not more than 10 μm.

Technical Field

The invention relates to an industrial waste value-added utilization approach and a preparation method, in particular to a method for preparing a refractory castable for a blast furnace bottom hearth in situ by using industrial waste, belonging to the technical field of synthesis of inorganic non-metallic materials.

Background

In recent years, the usage amount of polycrystalline silicon in solar cells in China is getting larger, a cutting process is one of indispensable flows in the production process of the solar cells, no matter the traditional mortar wire saw cutting technology or the emerging diamond wire cutting technology, a large amount of polycrystalline silicon cutting waste materials are generated in the cutting process, and the polycrystalline silicon cutting waste materials are accumulated and stockpiled over years, so that the environment pollution and the resource waste are caused. These wastes often contain large amounts of metallic silicon, silica, abrasive materials (iron oxide or carbon), etc., and are ideal raw materials for preparing silicon carbide refractory materials.

Meanwhile, with the advance of ecological civilized construction, the steel industry is influenced by environmental protection policies, frequent technical improvement and seasonal yield limitation lead to long-term non-continuous operation of the blast furnace, the risks of corrosion of the furnace bottom and burning-through of the furnace hearth are greatly increased, the service life of the blast furnace is obviously shortened, and the method becomes a technical problem which troubles the steel smelting industry in China. As a traditional furnace bottom and hearth refractory material, the carbon brick utilizes the high thermal conductivity, low thermal expansion and non-wettability with slag of graphite. Thermal stress instability and furnace shock caused by frequent furnace shutdown ignition accelerate expansion cracking and pulverization of the carbon bricks, and the erosion of molten iron to the carbon bricks is seriously aggravated. The plastic refractory casting material is a novel refractory material for the bottom and the hearth of the blast furnace which is integrally formed, and compared with carbon bricks which are poor in heat conductivity and easy to crack and pulverize, the refractory casting material has better high-temperature heat conductivity, shock resistance and compressive strength at high temperature.

Therefore, the invention takes industrial solid wastes such as industrial wastes and waste motor particles generated in the polysilicon industry as raw materials, utilizes the heat source of the blast furnace production process to prepare and synthesize the refractory castable for the hearth and the hearth of the blast furnace in situ, and the prepared refractory castable has high thermal conductivity, good thermal shock resistance and excellent high-temperature compressive strength.

Disclosure of Invention

The invention aims to develop a process method for preparing a blast furnace bottom hearth castable in situ by using industrial waste, and realize high-value utilization of the industrial waste.

The invention realizes the aim through the following technical scheme, and provides a method for preparing a refractory castable for a blast furnace bottom hearth in situ by using industrial waste, which comprises the following steps:

(1) selecting raw materials, namely: the cutting waste of polysilicon is used as silicon source and the waste electrode is used asAs carbon source, silica sol, pitch, α -Al₂O₃Micro powder and catalyst as auxiliary materials.

(2) The castable is prepared from (by weight) polysilicon cutting waste 50-60%, waste electrode 15-25%, asphalt 10-15%, silica sol 3-8%, and α -Al₂O₃3-8% of micro powder and 1-3% of catalyst.

(3) The selected polycrystalline silicon cutting waste is photovoltaic industry processing waste, and the main components of the polycrystalline silicon cutting waste are metal silicon, silicon dioxide, silicon carbide, a small amount of iron oxide and the like. Grinding and screening the polysilicon cutting waste into different grain size distributions (0-48 μm, 48-150 μm and 150-1000 μm);

(4) the selected waste electrode is an industrial waste graphite electrode, wherein the fixed carbon is more than 70 percent, and the waste electrode is ground into particles (150-;

(5) the selected silica sol and asphalt belong to binders of systems at medium and low temperatures and can be used as sources of silicon elements and carbon elements respectively.

(6) The catalyst comprises ferric oxide, borax (or boron oxide), nickel sulfate (or nickel oxide) and the like.

(7) Cutting waste material of polysilicon, waste electrode particles, asphalt, silica sol, α -Al₂O₃And (3) placing the micro powder and the catalyst into a stirrer to be mixed for 2 minutes at room temperature, pouring after the mixing is finished, and placing for 12-24 hours after the pouring is finished to finish the hardening and forming at low temperature.

Preferably, the grain size distribution of the polycrystalline silicon cutting waste is 0-48 mu m, 40%; the granularity is 48-150 mu m and 30 percent; the particle size is 150-1000 μm, 30%.

The waste electrode is an industrial waste graphite electrode, wherein the fixed carbon is more than 70%. The waste electrode is ground into particles of 150-1000 μm.

The silica sol and the asphalt belong to binders of systems at medium and low temperatures and can be used as sources of silicon elements and carbon elements respectively.

The catalyst is one or more of ferric oxide, borax, boron oxide, nickel sulfate and nickel oxide.

α-Al₂O₃The particle size of the micro powder is not more than 10 μm.

The pitch of the present invention uses a mesophase pitch. Asphalt is also commonly used as a refractory binder, and the asphalt has the functions of physical bonding and carbonization, and belongs to physical bonding at a lower temperature, and the function of the asphalt is similar to that of silica sol. With the increase of the temperature, the asphalt can be carbonized and graphitized to form a chemical bonding effect with higher strength. The data in the table are a study comparing the effect of temperature increase on material strength when phenolic resin and mesophase pitch are used as binder in refractory materials, respectively.

Compressive strength of two types of adhesive blocks at different temperatures

The baking temperature (above 300 ℃) is mentioned mainly because the carbonization transformation starting temperature of the asphalt is about 300 ℃, and the contribution of the asphalt to the strength is different from that of the silica gel at the stage and is slowly increased.

The invention has the beneficial effects that: the raw materials are mixed and poured, and are firstly molded at low temperature, the acting binders are mainly silica sol and asphalt, then the asphalt begins to be carbonized along with the operation of a baking furnace when the temperature is increased, the contribution to the strength is increased, the strength is further increased, and then the polysilicon cutting material reacts with a waste electrode to generate silicon carbide in situ after the temperature reaches 1500-. The prepared furnace bottom and furnace hearth high-heat-conductivity castable has good high-temperature mechanical property and good heat conductivity, is suitable for being applied to severe working environments such as the furnace bottom and the furnace hearth of a blast furnace, and the like, and the raw material source is industrial waste, so that the existing problems in the operation of the blast furnace are solved, the high-valued utilization of the industrial waste is realized, and the economic and ecological benefits are remarkable.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.