CN101857439A

CN101857439A - Method for synthesizing SiC powder by utilizing gold mine tailings

Info

Publication number: CN101857439A
Application number: CN 201010210328
Authority: CN
Inventors: 徐利华; 仉小猛; 郝洪顺; 张作顺
Original assignee: University of Science and Technology Beijing USTB
Current assignee: University of Science and Technology Beijing USTB
Priority date: 2010-06-18
Filing date: 2010-06-18
Publication date: 2010-10-13

Abstract

The invention belongs to the technical field of comprehensive utilization of ceramics, refractory materials and mineral waste, and provides a method for synthesizing SiC powder by utilizing gold mine tailings, which has simple process, easy control and low raw material cost. The invention takes gold mine tailings as a main raw material, adds appropriate amount of quartz sand, and takes carbon powder as a reducing agent so as to obtain a uniform green body by mechanical pressing. In the preparation process, by controlling the charge ratio, sintering temperature, heating system, holding time and other process parameters, SiC-based mixed powder can be obtained. The invention has simple preparation, and no need for complex technological equipment and process, and simultaneously takes a large amount of waste tailings as a raw material, thereby turning waste into wealth so as to relieve the pressure of waste tailings on the environment. The SiC-based mixed powder can be obtained. The SiC powder can be widely used in metallurgy, chemical industry, electric power, energy resources and other industrial fields.

Description

A kind of method of utilizing the synthetic SiC powder of gold mine tailings

Technical field

The invention belongs to pottery, refractory materials and mineral products waste ' s reclamation technical field, a kind of method with the synthetic SiC powder of gold mine tailings is provided, technology simply is easy to control, and raw materials cost is low.

Background technology

Silicon carbide is a kind of strong covalent bond compound-material, have distinguishing features such as excellent hot strength, wear resistance, erosion resistance, anti-irradiation, high rigidity, high elastic coefficient, high heat conductance, hot strength, thermal expansivity are little, thermal shock resistance is good, obtained using widely in industries such as Aeronautics and Astronautics, automobile, machinery, petrochemical industry, metallurgy and electronics.

Carbothermic method is the common method of synthetic SiC powder, technology maturation, and technology is simple, be easy to control, but powder quality is not high, foreign matter content is big.

A kind of method of utilizing refinery coke chemistry reaction method to prepare the SiC ceramic powder is provided in the Chinese invention patent application of publication number for CN1511806A; with Si powder and refinery coke is raw material; under protection of inert gas atmosphere; light base substrate at 500 ℃～700 ℃ with the tungsten filament electric ignition, prepare the SiC ceramic powder.It is raw material that this method adopts silica flour, and price is higher, refinery coke composition instability, and this has just brought inconvenience to actual production.

The processing method of the high-purity alpha-SiC micropowder of a kind of direct generation is provided in the Chinese invention patent application of publication number for CN1163859A, is main raw material with silica powder, directly generates the high temperature modification silicon carbide (powder of α-SiC) through the low temperature carbothermic reduction.That this method obtains is high temperature modification α-SiC, and energy consumption is bigger, and nowadays pottery, refractories industry raw material adopt coking property β-SiC preferably more.

Nowadays, the report that much prepares the SiC powder about carbothermic reduction is arranged, the present invention has following outstanding feature by comparison: main raw material is environmentally hazardous gold mine tailings, and cost is low and help environment protection; Technology simply is easy to control; Used binding agent is PVA (polyvinyl alcohol), and reductive agent is carbon dust, and is cheap and easy to get.

Summary of the invention

The invention provides a kind of method of utilizing environmentally hazardous gold mine tailings for feedstock production SiC powder, purpose is to reduce production costs, and reduces environmental pollution.

A kind of method with the synthetic SiC powder of gold mine tailings, the present invention is main raw material with the gold mine tailings, adds appropriate amount of quartz sand, is reductive agent with the carbon dust, mechanical pressing obtains the uniform ingredients base substrate.In preparation process,, can obtain mixed powder based on SiC by processing parameters such as control ratio of components, sintering temperature, temperature increasing schedule, soaking times.Technical process is as follows:

1, related gold mine tailings principal constituent is SiO among the present invention ₂, also contain a small amount of A1 ₂O ₃, CaO, Fe ₂O ₃Deng composition.

2, gold mine tailings raw material pulverizing is crossed the 0.074mm standard sieve, then with mine tailing, SiO ₂, carbon dust (graphite or carbon black) is according to 2.5: the mass percent of 0.7-1.2: 1.7-2.2 is mixed;

3, add dehydrated alcohol in the compound as dispersion agent and grinding aid, ground at normal temperatures 5-7 hour, make it full and uniform mixing; The add-on of dehydrated alcohol is the 4-10% of compound total mass;

4, mixed powder mixes binding agent, places the grinding tool mechanical pressing, after the demoulding under 50-100 ℃ of temperature dry 18-24 hour; Per 10 gram hybrid reaction material adding additives amounts are 1～6ml; Binding agent is 3-5%PVA (polyvinyl alcohol), and all the other are water;

5, base substrate after the drying is put into crucible, bury carbon dust, place tube furnace then, following temperature increasing schedule heats up: 5-35 ℃ 60min to 200 ℃, 200 ℃ through 200min to 800 ℃, insulation 30min, temperature rise rate with 2-8 ℃/min is warming up to 1450-1650 ℃ then, be incubated 4-8 hour, naturally cool to 5-35 ℃, take out goods; And then put into 800 ℃ of retort furnaces and removed carbon residue in 5-7 hour.Obtain the mixed powder that principal crystalline phase is SiC.

The invention has the advantages that:

1, preparation technology is simple, need not complicated processing unit and technological process, and the while, turns waste into wealth as raw material with a large amount of discarded tailings, alleviates the pressure of depleted mine tailing to environment.

2, obtain mixed powder based on SiC.Can be widely used in industrial circles such as metallurgy, chemical industry, electric power, the energy.

Description of drawings

Fig. 1 is the XRD figure spectrum of the final powder product of gained.

Embodiment

Gold mine tailings consists of:

Composition	??SiO ₂	??Al ₂O ₃	??Fe ₃O ₄	????CaO	Surplus
Composition	??SiO ₂	??Al ₂O ₃	??Fe ₃O ₄	????CaO	Surplus	Mass percent/%	??90-94	??3-4	??1-2	????0.5-1	????1-5.5

Embodiment 1

With gold mine tailings, SiO ₂, carbon (graphite or carbon black) is according to 2.500: 0.846: 1.824 mass percent batch mixing, in anhydrous ethanol medium, ground 6 hours.

Take out mixed powder, drying is added binding agent, and mechanical pressing is the circular sample piece of Φ 10 * 4mm under 40MPa pressure then, after the demoulding under 80 ℃ of temperature dry 20 hours.

Base substrate after the drying is put into tube furnace, and room temperature is through 60min to 200 ℃, and 200 ℃ through 200min to 800 ℃, insulation 30min is warming up to 1200 ℃ with 5 ℃/min temperature rise rate then, insulation 30min, be warming up to 1500 ℃ with 3 ℃/min temperature rise rate again, be incubated 5 hours.

Sintering oven is reduced to 1200 ℃ with the speed of 4 ℃/min, then at 1200 ℃ of insulation 30min; Naturally cool to room temperature, take out goods; And then put into 6 hours burning-off carbon residue of 800 ℃ of retort furnaces insulation.Obtain the mixed powder that principal crystalline phase is SiC.

Embodiment 2

With gold mine tailings, SiO ₂, carbon (graphite or carbon black) is according to 2.500: 0.925: 1.936 mass percent batch mixing, in anhydrous ethanol medium, ground 6 hours.

Base substrate after the drying is put into tube furnace, and room temperature is through 60min to 200 ℃, and 200 ℃ through 200min to 800 ℃, insulation 30min is warming up to 1200 ℃ with 5 ℃/min temperature rise rate then, insulation 30min, be warming up to 1500 ℃ with 3 ℃/min temperature rise rate again, be incubated 7 hours.

Sintering oven is reduced to 1200 ℃ with the speed of 4 ℃/min, then at 1200 ℃ of insulation 30min; Naturally cool to room temperature, take out goods; And then put into 4 hours burning-off carbon residue of 800 ℃ of retort furnaces insulation.Obtain the mixed powder that principal crystalline phase is SiC.

Claims

1. a method of utilizing the synthetic SiC powder of gold mine tailings is characterized in that with the gold mine tailings being main raw material, adds appropriate amount of quartz sand, is reductive agent with the powdered carbon, and technical process is as follows:

(1), the gold mine tailings raw material pulverizing, cross the 0.074mm standard sieve, then with mine tailing, SiO ₂, carbon dust is according to 2.5: the mass percent of 0.7-1.2: 1.7-2.2 is mixed;

(2), add dehydrated alcohol in the compound as dispersion agent and grinding aid, ground at normal temperatures 5-7 hour, make it full and uniform mixing; The add-on of dehydrated alcohol is the 4-10% of compound total mass;

(3), mixed powder mixes binding agent, places the grinding tool mechanical pressing, after the demoulding under 50-100 ℃ of temperature dry 18-24 hour; Per 10 gram hybrid reaction material adding additives amounts are 1～6ml;

(4), base substrate after the drying is put into crucible, bury carbon dust, place tube furnace then, heat up by following temperature increasing schedule: 5-35 ℃ 60min to 200 ℃, 200 ℃ through 200min to 800 ℃, insulation 30min, temperature rise rate with 2-8 ℃/min is warming up to 1450-1650 ℃ then, be incubated 4-8 hour, naturally cool to 5-35 ℃, take out goods; And then put into 800 ℃ of retort furnaces and removed carbon residue in 5-7 hour; Obtain the mixed powder that principal crystalline phase is SiC.

2. a kind of according to claim 1 method of utilizing the synthetic SiC powder of gold mine tailings is characterized in that carbon dust is graphite or carbon black.

3. a kind of according to claim 1 method of utilizing the synthetic SiC powder of gold mine tailings is characterized in that binding agent is the 3-5% polyvinyl alcohol, and all the other are water.