CN109607538A - A method of by pretreated coal ash for manufacturing for silicon carbide - Google Patents
A method of by pretreated coal ash for manufacturing for silicon carbide Download PDFInfo
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- CN109607538A CN109607538A CN201910045974.4A CN201910045974A CN109607538A CN 109607538 A CN109607538 A CN 109607538A CN 201910045974 A CN201910045974 A CN 201910045974A CN 109607538 A CN109607538 A CN 109607538A
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- silicon carbide
- flyash
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/90—Carbides
- C01B32/914—Carbides of single elements
- C01B32/956—Silicon carbide
- C01B32/963—Preparation from compounds containing silicon
- C01B32/97—Preparation from SiO or SiO2
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
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Abstract
The present invention relates to the technologies for the silicon carbide for adding carbon dust heating preparation purity is high by pretreated flyash, more particularly to it is a kind of by pretreated coal ash for manufacturing for the method for silicon carbide, the present invention is in advance to flyash processing, eliminate calcium, magnesium, the iron tramp in flyash, obtain high-purity silicon dioxide, synthesize the higher silicon carbide of purity using obtained high-purity silicon dioxide and carbon dust later, to widen its application range and to improve application life.
Description
Technical field
The present invention relates to the technologies for the silicon carbide for adding carbon dust heating preparation purity is high by pretreated flyash, specifically relate to
And it is a kind of by pretreated coal ash for manufacturing for the method for silicon carbide, the skill of silicon carbide can be prepared in lower temperature by induction furnace
Art.
Background technique
Flyash is the product left after coal-burning utilities coal dust firing, since large-scale steam power plant consumes up to 5000 per hour
Ton coal about generates the flyash of 5%-45% even 60% after one ton of coal combustion, along with desulfurating dust-removing equipment is often de-
The CaO of sulphur is also discharged in flyash, causes the Chinese annual flyash for generating about 600,000,000 tons.With the development powder of power industry
The discharge amount of coal ash is also in the trend of cumulative year after year.The huge flyash of yield is dealt with improperly, to air, water and soil and human health
It will cause harm.
The comprehensive utilization of flyash is constantly subjected to the concern and attention of various countries for a long time.Europe, Japanese, the U.S. fine coal
Ash, which utilizes, reaches 90% or more.In the 1980s, China is classified as comprehensive utilization of resources one great economy of economic construction
After technical policy, utilization of fly ash rates from the 28.3% of nineteen ninety rise to 2010 69%, flyash in building materials, pave the way, agriculture
The every field such as industry chemical industry are all widely applied.It is mainly with coal ash for manufacturing cement and energy-saving heat preserving material in terms of building materials
Material；It repairs the roads, is directly to be used to pave the way as normal soil by flyash, saves arable land；Agriculture aspect mainly utilizes flyash
Containing microelement, the modifying agent as soil；Mainly with coal ash for manufacturing for molecular sieve, white carbon black and oxidation in terms of chemical industry
Aluminium etc..
It is a kind of secondary resource with value of exploiting and utilizing containing the silica of 50%-70% in flyash.Carbon is also
Former pretreated coal ash for manufacturing can not only expand the utilization ways of flyash, so that flyash high added value for silicon carbide
It utilizes, moreover it is possible to extend the sustainable development of Coal Industrial chain and coal and power industry.
Patent CN102502640A describes a kind of microwave heating of pulverized fuel ash and aluminium electroloysis waste cathode carbon block synthesizing silicon carbide
Method, use ammonium sulfate roasting to be milled to the flyash of 300 mesh, add sulfuric acid leaching to obtain siliceous solid material, by flotation
The carbon dust that aluminium electroloysis waste cathode carbon block obtains is uniformly mixed with above-mentioned solid material, in the microwave field of 2450MHz or 916MHz
30-300min is synthesized, silicon carbide products are obtained.This method cleans not enough thoroughly first, obtains that product purity is low；Secondly, micro-
Wave method can not expanding production, limit the application of this technology.Patent CN107399988A describes a kind of utilization aluminium silicon systems work
The method that industry waste residue prepares aluminum oxide-silicon carbide composite porous ceramic, directly with coal ash for manufacturing for silicon carbide class composite ceramics by
Also containing iron and other impurities in flyash will be greatly reduced ceramic performance.Shen red flag has studied the shadow of flyash concrete performance
It rings；Li Qingfan, Gao Lianyu, Zhao Chengwen have studied fly ash concrete mini hollow block；Feng Chunhua, Li Dongxu have studied fine coal
The extent of reaction of the ash in cement slurry；Li Liang has studied coal ash for manufacturing for haydite；Xiao Cuiwei etc. has studied flyash for water
The feasibility of processing；Du Haishun etc. has studied application of the coal ash fiber in papermaking；It is standby that we have studied coal ash for manufacturing before
Molecular sieve and its application.These researchs are that making full use of for flyash provides number of ways.
Silicon carbide also known as diamond dust are yellow to green, blue to black crystals.Silicon carbide due to stable chemical performance,
Thermal coefficient is high, thermal expansion coefficient is small, wear-resisting property is good, is widely used in abrasive material, anti-wear agent, grinding tool, high grade refractory, fine
Ceramics etc..Except this is in addition to, there are also a lot of other purposes, such as: silicon carbide powder is coated on special process by turbine impeller
Or the inner wall of cylinder block, its wearability can be improved and prolong the service life 1~2 times；It is heat-resisting to manufactured high grade refractory
Shake, small in size, light-weight and intensity is high, energy-saving effect is good.Silicon carbide is fabulous deoxidier, can be accelerated to make steel speed with it,
And convenient for control chemical component, the quality of steel is improved.Silicon carbide is also largely used to production heating element Elema.
Summary of the invention
In order to solve the above technical problems, the present invention provides a kind of method by pretreated coal ash for manufacturing for silicon carbide.
Specific technical solution is as follows:
A method of by pretreated coal ash for manufacturing for silicon carbide, include the following steps:
(1) by flyash grinding to 300 mesh hereinafter, with fine coal ashes and NaOH or Na2CO3The ratio of mass ratio 1:1.5-2.5
Example mix, in high temperature furnace 600-800 DEG C calcining 2-3 hours；
(2) calcined product is leached with the NaOH aqueous solution of mass percent 10-15%, it is miscellaneous is filtered to remove calcium, iron, magnesium etc.
Matter obtains the solution of silicon-aluminum containing；
(3) above-mentioned solution acid adding is adjusted to pH less than 1, filtering, obtains silicic acid precipitating, while by Al3+It stays in the solution；
(4) obtained pure silicic acid is deposited in muffle furnace and is heated in 300 DEG C, the SiO that will be obtained after dehydration2With carbon
Powder, binder mix simultaneously, and mixed carbon comtent is 0.5-2 times, depress to bulk in pressure-like machine in 5Mpa；
(5) block-like sample will be pressed into step (4) to be placed in graphite crucible, 1500- is gradually heated in induction furnace
1600 DEG C of heating, are passed through nitrogen as protective atmosphere in the process, generate a large amount of yellow silicon carbide flue dust in low temperature, when high temperature
Then generate black silicon carbide；
(6) heat 1 hour or so and stop, taking out sample after cooling, it can be seen that crucible walls by a large amount of ferrous metal gloss,
Glistening silicon carbide product generates.
Binder described in step (4) is starch.
Silicon carbide product described in step (6) reaches 80.03%-91.04% by XRF analysis, carborundum content, single
Matter silicone content is 2.61%-0, iron content 3.95%-0, remaining is the complete carbon dust of unreacted.
Compared with prior art, the advantageous effects of this method are as follows:
(1) silicon carbide of high-purity can improve its intensity and thermal conductivity, and be not easy fragmentation, for this purpose, the present invention is preparatory
To flyash processing, calcium, magnesium, the iron tramp in flyash are eliminated, high-purity silicon dioxide is obtained, it is high-purity using what is obtained later
Silica and carbon dust synthesize the higher silicon carbide of purity, to widen its application range and to improve application life.
(2) iron tramp removed can be used to prepare iron oxide red, and further deep processing can obtain sponge iron, for making steel.It obtains
Aluminium ion solution purity it is high, can be used to produce aluminium oxide, further be also used as the raw material production electrolytic aluminium of electrolytic aluminium.
Since silicon and aluminium have accounted for 70% or more of flyash quality, if carrying out the two using flyash almost without residue, this
The also available solution of the problem of sample flyash storage land occupation, and obtain economic benefit.
Detailed description of the invention
Fig. 1 is influence of the mixed carbon comtent to reaction product.
Specific embodiment
The present invention is described in detail with reference to the accompanying drawings and examples, but protection scope of the present invention not by attached drawing and
Embodiment is limited.
Embodiment 1
By flyash grinding to 300 mesh hereinafter, the NaOH with 1.5 times of mass ratioes is mixed, calcined in high temperature furnace at 600 DEG C
2 hours；Calcined product is leached with 10% or so NaOH aqueous solution, the impurity such as calcium, iron, magnesium is filtered to remove, obtains silicon-aluminum containing
Solution；Above-mentioned solution acid adding is adjusted to pH less than 1, obtains silicic acid precipitating, while by Al3+It stays in the solution；It is pure by what is obtained
Net silicic acid is deposited in muffle furnace to be heated in 300 DEG C, the SiO that will be obtained after dehydration2It is mixed simultaneously with binders such as carbon dust, starch
It closes, mixed carbon comtent is 0.5 times, depresses to bulk in pressure-like machine in 5Mpa；Block-like sample will be pressed into be placed in graphite crucible, in sense
It answers and is gradually heated to 1500 DEG C in furnace, be passed through nitrogen in the process as protective atmosphere；Stop within heating 1 hour or so, after cooling
Sample is taken out, i.e., it can be seen that crucible walls have a large amount of ferrous metal gloss, glistening silicon carbide to generate.Pass through XRF analysis, carbon
SiClx content reaches 80.03%, and simple substance silicone content is 2.61%, iron content 3.95%, remaining is the complete dioxy of unreacted
SiClx and carbon dust.
Embodiment 2:
By flyash grinding to 300 mesh hereinafter, Na with 2 times of mass ratioes2CO3It mixes, is calcined in high temperature furnace at 800 DEG C
2.5 hour；Calcined product is leached with 13% or so NaOH aqueous solution, the impurity such as calcium, iron, magnesium is filtered to remove, obtains silicon-aluminum containing
Solution；Above-mentioned solution acid adding is adjusted to pH less than 1, obtains silicic acid precipitating, while by Al3+It stays in the solution；By what is obtained
Pure silicic acid is deposited in muffle furnace to be heated in 300 DEG C, the SiO that will be obtained after dehydration2It is mixed simultaneously with binders such as carbon dust, starch
It closes, mixed carbon comtent is 1 times, depresses to bulk in pressure-like machine in 5Mpa；Block-like sample will be pressed into be placed in graphite crucible, in induction
It is gradually heated to 1550 DEG C in furnace, is passed through nitrogen in the process as protective atmosphere；Stop within heating 1 hour or so, is taken after cooling
Sample out, i.e., it can be seen that crucible walls have a large amount of ferrous metal gloss, glistening silicon carbide to generate.Pass through XRF analysis, carbonization
Silicone content reaches 85.03%, and simple substance silicone content is 2.04%, remaining is the complete silica of unreacted and carbon dust.
Embodiment 3:
By flyash grinding to 300 mesh hereinafter, the NaOH with 2.5 times of mass ratioes is mixed, calcined in high temperature furnace at 600 DEG C
3 hours；Calcined product is leached with 15% or so NaOH aqueous solution, the impurity such as calcium, iron, magnesium is filtered to remove, obtains silicon-aluminum containing
Solution；Above-mentioned solution acid adding is adjusted to pH less than 1, obtains silicic acid precipitating, while by Al3+It stays in the solution；It is pure by what is obtained
Net silicic acid is deposited in muffle furnace to be heated in 300 DEG C, the SiO that will be obtained after dehydration2It is mixed simultaneously with binders such as carbon dust, starch
It closes, mixed carbon comtent is 1.5 times, depresses to bulk in pressure-like machine in 5Mpa；Block-like sample will be pressed into be placed in graphite crucible, in sense
It answers and is gradually heated to 1600 DEG C in furnace, be passed through nitrogen in the process as protective atmosphere；Stop within heating 1 hour or so, after cooling
Sample is taken out, i.e., it can be seen that crucible walls have a large amount of ferrous metal gloss, glistening silicon carbide to generate.Pass through XRF analysis, carbon
SiClx content reaches 90.98%, and simple substance silicone content is 0, remaining is the complete silica of unreacted and carbon dust.
Embodiment 4:
By flyash grinding to 300 mesh hereinafter, the NaOH with 2 times of mass ratioes is mixed, 2 are calcined at 700 DEG C in high temperature furnace
Hour；Calcined product is leached with 15% or so NaOH aqueous solution, the impurity such as calcium, iron, magnesium is filtered to remove, obtains the molten of silicon-aluminum containing
Liquid；Above-mentioned solution acid adding is adjusted to pH less than 1, obtains silicic acid precipitating, while by Al3+It stays in the solution；It is pure by what is obtained
Silicic acid is deposited in muffle furnace to be heated in 300 DEG C, the SiO that will be obtained after dehydration2It is mixed simultaneously with binders such as carbon dust, starch,
Mixed carbon comtent is 2 times, depresses to bulk in pressure-like machine in 5Mpa；Block-like sample will be pressed into be placed in graphite crucible, in induction furnace
In be gradually heated to 1500 DEG C, be passed through nitrogen in the process as protective atmosphere；Stop within heating 1 hour or so, is taken out after cooling
Sample, i.e., it can be seen that crucible walls have a large amount of ferrous metal gloss, glistening silicon carbide to generate.Pass through XRF analysis, silicon carbide
Content reaches 91.04%, and simple substance silicone content is 0, remaining is the complete silica of unreacted and carbon dust.
Mixed carbon comtent refers to plus carbon amounts generates the ratio of carbon amounts required for silicon carbide with real reaction, and mixed carbon comtent produces reaction
The influence of object is as shown in Figure 1, as seen from Figure 1, the content of aluminium oxide and monocrystalline silicon gradually decreases, and the content of silicon carbide gradually increases
Add, when mixed carbon comtent is greater than 1.5 times, without the diffraction maximum of aluminium oxide and monocrystalline silicon in XRD diagram, at this point, silicon carbide purity
90% or more is had reached, remaining ingredient is carbon dust.
Claims (3)
1. it is a kind of by pretreated coal ash for manufacturing for the method for silicon carbide, which comprises the steps of:
(1) by flyash grinding to 300 mesh hereinafter, with fine coal ashes and NaOH or Na2CO3The ratio of mass ratio 1:1.5-2.5 is mixed
It is even, in high temperature furnace 600-800 DEG C calcining 2-3 hours；
(2) calcined product is leached with the NaOH aqueous solution of mass percent 10-15%, is filtered to remove the impurity such as calcium, iron, magnesium, obtains
To the solution of silicon-aluminum containing；
(3) above-mentioned solution acid adding is adjusted to pH less than 1, filtering, obtains silicic acid precipitating, while by Al3+It stays in the solution；
(4) obtained pure silicic acid is deposited in muffle furnace and is heated in 300 DEG C, the SiO that will be obtained after dehydration2With carbon dust, bonding
Agent mixes simultaneously, and mixed carbon comtent is 0.5-2 times, depresses to bulk in pressure-like machine in 5Mpa；
(5) block-like sample will be pressed into step (4) to be placed in graphite crucible, 1500-1600 is gradually heated in induction furnace
DEG C heating, be passed through nitrogen in the process as protective atmosphere, a large amount of yellow silicon carbide flue dust, high temperature Shi Zesheng generated in low temperature
At black silicon carbide；
(6) it heats 1 hour or so and stops, taking out sample after cooling, it can be seen that crucible walls are by a large amount of ferrous metal gloss, spar
Brilliant silicon carbide product generates.
2. it is according to claim 1 by pretreated coal ash for manufacturing for the method for silicon carbide, it is characterised in that: step
(4) binder described in is starch.
3. it is according to claim 1 by pretreated coal ash for manufacturing for the method for silicon carbide, it is characterised in that: step
(6) the silicon carbide product described in is by XRF analysis, and carborundum content reaches 80.03%-91.04%, and simple substance silicone content is
2.61%-0, iron content 3.95%-0, remaining is the complete carbon dust of unreacted.
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| CN201910045974.4A CN109607538A (en) | 2019-01-18 | 2019-01-18 | A method of by pretreated coal ash for manufacturing for silicon carbide |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101041450A (en) * | 2006-03-15 | 2007-09-26 | 中国地质大学（北京） | Clean production technique for preparation of aluminium oxide and white carbon black by using high-alumina coal ash |
| CN101428800A (en) * | 2008-11-28 | 2009-05-13 | 首钢总公司 | Method for synthesis of SiC with used refractory materials |
| CN107337214A (en) * | 2017-07-26 | 2017-11-10 | 东北大学 | A kind of alkali fusion alkali solution technique purification and impurity removal technique of flyash |
-
2019
- 2019-01-18 CN CN201910045974.4A patent/CN109607538A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101041450A (en) * | 2006-03-15 | 2007-09-26 | 中国地质大学（北京） | Clean production technique for preparation of aluminium oxide and white carbon black by using high-alumina coal ash |
| CN101428800A (en) * | 2008-11-28 | 2009-05-13 | 首钢总公司 | Method for synthesis of SiC with used refractory materials |
| CN107337214A (en) * | 2017-07-26 | 2017-11-10 | 东北大学 | A kind of alkali fusion alkali solution technique purification and impurity removal technique of flyash |
Non-Patent Citations (1)
| Title |
|---|
| 周忠华: "用铝回收后的粉煤灰残渣制备碳化硅", 《粉煤灰综合利用》 * |
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Application publication date: 20190412 |