CN102602941B - Method for protecting original porous texture of rice hulls at high temperature - Google Patents
Method for protecting original porous texture of rice hulls at high temperature Download PDFInfo
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Abstract
The invention relates to a method for protecting the original porous texture of rice hulls at a high temperature. The technical scheme of the invention is as follows: placing the rice hulls in a hydrochloric acid, sulfuric acid or oxalic acid solution, soaking for 1-2h at 90-100 DEG C with a stirring speed of 350-450r/min, filtering, washing the acid-leached rice hulls with water until the pH of the filtrate is 6-8, and insulating for 24-30h at 80-100 DEG C to obtain pretreated rice hulls; adding the pretreated rice hulls to an oxide sol in a proportion of 1kg:(25-35L), standing for 0.5-12h by a vacuum degree of 0.07-0.08MPa, relieving the negative pressure, placing for 2-24h at room temperature, and insulating for 24-30h at 80-100 DEG C to obtain retreated rice hulls; and then keeping the retreated hulls for 3-4h at 900-1600 DEG C to obtain the high-temperature treated rice hulls. The rice hulls treated by the method provided by the invention can keep the original porous texture at a high temperature and form a compound with an infrared screening agent in-situ, and the method realizes high-efficiency and comprehensive utilization of wastes.
Description
Technical field
The invention belongs to the compound porous lagging material technical field of rice husk, be specifically related to a kind of method of at high temperature protecting the original porous texture of rice husk.
Background technology
Annual more than 400,000,000 ton of the paddy of producing of China, can produce more than 8,000 ten thousand tons, rice husk, accounts for more than 30% of Gross World Product, rank first in the world, and mostly as the primary fuel utilization, comprehensive utilization ratio less than 10%; Because its density is little, volume is large, environment has been caused to pollution, and mostly not processing of the rice hull ash formed after burning, become agricultural wastes in many places, environment is exerted heavy pressures on.Therefore, seek for rice husk the very big concern that suitable outlet has caused scientific and technical personnel.
Be rich in silicon-dioxide in rice husk, mainly be distributed in the appearance internal layer of rice husk, granular size is in the 50nm left and right, mainly to exist with metamict, massfraction shared in rice husk is 3.0%～22.0%, and in rice husk, remaining overwhelming majority is organism, also has a small amount of inorganic oxide.The research discovery, forming amorphous silica by biomineralization in organism is to complete under gentle physiological status.These biogenic silicon-dioxide have accurate Genetic Control, present the exquisite structure of nanometer level, at aspects such as density, component, calorifics and mechanical properties, have diversity widely, are that the mankind at present can't be produced.SiO in soil
2through thering is the features such as high-purity, active after biological action, the more important thing is through the plant SiO of " processing " again
2nanostructure with structure exquisiteness, different modeling.This structure had both been constructed a large amount of nanoaperture, the porous SiO obtained by plant simultaneously
2overcome the shortcoming that aerogel intensity is low, fragility is large, from nanoscale, progressively strengthened SiO
2the mechanical strength of porous material.The silicon-dioxide extracted in rice husk is more laborsaving and more economical than synthetic other nano materials, directly from rice husk, prepares nanoporous SiO
2and matrix material is to solve the key point that rice husk utilizes, it not only can expand the comprehensive utilization of rice husk, also can deepen the theoretical investigation of rice husk, has broad application prospects.Prepare porous SiO with rice husk as raw material
2it is a desirable selection.
But rice husk needs to carry out pyroprocessing in extracting the silicon-dioxide process, can destroy most original porous texture of rice husk in high-temperature process, this just can only obtain high-purity silicon dioxide, and can not obtain the high-purity silicon dioxide of porous.And, want to reach the requirement of super insulating material performance each side, must introduce infrared screening agent in material.Existing infrared screening agent all exists with particle form, and the nanostructure because the distinctive plant materials of rice husk comes in every shape, be difficult to realize that by simple physical blending method infrared screening agent is at SiO
2in dispersed, and can further destroy SiO in rice husk
2vesicular structure, and then certainly will affect the heat-insulating property of material.Thereby if rice husk reaches good application, be necessary how research obtains SiO in high-purity porous silica and infrared screening agent and rice husk
2complex method.
At present mainly at it, prepared aspect gac and fine silica powder by the research of rice husk: " a kind of rice husk prepares the method for gac " (CN201010570920.9)) patented technology, a kind of method that rice husk, zinc oxide, dilute hydrochloric acid, sodium hydroxide are the raw material production gac of utilizing is disclosed, it is large that the method defect is mainly reflected in zinc oxide dosage, cost is high, rice husk after high-temperature activation after carbon content low, so the yielding poorly of gac; " utilize rice husk to prepare the method for HIGH-PURITY SILICON " (CN20101027008.6) patent patented technology, a kind of method of utilizing rice husk to prepare HIGH-PURITY SILICON is disclosed, the method complex process, also need the pyroprocessing of 1000 ~ 2000 ℃ in technique, cost is high, and after pyroprocessing, the porous texture of rice husk silicon-dioxide is destroyed.
On the whole, current research method is very low to the utilization ratio of rice husk, and has only utilized silicon-dioxide or the carbon in the rice husk, to the utilization of its porous texture, in space state, does not also have a kind of processing method to make rice husk well be utilized industrial.
Summary of the invention
The present invention is intended to overcome the prior art defect, and a kind of high-efficiency comprehensive utilization to waste that purpose is to provide, with low cost, technique is simple and the high method of at high temperature protecting the original porous texture of rice husk of product added value; Rice husk after processing by the method can at high temperature keep original porous texture and the compound infrared screening agent of energy original position.
For achieving the above object, the technical solution used in the present invention comprises the following steps:
The pre-treatment of step 1, rice husk
Rice husk is placed in to hydrochloric acid, sulfuric acid or oxalic acid solution, under the condition of 90 ~ 100 ℃ of temperature and 350 ~ 450r/min stir speed (S.S.), soaks 1 ~ 2h, filter, obtain the acidleach rice husk; Water cleaning acidleach rice husk to the pH value of filtrate is 6 ~ 8 again, then under 80 ~ 100 ℃ of conditions, is incubated 24 ~ 30 hours, obtains the pre-treatment rice husk.
Processing again of step 2, rice husk
The pre-treatment rice husk is joined in oxide sol, the ratio of pre-treatment rice husk and oxide sol is 1kg ︰ (25 ~ 35L), in vacuum tightness, be standing 0.5 ~ 12h under 0.07 ~ 0.08MPa condition, remove again negative pressure, place 2 ~ 24h under the room temperature normal pressure, then be incubated 24 ~ 30 hours under 80 ~ 100 ℃ of conditions, obtain processing again rice husk.
The pyroprocessing of step 3, rice husk
To process again rice husk and be incubated 3 ~ 4h under 900 ~ 1600 ℃ of conditions, obtain the pyroprocessing rice husk.
In technique scheme: described hydrochloric acid, sulfuric acid and oxalic acid solution concentration are 0.2 ~ 5wt%; Described oxide sol is a kind of in zirconia sol, titanium oxide sol and ferric oxide colloidal sol, and zirconia sol concentration wherein is 0.3 ~ 5mol/L.
Owing to adopting technique scheme, the present invention, by rice husk being carried out to pre-treatment, adopting oxide sol to the processing again of rice husk and heat-treat under differing temps processing rice husk again, obtains the rice husk of pyroprocessing.The present invention compared with prior art, has following advantage:
1, having solved rice husk original porous texture after pyroprocessing caves in and is unfavorable for the problem as the high-performance porous material;
2, effectively solved the problem that rice husk silicon-dioxide is reunited;
3, the original position of rice husk silicon-dioxide and infrared screening agent is compound, and on the basis that has retained rice husk porous silica texture, original position has formed the material with infrared shielding effect, for rice husk prepares the High Performance Adiabatic material, lays a good foundation.
Rice husk after the present invention processes is after testing: show pyroprocessing under 900 ~ 1600 ℃ of conditions, various oxide sols are processed in rice husk and have still been retained the original porous texture of rice husk, but the equal infrared screening agent of original position composition generation, and be evenly distributed, the rice husk SiO after pyroprocessing
2agglomeration obtained effective improvement.
That the present invention has is with low cost, technique simple and the high characteristics of product added value, the rice husk after processing can at high temperature keep original porous texture, the compound infrared screening agent of original position, realize the high-efficiency comprehensive utilization to waste.
Embodiment
Below in conjunction with embodiment, the invention will be further described, is not the restriction to its protection domain:
embodiment 1
A kind of method of at high temperature protecting the original porous texture of rice husk, the method comprises the following steps:
The pre-treatment of step 1, rice husk
Rice husk is placed in to the hydrochloric acid soln that concentration is 3 ~ 5wt%, under the condition of 90 ~ 100 ℃ of temperature and 350 ~ 450r/min stir speed (S.S.), soaks 1 ~ 2h, filter, obtain the acidleach rice husk; Water cleaning acidleach rice husk to the pH value of filtrate is 6 ~ 8 again, then under 80 ~ 100 ℃ of conditions, is incubated 24 ~ 30 hours, obtains the pre-treatment rice husk.
Processing again of step 2, rice husk
The pre-treatment rice husk is joined in the zirconia sol that concentration is 0.3 ~ 1.5mol/L, the ratio of pre-treatment rice husk and zirconia sol is 1kg ︰ (20 ~ 25L), in vacuum tightness, be standing 6 ~ 12h under 0.07 ~ 0.08MPa condition, remove again negative pressure, place 10 ~ 18h under the room temperature normal pressure, then be incubated 24 ~ 30 hours under 80 ~ 100 ℃ of conditions, obtain processing again rice husk.
The pyroprocessing of step 3, rice husk
To process again rice husk and be incubated 3 ~ 4h under 900 ~ 1200 ℃ of conditions, obtain the pyroprocessing rice husk.
Rice husk after the present embodiment is processed is after testing: SEM shows pyroprocessing under 900 ~ 1200 ℃ of conditions, and zirconia sol is processed in rice husk and still retained the original porous texture of rice husk, the rice husk SiO after processing
2be uniformly dispersed, particle diameter is below 100 nm, and the reunion of processing front rice husk is serious, rice husk SiO after processing
2agglomeration obtained effective improvement; The XRD result shows that zirconium colloidal sol processing rice husk all has zirconium silicate to generate under 900 ~ 1200 ℃; SEM-EDX the analysis showed that, the rice husk surface Zr after the present embodiment is processed is evenly distributed, and content is 50 ~ 70 wt%.
embodiment 2
A kind of method of at high temperature protecting the original porous texture of rice husk, the method comprises the following steps:
The pre-treatment of step 1, rice husk
Rice husk is placed in to the sulphuric acid soln that concentration is 0.2 ~ 1wt%, under the condition of 90 ~ 100 ℃ of temperature and 350 ~ 450r/min stir speed (S.S.), soaks 1 ~ 2h, filter, obtain the acidleach rice husk; Water cleaning acidleach rice husk to the pH value of filtrate is 6 ~ 8 again, then under 80 ~ 100 ℃ of conditions, is incubated 24 ~ 30 hours, obtains the pre-treatment rice husk.
Processing again of step 2, rice husk
The pre-treatment rice husk is joined in the zirconia sol that concentration is 1 ~ 3mol/L, the ratio of pre-treatment rice husk and zirconia sol is 1kg ︰ (30 ~ 35L), in vacuum tightness, be standing 1 ~ 6h under 0.07 ~ 0.08MPa condition, remove again negative pressure, place 2 ~ 10h under the room temperature normal pressure, then be incubated 24 ~ 30 hours under 80 ~ 100 ℃ of conditions, obtain processing again rice husk.
The pyroprocessing of step 3, rice husk
To process again rice husk and be incubated 3 ~ 4h under 1100 ~ 1300 ℃ of conditions, obtain the pyroprocessing rice husk.
Rice husk after the present embodiment is processed is after testing: SEM shows 1100 ~ 1300 ℃ of lower pyroprocessing, and zirconia sol is processed in rice husk and still retained the original porous texture of rice husk, the rice husk SiO after processing
2be uniformly dispersed, particle diameter below 100 nm, the rice husk SiO after processing
2agglomeration obtained effective improvement.The XRD result shows that zirconium colloidal sol processing rice husk all has zirconium silicate to generate under 1100 ~ 1300 ℃.SEM ~ EDX the analysis showed that, rice husk surface Zr is evenly distributed, and content is 45 ~ 70wt%.
embodiment 3
A kind of method of at high temperature protecting the original porous texture of rice husk, the method comprises the following steps:
The pre-treatment of step 1, rice husk
Rice husk is placed in to the oxalic acid solution that concentration is 1 ~ 3wt%, under the condition of 90 ~ 100 ℃ of temperature and 350 ~ 450r/min stir speed (S.S.), soaks 1 ~ 2h, filter, obtain the acidleach rice husk; Water cleaning acidleach rice husk to the pH value of filtrate is 6 ~ 8 again, then under 80 ~ 100 ℃ of conditions, is incubated 24 ~ 30 hours, obtains the pre-treatment rice husk.
Processing again of step 2, rice husk
The pre-treatment rice husk is joined in the zirconia sol that concentration is 3 ~ 5mol/L, the ratio of pre-treatment rice husk and zirconia sol is 1kg ︰ (25 ~ 30L), in vacuum tightness, be standing 0.5 ~ 1h under 0.07 ~ 0.08MPa condition, remove again negative pressure, place 16 ~ 24h under the room temperature normal pressure, then be incubated 24 ~ 30 hours under 80 ~ 100 ℃ of conditions, obtain processing again rice husk.
The pyroprocessing of step 3, rice husk
To process again rice husk and be incubated 3 ~ 4h under 1300 ~ 1600 ℃ of conditions, obtain the pyroprocessing rice husk.
Rice husk after the present embodiment is processed is after testing: SEM shows 1100 ~ 1300 ℃ of lower pyroprocessing, and zirconia sol is processed in rice husk and still retained the original porous texture of rice husk, the rice husk SiO after processing
2be uniformly dispersed, particle diameter, below 100 nm, is processed rear rice husk SiO
2agglomeration obtained effective improvement.The XRD result shows that zirconium colloidal sol processing rice husk all has zirconium silicate to generate under 1300 ~ 1600 ℃.SEM ~ EDX the analysis showed that, rice husk surface Zr is evenly distributed, and content is 40 ~ 50wt%.
embodiment 4
A kind of method of at high temperature protecting the original porous texture of rice husk, the method comprises the following steps:
The pre-treatment of step 1, rice husk
Rice husk is placed in to the hydrochloric acid soln that concentration is 3 ~ 5wt%, under the condition of 90 ~ 100 ℃ of temperature and 350 ~ 450r/min stir speed (S.S.), soaks 1 ~ 2h, filter, obtain the acidleach rice husk; Water cleaning acidleach rice husk to the pH value of filtrate is 6 ~ 8 again, then under 80 ~ 100 ℃ of conditions, is incubated 24 ~ 30 hours, obtains the pre-treatment rice husk.
Processing again of step 2, rice husk
The pre-treatment rice husk is joined in titanium oxide sol, the ratio of pre-treatment rice husk and zirconia sol is 1kg ︰ (20 ~ 25L), in vacuum tightness, be standing 6 ~ 12h under 0.07 ~ 0.08MPa condition, remove again negative pressure, place 10 ~ 18h under the room temperature normal pressure, then be incubated 24 ~ 30 hours under 80 ~ 100 ℃ of conditions, obtain processing again rice husk.
The pyroprocessing of step 3, rice husk
To process again rice husk and be incubated 3 ~ 4h under 900 ~ 1200 ℃ of conditions, obtain the pyroprocessing rice husk.
Rice husk after the present embodiment is processed is after testing: SEM shows 900 ~ 1200 ℃ of lower pyroprocessing, and each concentration titanium oxide sol is processed in rice husk and still retained the original porous texture of rice husk, the rice husk SiO after processing
2be uniformly dispersed, particle diameter below 100 nm, the rice husk SiO after processing
2agglomeration obtained effective improvement.The XRD result shows that titanium oxide sol processing rice husk has rutile titanium dioxide to generate in the time of 900 ~ 1200 ℃.SEM-EDX the analysis showed that, rice husk surface Ti is evenly distributed, and content is 50 ~ 80wt%.
embodiment 5
A kind of method of at high temperature protecting the original porous texture of rice husk, the method comprises the following steps:
The pre-treatment of step 1, rice husk
Rice husk is put to concentration in the sulphuric acid soln of 0.2 ~ 1wt%, soak 1 ~ 2h under the condition of 90 ~ 100 ℃ of temperature and 350 ~ 450r/min stir speed (S.S.), filter, obtain the acidleach rice husk; Water cleaning acidleach rice husk to the pH value of filtrate is 6 ~ 8 again, then under 80 ~ 100 ℃ of conditions, is incubated 24 ~ 30 hours, obtains the pre-treatment rice husk
Processing again of step 2, rice husk
The pre-treatment rice husk is joined in titanium oxide sol, the ratio of pre-treatment rice husk and zirconia sol is 1kg ︰ (25 ~ 30L), in vacuum tightness, be standing 1 ~ 6h under 0.07 ~ 0.08MPa condition, remove again negative pressure, place 2 ~ 10h under the room temperature normal pressure, then be incubated 24 ~ 30 hours under 80 ~ 100 ℃ of conditions, obtain processing again rice husk.
The pyroprocessing of step 3, rice husk
To process again rice husk and be incubated 3 ~ 4h under 1100 ~ 1300 ℃ of conditions, obtain the pyroprocessing rice husk.
Rice husk after the present embodiment is processed is after testing: SEM shows 1100 ~ 1300 ℃ of lower pyroprocessing, in the rice husk that each concentration titanium oxide sol is processed, has still retained the original porous texture of rice husk, the rice husk SiO after processing
2be uniformly dispersed, particle diameter below 100 nm, the rice husk SiO after processing
2agglomeration obtained effective improvement.The XRD result shows that titanium oxide sol processing rice husk has rutile titanium dioxide to generate in the time of 1100 ~ 1300 ℃.SEM-EDX the analysis showed that, rice husk surface Ti is evenly distributed, and content is 40 ~ 60wt%.
embodiment 6
A kind of method of at high temperature protecting the original porous texture of rice husk, the method comprises the following steps:
The pre-treatment of step 1, rice husk
Rice husk is placed in to the oxalic acid solution that concentration is 1 ~ 3wt%, under the condition of 90 ~ 100 ℃ of temperature and 350 ~ 450r/min stir speed (S.S.), soaks 1 ~ 2h, filter, obtain the acidleach rice husk; Water cleaning acidleach rice husk to the pH value of filtrate is 6 ~ 8 again, then under 80 ~ 100 ℃ of conditions, is incubated 24 ~ 30 hours, obtains the pre-treatment rice husk.
Processing again of step 2, rice husk
The pre-treatment rice husk is joined in titanium oxide sol, the ratio of pre-treatment rice husk and zirconia sol is 1kg ︰ (30 ~ 35L), in vacuum tightness, be standing 0.5 ~ 1h under 0.07 ~ 0.08MPa condition, remove again negative pressure, place 16 ~ 24h under the room temperature normal pressure, then be incubated 24 ~ 30 hours under 80 ~ 100 ℃ of conditions, obtain processing again rice husk.
The pyroprocessing of step 3, rice husk
To process again rice husk and be incubated 3 ~ 4h under 1300 ~ 1600 ℃ of conditions, obtain the pyroprocessing rice husk.
Rice husk after the present embodiment is processed is after testing: SEM shows 1300 ~ 1600 ℃ of lower pyroprocessing, and each concentration titanium oxide sol is processed in rice husk and still retained the original porous texture of rice husk, the rice husk SiO after processing
2disperse phase is to evenly, particle diameter below 100 nm, the rice husk SiO after processing
2agglomeration obtained effective improvement.The XRD result shows that titanium oxide sol processing rice husk has rutile titanium dioxide to generate in the time of 1300 ~ 1600 ℃.SEM-EDX the analysis showed that, rice husk surface Ti is evenly distributed, and content is 50 ~ 70wt%.
embodiment 7
A kind of method of at high temperature protecting the original porous texture of rice husk, the method comprises the following steps:
The pre-treatment of step 1, rice husk
Rice husk is placed in to the hydrochloric acid soln that concentration is 3 ~ 5wt%, under the condition of 90 ~ 100 ℃ of temperature and 350 ~ 450r/min stir speed (S.S.), soaks 1 ~ 2h, filter, obtain the acidleach rice husk; Water cleaning acidleach rice husk to the pH value of filtrate is 6 ~ 8 again, then under 80 ~ 100 ℃ of conditions, is incubated 24 ~ 30 hours, obtains the pre-treatment rice husk.
Processing again of step 2, rice husk
The pre-treatment rice husk is joined in ferric oxide colloidal sol, the ratio of pre-treatment rice husk and ferric oxide colloidal sol is 1kg ︰ (20 ~ 25L), in vacuum tightness, be standing 6 ~ 12h under 0.07 ~ 0.08MPa condition, remove again negative pressure, place 10 ~ 18h under the room temperature normal pressure, then be incubated 24 ~ 30 hours under 80 ~ 100 ℃ of conditions, obtain processing again rice husk.
The pyroprocessing of step 3, rice husk
To process again rice husk and be incubated 3 ~ 4h under 900 ~ 1200 ℃ of conditions, obtain the pyroprocessing rice husk.
Rice husk after the present embodiment is processed is after testing: SEM shows 900 ~ 1200 ℃ of lower pyroprocessing, and each concentration ferric oxide colloidal sol is processed in rice husk and still retained the original porous texture of rice husk, colloidal sol treatment S iO
2be uniformly dispersed, particle diameter below 100 nm, the rice husk SiO after processing
2agglomeration obtained effective improvement.The XRD result shows that ferric oxide colloidal sol processing rice husk has Z 250 to generate at 900 ~ 1200 ℃.SEM-EDX the analysis showed that, rice husk surface Fe is evenly distributed, and content is 40 ~ 60wt%.
embodiment 8
A kind of method of at high temperature protecting the original porous texture of rice husk, the method comprises the following steps:
The pre-treatment of step 1, rice husk
Rice husk is placed in to the sulphuric acid soln that concentration is 0.2 ~ 1wt%, under the condition of 90 ~ 100 ℃ of temperature and 350 ~ 450r/min stir speed (S.S.), soaks 1 ~ 2h, filter, obtain the acidleach rice husk; Water cleaning acidleach rice husk to the pH value of filtrate is 6 ~ 8 again, then under 80 ~ 100 ℃ of conditions, is incubated 24 ~ 30 hours, obtains the pre-treatment rice husk
Processing again of step 2, rice husk
The pre-treatment rice husk is joined in ferric oxide colloidal sol, the ratio of pre-treatment rice husk and ferric oxide colloidal sol is 1kg ︰ (25 ~ 30L), in vacuum tightness, be standing 1 ~ 6h under 0.07 ~ 0.08MPa condition, remove again negative pressure, place 2 ~ 10h under the room temperature normal pressure, then be incubated 24 ~ 30 hours under 80 ~ 100 ℃ of conditions, obtain processing again rice husk.
The pyroprocessing of step 3, rice husk
To process again rice husk and be incubated 3 ~ 4h under 1100 ~ 1300 ℃ of conditions, obtain the pyroprocessing rice husk.
Rice husk after the present embodiment is processed is after testing: SEM shows 1100 ~ 1300 ℃ of lower pyroprocessing, and each concentration ferric oxide colloidal sol is processed in rice husk and still retained the original porous texture of rice husk, the rice husk SiO after processing
2be uniformly dispersed, particle diameter below 100 nm, the rice husk SiO after processing
2agglomeration obtained effective improvement.The XRD result shows that ferric oxide colloidal sol processing rice husk has Z 250 to generate in the time of 1100 ~ 1300 ℃.SEM-EDX the analysis showed that, rice husk surface Fe is evenly distributed, and content is 50 ~ 70wt%.
embodiment 9
A kind of method of at high temperature protecting the original porous texture of rice husk, the method comprises the following steps:
The pre-treatment of step 1, rice husk
Rice husk is placed in to the oxalic acid solution that concentration is 1 ~ 3wt%, under the condition of 90 ~ 100 ℃ of temperature and 350 ~ 450r/min stir speed (S.S.), soaks 1 ~ 2h, filter, obtain the acidleach rice husk; Water cleaning acidleach rice husk to the pH value of filtrate is 6 ~ 8 again, then under 80 ~ 100 ℃ of conditions, is incubated 24 ~ 30 hours, obtains the pre-treatment rice husk.
Processing again of step 2, rice husk
The pre-treatment rice husk is joined in ferric oxide colloidal sol, the ratio of pre-treatment rice husk and ferric oxide colloidal sol is 1kg ︰ (30 ~ 35L), in vacuum tightness, be standing 0.5 ~ 1h under 0.07 ~ 0.08MPa condition, remove again negative pressure, place 16 ~ 24h under the room temperature normal pressure, then be incubated 24 ~ 30 hours under 80 ~ 100 ℃ of conditions, obtain processing again rice husk.
The pyroprocessing of step 3, rice husk
To process again rice husk and be incubated 3 ~ 4h under 1300 ~ 1600 ℃ of conditions, obtain the pyroprocessing rice husk.
Rice husk after the present embodiment is processed is after testing: SEM shows 1300 ~ 1600 ℃ of lower pyroprocessing, and each concentration ferric oxide colloidal sol is processed in rice husk and still retained the original porous texture of rice husk, the rice husk SiO after processing
2be uniformly dispersed, the rice husk SiO after processing
2agglomeration obtained effective improvement.The XRD result shows that ferric oxide colloidal sol processing rice husk has Z 250 to generate in the time of 1300 ~ 1600 ℃.SEM-EDX the analysis showed that, rice husk surface Fe is evenly distributed, and content is 40 ~ 50wt%.
This embodiment, by rice husk being carried out to pre-treatment, adopting oxide sol to the processing again of rice husk and heat-treat under differing temps processing rice husk again, obtains the rice husk of pyroprocessing.The present invention compared with prior art, has following advantage:
1, having solved rice husk original porous texture after pyroprocessing caves in and is unfavorable for the problem as the high-performance porous material;
2, effectively solved the problem that rice husk silicon-dioxide is reunited;
3, the original position of rice husk silicon-dioxide and infrared screening agent is compound, and on the basis that has retained rice husk porous silica texture, original position has formed the material with infrared shielding effect, for rice husk prepares the High Performance Adiabatic material, lays a good foundation.
Rice husk after this embodiment is processed is after testing: show pyroprocessing under 900 ~ 1600 ℃ of conditions, various oxide sols are processed in rice husk and have still been retained the original porous texture of rice husk, but the equal infrared screening agent of original position composition generation, and be evenly distributed, the rice husk SiO after pyroprocessing
2agglomeration obtained effective improvement.
That this embodiment has is with low cost, technique simple and the high characteristics of product added value, the rice husk after processing can at high temperature keep original porous texture, the compound infrared screening agent of original position, realize the high-efficiency comprehensive utilization to waste.
Claims (3)
1. a method of at high temperature protecting the original porous texture of rice husk is characterized in that the method comprises the following steps:
The pre-treatment of step 1, rice husk
Rice husk is placed in to hydrochloric acid, sulfuric acid or oxalic acid solution, under the condition of 90 ~ 100 ℃ of temperature and 350 ~ 450r/min stir speed (S.S.), soaks 1 ~ 2h, filter, obtain the acidleach rice husk; Water cleaning acidleach rice husk to the pH value of filtrate is 6 ~ 8 again, then under 80 ~ 100 ℃ of conditions, is incubated 24 ~ 30 hours, obtains the pre-treatment rice husk;
Processing again of step 2, rice husk
The pre-treatment rice husk is joined in oxide sol, the ratio of pre-treatment rice husk and oxide sol is 1kg ︰ (25 ~ 35L), in vacuum tightness, be standing 0.5 ~ 12h under 0.07 ~ 0.08MPa condition, remove again negative pressure, place 2 ~ 24h under the room temperature normal pressure, then be incubated 24 ~ 30 hours under 80 ~ 100 ℃ of conditions, obtain processing again rice husk;
The pyroprocessing of step 3, rice husk
To process again rice husk and be incubated 3 ~ 4h under 900 ~ 1600 ℃ of conditions, obtain the pyroprocessing rice husk;
Described oxide sol is a kind of in zirconia sol, titanium oxide sol and ferric oxide colloidal sol.
2. the method for at high temperature protecting the original porous texture of rice husk according to claim 1, is characterized in that described hydrochloric acid, sulfuric acid and oxalic acid solution concentration are 0.2 ~ 5wt%.
3. the method for at high temperature protecting the original porous texture of rice husk according to claim 1, is characterized in that described zirconia sol concentration is 0.3 ~ 5mol/L.
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| CN103803554B (en) * | 2014-03-04 | 2015-09-16 | 武汉科技大学 | A kind of carbon nanotube/porous silica composite granule and preparation method thereof |
| CN105923637A (en) * | 2016-04-18 | 2016-09-07 | 佛山市东旸化工科技有限公司 | Silicon dioxide microcrystalline powder equipment and manufacturing technology |
| CN105883819A (en) * | 2016-04-18 | 2016-08-24 | 佛山市东旸化工科技有限公司 | Silicon dioxide microcrystal powder preparation equipment and preparation method |
| CN110255631B (en) * | 2019-07-22 | 2022-01-04 | 浙江科技学院 | Preparation method of rice husk-based porous metal oxide |
| CN114890810B (en) * | 2022-04-18 | 2023-04-28 | 焦作诺尔曼炉业有限公司 | Mullite lightweight aggregate with rice hull genetic structure and preparation method thereof |
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| CN1202993C (en) * | 2003-05-20 | 2005-05-25 | 吉林大学 | Process for preparing high-purity nano silicon dioxide from rice husk |
| CN101653960B (en) * | 2009-08-26 | 2011-10-05 | 武汉科技大学 | Light heat-insulation and heat-preservation material and preparation method thereof |
| CN101941704A (en) * | 2010-09-03 | 2011-01-12 | 吉林大学 | New method for preparing silicon dioxide by utilizing rice hull ash |
| CN102145280B (en) * | 2011-02-15 | 2012-11-28 | 常州大学 | Method for preparing rice hull active carbon/silicon dioxide/titanium dioxide composite material |
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| JP6017730B2 (en) * | 2014-04-01 | 2016-11-02 | Ｒａｐａｓ株式会社 | Method for recovering silica from a silica-containing plant using titanium oxide |
| EP3127864A4 (en) * | 2014-04-01 | 2017-11-29 | Rapas Corporation | Method for recovering silica from silica-containing plant body using titanium oxide |
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