WO2010012124A1 - A method for preparing a product containing silicon from plant - Google Patents

Abstract

A method for preparing a product containing silicon from plant is provided. The plant is hydrolyzed by mixed strong acid solution to get glucide and mixture of lignin and silicate, and the mixed strong acid solution can be recycled for reuse in the hydrolyzation step. The glucide can be used to produce alcohol which can serve as biological energy source through ferment. The mixture of lignin and silicate is claimed at high temperature to produce high purity product containing silicon for factory use. This method can recycle the acidity solution for reuse.

Description

 Method for preparing silicon-containing products from plants

 The present invention relates to a method for preparing a silicon-containing product from a plant, and more particularly to a method for producing a silicon-containing product by a step of fermenting a plant material through a strong acid mixture and high temperature calcination, and belongs to the field of chemical engineering. Background technique

 Silicon is one of the most abundant elements on the earth's surface and is deposited on the surface in the form of silica sand (silica). Its use has been made from the manufacture of art and industrial glass from silica sand, until the semiconductor properties of silicon have been discovered and used in the electronics and computer industries. Today's high-tech industries, such as silicon wafers, optical fibers, solar cells, etc., are all silicon. Derivatives, in addition to the grade of silicon, can also be used in pharmaceuticals or cosmetics.

 At present, high-purity silicon ore (silica) is commercially exploited, and the silicon-containing minerals are further refined and purified physically or chemically. Because each silicon-containing mineral has different silicon content and purity, such as river sand, it is not cost-effective and demand to refine this low-content, low-purity silicon-containing mineral for high-purity industrial use. Therefore, high-content and high-purity silicon-bearing ore is the raw material that modern technology is looking for. Since the mining industry usually depends on the content of the veins, once it is depleted, there is no raw material for refining and purification. Many studies have therefore turned to plants as a new source of silica. Many plant and agricultural wastes contain high levels of silica. For example, rice straw contains about 11% silica, and rice husk contains about 15-23% silica.

 Plant materials such as straw and rice husk are often disposed of and have no substantial economic benefits. Therefore, if silicon-containing products for industrial and medical uses can be extracted from these plant materials, the depletion of the mineral source can be alleviated. These agricultural by-products can be effectively utilized.

U.S. Patent No. 5,562,777 (hereinafter referred to as Citation No. 1) discloses a method of producing a saccharide using a strong acid hydrolyzed cellulose and a hemicellulose material. The method comprises (1) adding a cellulose and a hemicellulose material, adding 25-90% by weight of sulfuric acid, destroying the state of matter (decrystallize), forming a gelatinous substance, the gelatinous substance containing Solid and liquid fraction; (2) diluting the sulfuric acid in the colloidal substance to a concentration of 20-30%, and heating to 80-100 ° C for the first hydrolysis; (3) after filtering the first hydrolyzed product A liquid containing acid and sugar can be obtained; (4) the solid portion after filtration, and then 25-90% sulfuric acid, again destroying the state of the object to obtain a second gelatinous substance; (5) diluting the first The sulfuric acid in the second gelatinous substance is brought to a concentration of 20-30%, and heated to 80-100 ° C for a second hydrolysis; (6) filtering the second hydrolyzed product to obtain a liquid containing acid and sugar; 7) Resin the acid in steps (3) and (6), and separate and purify the sugar by a column to obtain about 15% of the sugar and the acid content is less than 3%. 1 also mentions that 5-10% of strong alkali (sodium hydroxide, NaOH) is mixed with the solid product (lignin, lignin) of step (2), heated to 80 ° C, reacted for 90 minutes, and then concentrated hydrochloric acid (HC1) The pH value of the basic gelatinous substance was lowered from pH 12 to pH 10, filtered, and then ll% NaOCl solution was added for bleaching to obtain an off-white silica colloid.

 However, in the case of reference 1, the plant material needs to be ground to a finer powder to carry out the reaction, and the higher temperature and strong acid are required for hydrolysis. After separation by the column, the reaction is carried out in a strong base and a strong acid to obtain two. Oxidized silica gel body, due to the high temperature and 20-30% sulfuric acid hydrolysis during the hydrolysis process, the efficiency is poor and the risk is high.

U.S. Patent No. 5,735,916 (the disclosure of which is incorporated herein by reference in its entirety in its entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire all The method comprises (1) honing the plant material with a hammer/ball mill to a size of about 45 to 55 mesh, preferably 50 mesh; (2) the step of the step (1) The milled product is sent to a first counter-current extractor and mixed with a weakly acidic solvent. The pH of the weakly acidic solvent is between 3.0 and 5.0, preferably 4.0; wherein the temperature of the acidic solvent is maintained at 40-60 ° C, preferably 50 ° C; the reaction time is 50-70 minutes, preferably 60 minutes. A weak acid is used to adjust the acidity and alkalinity of the above acidic solvent, wherein the weak acid may be acetic acid, carbonic acid, hydrochloric acid, or sulfuri cacid, preferably It is carbonic acid (carboni cacid). (3) filtering the product of the step (2), and then filtering the product obtained by containing the five-carbon sugar, the soluble salt, the soluble vegetable protein and the soluble peptide, and feeding it to a fermentation unit for fermentation, and using the microorganism to convert the five carbons. The sugar is fermented into ethanol (Ethanol); (4) the solid matter left in the first reverse extraction machine is passed through a belt press filter to dehydrate the solid matter to a total amount of 70-80% solid state. , sending the dehydrated solid shield into the second reverse extraction machine, and then feeding the strong alkaline solvent into the second reverse extraction machine, the strong alkali solution is potassium hydroxide (KOH) or sodium hydroxide (NaOH) Preferably, the sodium hydroxide; the strong alkaline solution has a concentration of 5 ° /. -50%, preferably 50%; the temperature of the strongly alkaline solution is between 40 and 60 ° C, preferably 50 ° (: The reaction time of the solid material in the second reverse extraction machine is 110-130 minutes, preferably 120 minutes. The strong alkali solution is used to dissolve lignin and silica. The mixed product is an alkali silicate and lignin; (5) The mixed product (lignin and caustic silicate) in the step (4) is sent to an ultrafiltration unit having a polysulfone membrane for mixing The product passes through the membrane to separate the lignin and alkaline silicate solution, thereby collecting and concentrating the lignin, allowing the lignin to be concentrated to a solid state of 38-42%, preferably 40%. The concentrated lignin is washed to a pH of 6.5-7.0 to a target pH of 6.7, and the lignin is dried for storage; (6) an alkaline silicate solution after passing through the membrane, It is sent to the bleeder system to extract a portion of the filtered silicate which can be packaged for sale. Another portion of the alkaline silicate solution is fed back to the second reverse extraction machine to continue the reaction with the new strong alkaline solution; (7) the solid material remaining in the second reverse extraction machine (most For cellulose, it is first sent to a continuous centrifuge with a water scrubber, followed by sacchrification and fermentation, which uses a weaker mineral acid (eg sulfuric acid or hydrochloric acid; pH2- 3. Preferably, 2.5) is subjected to partial saccharification. The hydrolysis is drunk as Rutgers UniversityRut-C-30 or other Trichodermareesei (virde), preferably T. reesei (virde), after the enzyme is added, the cellulose is converted into monosaccharide (glucose); (8) will be six Carbohydrate (glucose) and five-carbon sugar are fermented by genetically modified strains to obtain ethanol and a fermented product, and the strain Bacillusstearothermophilus is LLD-R. This species was developed by Agrol(R) td. (U.S. Patent No. 51/82,199). The ferment has a high protein content and can be used as an animal food supplement. After fermentation, the concentration of ethanol is between 3-5%, preferably 4%; (9) The low concentration of ethanol is sent to a distillation system, and the ethanol is distilled to a concentration of 100% (200 proof), and then Mix dry powdered lignin with 200proof ethanol as a high energy fuel. The ratio of ethanol to lignin is between 3:1 and 3.8:1, preferably 3.5:1.

 In the case of reference 2, the plant material should be ground to a finer powder and hydrolyzed several times with weak acid. In addition, in the case of reference 2, the sugar and other substances dissolved in the acidic solution should be separated from the wood shield, and then the strong base is used. The second extraction is carried out to obtain silicates and sugars, which is cumbersome and has a long reaction time.

U.S. Patent No. 2005/0227868A1 (hereinafter referred to as Citation No. 3) and its partial continuation US2006/0089258A1 (hereinafter referred to as Citation No. 4) disclose a process for preparing a silicon-containing product and a product thereof. The method comprises (1) grinding the plant material to contain at least about 3% by weight of silica, non-silica material and metal; (2) mixing the plant material of step (1) with a liquid sulfuric acid solution, The sulfuric acid concentration is between 0.01-30% by weight; (3) heating the mixture of step (2), the heating temperature is between 10 and 250 ° C, and the reaction time is between 6 seconds and 48 hours; (4) the filtration step a reaction product of (3) to obtain a carbon-silica product, which can be adjusted for carbon fixation according to the needs of subsequent reactions (fixed Carbon) relative to the ratio of silica, at least 1.0: 1; (5) removing the acidic solution from the carbon-silicon product of step (4); (6) removing the product of step (5) Devolatilization, which can be Thermal Devolatilization or Acid Devolatilization; (7) Final carbon-silicon product or de-volatiles-derived carbon-silicon product (Devolatilized carbon) -silica product) A Carbothermal Process is carried out to obtain a silicon-containing product having a thermal reaction temperature of from 1250 to 2200. C, the silicon-containing product comprises silicon, silicon carbide, silicon tetrachloride, and silicon nitride, and the purity of the silicon-containing product is also mentioned, depending on the material. The concentration, type, treatment time and temperature of the acid used in the hydrolysis with an acid.

 In Citation 3 and Citation 4, the plant material should be ground to a finer powder for reaction, and hydrolyzed with 0.01-30% sulfuric acid. After the acidic solution is volatilized, the carbothermal reaction is carried out in an ultra-high temperature reactor. To obtain its silicon-containing product, it requires high heat energy and is highly risky to operate.

 Thus, the existing methods for preparing silicon-containing products from plant materials have many drawbacks and need to be improved. Summary of the invention

 SUMMARY OF THE INVENTION An object of the present invention is to provide a process for preparing a silicon-containing product from a plant which is mainly prepared by hydrolyzing a plant with a strong acid mixture and then calcining to prepare a silicon-containing product for industrial use. The acidic solution and the extraction solution of the method can be recycled and reused. The by-product of the method is high-purity alcohol, which can be utilized as biomass energy. Another by-product of the method is a protein-rich nutrient fermented product, which can be used as Feed supplements.

 The above object of the present invention is achieved by the following technical solutions:

 A method of preparing a silicon-containing product from a plant, comprising the steps of:

 Step 1: Chop the plant;

 Step 2: The chopped plant and the acidic solution are mixed in a weight ratio of 1:4, and then placed in a reaction furnace, and the first reaction furnace is heated by a heating device to carry out a hydrolysis reaction to obtain an acidic hydrolyzate; Step 3: The acidic hydrolyzate is injected into the second reaction furnace through a conduit, and the extractant is added to the second reaction furnace to perform an extraction reaction to promote precipitation of the acidic hydrolyzate to obtain a mixed solution and a precipitate, respectively;

Step 4: After the mixed solution of the third step is extracted from the second reaction furnace, the water is added to the second reaction. In the furnace, the sugar in the precipitate is dissolved in water and filtered through a sieve to obtain a filtrate of the saccharide solution and an insoluble lignin-silicate mixture filter residue;

 Step 5: The lignin-silicate mixture filter residue in the fourth step is placed in a calciner and calcined by a heating device to obtain a silicon-containing product.

 In the above method for preparing a silicon-containing product from a plant, the plant preferably contains at least 3% of silica, for example, including but not limited to Corn stover, Rice straw, Rice husk ( Rice hull), Wheat straw, Broomcom straw, Sugar cane bagasse, Napier grass, Softwood, Hardwood or crop waste;

 The acidic solution described in the second step is preferably a mixed acid solution containing 30-60% sulfuric acid and 5-45% phosphoric acid, wherein 50% sulfuric acid and 25°/. a mixed acid of phosphoric acid is preferred;

 The acidic hydrolyzate described in the second step comprises a mixture of a saccharide and an acid Mudulin-silicate; the temperature of the hydrolysis reaction described in the second step is preferably less than 100 ° C, of which 55. C is optimal; the hydrolysis reaction time is preferably 1.5 to 4 hours, of which 2.5 hours is most preferred.

 Wherein, the extracting agent described in the third step is preferably a ketone-alcohol mixture, and further preferably, the ketone-alcohol mixture comprises a C1-C4 alcohol and a C3-C6 ketone body; most preferably, The extractant is a ketone, and particularly preferably 2-butanone. The extraction reaction time is preferably from 0.5 to 3 hours, more preferably 0.5 hours. The mixed solution comprises an acidic solution and an extraction solution, and the column method can be utilized

(For example, it may be a distillation column method or a chromatography column method, more preferably a distillation column method) to separate the extraction solution, and the separated acidic solution is boiled by a heating device to evaporate the water, and the acidic solution is concentrated and recovered. The recovered acidic solution can be reused in the second step; the recovered extraction solution can be reused in the third step. The precipitate comprises a mixture of saccharides and lignin-silicates.

 In the fifth step, the calcination temperature is preferably 600 to 900 ° C, more preferably 600. The calcination time is preferably from 10 to 32 hours, more preferably from 16 hours. The silicon-containing product is silica.

In order to achieve better technical effects, in step 5, the lignin-silicate mixture filter residue and the 1% sulfuric acid filtered in step 4 are first placed in a purification furnace, and heated to 140 ° C for purification. After purification for 3 hours, The product is placed in a calciner, heated to 600 ° C, and calcined for 11 hours to obtain a silicon-containing product; or the lignin-silicate mixture filter residue filtered in step 4 is first placed in a calciner. Heat to 600. C, calcined for 16 hours, and then placed in a purification furnace with 1% nitric acid and calcined product, heated to 130. Purification by C and purification for 2 hours gave a silicon-containing product. In the method of the present invention, after the filtered sugar solution in the fourth step is extracted by the extracting device, the saccharide solution is placed in the third reaction furnace, and heated by the heating device to promote the decomposition of the oligosaccharide into a monosaccharide. If the saccharide solution contains residual acidic solution, it can be neutralized by adding calcium carbonate, calcium oxide or calcium hydroxide in the third reaction furnace to form gypsum, which is filtered through a sieve to make the saccharide solution and residual acidity. The solution is separated. The saccharide solution is placed in a fermentation tank, and the monosaccharide is fermented by the microorganism to obtain a low concentration of alcohol and a fermented product, wherein the fermented product is a protein-rich nutrient fermented product and can be used as a feed additive. The low concentration alcohol can be passed through a distillation process to obtain 100% alcohol.

 The method for preparing a silicon-containing product from a plant provided by the present invention has the following advantages in comparison with the prior art:

 1. The method for preparing a silicon-containing product from a plant provided by the invention has fewer steps than the existing method, and has low cost and high efficiency.

 2. A method of preparing a silicon-containing product from a plant provided by the present invention recovers an acidic and alkaline solution for reuse. DRAWINGS

 Figure 1 is a flow diagram for the preparation of silicon-containing products from plants.

 DESCRIPTION OF REFERENCE NUMERALS 11 step one; 12 step two; 13 step three; 14 step four; detailed description

 Referring to Figure 1, a method for preparing a silicon-containing product from a plant provided by the present invention mainly comprises the following steps:

 Step one 11:

The plant is chopped into lumps, wherein the plant contains at least 3% silica, including but not limited to Corn stover > Rice straw, Rice hull. Wheat stalk ( wheat straw) ^ sorghum Gan (Broomcorn straw) _¾ Gan; ^, Charles (Sugar cane bagasse), Pennisetum (Napier grass), softwood (Softwood is), hardwood (hardwood) or farming waste, the preferred embodiment is Rice straw and rice husk o Step 2:12

The chopped plant and the acidic solution are mixed in a ratio of 1:4 in the first reaction furnace, through the addition The heat device heats the first reaction furnace to carry out a hydrolysis reaction, and the hydrolysis reaction temperature is 100. C, the preferred embodiment is 55 ° C, the hydrolysis reaction time is 1.5 to 4 hours, and the preferred embodiment is 2.5 hours, and an acidic hydrolyzate containing saccharides is obtained. Acidic lignin-silicate mixture.

 Wherein the acidic solution comprises a single acid or a mixed acid, wherein the single acid includes, but is not limited to, acetic acid, carbonic acid, hydrochloric acid, phosphoric acid or sulfuric acid; The mixed acid solution contains 30-60% sulfuric acid and 5-45% phosphoric acid, and the preferred embodiment is 50 °/. A mixed acid solution of sulfuric acid and 25% phosphoric acid. Step three 13:

 The acidic hydrolyzate is injected into the second reaction furnace through a conduit, and the extraction solution is introduced into the second reaction furnace, and an extraction reaction is carried out to promote precipitation of the acidic hydrolyzate to produce a mixture comprising the mixed solution and the precipitate. Wherein the extraction solution may be a ketone or a ketone-alcohol mixture, wherein the ketone-alcohol mixture comprises a C 1 -C 4 alcohol (alcohol) and a C 3 -C 6 ketone (ketone); wherein the ketone It is methylethyl ketone, wherein the extraction reaction time of the acidic hydrolyzate and the extraction solution is between 0.5 and 3 hours, and the preferred embodiment is 0.5 hour. Wherein the mixed solution comprises an acidic solution and an extraction solution; wherein the precipitate comprises a saccharin, a lignin-silicate mixture » Step 4:

 After the extraction solution of the third step is extracted from the second reaction furnace by the extracting device, the water is added to the second reaction furnace and mixed with the precipitate to promote the dissolution of the sugar of the precipitate in the water, which is lignin- The physical property of the silicate mixture insoluble in water is filtered by a sieve to separate the water-soluble saccharide and the water-insoluble lignin-silicate mixture, respectively, to obtain a saccharide solution and lignin-silicon. Acid salt mixture. The saccharide solution comprises oligosaccharide, pentose and hexose. Step 5 15: Calcination

 The lignin-silicate mixture filtered in the fourth step is placed in a calciner and calcined by a heating device, the calcination temperature is between 600 and 900 ° C, and the preferred embodiment is 600 ° C. The calcination time is between 10 and 32 hours, and the preferred embodiment is 16 hours, and a silicon-containing product can be obtained, wherein the silicon-containing product can be silica, silicon carbide, silicon nitride. (silicon nitride), a preferred embodiment is silica.

In addition, in step 5, the lignin-silicate mixture filtered in step 4 can be firstly diluted with 1%. The acid (H ₂ SO ₄ ) is placed in a purification furnace, and is heated by heating to 140 ° C for purification, and after purification for 3 hours; the purified lignin-silicate mixture is placed in a calciner to heat The device is subjected to calcination, the calcination temperature is 600 ° C, and the calcination time is 11 hours, and a silicon-containing product may also be obtained, wherein the silicon-containing product may be silica or silicon carbide. ), silicon nitride, a preferred embodiment is silicon dioxide.

In addition, in step 5, the lignin-silicate mixture filtered in step 4 may be first placed in a calcining furnace, and calcined by a heating device, the calcination temperature is 600 ° C, forging The calcination time is 16 hours, and the calcined product is further placed in a purification furnace with 1% nitric acid (HNO ₃ ), purified, heated to 130 ° C by a heating device, and purified for 2 hours to obtain silicon-containing. The product, wherein the silicon-containing product can be silica, smcon carbide, smcon nitride, and the preferred embodiment is silica.

 In addition, the mixed solution of the third step comprises an acidic solution and an extraction solution, and is separated by a column method. Since the physical properties of the acidic solution and the extraction solution are different, such as boiling point, volatilization rate, etc., different solutions can be separated and recovered at different boiling points, so The extraction solution can be recovered. In addition, the separated acidic solution is boiled by a heating device to evaporate water, and the acidic solution is concentrated to recover a high concentration of the acidic solution; wherein the recovered acidic solution can be repeatedly used in the second step, and the recovered extraction solution can be in the third step. reuse. The column method may be a distillation column method or a chromatography column method, wherein the chromatography column method includes but is not limited to chromatography, ion exchange analysis, affinity analysis, hydrophobic analysis, colloid analysis or reversed phase. Chromatography, the preferred embodiment is a distillation column method.

 High purity yields of silicon-containing products can be prepared from plants by the above steps. In addition, after the filtered sugar solution is extracted by the extracting device in step 4, the saccharide solution is placed in the third reaction furnace and heated by the heating device to cause the oligosaccharide to be decomposed into monosaccharides. If the saccharide solution contains a residual acidic solution, it can be neutralized by adding calcium carbonate, calcium oxide or calcium hydroxide in a third reaction furnace to form gypsum, which is filtered through a sieve to make the saccharide solution and the residual The acidic solution is separated. The saccharide solution is placed in a fermentation tank, and the monosaccharide is fermented by the microorganism to obtain a low concentration of alcohol and a fermented product, wherein the fermented product is a protein-rich nutrient fermented product and can be used as a feed additive. The low-concentration alcohol can be distilled again to obtain 100% alcohol.

Wherein the microorganism including but not limited to Candida kefyr, Pichia stipitis> Bacillus stearothermophilus (Bacillus stearothermophilus), ^p Peel wine yeast (Saccharomyces cerevisiae), Hansenula anomala, Hansenula jadinii, Hansenula fabianii and Pachysolen Tannophilus.

 Further, the heating device as described above includes, but is not limited to, a heating device such as a gas heating device, a coal heating device, and an electric heating device. The extraction device as described above may be a pumping device such as a pumping pump.

 The method for preparing a silicon-containing product from a plant provided by the present invention has the following advantages when compared with the aforementioned cited documents and other prior art:

 3. The method for preparing a silicon-containing product from a plant provided by the present invention has fewer steps, lower cost and higher efficiency than the prior art method.

 4. A method of preparing a silicon-containing product from a plant provided by the present invention recovers an acidic and alkaline solution for reuse.

 The above detailed description is a detailed description of a possible embodiment of the present invention, but is not intended to limit the scope of the invention, and equivalents or modifications, such as: Materials, reaction temperatures, reaction times, and microorganisms should all be included in the patent scope of this case.

Claims

Rights request  1. A method of preparing a silicon-containing product from a plant, comprising the steps of:  Step 1: Chop the plant;  Step 2: The chopped plant and the acidic solution are mixed in a weight ratio of 1:4, and then placed in the first reaction furnace, and the first reaction furnace is heated by a heating device to carry out a hydrolysis reaction to obtain an acidic hydrolyzate; Step 3: The acidic hydrolyzate is injected into the second reaction furnace through a conduit, and the extractant is added to the second reaction furnace to perform an extraction reaction to promote precipitation of the acidic hydrolyzate to obtain a mixed solution and a precipitate, respectively;  Step 4: After the mixed solution of the third step is extracted from the second reaction furnace, water is added to the second reaction furnace, the sugar in the precipitate is dissolved in water, and filtered through a sieve to obtain a filtrate of the saccharide solution. And insoluble lignin-silicate mixture filter residue;  Step 5: The lignin-silicate mixture filter residue in the fourth step is placed in a calciner and calcined by a heating device to obtain a silicon-containing product.  2. A method according to claim 1 wherein: said plant contains at least 3% silica.  3. A method according to claim 1 wherein: said plant comprises corn stalks, rice straw, rice hulls, wheat stalks, sorghum stalks, bagasse, pennisetum, cork, hardwood or crop waste.  4. The method according to claim 1, wherein the acidic solution described in the second step is a mixed acid solution comprising 30-60% sulfuric acid and 5-45% phosphoric acid.  5. The method of claim 4 wherein: the acidic solution of step two comprises 50% sulfuric acid and 25% phosphoric acid.  6. A method according to claim 1, characterized in that the temperature of the hydrolysis reaction described in the second step is below 100 ° C, with 55 ° C being most preferred.  7. The method according to claim 1, wherein the hydrolysis reaction is carried out for 1.5 to 4 hours, of which 2.5 hours is most preferred.  8. The method according to claim 1, wherein: the extracting agent in the third step is a ketone-alcohol mixture, preferably, the ketone-alcohol mixture comprises a C1-C4 alcohol and C3. -C6 ketone body. 9. The method of claim 1 wherein: the extractant of step three is The ketone is preferably 2-butanone.  10. A method according to claim 1, characterized in that the extraction reaction time described in the third step is from 0.5 to 3 hours, preferably 0.5 hours.  1 1. The method according to claim 1, wherein: the mixed solution obtained in the third step is separated by a column method to recover the extraction solution, and the separated acidic solution is boiled by a heating device to evaporate the water. The acidic solution is concentrated and recovered, and the recovered acidic solution can be repeatedly used in the second step; the recovered extraction solution can be repeatedly used in the third step; wherein the column method is preferably a distillation column method or a chromatography tube. The column method is more preferably a distillation column method.  12. The method according to claim 1, wherein in the fifth step, the calcining temperature is 600 to 900. C, preferably 600° (:.  13. The method of claim 1 wherein: in step five, said calcining time is from 10 to 32 hours, preferably 16 hours.  A method of preparing a silicon-containing product from a plant according to claim 1, wherein the silicon-containing product of step 5 is silica.  15. A method of preparing a silicon-containing product from a plant, comprising the steps of:  Step 1: The plant is chopped through a chopper;  Step 2: the chopped plant and the acidic solution are mixed in a ratio of 1:4, and then placed in the first reaction furnace, and the first reaction furnace is heated by a heating device to carry out a hydrolysis reaction to obtain an acidic hydrolyzate;  Step 3: The acidic hydrolyzate of step two is injected into the second reaction furnace through a conduit, and the extraction solution is added to the second reaction furnace to carry out an extraction reaction to promote precipitation of the acidic hydrolyzate, thereby obtaining a mixture comprising Mixing the solution and the precipitate;  Step 4: After extracting the mixed solution of the third step from the second reaction furnace by using an extracting device, adding water to the second reaction furnace, dissolving the sugar in the precipitate in the water, and filtering through the sieve. The filtered sugar solution and the insoluble lignin-silicate mixture are respectively obtained;  Step 5: First, the lignin-silicate mixture filtered in step 4 and 1% sulfuric acid are placed in a purification furnace, and heated by heating to 140 ° C for purification. After purification for 3 hours, the lignin-silicon is further The acid salt mixture was placed in a calciner and heated to 600 with a heating device. C, calcination was carried out for 11 hours to obtain a silicon-containing product. 16. A method of preparing a silicon-containing product from a plant, comprising the steps of: Step 1: The plant is chopped through a chopper;  Step 2: the chopped plant and the acidic solution are mixed in a ratio of 1:4, and then placed in the first reaction furnace, and the first reaction furnace is heated by a heating device to carry out a hydrolysis reaction to obtain an acidic hydrolyzate;  Step 3: The acidic hydrolyzate of step two is injected into the second reaction furnace through a conduit, and the extraction solution is added to the second reaction furnace to carry out an extraction reaction to promote precipitation of the acidic hydrolyzate, thereby obtaining a mixture comprising Mixing the solution and the precipitate;  Step 4: After extracting the mixed solution of the third step from the second reaction furnace by using an extracting device, adding water to the second reaction furnace, dissolving the sugar in the precipitate in the water, and filtering through the sieve. The filtered sugar solution and the insoluble lignin-silicate mixture are respectively obtained;  Step 5: Firstly, the Mudun-silicate mixture filtered in the fourth step is placed in a calciner, heated to 600 ° C by a heating device, calcined for 16 hours, continued with 1% nitric acid and calcined. The product was placed in a purification furnace and heated to 130 with a heating device. Purification was carried out for 2 hours to obtain a silicon-containing product.