Method for preparing white carbon black from secondary carbon component

The twice carbon separating process for preparing silica white includes introducing CO2 gas to sodium silicate solution to lower the pH value to 9-10.5, solid-liquid separating, further introducing CO2 gas to the solution to lower the pH value to 7-8, solid-liquid separating, washing and stoving to obtain coarse silica while product, soaking or boiling in strong acid solution, washing and stovingto obtain silica while product. The present invention may have the sodium silicate solution obtained through soaking high silicon slag from producing aluminum sulfate, aluminum chloride, ferrous metal and non-ferrous metal and with high impurity content as the material, and the silica while product has high purity, fine granularity and high whiteness.

Method for preparation of sodium metasilicate pentahydrate by fly ash

The invention discloses a method for the preparation of sodium metasilicate pentahydrate by fly ash, which comprises the steps: using sodium hydroxide solution to alkaline-hydrolyze sodium silicate solution with the silicon dioxide preparation modulus of 0.4-0.8 in the fly ash, carbonizing amorphous hydrated silicon dioxide with the partial sodium hydroxide solution, then re-dissolving the amorphous hydrated silicon dioxide with the sodium hydroxide solution to formulate crystallization solution with the ratio of SiO2 to Na2O of 1:0.8-1.2, removing suspended matters by filtration, heating andconcentration, cooling and crystallizing, and performing solid-liquid separation at 35 DEG C to result in sodium metasilicate pentahydrate. The method has the advantages of simple process, inexpensive raw material, great easiness for industrialization and tremendous economical and environmental benefits.

Method for preparing white carbon black from secondary carbon component

The twice carbon separating process for preparing silica white includes introducing CO2 gas to sodium silicate solution to lower the pH value to 9-10.5, solid-liquid separating, further introducing CO2 gas to the solution to lower the pH value to 7-8, solid-liquid separating, washing and stoving to obtain coarse silica while product, soaking or boiling in strong acid solution, washing and stoving to obtain silica while product. The present invention may have the sodium silicate solution obtained through soaking high silicon slag from producing aluminum sulfate, aluminum chloride, ferrous metal and non-ferrous metal and with high impurity content as the material, and the silica while product has high purity, fine granularity and high whiteness.

Method and device for online cleaning filtering cloth for filtering sodium aluminate slurry

The invention discloses a method and a device for online cleaning filtering cloth for filtering sodium aluminate slurry, which is characterized in that a dissolving and washing groove filled with 5-30wt% sodium hydroxide solution and a washing groove filled with 1-5wt% diluted sodium hydroxide solution are additionally arranged on a returning path of filtering cloth of a horizontal belt type vacuum filter, firstly the filtering cloth enters the dissolving and washing grooves to rapidly dissolve aluminum hydroxide crystal on the surface of the filtering cloth and in a capillary passage, generated sodium aluminate enters the solution, and then the sodium aluminate carried by the filtering cloth is diluted by the diluted sodium hydroxide solution, thereby achieving the purpose of avoiding the hardening of the filtering cloth and recycling the filtering cloth after the regeneration. The invention has simple theory and easy application, and is especially suitable for rapidly dissolving out clinker ...

Method and device for online cleaning filtering cloth for filtering sodium aluminate slurry

The invention discloses a method and a device for online cleaning filtering cloth for filtering sodium aluminate slurry, which is characterized in that a dissolving and washing groove filled with 5-30wt% sodium hydroxide solution and a washing groove filled with 1-5wt% diluted sodium hydroxide solution are additionally arranged on a returning path of filtering cloth of a horizontal belt type vacuum filter, firstly the filtering cloth enters the dissolving and washing grooves to rapidly dissolve aluminum hydroxide crystal on the surface of the filtering cloth and in a capillary passage, generated sodium aluminate enters the solution, and then the sodium aluminate carried by the filtering cloth is diluted by the diluted sodium hydroxide solution, thereby achieving the purpose of avoiding the hardening of the filtering cloth and recycling the filtering cloth after the regeneration. The invention has simple theory and easy application, and is especially suitable for rapidly dissolving outclinker ...

PROCESS FOR RECOVERY OF SILICA FOLLOWED BY ALUMINA FROM COAL FLY ASH

A process for recovery of silica and alumina from fly ash, in which, Si is leached out from the fly ash in the form of Na2SiO3 using a NaOH solution of NaOH >40% (w/w), followed by separation to obtain a Na2SiO3 solution and a residue having AlSi ratio 2; vaporizing the solution to obtain Na2SiO3 solutions of various concentrations, or producing silica by carbonation, and producing Al2O3 by prior art methods from residues obtained after alkali-leaching, ultimately producing filler or cement from the residue after the recovery of Al. The method permits recovery of Al2O3 directly from fly ash by removing Si before recovering the Al, which raises the AlSi ratio of the residue after alkali-leaching and thus simplifies the recovery of Al2O3 and raises the rate of Al recovery from fly ash. The invention further includes calcining high Al coal gangue, kaolinite and middle-low-class bauxite at 900-1100° C.

Method for extracting aluminum oxide from sodium-free desiliconized fly ash

The invention relates to a method for extracting aluminum oxide from sodium-free desiliconized fly ash, which comprises the following steps of: taking dried sodium-free desiliconized fly ash, carrying out saturation calcium matching with limestone powder and/or slaking slag powder, sintering at 1330-1390 DEG C, controlling to cool the sintered material to obtain the self-pulverizing material, putting into a Na2CO3 solution to quickly dissolve out aluminum oxide, separating a solid from a liquid, extracting aluminum oxide according to the conventional method, and washing residues to obtain the low-sodium calcium-silicon slag. In the method, sodium-free desiliconized fly ash from which silicon dioxide is extracted and sodium oxide is removed is adopted as the raw material; the limestone sintering process can be used for extracting aluminum oxide, and low-sodium calcium-silicon slag can be obtained after extracting aluminum oxide; and both the aluminum oxide and the low-sodium calcium-silicon ...

Method for extracting aluminum oxide from sodium-free desiliconized fly ash

The invention relates to a method for extracting aluminum oxide from sodium-free desiliconized fly ash, which comprises the following steps of: taking dried sodium-free desiliconized fly ash, carrying out saturation calcium matching with limestone powder and/or slaking slag powder, sintering at 1330-1390 DEG C, controlling to cool the sintered material to obtain the self-pulverizing material, putting into a Na2CO3 solution to quickly dissolve out aluminum oxide, separating a solid from a liquid, extracting aluminum oxide according to the conventional method, and washing residues to obtain thelow-sodium calcium-silicon slag. In the method, sodium-free desiliconized fly ash from which silicon dioxide is extracted and sodium oxide is removed is adopted as the raw material; the limestone sintering process can be used for extracting aluminum oxide, and low-sodium calcium-silicon slag can be obtained after extracting aluminum oxide; and both the aluminum oxide and the low-sodium calcium-silicon ...

Method for firstly extracting silicon and secondly extracting aluminum from fly ash

The invention relates to a method to withdraw silicon and aluminum in sequence from coal ash; a NaOH solution with a mass concentration larger than 40 percent is used for leaching the coal ash, the silicon of the coal ash is dissolved in the form of sodium silicate, and after being separated, sodium silicate solutions and alkaline leaching residues with a ratio between aluminum and silicone more than or equal to 2 are produced; the dissolved sodium silicate solution is condensed into sodium silicate solutions of different concentrations, or used for preparing white carbon through a carbonationmethod; the alkaline residues are used for producing Al(OH)3 through a sodalime sintering method or limestone sintering method and further producing Al2O3, and the residues after the aluminum being extracted are made into stuff or used for producing concrete. The invention breakthroughs the original idea of directly extracting Al2O3 from the coal ash, and adopts the wholly novel technical route of ...

Method for extracting silicon dioxide from flyash

The invention discloses a method for extracting silicon dioxide from flyash, which comprises the following steps of: performing alkaline hydrolysis on the silicon dioxide in the flyash by using sodium hydroxide solution to prepare sodium silicate solution with the modulus between 0.4 and 0.8; directly heating to evaporate the sodium silicate solution so as to concentrate the sodium silicate solution until the solid content is 30 to 56 percent; and discharging into a cooling crystallization tank, reducing the temperature to 55-65 DEG C, adding a proper amount of seed crystals, continuously cooling to the temperature of between 30 and 35 DEG C, and performing filtering separation to obtain sodium metasilicate crystals with the modulus of 1 and NaOH solution. The NaOH solution is subjected to alkali make-up adjustment and then returns to the procedure of alkaline hydrolysis of the flyash for recycling, and the sodium metasilicate crystals are used for producing sodium metasilicate pentahydrate ...

Method for firstly extracting silicon and secondly extracting aluminum from fly ash

The invention relates to a method to withdraw silicon and aluminum in sequence from coal ash; a NaOH solution with a mass concentration larger than 40 percent is used for leaching the coal ash, the silicon of the coal ash is dissolved in the form of sodium silicate, and after being separated, sodium silicate solutions and alkaline leaching residues with a ratio between aluminum and silicone more than or equal to 2 are produced; the dissolved sodium silicate solution is condensed into sodium silicate solutions of different concentrations, or used for preparing white carbon through a carbonation method; the alkaline residues are used for producing Al(OH)3 through a sodalime sintering method or limestone sintering method and further producing Al2O3, and the residues after the aluminum being extracted are made into stuff or used for producing concrete. The invention breakthroughs the original idea of directly extracting Al2O3 from the coal ash, and adopts the wholly novel technical route of ...

Method for removing sodium oxide from desilicated fly ash

The invention relates to a method for removing sodium oxide from desilicated fly ash, which comprises the following steps: mixing digestive lime milk with the molar ratio of CaO and Na2O being 2:1-5:1 based on the Na2O content in desilicated fly ash as a reference, adjusting the liquid-solid ratio of the reaction system to be 2-8, mixing for 30-300 minutes at the temperature higher than or equal to 65 DEG C for reaction, keeping static for settlement, carrying out solid-liquid separation, recycling the supernatant and the filtrate to obtain low-concentration NaOH solution, and washing the filter cake with clean water to obtain low-Na desilicated ash. When in use, the method of the invention can effectively remove sodium oxide from alumyte or fly ash slag treated with concentrated alkali with the Na2O content reduced to below 1.2 percent and the removal rate higher than or equal to 75 percent, thereby satisfying the requirements for alumina extraction in the limestone sintering method.

Method for producing 4A molecular sieve

A method for producing a 4A molecular sieve comprises the following steps: (a) an intermediate product sodium silicate solution or a product carbon white obtained in the process of extracting silicon dioxide by a fly ash alkali solution method, (b) an intermediate product sodium aluminate solution or products aluminum hydroxide and aluminum oxide obtained in the process of extracting aluminum oxide by a fly ash soda lime sintering method, (c) NaOH and (d). H2O are taken as raw materials which meet the following mol ratios: Na2O:SiO2=1.6-3.8:1 and SiO2:Al2O3=1.7-2.1:1, and water added is controlled at the mol ratio of H2O:Na2O=30-60:1; and the raw materials are evenly mixed, stirred and gelled at 50-80 DEG C, heated to 90-120 DEG C, kept standing and crystallized for 3-6 hours, filtered, washed and dried to obtain the 4A molecular sieve. The calcium exchange capacity of the produced 4A molecular sieve is not less than 310mgCaCO3/g, and the sieving rate of a 1.25mm sieve is not lower than ...

Process for recovery of silica followed by alumina from coal fly ash

A process for recovery of silica and alumina from fly ash, in which, Si is leached out from the fly ash in the form of Na2SiO3 using a NaOH solution of NaOH >40% (w/w), followed by separation to obtain a Na2SiO3 solution and a residue having AlSi ratio 2; vaporizing the solution to obtain Na2SiO3 solutions of various concentrations, or producing silica by carbonation, and producing Al2O3 by prior art methods from residues obtained after alkali-leaching, ultimately producing filler or cement from the residue after the recovery of Al. The method permits recovery of Al2O3 directly from fly ash by removing Si before recovering the Al, which raises the AlSi ratio of the residue after alkali-leaching and thus simplifies the recovery of Al2O3 and raises the rate of Al recovery from fly ash. The invention further includes calcining high Al coal gangue, kaolinite and middle-low-class bauxite at 900-1100° C.

Method for producing silicon dioxide and alumina by using fly ash

Method for preparing high-modulus sodium silicate

The invention discloses a method for producing high-modulus sodium silicate at low temperature and normal pressure. The method comprises the following steps: the activated silicon dioxide from fly ash-typed industrial waste is leached by caustic lye of soda to produce low-modulus sodium silicate solution, the solution is decomposed by carbonation to prepare silicic acid (SiO2nH2O), then the silicic acid, the low-modulus sodium silicate and/or sodium hydroxide solution are mixed at the modulus index required by the final sodium silicate products and stirred to dissolve at temperature lower than liquid boiling point, therefore, the high-modulus sodium silicate is produced. Compared with the existing drying and wet methods for producing sodium silicate, the method of the invention has the advantages of wide raw material resources, low cost and energy consumption, no pollution; the method can be used for producing the sodium silicate with any modulus (M) from 1 to 4, in particular to the high-modulus ...

Method for preparation of sodium metasilicate pentahydrate by fly ash

The invention discloses a method for the preparation of sodium metasilicate pentahydrate by fly ash, which comprises the steps: using sodium hydroxide solution to alkaline-hydrolyze sodium silicate solution with the silicon dioxide preparation modulus of 0.4-0.8 in the fly ash, carbonizing amorphous hydrated silicon dioxide with the partial sodium hydroxide solution, then re-dissolving the amorphous hydrated silicon dioxide with the sodium hydroxide solution to formulate crystallization solution with the ratio of SiO2 to Na2O of 1:0.8-1.2, removing suspended matters by filtration, heating and concentration, cooling and crystallizing, and performing solid-liquid separation at 35 DEG C to result in sodium metasilicate pentahydrate. The method has the advantages of simple process, inexpensive raw material, great easiness for industrialization and tremendous economical and environmental benefits.