Search

CN-118791150-B - Impurity removal regeneration method of coal ash removal alkali liquor and coal ash removal method

CN118791150BCN 118791150 BCN118791150 BCN 118791150BCN-118791150-B

Abstract

The invention provides a method for removing impurities and regenerating ash-removing alkali liquor of coal and a method for removing ash of coal, by adopting the technical scheme provided by the invention, the method can effectively remove impurities in the coal ash removal alkali liquor, so that alkali in the coal ash removal alkali liquor is effectively regenerated, the method can be recycled, and the economical efficiency of coal ash removal is improved. The impurity removal and regeneration method comprises the following steps of 1) adjusting the alkali content in the coal ash removal alkali liquor, 2 a) performing low-temperature impurity removal operation when the ratio of the sum of the molar amounts of Al element and Fe element to the molar amount of Si element in the coal ash removal alkali liquor in the step 1) is more than or equal to 5 and preferably more than or equal to 10, and 2 b) performing low-temperature impurity removal and high-temperature impurity removal operation when the ratio of the sum of the molar amounts of Al element and Fe element to the molar amount of Si element in the coal ash removal alkali liquor in the step 1) is less than 10 and preferably less than 5.

Inventors

  • ZHAO LIJUN
  • GUO YI

Assignees

  • 国家能源投资集团有限责任公司
  • 北京低碳清洁能源研究院

Dates

Publication Date
20260512
Application Date
20230412

Claims (15)

  1. 1. The impurity removal regeneration method of the coal ash removal alkali liquor is characterized by comprising the following steps of: 1) Regulating the alkali content in the coal ash removal alkali liquor, and enabling the alkali content to be less than or equal to 35wt%; 2a) When the ratio of the sum of the molar amounts of Al element and Fe element to the molar amount of Si element in the coal ash removal alkali liquor in the step 1) is more than or equal to 5, the steps of mixing the coal ash removal alkali liquor with a impurity removal medicament for low-temperature reaction, and then filtering to obtain regenerated alkali liquor; 2b) When the ratio of the sum of the molar amounts of Al element and Fe element to the molar amount of Si element in the coal ash removal alkali liquor in the step 1) is less than 5, the following steps are carried out: Mixing the coal ash removal alkali liquor with the impurity removal medicament for low-temperature reaction, filtering, continuously mixing the obtained filtrate with the impurity removal medicament for high-temperature reaction, and filtering to obtain regenerated alkali liquor; the reaction temperature of the low-temperature reaction is 10-99 ℃, and the reaction temperature of the high-temperature reaction is 120-220 ℃.
  2. 2. The method for regenerating a coal ash removal alkali liquor according to claim 1, wherein in step 1), the alkali content in the coal ash removal alkali liquor is adjusted so that the alkali content is not more than 25wt%.
  3. 3. The method for regenerating coal ash removal lye according to claim 1, wherein in step 1), the alkali content in the coal ash removal lye is adjusted by dilution.
  4. 4. The method for removing impurities from and regenerating ash removing alkali liquor of coal according to claim 1, wherein the impurity removing agents in each step 2 a) or step 2 b) are respectively and independently selected from one or more of calcium agent and magnesium agent.
  5. 5. The method for removing impurities from ash removal alkali liquor of coal according to claim 4, wherein the calcium agent is one or more selected from the group consisting of calcium oxide, calcium hydroxide and lime milk, and the magnesium agent is one or more selected from the group consisting of magnesium oxide, magnesium hydroxide and magnesium hydroxide emulsion.
  6. 6. The method for regenerating a coal ash removal alkali liquor according to claim 4, wherein in the step 2 a) or the step 2 b), the ratio of the amount of the impurity removal chemical to the sum of the molar amounts of the aluminum element and the iron element in the reaction solution is 1 to 3, based on the sum of the molar amounts of the calcium element and the magnesium element, when the low-temperature reaction is performed.
  7. 7. The method for regenerating a coal ash removal alkali liquor according to claim 4, wherein in the step 2 b), the impurity removal agent is used in a ratio of 0.8 to 2.2 in terms of the sum of the molar amounts of calcium element and magnesium element to the molar amount of silicon element in the reaction solution when the high temperature reaction is carried out.
  8. 8. The method for regenerating ash removal alkali liquor for coal according to any one of claims 1 to 7, wherein in step 2 a) or step 2 b), the reaction time of the low temperature reaction is 0.1 to 6 hours; And/or, in the step 2 b), the reaction time of the high-temperature reaction is 0.1-6 h.
  9. 9. The method for regenerating ash removal alkali liquor for coal according to any one of claims 1 to 7, wherein in step 2 b), the reaction temperature of the high temperature reaction is 140 to 180 ℃.
  10. 10. The method for regenerating ash removal alkali liquor for coal according to claim 9, wherein in the step 2 b), the reaction time of the high temperature reaction is 0.25-3h.
  11. 11. The method for regenerating a coal ash removal alkali liquor according to any one of claims 1 to 7, wherein in step 2 b), when the ratio of the sum of the molar amounts of Al element and Fe element to the molar amount of Si element in the coal ash removal alkali liquor is <5, the ratio is made to be equal to or larger than 5 by adding an iron agent and/or an aluminum agent.
  12. 12. The method for removing impurities from and regenerating coal ash removal alkali liquor according to claim 11, wherein the iron agent is selected from one or more of ferric chloride, ferric sulfate, ferric nitrate, sodium ferrite or other substances capable of converting or generating ferric hydroxide in the alkali liquor, and the aluminum agent is selected from one or more of aluminum chloride, aluminum sulfate, aluminum nitrate, sodium aluminate or other aluminum-containing substances capable of being dissolved in the alkali liquor.
  13. 13. A method for ash removal of coal, characterized in that regenerated alkali liquor obtained in the impurity removal and regeneration method according to any one of claims 1 to 12 is used for ash removal of coal by an alkali method.
  14. 14. The coal ash removal method of claim 13, including the steps of: 1) Crushing coal; 2) Performing alkali ash removal on the coal in the step 1) at 100-250 ℃ and filtering to obtain coal ash removal alkali liquor and a filter cake; 3) Carrying out acid washing and ash removal on the filter cake to obtain low ash coal and filter cake washing liquid, and treating the coal ash removal alkali liquor according to the impurity removal regeneration method of any one of claims 1-12 to obtain regenerated alkali liquor; 4) And (2) using the regenerated alkali liquor in the step (2) to carry out the alkali ash removal.
  15. 15. The coal ash removal method of claim 14, wherein the crushing is crushing to a particle size of less than 3mm.

Description

Impurity removal regeneration method of coal ash removal alkali liquor and coal ash removal method Technical Field The invention relates to the technical field of coal acid-alkali ash removal, in particular to an impurity removal regeneration method of coal ash removal alkali liquor and a coal ash removal method. Background The traditional coal ash removal mainly comprises a jigging method, a heavy medium method and a flotation method, the ash removal efficiency is low, and the ash content can only reach about 10-30%. It is generally not usable as a carbon material, and a small amount is used as a high ash carbon material such as an electrode paste and a high ash carbon block. The refining and ash removal is carried out on the basis of the traditional coal ash removal, and can be divided into two main types, namely a physical method and a chemical method. The chemical method is mainly divided into four methods of hydrofluoric acid method, conventional acid-base method, molten alkali leaching method and chemical coal method. The conventional acid-base method adopts alkali liquor to react with ash of minerals in coal to generate acid-soluble products, then the acid-soluble products react with acid to enter a liquid phase, and organic matters in the coal are separated by filtration and washing. The conventional acid-base chemical ash removal has comprehensive advantages in the aspects of ash removal efficiency, economy, environmental benefit and the like. The ash removal by adopting the conventional chemical method can obtain coal with ash content less than 1% or less, and can be used for preparing carbon anodes and other carbon materials, such as supercapacitor electrodes, high-quality activated carbon, advanced carbon materials such as graphene and the like by replacing petroleum coke in a large amount. When ash is removed by a conventional acid-alkali method, alkali liquor needs to act with coal and contained minerals, and the minerals dissolved in the alkali liquor consume the alkali liquor, so that the effective alkali content is reduced, the accumulated alkali liquor for treating the coal cannot be recycled, and the economy of ash removal of the coal is reduced. Alkali is the most important reagent consumption in the conventional ash removal of coal, and is the main cost component of coal ash removal. In the technical monograph of coal washing and processing (P86-87), some chemical reactions possibly occurring in the conventional chemical method of coal ash removal and the action mechanism of adding calcium oxide into ash removal alkali liquor of coal are given. However, the theory is not supported by experiments, and the complex effect of inorganic components of ash removal lye is not discussed deeply. Patent CN200380102494.4 (demineralization method of coal) proposes that calcium oxide, calcium hydroxide, magnesium oxide or magnesium hydroxide, etc. can be added, and the alkali lost by ash dissolved in alkali liquor can be regenerated and reused through causticization reaction. However, the conditions for regeneration of the lye are not clearly defined. Therefore, the mature technical scheme is still lacking at present for the removal of inorganic mineral components in the ash removal alkali liquor of coal and the regeneration of alkali liquor. Disclosure of Invention The inventor discovers that the inorganic mineral composition which is soluble in alkali liquor in coal mainly comprises aluminum, silicon and iron, and is a main target impurity for the impurity removal and regeneration of the ash removal alkali liquor of coal. The invention aims to provide a method for removing impurities and regenerating ash removing alkali liquor of coal and a method for removing ash of coal, which have higher impurity removal rate by adopting the technical scheme provided by the invention, the method can effectively remove aluminum, silicon and iron in the coal ash removal alkali liquor, so that alkali in the coal ash removal alkali liquor is effectively regenerated, can be recycled, and is beneficial to improving the economy of coal ash removal. The invention provides the following technical scheme for achieving the purpose: the invention provides a method for removing impurities and regenerating ash-removing alkali liquor of coal, which comprises the following steps: 1) Adjusting the alkali content in the coal ash removal alkali liquor to be less than or equal to 35wt%, preferably less than or equal to 25wt%; 2a) When the ratio of the sum of the molar amounts of Al element and Fe element to the molar amount of Si element in the coal ash removal alkali liquor in the step 1) is more than or equal to 5, preferably more than or equal to 10, the steps are carried out, namely, mixing the coal ash removal alkali liquor with an impurity removal reagent for low-temperature reaction, and then filtering to obtain regenerated alkali liquor; 2b) When the ratio of the sum of the molar amounts of Al element and Fe element to the