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CN-118744139-B - Treatment method of iron-aluminum slag

CN118744139BCN 118744139 BCN118744139 BCN 118744139BCN-118744139-B

Abstract

The present invention relates to a treatment method of iron-aluminum slag, which belongs to the technical field of slag treatment. At least one of water-soluble silicon and water-soluble phosphorus is utilized to treat the iron-aluminum slag, and alkali is added twice to adjust the pH value within a specific range, so that the extractable content of Ni, co and Mn in the iron-aluminum slag is reduced, and the environmental pollution caused by heavy metal leaching in the iron-aluminum slag is reduced.

Inventors

  • LI LI
  • RUAN DINGSHAN
  • ZENG ZHIJIA
  • CHEN JIAJIA
  • CHEN RUOKUI
  • LI CHANGDONG

Assignees

  • 湖南邦普循环科技有限公司
  • 广东邦普循环科技有限公司

Dates

Publication Date
20260505
Application Date
20240614

Claims (9)

  1. 1. The treatment method of the iron-aluminum slag is characterized by comprising the following steps of: Mixing and dispersing iron-aluminum slag to be treated, at least one of water-soluble silicon and water-soluble phosphorus and water to obtain a solid-liquid mixture, wherein the iron-aluminum slag is waste slag generated by removing iron and aluminum in the recovery process of the nickel-cobalt-manganese ternary battery anode material; Adding alkali into the solid-liquid mixture to adjust the pH value to 4-5, then aging for the first time, adding alkali to adjust the pH value to more than 7, then aging for the second time, and separating solid from liquid, wherein the obtained solid is the target ferro-aluminum slag; wherein the time of the first aging and the time of the second aging are respectively independent and are more than or equal to 0; the water-soluble phosphorus is capable of ionizing out at least one of phosphate, phosphite and hypophosphite in an acidic and/or neutral aqueous solution; the water-soluble silicon is capable of ionizing out silicate groups in acidic and/or neutral aqueous solutions and/or alkaline aqueous solutions with a pH < 11.
  2. 2. The method for treating iron-aluminum slag according to claim 1, wherein the iron-aluminum slag to be treated is mixed and dispersed with water-soluble silicon during the preparation of the solid-liquid mixture, wherein the method for treating iron-aluminum slag satisfies x=a m+b N, wherein, X mol is the molar amount of silicate in the water-soluble silicon; m mol is the molar quantity of Mn element in the iron-aluminum slag; n mol is the sum of the molar amounts of Co element and Ni element in the iron-aluminum slag; a=4-7; b=2-5。
  3. 3. the method for treating iron-aluminum slag according to claim 1, wherein the iron-aluminum slag to be treated is mixed and dispersed with water-soluble phosphorus during the preparation of the solid-liquid mixture, wherein the method for treating iron-aluminum slag satisfies y=c N, wherein, Y mol is the sum of the molar amounts of phosphate, phosphite and hypophosphite in the water-soluble phosphorus; n mol is the sum of the molar amounts of Co element and Ni element in the iron-aluminum slag; c=1.5-3。
  4. 4. The method for treating iron-aluminum slag according to claim 1, wherein iron-aluminum slag to be treated is mixed and dispersed with water-soluble silicon and water-soluble phosphorus during the preparation of the solid-liquid mixture.
  5. 5. The method for treating iron-aluminum slag according to claim 1, wherein the water-soluble silicon comprises at least one of silicic acid, sodium silicate, potassium silicate, water glass and silicon-containing wastewater, and/or The water-soluble phosphorus includes at least one of sodium phosphate, potassium phosphate, ammonium phosphate, phosphoric acid, sodium phosphite, calcium phosphate, and phosphorus-containing wastewater.
  6. 6. The method for treating iron-aluminum slag according to any one of claims 1 to 5, wherein at least one of the conditions (1) to (3) is satisfied: (1) The time of the first aging is 0-5h, and the time of the second aging is 0-4h; (2) Adding alkali into the solid-liquid mixture to adjust the pH value to 4-5, then performing first aging, adding alkali to adjust the pH value to more than 7, and then performing second aging at 15-80 ℃; (3) And adding alkali to adjust the pH value to 7 or more, and then, aging for the second time, wherein the pH value is adjusted to 7-9 by adding alkali.
  7. 7. The method for treating iron-aluminum slag according to claim 6, wherein at least one of the conditions S1 to S2 is satisfied: s1, the time of the first aging is 3-5h, and the time of the second aging is 2-4h; s2, adding alkali into the solid-liquid mixture to adjust the pH value to be 4-5, then performing first aging, adding alkali to adjust the pH value to be more than 7, and then performing second aging at 15-30 ℃.
  8. 8. The method of treating iron-aluminum slag according to any one of claims 1 to 5, wherein the solid content in the solid-liquid mixture is 30wt.% to 80wt.%.
  9. 9. The method for treating ferro-aluminum slag according to any one of claims 1 to 5, wherein the ferro-aluminum slag comprises the following elements, by mass, 14% -20% of Fe, 5% -9% of Al, 10% -15% of S, 4% -8% of Na, 0.8% -1.2% of Ni, 0.3% -0.6% of Co, and 0.4% -0.6% of Mn, wherein, The existence form of Fe comprises ferric sulfate and/or ferric hydroxide; the existence form of Al comprises aluminum sulfate and/or aluminum hydroxide; the existence form of Ni comprises sulfate and/or hydroxide; the existence form of Co comprises sulfate and/or hydroxide; the Mn exists in the form of sulfate and/or hydroxide.

Description

Treatment method of iron-aluminum slag Technical Field The invention relates to the technical field of waste residue treatment, in particular to a treatment method of iron-aluminum slag. Background The Fe-Al slag is waste slag generated in the impurity removal process in the battery recycling industry, and the main constituent elements of the Fe-Al slag are Fe, al, S and Na, and also contain a small amount of Ni, co and Mn. Because the metal compounds in the iron-aluminum slag mainly exist in the form of sulfate with strong solubility, the metal compounds are easy to pollute the environment due to leakage of heavy metals in the stacking process. In order to avoid the problem of heavy metal leakage, naOH or Na 2CO3 is usually adopted at the present stage to stabilize heavy metals Ni, co and Mn and then stacked, but the problem of poor stability of heavy metals still exists. In particular, for Co metal, only alkali liquor is used for stabilization treatment, and the acid extractable state (measured by a BCR continuous extraction method) of cobalt still accounts for more than 80 percent. The iron-aluminum slag is waste slag with very high yield in the battery recycling process, and has complex components, difficult high added value utilization and limited market consumption, so that a stabilization method of heavy metals in the iron-aluminum slag is necessary to be explored, and the pollution of the iron-aluminum slag to the environment in the stacking process is reduced. Disclosure of Invention The aim of the present invention is to overcome the defects of the prior art and provide a treatment method of iron-aluminum slag, so as to reduce the extractable content of Ni, co and Mn in the iron-aluminum slag and reduce the environmental pollution caused by heavy metal leaching in the iron-aluminum slag. To achieve the above object, there is provided a method for treating ferro-aluminum slag, comprising the steps of: Mixing and dispersing iron-aluminum slag to be treated, at least one of water-soluble silicon and water-soluble phosphorus and water to obtain a solid-liquid mixture; Adding alkali into the solid-liquid mixture to adjust the pH value to 4-5, then aging for the first time, adding alkali to adjust the pH value to more than 7, then aging for the second time, and separating solid from liquid, wherein the obtained solid is the target ferro-aluminum slag; wherein the time of the first aging and the time of the second aging are respectively independent and are more than or equal to 0; the water-soluble phosphorus is capable of ionizing out at least one of phosphate, phosphite and hypophosphite in an acidic and/or neutral aqueous solution; the water-soluble silicon is capable of ionizing out silicate groups in acidic and/or neutral aqueous solutions and/or alkaline aqueous solutions with a pH < 11. The treatment method utilizes at least one of water-soluble silicon and water-soluble phosphorus to treat the iron-aluminum slag, wherein the silicon in the water-soluble silicon is subjected to pH adjustment and aging treatment by adding alkali to form network gel, ni, co, mn and other elements in the iron-aluminum slag are wrapped in the gel structure, the water-soluble silicon can form MnSiO 3 with Mn in the iron-aluminum slag and poor in water solubility, so that the extractable state content of Ni, co and Mn in the iron-aluminum slag is reduced, the water-soluble phosphorus can form CoNiFePO 4 with poor water solubility with Ni, co and Fe in the iron-aluminum slag, the stabilizing treatment effect of Ni, co and Mn in the iron-aluminum slag is improved, and the extractable state content of Ni, co and Mn in the iron-aluminum slag is reduced. When the water-soluble phosphorus is not utilized, the water-soluble silicon is not utilized to treat the iron-aluminum slag, the extractable state content of Ni, co and Mn in the obtained target iron-aluminum slag is lower, and the phosphorus is not additionally introduced, so that the method is more suitable for being applied to the construction industry, and is beneficial to realizing the recycling of waste residues. In the treatment method, the purpose of the first pH adjustment is to form a macromolecular gel precursor of aluminum (and silicon in water-soluble silicon, if any) in the iron-aluminum slag, the purpose of the first aging is to form a network-like gel structure of aluminum (and silicon, if any), the purpose of the second pH adjustment is to form a metal hydroxide with poor water solubility (water-soluble silicon is used to form MnSiO 3 with poor water solubility, water-soluble phosphorus is used to form CoNiFePO 4 with poor water solubility), and the purpose of the second aging is to stabilize the structure of the substance with poor water solubility and complete crystal forms. The target pH value of the two pH adjustments is controlled within the specific range, so that the extractable content of Ni, co and Mn in the iron-aluminum slag is effectively reduce