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CN-121992194-A - Method for reducing dosage of neutralization auxiliary agent in acid leaching slurry

CN121992194ACN 121992194 ACN121992194 ACN 121992194ACN-121992194-A

Abstract

The invention provides a method for reducing the consumption of an acid leaching slurry neutralization auxiliary agent, which comprises the steps of adding a composite dispersing agent into the acid leaching slurry to obtain pretreated slurry, adding the neutralization auxiliary agent into the pretreated slurry to perform primary neutralization, adding a composite catalyst into the slurry after primary neutralization to perform catalytic auxiliary neutralization, and adding the neutralization auxiliary agent to perform secondary deep neutralization to obtain target acid leaching slurry. The invention adjusts the ion composition and particle characteristics of the acid leaching slurry through pretreatment, combines a sectional neutralization process and a catalysis auxiliary means, adopts a mechanochemical strengthening neutralization reaction process, obviously reduces the dosage of a neutralization auxiliary agent on the premise of ensuring that the pH value of the slurry reaches the standard and the subsequent separation process is stable, and compared with the traditional method, the invention reduces the dosage of the neutralization auxiliary agent by 30-50%, reduces the yield of the neutralization slag by 15-50%, does not influence the leaching rate and the subsequent recovery efficiency of target metal, and has obvious economic and environmental benefits.

Inventors

  • LI HUIQUAN
  • YANG CHENNIAN
  • WANG CHENYE
  • SUN ZHENHUA

Assignees

  • 中国科学院过程工程研究所

Dates

Publication Date
20260508
Application Date
20260311

Claims (10)

  1. 1. A method for reducing the amount of acid leach slurry neutralization aid, the method comprising the steps of: adding a composite dispersing agent into the acid leaching slurry to obtain a pretreated slurry; Adding a neutralizing auxiliary agent into the pretreatment slurry to perform primary neutralization; Adding a composite catalyst into the primary neutralized slurry to perform catalytic auxiliary neutralization; and adding a neutralizing auxiliary agent for secondary deep neutralization to obtain the target acid leaching slurry.
  2. 2. The method according to claim 1, wherein the acid leaching slurry has a liquid-to-solid ratio of (0.5-10) 1 mL/g; preferably, the acid leach slurry has an initial pH <2.
  3. 3. The method according to claim 1 or 2, wherein the composite dispersant is added in an amount of 0.5-3 wt%; Preferably, the complex dispersant includes a polycarboxylic acid dispersant and an inorganic dispersant; preferably, the mass ratio of the polycarboxylic acid dispersant to the inorganic dispersant is (1-5): 1; Preferably, the inorganic dispersant comprises any one or a combination of at least two of sodium pyrophosphate, sodium tripolyphosphate, or sodium hexametaphosphate.
  4. 4. A method according to any one of claims 1 to 3, wherein the acid leach slurry is added with a composite dispersant and then subjected to a first agitation; preferably, the first stirring speed is 50-600 r/min; Preferably, the temperature of the first agitation is 20-90 ℃; preferably, the first stirring time is 5-180 min.
  5. 5. The method of any one of claims 1-4, wherein the neutralization aid comprises any one or a combination of at least two of calcium hydroxide, sodium hydroxide, ammonia, or calcium carbonate.
  6. 6. The method according to any one of claims 1 to 5, wherein the primary neutralization controls the pH of the slurry to 2-4; preferably, the temperature of the primary neutralization is from 20 to 90 ℃; preferably, the primary neutralization time is 5-180 min; preferably, the primary neutralization comprises a second agitation; preferably, the second stirring speed is 50-600 r/min.
  7. 7. The method according to any one of claims 1 to 6, wherein the addition amount of the composite catalyst is 0.1 to 5 wt%; Preferably, the composite catalyst comprises a basic oxide and a base; preferably, the mass ratio of the basic oxide to the alkali is (1-3): 1; preferably, the basic oxide comprises calcium oxide and/or magnesium oxide; Preferably, the base comprises calcium hydroxide and/or sodium hydroxide.
  8. 8. The method of any one of claims 1-7, wherein the catalytic assisted neutralization comprises a third agitation; preferably, the third stirring time is 10-60 min; Preferably, the speed of the third stirring is 200-300 r/min.
  9. 9. The method according to any one of claims 1 to 8, wherein the secondary depth neutralization temperature is 20-90 ℃; Preferably, the secondary depth neutralization time is 40-80 min; preferably, the secondary deep neutralization controls the slurry pH to 5-7.
  10. 10. The method according to any one of claims 1 to 9, wherein the secondary depth neutralization is performed mechanically; preferably, the mechanical method comprises ball milling and/or stirred milling; Preferably, the ball-milling ball-material ratio is (1-2): 1; preferably, the rotation speed of the ball milling is 50-300 r/min.

Description

Method for reducing dosage of neutralization auxiliary agent in acid leaching slurry Technical Field The invention relates to the technical field of wet leaching of metal minerals, in particular to a method for reducing the consumption of a neutralization auxiliary agent in acid leaching slurry. Background In the hydrometallurgical process of metal minerals, acid leaching is a core unit operation with extremely wide application, and the core principle is to convert target metals (such as lithium, copper, nickel, zinc and the like) in a combined state in a mineral lattice into a soluble metal ion state by means of the chemical action of acid agents such as sulfuric acid, hydrochloric acid and the like, so that the target metals are dissolved out of a solid mineral matrix and enter a liquid phase system, and a foundation is laid for the subsequent separation and purification procedures such as extraction, precipitation, electrodeposition and the like. However, the slurry obtained after the acid leaching is finished often shows stronger acidity, the pH value of the slurry is usually less than 2.0, and a large amount of free acid which does not participate in the reaction remains in the system, and target metal ions and impurity metal ions such as iron, aluminum and the like are dissolved. If the high-acidity slurry is directly sent to a subsequent separation unit for filtering and extracting, on one hand, serious corrosion is caused to metal materials of equipment, the service life of the equipment is greatly shortened, the maintenance cost is increased, and on the other hand, the strong acid environment also can interfere the selective complexing capacity of the extractant or cause the blockage of a filter medium, so that the efficiency and the product purity of a separation procedure are reduced. Therefore, after the acid leaching process, the pH value of the slurry must be regulated and controlled by neutralization treatment, so that not only can the excessive free acid be neutralized and the equipment corrosion problem be relieved, but also partial impurity metal ions can be promoted to hydrolyze and precipitate, and favorable conditions are created for subsequent high-efficiency separation. At present, the neutralization treatment in the hydrometallurgy field mostly adopts a mode of adding a neutralization auxiliary agent at one time, and commonly used auxiliary agents comprise alkaline materials such as calcium hydroxide, sodium hydroxide, calcium carbonate and the like, and the core principle is that the free acid remained in the acid leaching slurry is directly consumed through an acid-base neutralization reaction so as to quickly adjust the pH value of a system. However, this neutralization approach has a number of technical drawbacks. Firstly, besides target metal ions, a large amount of impurity metal ions such as iron, aluminum and the like which are easy to hydrolyze coexist in the acid leaching slurry, and the ions can react with a neutralization auxiliary agent first to generate insoluble hydroxide precipitate. Secondly, the one-time centralized addition of the auxiliary agent is extremely easy to cause local severe reaction, the neutralization reaction rate of acid and alkali in a slurry system is difficult to uniformly control, the generated neutralization slag is mostly colloidal substances with fine particles, the filtering and sedimentation performances are extremely poor, and meanwhile, the large amount of impurity metal hydroxide precipitates are generated, so that the overall yield of the neutralization slag is high, and great challenges are brought to subsequent solid-liquid separation, slag stacking and harmless disposal. Thirdly, excessive addition of the neutralizing auxiliary agent often causes severe fluctuation of the pH value of the slurry, and once the pH value exceeds the proper process range, the stability of target metal ions in the solution can be damaged, even partial target metal is precipitated in advance and lost, and the efficiency of the subsequent separation and purification process and the recovery rate of the final metal product are seriously influenced. Therefore, under the current great trend of cost reduction, synergy and green low carbon in the metal hydrometallurgy industry, a novel neutralization regulation and control method for accurately adapting to the characteristics of acid leaching slurry is developed, and the core aims at not only pointedly inhibiting the ineffective consumption of neutralizing auxiliary agents by impurity metal ions such as iron, aluminum and the like so as to greatly reduce the consumption of auxiliary agents such as calcium hydroxide, calcium carbonate and the like, but also reducing the generation of colloidal impurity precipitation through optimizing a reaction process so as to effectively improve the filtration rate, and simultaneously ensuring that the stability of a slurry system is accurately maintained in the process of regul