Method for chlorides from zinc alkali solution

An alkaline solution and chloride technology, applied in the field of removing chlorides in zinc alkaline solution, can solve problems such as anode plate corrosion, and achieve a remarkable and stable purification effect.

Inactive Publication Date: 2009-06-17
TONGJI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, a large amount of Cl in the alkaline zinc solution - The purification and removal research has not yet seen relevant reports
[0004] In the traditional acid zinc smelting process, since the anode plate is easily corroded by chloride ions in the acid electrolyte, the chlorine content in the raw material is required to be very low, and a small amount of Cl entering the solution - (generally lower than 700mg / L) can be removed by silver chloride precipitation, copper slag dechlorination or alkali washing dechlorination, but the above methods are not suitable for Cl in zinc-containing strong alkaline solution - Neither removes

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  • Method for chlorides from zinc alkali solution

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Effect test

Embodiment 1

[0015] A certain zinc oxide dust is used as raw material, and the chlorine content is 5.33%. The zinc is extracted by alkali leaching-electrolysis process to produce metal zinc powder, and the lye is recycled. After the number of times of leaching reaches 80 times, the purification solution that has removed metal ions such as lead is analyzed (the composition is shown in Table 1). It can be seen from Table 1 that the chloride ion concentration has reached 75.50g / L and needs to be removed. Take 200 mL of this solution in a 250 mL Erlenmeyer flask, add 90 g of NaOH and 19 g of ZnO (both analytically pure), cover the Erlenmeyer flask with a small funnel (to prevent the solution from volatilizing), heat and stir at 85 ° C for 4 hours, and promote the full dissolution of NaOH and ZnO , then cooled to normal temperature (23°C) and continued to stir for 30 minutes, let it stand for 100 minutes, suction filtered and took the filtrate for analysis. The concentration of NaOH in the solu...

Embodiment 2

[0025] A certain zinc oxide scum is used as raw material, and the chlorine content is 2.65%. The zinc is extracted by alkali leaching-electrolysis process to produce metal zinc powder, and the lye is recycled. After the number of times of leaching reaches 320 times, the purification solution that has removed metal ions such as lead is analyzed (the composition is shown in Table 3). It can be seen from Table 3 that the chloride ion concentration has reached 72.35g / L and needs to be removed. Take 200mL of this solution in a 250mL Erlenmeyer flask, heat and stir at 90°C for 8h to concentrate the solution, cool to room temperature (18°C), continue to stir for 40min, let it stand for 90min, and obtain 75mL of filtrate by suction filtration. Analysis shows that the concentration of NaOH in the solution is 495.65g / L, Zn 94.10g / L, Cl - The concentration dropped from 72.35g / L to 12.85g / L. The resulting filtrate was diluted to 200 mL with distilled water, and the solution was analyze...

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Abstract

The invention discloses a method for removing chloride from an alkaline zinc solution, relates to a process for removing impurities such as chloride ion and the like from a process for producing high-purity metallic zinc by taking zinc oxide ore, powder or slag as a raw material through alkaline leaching-electrolysis. The method comprises the following steps: NaOH and the zinc oxide are added with stirring to the alkaline zinc solution the Cl<-> concentration of which is more than 70g/L, or/and the solution is heated for concentration to increase the NaOH concentration to 400-600g/L and the Zn concentration to 60-120g/L; the mixture is cooled to normal temperature, continuously stirred for 20-60min and kept standing for 40-120min during which a large amount of chloride is crystallized and separated out from the solution because of the sharp decrease of the solubility; then the solid is separated from the liquid, and filtrate is diluted with water and adjusted to the alkaline zinc concentration level before purification, so that the Cl<-> concentration decrease to less than 5g/L and the impurity ions such as Fe, Cu, As, Cd and the like in the solution are also removed at the same time, which meets the requirements of the subsequent electrolysis process operation; and purification slag is sold to the chlor-alkali industry as a raw material. The method has the advantages of significant Cl<-> removal effect, simple operation and the like, thoroughly solves the problem of causing damage to the zinc electrowinning and extracting from the alkaline zinc solution due to continuous accumulation of the Cl<-> impurity.

Description

technical field [0001] The invention relates to a method for removing chloride in zinc alkali solution, which relates to a process for removing impurities such as chloride ions in the process of producing high-purity metal zinc by alkaline leaching-electrolysis using zinc oxide ore, ash or slag as raw materials. Background technique [0002] Using zinc oxide ore, ash or slag as raw materials to produce high-purity metal zinc by alkaline leaching-electrolysis has a Chinese invention patent publication number of CN 1450182A (named "A method for producing high-purity metal zinc by using zinc oxide ore") and published The number is disclosed in CN 1817518A (titled "a method for producing metal zinc powder with zinc dust and zinc scum"), and its main production process is to utilize a strong alkali solution containing NaOH 210-250g / L to leaching zinc oxide ore Or zinc oxide slag, obtain the alkaline zinc solution containing NaOH 170-210g / L, Zn 30-45g / L, the main impurity of this ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B3/12
CPCY02P10/20
Inventor 赵由才蒋家超易天晟韩丹梅娟
Owner TONGJI UNIV
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