Method for dechlorinating zinc sulfate solution

Abstract

The invention discloses a method for dechlorinating a zinc sulfate solution, the method for dechlorinating the zinc sulfate solution comprises a pretreatment step and a main reaction step, and the method specifically comprises the following steps: adjusting the pH value of the zinc sulfate solution to be treated to 1.5-3.5 to obtain a material a; adding a precipitator into the material a for stirring reaction to obtain a dechlorinated zinc sulfate solution; the precipitant is trialkyl bismuth, trialkyl antimony, trialkyl lead or trialkyl vanadium. According to the method, the chlorine removal efficiency and stability are improved by regulating and controlling reaction conditions such as the pH value, the temperature and the types of precipitants, and finally, an environment-friendly, economical and feasible treatment scheme is realized.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical technology, specifically relating to a method for dechlorination in zinc sulfate solution. Background Technology

[0002] Zinc sulfate, an important raw material for electrolytic zinc production, often contains a certain amount of chlorine impurities in its solution. If this chlorine is introduced directly into the next zinc production process without treatment, it will severely affect product quality. While various methods exist for chlorine removal, they often suffer from low efficiency, high cost, and operational complexity in practical applications. Therefore, developing a method that can solve these technical problems is essential. Summary of the Invention

[0003] The purpose of this invention is to provide a method for dechlorination in zinc sulfate solution.

[0004] The objective of this invention is achieved by the method for dechlorination in zinc sulfate solution, which includes pretreatment and a main reaction step, specifically including: A. Pretreatment: Adjust the pH of the zinc sulfate solution to be treated to 1.5~3.5 to obtain material a; B. Main reaction: Add a precipitant to material a and stir to obtain a dechlorinated zinc sulfate solution; The precipitant is trialkylbismuth, trialkylantimony, trialkyllead, or trialkylvanadium.

[0005] Its technical principle is as follows: Step 1: Pretreatment. Under acidic conditions, the carbon-metal bonds in alkyl metal compounds break, releasing metal ions and alkanes.

[0006] R3M + 3H + → M 3+ + 3RH↑ Step 2: The main reaction, releasing high-valence metal ions (M... 3+ It hydrolyzes and combines with chloride ions to form chloride oxide precipitates.

[0007] M 3+ + H2O + Cl − → MOCI↓ + 2H + The method for dechlorinating zinc sulfate solution described in this invention involves adjusting the pH of the chlorine-containing zinc sulfate solution to 1.5-3.5, adding a precipitant while stirring, controlling the mass ratio of chlorine to the precipitant in the solution to 1:1-100, heating the mixed solution to 50-80°C, reacting for 0.5-2 hours, separating the solid and liquid phases, and filtering to remove the chlorine oxide precipitate, thus completing the removal of chlorine from the zinc sulfate solution. The precipitant can be trialkylbismuth, trialkylantimony, trialkyllead, trialkylvanadium, etc. This invention improves the efficiency and stability of chlorine removal by controlling reaction conditions such as pH, temperature, and the type of precipitant, ultimately achieving an environmentally friendly and economically feasible treatment solution. Detailed Implementation

[0008] The present invention will be further described below with reference to embodiments, but this is not intended to limit the present invention in any way. Any modifications or substitutions made based on the teachings of the present invention shall fall within the protection scope of the present invention.

[0009] The method for dechlorination in zinc sulfate solution according to the present invention includes pretreatment and main reaction steps, specifically including: A. Pretreatment: Adjust the pH of the zinc sulfate solution to be treated to 1.5~3.5 to obtain material a; B. Main reaction: Add a precipitant to material a and stir to obtain a dechlorinated zinc sulfate solution; The precipitant is trialkylbismuth, trialkylantimony, trialkyllead, or trialkylvanadium.

[0010] The chloride ion content in the zinc sulfate solution to be treated in step A is 0.5~6 g / L.

[0011] The amount of precipitant added in step B is 4.5~5.5 g / L.

[0012] In step B, the stirring speed for the reaction is 100~200 r / min.

[0013] The temperature for stirring the reaction in step B is 50~70℃.

[0014] The stirring reaction time in step B is 1-3 hours.

[0015] The present invention will be further described below with reference to specific embodiments: Comparative Example 1 Chinese patent CN103572051A discloses a method for dechlorinating a zinc sulfate solution. The method involves dissolving a zinc sulfate solution containing 100–150 g / L of zinc and 0.5–5.0 g / L of chlorine in sulfuric acid to obtain an acidic solution with a sulfuric acid concentration of 20–75 g / L. The acidic solution is then subjected to a current density of 50–200 A / m at room temperature. 2 Under these conditions, selective electrodialysis was performed in a four-diaphragm electrolytic cell to obtain a low-chlorine solution containing 0.1–0.3 g / L of chlorine.

[0016] Example 1

[0017] Take 200 mL of zinc sulfate solution with a chlorine content of 0.58 g / L and adjust the pH to 2.0; add 5.0 g of trialkylbismuth while stirring, heat to 55~65℃, and react for 2 h. After the reaction is complete, separate the solid and liquid. The filter residue is bismuth oxychloride precipitate, and the chlorine content in the filtrate is 0.131 mg / L.

[0018] Example 2

[0019] Take 200 mL of zinc sulfate solution with a chlorine content of 0.51 g / L and adjust the pH to 1.5; add 4.5 g of trialkyl antimony while stirring, heat to 50-55℃, and react for 3 h. After the reaction is complete, separate the solid and liquid. The filter residue is bismuth oxychloride precipitate, and the chlorine content in the filtrate is 0.103 mg / L.

[0020] Example 3

[0021] Take 200 mL of zinc sulfate solution with a chlorine content of 6 g / L and adjust the pH to 3.5; stir and add 5.5 g of trialkyl lead, heat to 60~70℃, react for 1 h, and after the reaction is complete, separate the solid and liquid. The filter residue is bismuth oxychloride precipitate, and the chlorine content in the filtrate is 0.143 mg / L.

[0022] Example 4

[0023] Take 200 mL of zinc sulfate solution with a chlorine content of 4.86 g / L and adjust the pH to 2.5; add 4.83 g of trialkylvanadium while stirring, heat to 60-65℃, and react for 2 h. After the reaction is complete, separate the solid and liquid. The filter residue is bismuth oxychloride precipitate, and the chlorine content in the filtrate is 0.128 mg / L.

[0024] Example 5

[0025] Take 200 mL of zinc sulfate solution with a chlorine content of 3.88 g / L and adjust the pH to 2.8; add 4.8 g of trialkylbismuth while stirring, heat to 55-60℃, and react for 3 h. After the reaction is complete, separate the solid and liquid. The filter residue is bismuth oxychloride precipitate, and the chlorine content in the filtrate is 0.135 mg / L.

Claims

1. A method for dechlorination in zinc sulfate solution, characterized in that, The method for dechlorination in zinc sulfate solution includes pretreatment and main reaction steps, specifically including: A. Pretreatment: Adjust the pH of the zinc sulfate solution to be treated to 1.5~3.5 to obtain material a; B. Main reaction: Add a precipitant to material a and stir to obtain a dechlorinated zinc sulfate solution; The precipitant is trialkylbismuth, trialkylantimony, trialkyllead, or trialkylvanadium.

2. The method for dechlorination in zinc sulfate solution according to claim 1, characterized in that, The chloride ion content in the zinc sulfate solution to be treated in step A is 0.5~6 g / L.

3. The method for dechlorination in zinc sulfate solution according to claim 1, characterized in that, The amount of precipitant added in step B is 4.5~5.5 g / L.

4. The method for dechlorination in zinc sulfate solution according to claim 1, characterized in that, In step B, the stirring speed for the reaction is 100~200 r / min.

5. The method for dechlorination in zinc sulfate solution according to claim 1, characterized in that, The temperature for stirring the reaction in step B is 50~70℃.

6. The method for dechlorination in zinc sulfate solution according to claim 1, characterized in that, The stirring reaction time in step B is 1-3 hours.