Method for rapid manganese replenishment in a zinc hydrometallurgy electrolysis system

Abstract

This invention provides a method for rapid manganese replenishment in a hydrometallurgical zinc smelting system, belonging to the field of non-ferrous metal hydrometallurgical technology. It solves the problems of excessively low manganese ion concentration in hydrometallurgical zinc smelting systems leading to accelerated corrosion of the anode plate and excessive lead content in the cathode zinc. This invention provides two manganese replenishment methods: one is to mix manganese-containing anode mud from the electrolysis system with zinc concentrate and then roast it; the roasting product is then leached to reduce manganese to Mn. 2+ The invention employs two methods: first, the anode mud is introduced into the solution; second, it is mixed with sodium sulfite and electrolytic waste liquid for a reduction reaction, and the reaction slurry is returned to the leaching system to replenish manganese. This invention can rapidly increase the manganese ion concentration in the system, stabilize electrolytic production, and realize the resource utilization of anode mud. It has advantages such as high manganese replenishment efficiency, simple operation, low cost, and no introduction of harmful impurities, making it suitable for various hydrometallurgical zinc smelting enterprises.

Description

Technical Field

[0001] This invention belongs to the field of non-ferrous metal hydrometallurgical technology, specifically relating to a method for rapidly replenishing manganese in a hydrometallurgical zinc electrolysis system. Background Technology

[0002] Hydrometallurgical zinc refining is the mainstream process for zinc smelting worldwide, mainly including roasting, leaching, purification, electrolysis, and casting. In the sulfuric acid system hydrometallurgical zinc refining process, manganese ions play a crucial role. During the leaching stage, manganese powder (mainly MnO2) is typically added to remove Fe from the solution. 2+ Oxidized to Fe 3+ And under conditions where the pH value is controlled at approximately 4.8–5.2, Fe 3+ Hydrolysis produces Fe(OH)3 precipitate, which simultaneously adsorbs and removes impurities such as arsenic, antimony, and germanium, thus achieving purification and impurity removal. During electrolysis, Mn in the electrolyte... 2+ An electrochemical reaction occurs in the anode region to generate solid MnO2. Part of it adheres to the surface of the anode plate, forming a robust anode protective layer with the PbO2 film, which protects the anode and extends the service life of the anode plate. At the same time, it effectively inhibits the lead content of the cathode zinc from exceeding the standard and improves product quality. The other part settles at the bottom of the electrolytic cell to form anode mud.

[0003] Therefore, the manganese ion content in the system has a decisive impact on the stable operation of the electrolysis system and product quality. When the manganese ion concentration in the system is too low, a dense MnO2 protective film cannot form on the surface of the anode plate, leading to accelerated corrosion of the anode plate, excessive lead content in the cathode zinc, increased anode loss, and seriously affecting the zinc ingot grade. When the manganese ion concentration in the system is too high, the amount of anode mud precipitation increases, the electrolyte viscosity increases, the cell voltage rises, the current efficiency decreases, the DC power consumption increases, and the production cost increases. Therefore, maintaining the manganese ion concentration in the system at a reasonable level is the key to achieving stable and efficient operation of the hydrometallurgical zinc smelting electrolysis system.

[0004] In hydrometallurgical zinc refining systems, the main source of manganese ions is the manganese powder added during the leaching process of roasted ore. The main pathways for manganese ion consumption and removal are precipitation in the form of anode mud during electrolysis and loss with the leaching residue. The system's manganese ion content depends primarily on the residual sulfur and ferrous content in the roasted ore. When the residual sulfur and ferrous content is high, the leaching system requires the addition of more manganese powder as an oxidant, thus introducing more manganese into the system. Conversely, when the residual sulfur and ferrous content is low, the amount of manganese powder added decreases, and the system's manganese ion content tends to decline. In actual production, due to factors such as changes in zinc concentrate ore sources and adjustments to roasting regimes, many enterprises often face the problem of excessively low system manganese ion levels, leading to excessive lead content in the electrolytic system products, high anode losses, and seriously affecting normal production operations and economic benefits.

[0005] Currently, the common methods for manganese replenishment in the hydrometallurgical zinc smelting industry are mainly as follows: First, iron and manganese are replenished simultaneously, that is, Fe is added to the system. 2+ And manganese powder, utilizing Fe 2+ Manganese powder undergoes a redox reaction in an acidic liquid, reducing high-valence manganese to Mn. 2 + There are several methods for adding manganese to the system. First, manganese can be added directly using manganese carbonate, which is relatively faster, but CO2 gas escapes during this process, potentially causing overflow. Second, manganese salts such as manganese sulfate and manganese nitrate can be used directly, but these are expensive, leading to higher production costs. Some companies also return electrolytic anode mud directly to the leaching system for manganese replenishment, but since the manganese in the anode mud is mainly in the form of MnO2, which has strong oxidizing properties, it is difficult to effectively convert it to Mn after direct return. 2+ When it enters the solution, the manganese replenishment efficiency is low, and it can easily have an adverse effect on the leaching system.

[0006] In view of the shortcomings of the existing technologies, there is an urgent need to develop a fast, efficient, low-cost method for manganese replenishment in wet zinc electrolysis systems that can achieve comprehensive resource utilization. Summary of the Invention

[0007] The purpose of this invention is to provide a method for rapidly replenishing manganese in a wet zinc electrolysis system, so as to solve the problems of excessively low manganese ion concentration in the wet zinc electrolysis system leading to aggravated corrosion of the anode plate and excessive lead content in the cathode zinc.

[0008] The technical solution of this invention is: a method for rapid manganese replenishment in a wet zinc electrolysis system, comprising at least one of the following approaches: pyrometallurgical roasting for manganese replenishment, wet reduction for manganese replenishment, and pyrometallurgical roasting combined with wet reduction for manganese replenishment. Method 1: Manganese supplementation through fire roasting The anode mud produced by the wet zinc electrolysis system is mixed evenly with zinc concentrate and then fed into a roasting furnace for co-roasting. The roasting product is then sent to a leaching system for treatment, so that manganese is converted into Mn. 2+ Form enters the solution; Method 2: Manganese supplementation through wet reduction The anode sludge produced by the wet zinc smelting electrolysis system is mixed with sodium sulfite and electrolytic waste liquid, and a reduction reaction is carried out under stirring conditions. After the reaction is completed, the slurry is returned to the leaching system, so that manganese is converted to Mn. 2+ Form enters the solution; Approach 3: Simultaneously employ Approach 1 and Approach 2 for synergistic manganese supplementation.

[0009] As a further improvement of the present invention, in the first method, the mass ratio of anode mud to zinc concentrate is 1:0.5 to 3.0.

[0010] As a further improvement of the present invention, in the first method, the temperature of the mixed roasting is 750-850°C and the roasting time is 1-3 hours.

[0011] As a further improvement of the present invention, in the first approach, the roasting furnace is a fluidized bed roasting furnace or a rotary kiln.

[0012] As a further improvement of the present invention, in the second method, the mass ratio of anode mud to sodium sulfite is 1:0.5 to 2.0, and the liquid-to-solid ratio of electrolytic waste liquid to anode mud is 3 to 8:1, where the liquid-to-solid ratio is the ratio of volume to mass.

[0013] As a further improvement of the present invention, in the second method, the reduction reaction temperature is 60-95°C and the reaction time is 1-4 hours.

[0014] As a further improvement of the present invention, in the second approach, the reduction reaction is carried out in a reaction tank equipped with a stirring device.

[0015] As a further improvement of the present invention, in the second method, the anode mud is manganese-containing anode mud produced by the wet zinc smelting electrolysis system, the main component of which is MnO2 and the manganese mass content is 20-45%; the electrolytic waste liquid is sulfuric acid-containing waste liquid discharged from the wet zinc smelting electrolysis process.

[0016] The technical principle of this invention is as follows: Principle of Approach 1: MnO2 in the anode mud and ZnS in the zinc concentrate undergo a coupled redox reaction during roasting. Zinc sulfide in the zinc concentrate is first oxidized to ZnO and SO2, then SO2 reduces MnO2 to soluble MnSO4. The generated MnSO4 dissolves into the solution during subsequent leaching, replenishing the system with Mn. 2+ At the same time, zinc in the zinc concentrate is recovered.

[0017] Principle of Approach Two: Under the acidic environment provided by the electrolytic waste liquid, MnO2 in the anode mud undergoes a redox reaction with sodium sulfite, reducing MnO2 to soluble Mn. 2+ Sodium sulfite is oxidized to sodium sulfate; the slurry is returned to the leaching system after the reaction, Mn 2+ It enters the electrolysis system along with the process flow to achieve rapid manganese replenishment. Relying on the acidic conditions of the electrolytic waste liquid (containing H2SO4) and the enhancement by heating, the reaction rate is fast and the manganese dissolution efficiency is high.

[0018] The beneficial effects of this invention are as follows: The purpose of this invention is to address the problems of high anode loss and excessive lead content in cathode zinc in hydrometallurgical zinc smelting systems caused by excessively low manganese ion levels, by providing a method for rapidly replenishing manganese in such systems. This method can rapidly increase the manganese ion concentration in the system, stabilize product quality, and simultaneously achieve comprehensive resource utilization of anode mud, reducing production costs.

[0019] Compared with the prior art, the present invention has the following beneficial effects: 1. Rapid and efficient manganese replenishment. Both methods can quickly convert sparingly soluble high-valent manganese into soluble Mn. 2+ Compared with the traditional iron-manganese co-compensation process, the manganese replenishment rate is significantly improved, which can quickly respond to abnormal conditions of insufficient manganese ions in the system and ensure the stable operation of the electrolysis system.

[0020] 2. Resource recycling and low production costs. Using manganese-containing anode mud, a byproduct of the electrolysis system, as the core manganese supplementary material, the system achieves closed-loop recovery and utilization of manganese, reducing the consumption of purchased manganese salts and lowering the cost of disposing of anode mud, thus achieving both economic and environmental benefits.

[0021] 3. Does not affect product quality. The manganese replenishment process does not introduce harmful impurities such as arsenic, antimony, and cadmium, and can stably control the manganese ion concentration in the system within a reasonable range, effectively inhibiting anode plate corrosion, reducing the lead content of cathode zinc, and ensuring the grade of zinc ingot products.

[0022] 4. Simple operation and easy industrial application. The process is simple and can be implemented using existing equipment such as roasting furnaces and reaction tanks without the need for new large-scale equipment, making it easy to promote and apply directly to existing hydrometallurgical zinc production lines. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the process flow for the rapid manganese replenishment method in the wet zinc electrolysis system of the present invention. Detailed Implementation

[0024] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the content described.

[0025] like Figure 1 As shown, the process is as follows: using the anode mud produced by the electrolysis system as raw material, it is divided into two manganese replenishment branches—the pyrometallurgical branch: the anode mud is mixed with zinc concentrate and then roasted in a roasting furnace, and the roasted product is connected to the leaching process; the wet branch: the anode mud is mixed with sodium sulfite and electrolytic waste liquid and then enters the reaction tank for reduction reaction, and the reaction slurry is connected to the leaching process; after the leaching process, it is connected to the purification and electrolysis processes in sequence, and finally produces cathode zinc. The anode mud produced in the electrolysis process is recycled back to the manganese replenishment system.

[0026] Example 1 (Manganese Supplementation Method via Pyrometallurgical Roasting) Mn in the electrolytic system of a hydrometallurgical zinc smelting plant 2+The concentration was 3.5 g / L, lower than the normal control range (4-6 g / L), resulting in excessive lead content in the cathode zinc and accelerated corrosion of the anode plate. Manganese-containing anode mud (38.5% manganese content, mainly MnO2) from the electrolysis system was mixed evenly with zinc concentrate at a mass ratio of 1:1.2 and fed into a fluidized bed roasting furnace. The roasting temperature was controlled at 820℃ for 2 hours. The roasted product was then sent to the leaching system for further processing.

[0027] After manganese supplementation, the Mn content in the electrolytic system... 2+ When the concentration was increased to 5.2 g / L, the lead content of the cathode zinc was reduced to within the acceptable range, and the corrosion condition of the anode plate was significantly improved.

[0028] Example 2 (Wet reduction manganese supplementation method) Mn in the electrolytic system of a hydrometallurgical zinc smelting plant 2+ The concentration was 3.8 g / L, requiring a rapid increase in manganese ion concentration. Manganese-containing anode mud (35.2% manganese by mass, mainly MnO2) from the electrolysis system was mixed with sodium sulfite at a mass ratio of 1:0.8. Electrolytic waste liquid was added, and the liquid-to-solid ratio (volume / mass) was controlled at 5:1. The mixture was heated to 85°C in a reaction tank equipped with a stirrer and stirred for 2.5 hours. After the reaction was complete, the slurry was returned to the leaching system.

[0029] After manganese supplementation, the Mn content in the electrolytic system... 2+ With the concentration increased to 5.0 g / L, all indicators of electrolysis production returned to normal.

[0030] Example 3 (Dual-pathway synergistic manganese supplementation) Due to adjustments in the roasting process, the manganese ion concentration in the system of a certain hydrometallurgical zinc smelting enterprise has been continuously decreasing, resulting in a decrease in Mn. 2+ The concentration was reduced to 2.2 g / L. Simultaneously, two methods—pyrometallurgical roasting and wet reduction—were used to synergistically supplement manganese: In the pyrometallurgical roasting method, the mass ratio of anode slime to zinc concentrate was 1:1.5, the roasting temperature was 830℃, and the roasting time was 2 hours; in the wet reduction method, the mass ratio of anode slime to sodium sulfite was 1:1.0, the liquid-to-solid ratio (volume / mass) was 6:1, the reaction temperature was 90℃, and the reaction time was 2 hours.

[0031] After the two approaches work together, the system Mn 2+ The concentration rapidly increased from 2.2 g / L to 5.8 g / L within 72 hours, and all indicators of the electrolysis system returned to normal, with the cathode zinc grade rate stabilizing at over 99.5%.

[0032] Based on the results of the above embodiments, it can be seen that both manganese replenishment methods proposed in this invention can efficiently achieve resource recovery and system manganese replenishment of manganese in electrolytic anode mud: when using a single method, the manganese ion concentration in the electrolytic system can be increased to a reasonable control range of 4-6 g / L in a short time, effectively solving the problems of anode corrosion and excessive lead content in cathode zinc caused by low manganese ion concentration, and meeting the manganese replenishment needs of normal production conditions; when using the dual methods in synergy, the manganese replenishment efficiency can be greatly improved. For extreme conditions where the manganese ion concentration drops sharply, the system can be quickly restored to normal operating level within 72 hours, ensuring production continuity. All three implementation methods can be carried out using existing process equipment in hydrometallurgical zinc refining. The operation process is simple, the manganese replenishment process does not introduce harmful impurities, and does not have a negative impact on product quality and subsequent process operation, verifying that the method of this invention has good industrial applicability and economic and environmental benefits.

[0033] The above description is only a preferred embodiment of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for rapidly replenishing manganese in a hydrometallurgical zinc smelting system, characterized in that: This includes at least one of the following methods for manganese supplementation: pyrometallurgical roasting, wet reduction, or a combination of pyrometallurgical roasting and wet reduction. Method 1: Manganese supplementation through fire roasting The anode mud produced by the wet zinc electrolysis system is mixed evenly with zinc concentrate and then fed into a roasting furnace for co-roasting. The roasting product is then sent to a leaching system for treatment, so that manganese is converted into Mn. 2+ Form enters the solution; Method 2: Manganese supplementation through wet reduction The anode sludge produced by the wet zinc smelting electrolysis system is mixed with sodium sulfite and electrolytic waste liquid, and a reduction reaction is carried out under stirring conditions. After the reaction is completed, the slurry is returned to the leaching system, so that manganese is converted to Mn. 2+ Form enters the solution; Approach 3: Simultaneously employ Approach 1 and Approach 2 for synergistic manganese supplementation.

2. The method for rapid manganese replenishment in a hydrometallurgical zinc smelting system according to claim 1, characterized in that: In method one, the mass ratio of anode mud to zinc concentrate is 1:0.5 to 3.

0.

3. The method for rapid manganese replenishment in a hydrometallurgical zinc smelting system according to claim 1, characterized in that: In method one, the temperature for mixed roasting is 750–850℃, and the roasting time is 1–3 hours.

4. The method for rapid manganese replenishment in a hydrometallurgical zinc smelting system according to claim 1, characterized in that: In the first approach, the roasting furnace is either a fluidized bed roasting furnace or a rotary kiln.

5. The method for rapid manganese replenishment in a hydrometallurgical zinc smelting system according to claim 1, characterized in that: In the second approach, the mass ratio of anode mud to sodium sulfite is 1:0.5 to 2.0, and the liquid-to-solid ratio of electrolytic waste liquid to anode mud is 3 to 8:1, where the liquid-to-solid ratio is the volume to mass ratio.

6. The method for rapid manganese replenishment in a hydrometallurgical zinc smelting system according to claim 1, characterized in that: In pathway two, the reduction reaction temperature is 60–95℃, and the reaction time is 1–4 hours.

7. The method for rapid manganese replenishment in a hydrometallurgical zinc smelting system according to claim 1, characterized in that: In pathway two, the reduction reaction is carried out in a reaction vessel equipped with a stirrer.

8. The method for rapid manganese replenishment in a hydrometallurgical zinc smelting system according to claim 1, characterized in that: In the second approach, the anode mud is manganese-containing anode mud produced by the wet zinc smelting electrolysis system, with MnO2 as its main component and a manganese mass content of 20-45%; the electrolytic waste liquid is sulfuric acid-containing waste liquid discharged from the wet zinc smelting electrolysis process.

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