CN111676490A - A method for optimizing zinc electrowinning process - Google Patents

Abstract

The present invention is a method for optimizing the zinc electrowinning process. The Lorentz force generated by the magnetic field is used to moderately thin the thickness of the chemical hydration layer of Zn ²⁺ and other positive and negative ions, and the size of the water molecule cluster is reduced; The magnetic field gradient force reduces the thickness of the chemical hydration layer of Zn ²⁺ again, reduces the size of water molecule clusters, and increases H ⁺ , Mn ²⁺ , Cu ²⁺ , Fe ²⁺ , Fe ³⁺ , Ge ⁴⁺ , Ni ² The thickness of the hydration layer of paramagnetic ions such as ⁺ , Co ²⁺ , Ca ²⁺ , Mg ²⁺ , etc., will reduce the voltage drop of the electrodeposition cell, increase the overvoltage of H ⁺ , and reduce the formation of calcium sulfate and magnesium sulfate. Mitigate the occurrence of cathode zinc burning and remelting. The invention can improve the quality of electro-deposited zinc without adding additional chemical reagents, hinder anode corrosion, and achieve the purpose of energy saving and consumption reduction.

Description

A method for optimizing zinc electrowinning process

technical field

The invention belongs to the technical field of zinc electrowinning, in particular to a method for optimizing a zinc electrowinning process.

Background technique

In the electrowinning process of hydrometallurgical zinc, the most concerned problem is the consumption of electric energy. Around the energy saving and consumption reduction of zinc electrolysis process, many scholars and zinc manufacturers have done a lot of work. The DC unit consumption of zinc electrowinning is related to two factors, namely current efficiency and cell voltage. The DC unit consumption is inversely proportional to the current efficiency and proportional to the tank voltage. Therefore, any measures that can improve the current efficiency and reduce the cell voltage can reduce the DC unit consumption of the zinc electrodeposition. Through the analysis of a large number of industrial test data and graphic data, it can be concluded that the factors affecting the current efficiency of the zinc electrodeposition include the cathode electrode. The current density of the plate, the concentration of zinc acid in the electrolyte, the temperature of the electrolyte, the content and type of impurities in the electrolyte, the surface state of precipitated zinc, and the electrolysis cycle. The specific effects of the above factors on the energy consumption of zinc electrowinning are as follows:

(1) Zinc acid concentration of electrolyte

The main components of the electrolyte are zinc ions and sulfuric acid. Stabilizing a certain concentration of zinc acid in the electrolyte is the basic condition for normal electrolysis. Under certain other conditions, as the zinc content in the electrolyte decreases and the acid content in the electrolyte increases, the current efficiency decreases. As the zinc content in the electrolyte increases and the acid content in the electrolyte decreases, the current efficiency increases. high. This is because the zinc content is too low or the acid content is too high, which will cause the concentration of sulfuric acid to increase relatively, causing the concentration of zinc ions near the cathode to undergo concentration polarization, causing the zinc precipitated on the cathode to dissolve back. At the same time, the electrode potential of hydrogen evolution also increases As the concentration of zinc ions in the solution decreases, the possibility of hydrogen evolution on the cathode increases.

(2) Cathode plate current density

Current density is defined as the ratio of current intensity to plate area. With the increase of the area current, the overvoltage of hydrogen increases. Generally speaking, it is beneficial to improve the current efficiency and to obtain metal zinc with dense crystals, but it must have the corresponding electrolyte composition and lower temperature conditions. match. The increase of the area current will also increase the resistance voltage drop of the electrolyte and increase the temperature, aggravating the precipitation of impurities.

(3) Impurity content in electrolyte

The impurity content in the electrolyte has a great influence on the energy consumption of zinc electrowinning. Any metal impurities in the electrolyte that can reduce the hydrogen overvoltage and can use zinc as the anode to form a micro-battery reaction that is more positive will cause zinc The increase in energy consumption of electrowinning may also cause unfavorable production phenomena such as burning of the board, precipitation of zinc and redissolving. Generally speaking, the control of the impurity content of the electrolyte is mainly in the purification step. The electrolysis process uses a purified and qualified electrolyte, but it is difficult to achieve deep purification at this stage.

Therefore, it can be known from the previous analysis that the higher the current density, the greater the power consumption. This is as a result of the significant increase in cell voltage in this case. However, if the current density is too small, the yield will be reduced, the current efficiency will be low, and the power consumption will also not be small. Current efficiency increases with decreasing electrolyte temperature, however, cell voltage decreases with increasing temperature. During the zinc electrowinning process, as the electrolytic current density increases, the power consumption decreases, and after reaching a certain limit, the power consumption increases again. The higher the current density of electrolytic deposition, the higher the allowable acid content in the electrolyte. When the acid content of the electrolyte is low, the electric power consumption is high due to the large resistance of the electrolyte. When the acid content of the electrolyte exceeds a certain value, the power consumption increases due to the significant reduction of the current efficiency. Through the above comprehensive analysis of factors affecting cell voltage and current efficiency, it can be known that improving current efficiency and reducing cell voltage are often contradictory. Therefore, under the premise of ensuring product quality, it is necessary to dialectically analyze the problem, and use the technical conditions to reduce the cell voltage and improve the current efficiency as much as possible to achieve the purpose of reducing power consumption. In the actual production process, in order to stabilize production and reduce electricity costs, many conditions are basically kept constant, and it is difficult to optimize the zinc electrowinning process in the prior art.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a method for optimizing the zinc electrodeposition process that reduces the amount of calcium sulfate and magnesium sulfate formed, and reduces the occurrence of scorching and remelting of cathode zinc.

In order to achieve the above object, a method for optimizing the zinc electrowinning process according to the present invention is characterized in that it includes the following steps: Step 1: measuring the concentrations of Zn ²⁺ , H ₂ SO ₄ and other impurity ions in the electrowinning solution, The magnetization device is connected to the liquid inlet pipe of the electrolytic cell, and the electrolyte is first subjected to the action of the Lorentz force through the magnetization device, and then is subjected to the action of the magnetic field gradient force. The magnetic induction intensity that generates the Lorentz force is 1-1.5T , the magnetic induction intensity that provides the magnetic field gradient force is 2-3T. When the electrolyte passes through the magnetic field that provides the Lorentz force, the pipeline takes shunting measures, that is, 1 set of the magnetic field that provides the Lorentz force needs to be matched with 2 sets to provide the magnetic field gradient The magnetic field acting by the force, the flow rate of the electrolyte is 120-240L/min when the electrolyte passes through the magnetization device that provides the Lorentz force, the flow rate of the electrolyte is 100-150L/min when the electrolyte passes through the magnetization device that provides the magnetic field gradient force, and the current density of the zinc electrodeposition process is 400-450A/m ² , and the temperature is 30-35℃;

Step 2: Carry out an electrowinning experiment. After the electrowinning experiment is completed, the residual electrode and cathode zinc are taken out, dried and weighed. Finally, the chemical composition of the dried cathode product is analyzed. The calculation formula is as follows:

In the formula, p is the power consumption, M is the mass of the deposited zinc, V is the cell voltage, f is the Faraday constant, z is the valence state of the deposited ions, m is the atomic weight, and t is the electrodeposition time.

In a method and technical scheme for optimizing the zinc electrowinning process of the present invention, the further preferred technical scheme features are:

1. The magnetic induction intensity that generates the Lorentz force in the step 1 is 1T, and the magnetic induction intensity that provides the magnetic field gradient force is 3T;

2. In the step 1, the flow rate of the electrolyte is 200L/min when the electrolyte passes through the magnetization device that provides the Lorentz force, the flow rate of the electrolyte is 100L/min when the electrolyte passes through the magnetization device that provides the magnetic field gradient force, and the current density of the zinc electrowinning process is 420A /m ² , the temperature is 35°C.

Compared with the prior art, the present invention can increase the overvoltage of H ⁺ , suppress the precipitation of hydrogen, weaken the oxidation reaction process of Mn ²⁺ , achieve the purpose of protecting the anode, and reduce the discharge of Cu ²⁺ , Ni ²⁺ and Co ²⁺ in the cathode. The probability of precipitation prevents the occurrence of "burning board" phenomenon. Prevent the redox reaction of Fe ²⁺ and Fe ³⁺ . At the same time, the generation of Ge hydride can be prevented, and the power consumption can be reduced. Promote the formation of salt bridges between Ca ²⁺ and Mg ²⁺ and SO ₄ ^2- , which will further reduce the crystallization of calcium sulfate, reduce its probability of increasing resistance, increase the internal energy of the system, and reduce the resistance and electrowinning of the electrolyte. voltage drop across the tank.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Embodiment 1, a method for optimizing zinc electrowinning process, including the following steps, step 1: measuring the concentration of Zn ²⁺ , H ₂ SO ₄ and other impurity ions in the electrowinning solution, and connecting the magnetization device to the inlet of the electrolytic cell. At the liquid pipe, the electrolyte is first subjected to the action of the Lorentz force through the magnetizing device, and then is subjected to the action of the magnetic field gradient force. 2-3T, when the electrolyte passes through the magnetic field that provides the Lorentz force, the pipeline takes the shunting measure, that is, one set of the magnetic field that provides the Lorentz force needs to be matched with 2 sets of the magnetic field that provides the magnetic field gradient force. The flow rate of the Lorentz force magnetization device is 120-240L/min, the flow rate of the electrolyte is 100-150L/min when the electrolyte passes through the magnetization device that provides the magnetic field gradient force, the current density of the zinc electrowinning process is 400-450A/m ² , the temperature The temperature is 30-35℃; Step 2: Carry out the electrowinning experiment. After the electrowinning experiment is completed, the residual electrode and cathode zinc are taken out, dried and weighed. Finally, the chemical composition of the dried cathode product is analyzed. The calculation formula is as follows:

In the formula, p is the power consumption, M is the mass of the deposited zinc, V is the cell voltage, f is the Faraday constant, z is the valence state of the deposited ions, m is the atomic weight, and t is the electrodeposition time. In the zinc electrowinning process, the current density is 400-450A/m ² , the temperature is about 30-35°C, the additives: 0.01-0.15g/L of cattle glue, 0.3-0.4g/L of strontium carbonate, and the anode: Pb-0.3Ag plate. ρ(H ₂ SO ₄ )/ρ(Zn ^{2 +} ) ranges from 3 to 3.9, and the range increases, and the zinc electrowinning process has strong adaptability. When the electrolyte passes through the magnetizing device that provides Lorentz force, the flow rate is 1.2-1.5 times that of the traditional zinc electrodeposition process. The invention firstly utilizes the Lorentz force generated by the magnetic field to moderately thin the thickness of the chemical hydration layer of Zn ²⁺ and other positive and negative ions, and reduces the size of the water molecule cluster; and then utilizes the magnetic field gradient force generated by the magnetic field to thin the Zn ²⁺ The thickness of the chemical hydration layer decreases the size of the water molecule clusters, increases H ⁺ , Mn ²⁺ , Cu ²⁺ , Fe ²⁺ , Fe ³⁺ , Ge ⁴⁺ , Ni ²⁺ , Co ²⁺ , Ca ²⁺ , Mg ²⁺ and other paramagnetic ions hydration layer thickness, in order to reduce the decomposition voltage and resistance voltage of zinc sulfate, reduce the magnetic energy and magnetic energy of hydrogen, manganese, copper, iron, germanium, nickel, cobalt, calcium, magnesium and other paramagnetic ions active.

Embodiment 2, in the method for optimizing the zinc electrowinning process according to Embodiment 1: the magnetic induction intensity for generating the Lorentz force in the step 1 is 1T, and the magnetic induction intensity for providing the magnetic field gradient force is 3T.

Embodiment 3, in the method for optimizing the zinc electrowinning process according to Embodiment 1 or 2: in the step 1, the flow rate of the electrolyte is 200L/min when the electrolyte passes through the magnetizing device that provides the Lorentz force, and the electrolyte passes through the magnetization device that provides the magnetic field. The flow rate of the gradient force magnetization device was 100 L/min, the current density in the zinc electrowinning process was 420 A/m ² , and the temperature was 35°C.

Embodiment 4, records the ion concentration in the electrowinning solution as follows:

完成后将阳极和始极片放置于电积槽中，计算进入电积液中的始极片面积S₃＝0.011m²、根据电流密度的公式J＝电流/S ₃确定电流的大小为4.6A，槽电压：0.35V，该过程中补充新液以保证酸锌浓度；(3)电积24h后，得到槽电压为3.57V，电流效率为89％，阴极锌出现烧板。(1) First, set the magnetic induction intensity that provides the Lorentz force to 0T, and the magnetic induction intensity that provides the magnetic field gradient force is 0T. The flow rate of the electrolyte is 200/min when it passes through the magnetizing device that provides the Lorentz force, and the flow rate is 100 L/min when the electrolyte passes through the magnetizing device that provides the magnetic field gradient force. The current density of the zinc electrodeposition process is 420A/m ² , the temperature is about 35°C, the additives: 0.15g/L of cattle glue, 0.4g/L of strontium carbonate, the anode: Pb-0.3Ag plate, and the Al plate is the cathode; (2 ) above steps

After completion, place the anode and the starting electrode sheet in the electrowinning tank, calculate the starting electrode sheet area S ₃ =0.011m ² into the electrowinning solution, and determine the size of the current to be 4.6 according to the formula of current density J=current/S ₃ A. Cell voltage: 0.35V. During the process, new solution was added to ensure the concentration of acid zinc; (3) After 24 hours of electrowinning, the cell voltage was 3.57V, the current efficiency was 89%, and the cathode zinc appeared burnt.

完成后将阳极和始极片放置于电积槽中，计算进入电积液中的始极片面积S₃＝0.011m²、根据电流密度的公式J＝电流/S ₃确定电流的大小为4.6A，槽电压：0.35V，该过程中补充新液以保证酸锌浓度；(3)电积24h后，得到槽电压为3.1V，电流效率为98％，阴极锌十分光滑。Embodiment 5, (1) first set the magnetic induction intensity that provides Lorentz force to be 1T, and the magnetic induction intensity that provides magnetic field gradient force is 3T; The flow rate was 100 L/min through the magnetizing device providing the magnetic field gradient force. The current density of the zinc electrodeposition process is 420A/m ² , the temperature is about 35°C, the additives: 0.15g/L of cattle glue, 0.4g/L of strontium carbonate, the anode: Pb-0.3Ag plate, and the Al plate is the cathode; (2 ) above steps

After completion, place the anode and the starting electrode sheet in the electrowinning tank, calculate the starting electrode sheet area S ₃ =0.011m ² into the electrowinning solution, and determine the size of the current to be 4.6 according to the formula of current density J=current/S ₃ A. Cell voltage: 0.35V. During the process, new solution was added to ensure the concentration of acid zinc; (3) After 24 hours of electrowinning, the cell voltage was 3.1V, the current efficiency was 98%, and the cathode zinc was very smooth.

完成后将阳极和始极片放置于电积槽中，计算进入电积液中的始极片面积S₃＝0.011m²、根据电流密度的公式J＝电流/S ₃确定电流的大小为4.6A，槽电压：0.35V，该过程中补充新液以保证酸锌浓度；(3)电积24h后，得到槽电压为3.43V，电流效率为92％，阴极锌较粗糙。Embodiment 6, (1) first set the magnetic induction intensity that provides the Lorentz force to be 1T, and the magnetic induction intensity that provides the magnetic field gradient force is 0T; The flow rate was 100 L/min through the magnetizing device providing the magnetic field gradient force. The current density of the zinc electrodeposition process is 420A/m ² , the temperature is about 35°C, the additives: 0.15g/L of cattle glue, 0.4g/L of strontium carbonate, the anode: Pb-0.3Ag plate, and the Al plate is the cathode; (2 ) above steps

After completion, place the anode and the starting electrode sheet in the electrowinning tank, calculate the starting electrode sheet area S ₃ =0.011m ² into the electrowinning solution, and determine the size of the current to be 4.6 according to the formula of current density J=current/S ₃ A. Cell voltage: 0.35V. During this process, new solution was added to ensure the concentration of acid zinc; (3) After 24 hours of electrowinning, the cell voltage was 3.43V, the current efficiency was 92%, and the cathode zinc was rough.

The above are only the preferred embodiments of the patent of the present invention, but the protection scope of the patent of the present invention is not limited to this. The equivalent replacement or modification of the technical solution and its invention patent concept shall fall within the protection scope of the invention patent.

Claims (3)

1. A method for optimizing a zinc electrodeposition process is characterized by comprising the following steps:

step 1: measuring Zn in electric liquid²⁺、H₂SO₄And the concentration of other impurity ions, connecting the magnetizer to the liquid inlet pipe of the electrolytic bath, leading the electrolyte to be firstly acted by Lorentz force through the magnetizer and then acted by magnetic field gradient force, wherein the magnetic induction intensity for generating the Lorentz force is 1-1.5T, the magnetic induction intensity for providing the magnetic field gradient force is 2-3T, when the electrolyte passes through the magnetic field for providing the Lorentz force, a pipeline adopts a flow dividing measure, namely 1 set of magnetic field for providing the Lorentz force needs to be matched with 2 sets of magnetic field for providing the magnetic field gradient force, the flow rate of the electrolyte passing through the magnetizer for providing the Lorentz force is 120-fold and 240L/min, the flow rate of the electrolyte passing through the magnetizer for providing the magnetic field gradient force is 100-fold and 150L/min, and the current density of the zinc electrodeposition process is 400-fold and 450A²The temperature is 30-35 ℃;

step 2: and (3) carrying out an electrodeposition experiment, taking out the residual anode and the cathode zinc after the electrodeposition experiment is finished, drying and weighing, and finally carrying out chemical component analysis on the dried cathode product, wherein the calculation formula is as follows:

wherein p is the power consumption, M is the mass of the deposited zinc, V is the cell voltage, f is the faraday constant, z is the valence state of the deposited ions, M is the atomic weight, and t is the electrodeposition time.

2. The method of optimizing a zinc electrodeposition process according to claim 1, wherein: the magnetic induction intensity of the Lorentz force generated in the step 1 is 1T, and the magnetic induction intensity of the magnetic field gradient force is 3T.

3. The method of optimizing a zinc electrodeposition process according to claim 1, wherein: in the step 1, the flow rate of the electrolyte passing through the magnetizing device providing the Lorentz force is 200L/min, the flow rate of the electrolyte passing through the magnetizing device providing the magnetic field gradient force is 100L/min, and the current density in the zinc electrodeposition process is 420A/m²The temperature was 35 ℃.