Experimental device for electric field reinforced arsenenite solid solution dissolution and application

Abstract

The invention discloses an experimental device for electric field reinforced arsenenite solid solution dissolution and application. An H-type electrolytic tank is designed, a proton membrane is used at a channel between a cathode and an anode to separate a cathode electrolysis chamber from an anode electrolysis chamber, meanwhile, the cathode and the anode both use titanium ruthenium plates as electrodes, certain current intensity is applied to different electrolytes, and the device for rapidly dissolving the arsenic lead ore solid solution is integrated. When the device and the application method are used for electrifying and dissolving the arsenic lead ore solid solution, the selective rapid dissolution of arsenic or lead can be obtained only by replacing different electrolytes.

Description

Technical Field

[0001] The present invention belongs to the field of environmental safety and technology, and relates to a device for rapidly dissolving arsenic (As) and lead (Pb) ores using electrical enhancement technology and its application, providing a new process and new device for the electric remediation of arsenic-lead contaminated soil and the resource utilization of arsenic-lead tailings. Background Art

[0002] Arsenic is a metalloid element that is widely present in rocks, soil, water and the atmosphere in nature. The global soil arsenic concentration is 6 mg / kg, while the soil arsenic concentration in my country is 11.2 mg / kg, almost twice the global soil arsenic concentration. Arsenic pollution comes from a wide range of sources. Natural sources are mainly due to crustal movement, volcanic eruptions, rock weathering, soil erosion, etc., which produce arsenic substances; while anthropogenic sources are mainly pollution caused by human production activities, which can be divided into agricultural pollution and industrial pollution. These activities allow arsenic to enter the environment in the form of smoke, wastewater, waste gas and waste residue, causing pollution to the soil, water and atmosphere, and thus posing huge health risks to humans. Studies have shown that trace amounts of arsenic can also be detected in normal humans. Reasonable arsenic is beneficial to human metabolism. The maximum arsenic intake of the human body per day is about 0.1 mg, but when the human body ingests a large amount of arsenic-containing substances, it will cause organ failure, damage to the nervous system and cancer. When the arsenic content in the human body reaches 10-50 mg, it will cause arsenic poisoning, and when it reaches 60-300 mg, it will cause death.

[0003] The remediation of arsenic pollution has always attracted the attention of many scientific researchers. At present, traditional physical and chemical remediation technologies have achieved certain results and formed some mature process flows. For arsenic pollution in water bodies, membrane separation, ion exchange, coagulation and precipitation are mainly used for remediation, while the traditional methods for remediation of arsenic pollution in soil mainly include physical remediation, chemical remediation, biological remediation, etc. In general, the selection of appropriate remediation technology is determined based on the depth of contaminated soil, metal concentration, type of pollutants and geological characteristics of the contaminated site. These factors make it possible to choose a method that is environmentally friendly, convenient, effective, stable, low-cost and easy to operate.

[0004] As one of the end-member components of the arsenite family of solid solutions, arsenite is the most common and stable mineral among arsenate minerals. 2+ 、AsO4 3- , Cl -When the arsenic and lead ions dissolved in the aqueous solution are fixed, the arsenic and lead ions will be quickly precipitated in the form of white and stable Pb5(AsO4)3Cl crystals. By utilizing this mechanism, the arsenic and lead ions dissolved in the aqueous solution can be fixed. The present invention provides a device for rapidly dissolving an arsenic-lead solid solution, which uses an electric field to enhance the rapid dissolution of arsenic and lead in the arsenic-lead solid solution, and provides a new process and a new device for the electric remediation of soil contaminated by arsenic and lead and the resource utilization of arsenic-lead tailings. Summary of the invention

[0005] The purpose of the present invention is to provide a new device for promoting the rapid dissolution of arsenic-lead ore solid solution by electric field. The prepared solid solution and the dissolved solid solution are subjected to infrared absorption spectroscopy (FT-IR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) solid phase characterization, and the leaching concentrations of Pb and As are tested under the conditions of no power supply and power dissolution using different electrolytes, and the solubility and stability are analyzed in detail experimentally, which provides technical support for exploring the remediation of soil contaminated by arsenic and lead and the resource utilization of arsenic and lead in tailings.

[0006] The idea of ​​the present invention is to design an H-type electrolytic cell, in which a proton membrane is used in the middle channel between the anode and cathode to separate the anode and cathode electrolytic chambers. At the same time, titanium ruthenium plates are used as electrodes for both the anode and cathode, and a certain current intensity is applied in different electrolytes to integrate a device for quickly dissolving arsenic lead ore solid solution.

[0007] Method for synthesizing arsenic lead ore solid solution: prepare fresh ultrapure water, weigh appropriate amounts of lead acetate, sodium arsenate and sodium chloride solids, and prepare 0.5 mol / L solutions for standby use. At room temperature, take 100 mL of 0.5 mol / L lead acetate solution in a 250 mL polyethylene bottle, put it into an intelligent magnetic stirrer, control the temperature to 25 ° C, and stir continuously at a speed of 300 r / min. During the process, seal the bottle mouth with plastic wrap and aerate it with nitrogen to remove impurities in the water and air. Slowly add 80 mL of 0.5 mol / L sodium arsenate solution and 0.5 mol / L sodium chloride solution in a ratio of 3:1 to mix the solution evenly, add it to the polyethylene bottle at a speed of 10 mL / min, the reaction time is 10 min, stop stirring, and then place it in a 25 ° C constant temperature water bath for aging for 24 h. After aging for 24 hours, solid-liquid separation is performed, and the obtained solid phase precipitate is washed with ultrapure water for multiple times. The washed solid phase precipitate is placed in a 90° C. forced air drying oven and dried for 24 hours to obtain an arsenic lead ore solid solution.

[0008] Arsenic and lead in the solid solution of arsenic-lead ore can be dissolved quickly in the electrolytic cell under the condition of power supply. The characteristic steps are:

[0009] (1) The experimental device mainly consists of a DC power supply, a cathode chamber, an anode chamber, electrodes, and an electrolyte.

[0010] (2) The DC power supply is connected to the electrodes by a pure copper power line, and the non-active electrode part is sealed with ceramic to isolate it from contact with the electrolyte.

[0011] (3) Both the cathode chamber and the anode chamber are made of plexiglass. A circular connecting port about 2 cm long and 1 cm in diameter is set between the two chambers. The proton membrane is placed in the middle of the connecting port and fixed with a fixing clamp. After the cathode chamber, anode chamber and connecting port are fixed, they form an H shape.

[0012] (4) The proton membrane uses a commercial PFSA proton exchange membrane to block the pH changes caused by the electric field drive and the free diffusion of ions, as well as the combination of heavy metal ions with the hydroxide ions in the cathode chamber, thereby shielding the lead ions from being precipitated and fixed again.

[0013] The specific steps of application are:

[0014] (1) Weigh 1g of arsenic lead ore solid solution that has passed through a 100-mesh sieve and place it in the anode chamber of an H-type electrolytic cell. Add 500 mL of electrolyte to the cathode and anode chambers of the H-type experimental device, respectively. Preferably, the electrolyte uses 0.1 mol / L KNO3 and Na2SO4 solutions. When a good lead ion dissolution rate and concentration are required, the electrolyte uses KNO3 solution; when a good arsenic ion dissolution rate and concentration are required, the electrolyte uses Na2SO4 solution. Use electric field electrodes as the cathode and anode electrodes of the H-type experimental device, and apply a constant current of 0.1A at the same time. Preferably, both the cathode and anode electrodes are titanium ruthenium electrodes, and the non-titanium ruthenium electrode parts are wrapped with ceramics to prevent the non-active conductive parts from contacting the electrolyte. The assembled H-type electrolytic cell after adding the electrolyte is covered and sealed, and placed at room temperature for electric field enhanced dissolution.

[0015] (2) During the operation of the experimental device for electric field enhanced dissolution of arsenic lead ore solid solution, the anode chamber was opened at 1, 3, 5, 10, 20, 40, 60, 90, 120, 180, 360, 720, 1440, 2880, 4320, and 5760 min, and a certain volume of supernatant sample was taken and filtered into a centrifuge tube through a 0.22 μm membrane filter. The liquid phase was analyzed using an ICP-OES instrument to determine the Pb 2+ The concentration of As was measured by atomic fluorescence spectrophotometer 5+ The concentration of lead and arsenic can be obtained by measuring the concentration of lead and arsenic.

[0016] The above-mentioned technical comparison shows that the dissolution concentrations of arsenic and lead ions in different processes at the same time are quite different: when arsenic lead ore is in 0.1 mol / L KNO3 solution as electrolyte and electricity is applied, the leaching concentration of lead ions is the highest, and it can be dissolved quickly and has the best effect; when ultrapure water is used as electrolyte, the effect is second; when 0.1 mol / L Na2SO4 solution is used as electrolyte, it is not conducive to the dissolution of lead ions, and its effect is even worse than the natural dissolution effect without electricity, and it is almost insoluble. When arsenic lead ore is in 0.1 mol / LNa2SO4 solution as electrolyte and electricity is applied, arsenic ions are dissolved quickly, and its dissolution concentration shows a trend of first rising and then falling. By utilizing this special change trend, arsenic ion resource utilization can be realized by controlling the electric field action time; the electrolyte using 0.1 mol / L KNO3 and Na2SO4 solutions can achieve the enhanced dissolution of arsenic ions in arsenic lead ore, and the final dissolved arsenic ion concentration is not much different, and arsenic ions are almost not dissolved when electricity is not applied and when ultrapure water is used for electricity. It can be inferred from this that under the action of different electrolytes and electric fields, arsenic ions and lead ions can be quickly dissolved in the solid solution of arsenic-lead ore, thereby realizing the resource utilization of arsenic-lead ore by utilizing the characteristics of different electrolyte types and different power-on times.

[0017] The present invention utilizes arsenate, lead ions and chloride ions to react and synthesize end-member components of arsenopyrite family minerals. Compared with arsenic and lead minerals synthesized by the traditional coprecipitation method, the arsenopyrite series solid solution synthesized by the water bath co-heating method has the characteristics of easy process control, purer solid products, high yield and high crystallinity. Moreover, under the condition of different electrolytes being energized, the dissolution concentrations of arsenic and lead ions of the minerals are rapidly dissolved. In a 0.1 mol / L KNO3 solution, the highest lead ion concentration is 3.9 times that of the dissolution under no energization. Under all energization conditions, the experimental group with the electrolyte added has a dissolution concentration of arsenic ions several orders of magnitude higher than that of the dissolution without energization. Therefore, the present invention can realize the resource utilization of arsenic and lead ions of arsenopyrite under different electrolyte types and different time energization dissolution conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A diagram of an H-type electrolytic cell apparatus designed for the present invention to rapidly dissolve arsenite solid solution.

[0019] Figure 2 This is a graph showing the change in lead ion concentration during the dissolution of the arsenic lead ore solid solution in Example 2-7 of the present invention.

[0020] Figure 3 This is a graph showing the change in arsenic ion concentration during the dissolution of the arsenic lead ore solid solution in Example 2-7 of the present invention. DETAILED DESCRIPTION

[0021] Example 1

[0022] At room temperature, 100 mL of 0.5 mol / L lead acetate solution was placed in a 250 mL polyethylene bottle, and an intelligent magnetic stirrer was placed. The temperature was controlled at 25 ° C, and the stirring was continued at a speed of 300 r / min. During the process, the bottle mouth was sealed with a plastic wrap, and nitrogen was used to aerate it to remove impurities in the water and air. 80 mL of 0.5 mol / L sodium arsenate solution and 0.5 mol / L sodium chloride solution were slowly added in a ratio of 3:1. The solution was evenly mixed and added to the polyethylene bottle at a speed of 10 mL / min. The reaction time was 10 min, and the stirring was stopped. Then, the solution was placed in a 25 ° C constant temperature water bath for aging for 24 h. After aging for 24 h, solid-liquid separation was performed, and the obtained solid phase precipitate was washed with ultrapure water for multiple times. The washed solid phase precipitate was placed in a 90 ° C blast drying oven for 24 h to obtain an arsenic lead ore solid solution.

[0023] Example 2

[0024] The synthesized arsenite solid solution was ground into powder using an agate mortar, and an appropriate amount of solid solution was weighed for natural dissolution. 1 g of the ground solid solution was weighed and placed in a 1000 mL polyethylene terephthalate (PET) bottle, and then 1000 mL of ultrapure water was added. The bottle was capped and placed at room temperature for dissolution (air conditioning 25°C). Pb was determined using an ICP-OES instrument. 2+ The concentration of As was measured by atomic fluorescence spectrophotometer 5+ concentration.

[0025] That is, the lead leaching concentration is 0.1473295 mmol / L;

[0026] Arsenic leaching concentration: 0.000011 mmol / L.

[0027] Example 3

[0028] The synthesized arsenite solid solution was ground into powder using an agate mortar, and an appropriate amount of solid solution was weighed for natural dissolution. 1 g of the ground solid solution was weighed and placed in a 1000 mL polyethylene terephthalate (PET) bottle, and then 1000 mL of 0.1 mol / L KNO3 solution was added. The bottle was capped and placed at room temperature for dissolution (air conditioning 25°C). Pb was determined using an ICP-OES instrument. 2+ The concentration of As was measured by atomic fluorescence spectrophotometer 5+ concentration.

[0029] That is, the lead leaching concentration is 0.2228282 mmol / L;

[0030] Arsenic leaching concentration: 0.0000149 mmol / L.

[0031] Example 4

[0032] The synthesized arsenite solid solution was ground into powder using an agate mortar, and an appropriate amount of solid solution was weighed for natural dissolution. 1 g of the ground solid solution was weighed and placed in a 1000 mL polyethylene terephthalate (PET) bottle, and then 1000 mL of 0.1 mol / L Na2SO4 solution was added. The bottle was capped and placed at room temperature for dissolution (air conditioning 25°C). Pb was determined using an ICP-OES instrument. 2+ The concentration of As was measured by atomic fluorescence spectrophotometer 5+ concentration.

[0033] That is, the lead leaching concentration is 0.0114865 mmol / L;

[0034] Arsenic leaching concentration: 0.0000067 mmol / L.

[0035] Example 5

[0036] The synthesized arsenic lead ore solid solution was ground into powder using an agate mortar, and an appropriate amount of solid solution was weighed for anode dissolution. 1g of the ground solid solution was weighed and passed through a 100-mesh sieve and placed in the anode chamber of a 1000 mL H-type organic glass reactor. 500 mL of ultrapure water was added to the cathode and cathode chambers respectively. A titanium ruthenium electrode was used, and a constant current of 0.1A was applied. All bottles were capped and placed at room temperature for dissolution (air conditioning 25°C). Pb was analyzed and determined using an ICP-OES instrument. 2+ The concentration of As was measured by atomic fluorescence spectrophotometer 5+ concentration.

[0037] That is, the lead leaching concentration is 0.0153089 mmol / L;

[0038] Arsenic leaching concentration: 0.0025976 mmol / L.

[0039] Example 6

[0040] The synthesized arsenic lead ore solid solution was ground into powder using an agate mortar, and an appropriate amount of solid solution was weighed for anode dissolution. 1g of the ground solid solution was weighed and passed through a 100-mesh sieve and placed in the anode chamber of a 1000 mL H-type organic glass reactor. 500 mL of 0.1 mol / L KNO3 solution was added to the cathode and cathode chambers, respectively. A titanium ruthenium electrode was used, and a constant current of 0.1A was applied. All bottles were capped and placed at room temperature for dissolution (air conditioning 25°C). Pb was analyzed and determined using an ICP-OES instrument. 2+ The concentration of As was measured by atomic fluorescence spectrophotometer 5+concentration.

[0041] That is, the lead leaching concentration is 0.6030405 mmol / L;

[0042] Arsenic leaching concentration: 0.0270226 mmol / L.

[0043] Example 7

[0044] The synthesized arsenic lead ore solid solution was ground into powder using an agate mortar, and an appropriate amount of solid solution was weighed for cathode dissolution. 1g of the ground solid solution was weighed and passed through a 100-mesh sieve and placed in the cathode chamber of a 1000 mL H-type organic glass reactor, and 500 mL of 0.1 mol / L Na2SO4 solution was added to the anode and cathode chambers, respectively. A titanium ruthenium electrode was used, and a constant current of 0.1A was applied. All bottles were capped and placed at room temperature for dissolution (air conditioning 25°C). Pb was analyzed and determined using an ICP-OES instrument. 2+ The concentration of As was measured by atomic fluorescence spectrophotometer 5+ concentration.

[0045] That is, the lead leaching concentration is 0.0079319 mmol / L;

[0046] Arsenic leaching concentration: 0.025012 mmol / L.

Claims

1. An experimental device for electric field-enhanced dissolution of arsenic lead ore solid solution, characterized in that: (1) The experimental device mainly consists of a DC power supply, a cathode chamber, an anode chamber, electrodes, and an electrolyte; (2) The DC power supply is connected to the electrodes by a pure copper power line, and the non-active electrode part is sealed with ceramic to isolate it from contact with the electrolyte; (3) Both the cathode chamber and the anode chamber are made of plexiglass. A circular connection port about 2 cm long and 1 cm in diameter is set between the two chambers. The proton membrane is placed in the middle of the connection port and fixed with a fixing clip. After the cathode chamber, anode chamber and connection port are fixed, they form an H shape; (4) The proton membrane uses a commercial PFSA proton exchange membrane to block the pH change caused by the electric field driving effect and the free diffusion of ions, as well as the combination of heavy metal ions with the hydroxide ions in the cathode chamber, thereby shielding the lead ions from being precipitated and fixed again; (5) Weigh 1 g of arsenic lead ore solid solution that has passed through a 100-mesh sieve and place it in the anode chamber of an H-type electrolytic cell; add 500 mL of electrolyte to the cathode chamber and cathode chamber of the H-type experimental device, respectively. Preferably, the electrolyte uses 0.1 mol / L KNO3 and Na2SO4 solutions. When a good lead ion dissolution rate and concentration are required, the electrolyte uses KNO3 solution; when a good arsenic ion dissolution rate and concentration are required, the electrolyte uses Na2SO4 solution; (6) Using electric field electrodes as the positive and negative electrodes of the H-type experimental device, and applying a constant current of 0.1A at the same time; preferably, both the positive and negative electrodes are titanium ruthenium electrodes, and the non-titanium ruthenium electrode parts are wrapped with ceramics to prevent the non-active conductive parts from contacting the electrolyte; the assembled H-type electrolytic cell after adding the electrolyte is covered and sealed, and placed at room temperature for electric field enhanced dissolution; (7) During the electric field enhanced dissolution process, a certain volume of supernatant samples were taken at 1, 3, 5, 10, 20, 40, 60, 90, 120, 180, 360, 720, 1440, 2880, 4320, and 5760 min, respectively, and filtered into a centrifuge tube through a 0.22 μm membrane filter; the liquid phase was analyzed using an ICP-OES instrument to determine Pb 2+ The concentration of As was measured by atomic fluorescence spectrophotometer 5+ The concentration of lead and arsenic can be obtained by measuring the concentration of lead and arsenic.

2. An experimental device for electric field enhanced dissolution of arsenite solid solution as claimed in claim 1, characterized in that The H-type connection in step (3); the PFSA proton exchange membrane in step (4); the electrolyte in step (5) is 0.1 mol / L KNO3, Na2SO4 and NaCl solution; and titanium ruthenium electrodes are used as the positive and negative electrodes in step (6).

3. An application of the experimental device for electric field enhanced dissolution of arsenite solid solution as claimed in claims 1 and 2, characterized in that By applying appropriate voltage, the electric field acts on the arsenic-lead ore solid solution to enhance the selective rapid dissolution effect of the arsenic-lead ore solid solution, which is applied to the remediation of arsenic-lead contaminated soil and the resource utilization of arsenic and lead in tailings.

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