A comprehensive treatment method for copper-arsenic-rich solid waste

Abstract

The present invention relates to the field of comprehensive recycling and utilization of metal resources, and specifically discloses a comprehensive treatment method for copper-arsenic-rich solid waste. The method comprises: adding the copper-arsenic-rich solid waste and a leaching agent to a reactor for leaching to obtain a leachate at a leaching temperature of 110-150°C for a leaching time of 1-3 hours, using black acid as the leaching agent; filtering the leachate using a first filter press to obtain a filtrate; adding the filtrate to a heat exchanger to preheat the leaching agent; adding an iron extractant to an extraction and iron removal unit to extract and remove iron from the filtrate; adding a copper extractant to an extraction and copper removal unit to remove copper from the iron-extracted residual solution; adding the copper-extracted residual solution to a reduction and arsenic precipitation unit, and then performing a filter press to obtain As2O3. This method extracts iron and copper separately, and standard cathode copper can be obtained by subsequent copper stripping. It can achieve the coordinated treatment of black acid, arsenic-copper slag, and high-arsenic smoke, achieving efficient separation and recycling of copper and arsenic, with a short process and high efficiency.

Description

Technical Field

[0001] The present invention relates to the field of comprehensive recycling of metal resources, and in particular to a comprehensive treatment method for copper-arsenic-rich solid waste. Background Art

[0002] In the copper electrolytic refining industry, waste electrolyte undergoes a two-stage electrowinning process to remove copper in the copper electrolytic refining unit, which produces arsenic-copper slag and black acid. Furthermore, pyrometallurgical smelting of copper, lead, and zinc produces a considerable amount of high-arsenic soot. These two types of high-copper-arsenic wastes contain high copper and arsenic content, making them valuable for recycling as resources. Furthermore, they should not be returned to the original smelting process, as this would cause impurities to accumulate within the system, ultimately impacting process flow and product quality.

[0003] Many studies have reported on the production of copper arsenate using black copper slag and high-arsenic smelting ash as raw materials. Copper arsenate can be used for wood preservation, but its application areas are still limited. Summary of the Invention

[0004] The present invention aims to provide a comprehensive treatment method for copper-arsenic-rich solid waste to solve the problem of limited application of black copper slag and high-arsenic smelting ash for the preparation of copper arsenate.

[0005] To achieve the above object, the present invention adopts the following technical solution: a comprehensive treatment method for copper-arsenic-rich solid waste, comprising the following steps:

[0006] Step 1: adding copper-arsenic-rich solid waste and a leaching agent into a reactor for leaching to obtain a leachate, the leaching temperature is 110-150° C., the leaching time is 1-3 hours, and the leaching agent is black acid;

[0007] Step 2: filtering the leaching liquid using a first filter press to obtain a filtrate;

[0008] Step 3: Add the filtrate to the heat exchanger to preheat the leaching agent, and discharge the cooled filtrate into the extraction iron removal unit;

[0009] Step 4: adding an iron extractant to the extraction and iron removal unit to extract and remove iron from the filtrate;

[0010] Step 5: adding a copper extractant to the extraction and copper removal unit to remove copper from the iron extraction residual solution;

[0011] Step 6: Add the copper extraction residual solution to the arsenic reduction precipitation unit, and then filter press to obtain As2O3.

[0012] Preferably, as an improvement, the leaching process in step 1 is kept P O2=0.1~0.4MPa, pH=0~2, leachate-solid ratio 10:1~15:1ml / g.

[0013] Preferably, as an improvement, the method further comprises stripping the iron-loaded organic phase in step 4 to remove iron, and storing the organic phase after stripping to remove iron in an iron-containing stripping liquid storage tank of an iron extractant.

[0014] Preferably, as an improvement, the iron-loaded organic phase in step 4 is stripped and iron removed by a sulfuric acid solution having a concentration of 1 to 3 mol / L, wherein the phase ratio is O / A = 1:1 to 1:3 L / min and the stripping stage number is 1 to 3 stages.

[0015] Preferably, as an improvement, the method further comprises stripping the copper-loaded organic phase in step 5 to remove copper, and storing the organic phase after stripping to remove copper in a copper sulfate solution storage tank of a copper extractant.

[0016] Preferably, as an improvement, the copper-loaded organic phase in step 5 is stripped and copper removed by a sulfuric acid solution having a concentration of 0.1 to 0.5 mol / L, wherein the ratio is O / A = 1:1 to 1:3 L / min, the operating temperature is 25 to 35 ° C, and the number of stripping stages is 1 to 3.

[0017] Preferably, as an improvement, the extraction temperature of iron in step 4 is 25-35° C., the extraction phase ratio is O / A=1:1-2:1 L / min, and the number of extraction stages is 1-3.

[0018] Preferably, as an improvement, the extraction temperature of copper in step 5 is 25-35° C., the extraction phase ratio is O / A=1:1-2:1 L / min, and the number of extraction stages is 1-3.

[0019] Preferably, as an improvement, oxygen is introduced into the step 1 for pressure leaching.

[0020] Preferably, as an improvement, step 6 specifically includes: introducing SO2 into the copper raffinate at a rate of 100 to 300 ml / min for a duration of 60 to 120 min, and the reduced solution enters a filter press to obtain As2O3.

[0021] This scheme uses the by-product black acid produced by the purification of copper electrolyte as a leaching agent, which can easily process the black acid; many studies have shown that for most copper extractants, Fe 3+The copper and arsenic will be extracted first before copper. This solution extracts and removes iron before extracting and removing iron, extracts iron and copper separately, and can obtain standard cathode copper through subsequent back-extraction of copper, thereby realizing copper recovery and utilization. The copper residual liquid is reduced with SO2, and the arsenic in the solution is recovered in the form of crude As2O3. The residual liquid is returned to the leaching process, ultimately realizing resource recovery and utilization of copper and arsenic. It can realize the coordinated treatment of black acid, arsenic-copper slag and high-arsenic smoke, and realize the efficient separation and recovery of copper and arsenic, with a short process and high efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a framework diagram of the system according to an embodiment of the present invention.

[0023] Figure 2 Schematic diagram of the structure of an embodiment of the present invention. DETAILED DESCRIPTION

[0024] The following is further described in detail through specific implementation methods:

[0025] The reference numerals in the drawings of the specification include: reactor 1, first filter press 2, heat exchanger 3, iron removal extraction unit 4, copper removal extraction unit 5, arsenic precipitation reduction unit 6, second filter press 7.

[0026] Example:

[0027] This solution provides a comprehensive treatment method for copper-arsenic-rich solid waste. Figure 1 and attached Figure 2 As shown, the following steps are included:

[0028] Step 1: Add copper-arsenic-rich solid waste and a leaching agent into a reactor 1 for leaching to obtain a leachate, the leaching temperature is 110-150° C., the leaching time is 1-3 hours, and the leaching agent is black acid; wherein, copper electrolyte purification produces arsenic copper slag and black acid, and the by-product black acid is used as a leaching agent to treat the by-product.

[0029] In this step, during the leaching process, oxygen is introduced into the reactor 1 to perform pressure leaching.

[0030] In this step, the leaching process maintains P O2 =0.1~0.4MPa, pH=0~2, leachate-solid ratio 10:1~15:1 (liquid volume: solid mass, unit: ml / g or L / kg).

[0031] Step 2: Using the first filter press 2 to filter the leaching liquid to obtain a filtrate.

[0032] Step 3: Add the filtrate to the heat exchanger 3 to preheat the leaching agent, and discharge the cooled filtrate into the extraction iron removal unit 4.

[0033] In this step, the heat of the filtrate is transferred to the immersion agent, avoiding the problem of wasting heat energy in the filtrate and causing additional energy consumption for cooling; the immersion agent is preheated in advance to speed up the reaction, while reducing the consumption of heating resources required for the reaction and saving energy.

[0034] Step 4: Add the iron extractant into the extraction and iron removal unit 4 to extract and remove iron from the filtrate.

[0035] In this step, the extraction temperature of iron is 25-35° C., the extraction phase ratio is O / A=1:1-2:1 L / min (volume ratio), and the extraction stage is 1-3.

[0036] The process also includes stripping the iron-loaded organic phase to remove iron, and storing the stripped organic phase in an iron-containing stripping liquid storage tank of an iron extractant. Specifically, the iron-loaded organic phase in step 3 is stripped to remove iron by a sulfuric acid solution having a concentration of 1 to 3 mol / L, wherein the ratio is O / A = 1:1 to 1:3 L / min (volume ratio), and the stripping stage is 1 to 3. Many studies have shown that for most copper extractants, Fe 3+ It will be extracted first before copper, so it is necessary to remove iron before extracting and recovering copper. 2+ To stably coexist with H₃AsO₄, the leachate must maintain a high acidity, making chemical precipitation an unsuitable method for iron removal. This technology uses extraction to remove over 98% of the iron impurities in the leachate. The iron-laden organic phase is stripped with dilute sulfuric acid to produce a ferric sulfate solution. The iron extractant regenerated from the stripping is then reused.

[0037] Step 5: Add the copper extractant into the extraction and copper removal unit 5 to remove copper from the iron extraction residual solution.

[0038] In this step, the copper extraction temperature is 25-35° C., the extraction phase ratio is O / A=1:1-2:1 L / min (volume ratio), and the extraction stage is 1-3.

[0039] The method also includes stripping the copper-loaded organic phase to remove copper, and storing the organic phase after stripping the copper in a copper sulfate solution storage tank of a copper extractant.

[0040] In this step, the copper-loaded organic phase in step 5 is stripped and copper removed by a 0.1-0.5 mol / L sulfuric acid solution, wherein the ratio is O / A=1:1-1:3 L / min (volume ratio), the operating temperature is 25-35° C., and the stripping stage is 1-3.

[0041] Step 6: Add the copper extraction raffinate to the arsenic reduction precipitation unit 6, and then filter press to obtain As2O. This step specifically includes: passing SO2 into the copper extraction raffinate at a rate of 100-300 ml / min for 60-120 minutes. The reduced solution enters the second filter press 7 to obtain crude As2O3.

[0042] This solution uses black acid produced during copper electrolyte purification as a leaching agent, employing oxygen pressure leaching. The leachate is first subjected to extraction to remove iron, followed by extraction-strip extraction to recover copper from the solution, resulting in a copper sulfate solution that is then electrolytically deposited to produce standard cathode copper. The residual copper from the copper extraction process is then reduced with SO2, and the arsenic in the solution is recovered as crude As2O3. The remaining solution is then returned to the leaching process, ultimately achieving resource recovery of copper and arsenic. This solution enables the coordinated treatment of black acid, arsenic-copper slag, and high-arsenic smoke, achieving efficient separation and recovery of copper and arsenic with a short process and high efficiency. Heat from the filtrate is transferred to the leaching agent, avoiding waste of heat energy in the filtrate and the resulting energy consumption for cooling. Preheating the leaching agent accelerates the reaction while reducing the heating resources required for the reaction, saving energy.

[0043] The present solution also provides a system for implementing the above-mentioned comprehensive treatment method of copper-arsenic-rich solid waste, which specifically includes a leaching unit, a first filtration unit, a heat exchange unit, an extraction unit, an arsenic reduction precipitation unit 6 and a second filtration unit.

[0044] The leaching unit is a reactor 1. The copper-arsenic-rich solid waste is added to the reactor 1 and passed into the reactor 1. The leaching agent is the black acid produced by the purification of the copper electrolyte. Copper is leached in the reactor 1. At the same time, O2 is added during the copper leaching process for pressurized leaching to maintain P O2 =0.1~0.4MPa, pH=0~2, leaching liquid-solid ratio 10:1~15:1 (liquid volume: solid mass, unit: ml / g or L / kg), leaching temperature 110~150℃, leaching time 1~3h.

[0045] The leachate enters the first filter unit from the discharge port of the reactor 1 for filtration to remove the filter residue. In this embodiment, the first filter unit is the first filter press 2. Then the filtrate generated by the first filter press 2 enters the heat exchange unit from the filtrate outlet of the first filter press 2. In this embodiment, the heat exchange unit is the heat exchanger 3. The filtrate specifically enters the heat exchanger 3 from the cold liquid inlet of the heat exchanger 3. The hot liquid inlet of the heat exchanger 3 is used to add the leaching agent, and the hot liquid outlet of the heat exchanger 3 is connected to the inlet of the reactor 1.

[0046] The heat of the filtrate is transferred to the immersion agent through the heat exchange unit to heat the immersion agent and cool the filtrate at the same time, avoiding the waste of heat energy in the filtrate and the problem of additional energy consumption for cooling; the reaction raw materials are preheated in advance to speed up the reaction, while reducing the consumption of heating resources required for the reaction and saving energy.

[0047] The extraction unit includes an extraction iron removal unit 4 and an extraction copper removal unit 5; the cold liquid outlet of the heat exchange unit is connected to the feed port of the extraction iron removal unit 4, and the discharge port of the extraction iron removal unit 4 is connected to the extraction copper removal unit 5.

[0048] In this embodiment, extraction-stripping is used for iron removal. The iron removal unit is provided with four inlets and outlets: leachate, residual solution after iron removal by extraction, residual solution after iron removal by extraction, and iron extractant. Iron is removed by extraction of iron extractant in the iron extractant storage tank. The iron extraction temperature is 25-35°C, the extraction ratio O / A=1:1-2:1L / min (volume ratio), and the extraction stage is 1-3. The iron-loaded organic phase is connected to the iron stripping unit through the inlet and outlet of the residual solution for iron removal. 1-3 mol / L sulfuric acid solution is used for stripping, with a ratio O / A=1:1-1:3L / min (volume ratio), and the stripping stage is 1-3. The organic phase regenerated by stripping is returned to the iron extractant storage tank. The iron-containing stripping solution (ferric sulfate) enters the iron-containing stripping solution storage tank for temporary storage. This technology chooses to use extraction for iron removal, which can remove more than 98% of iron impurities in the leachate. The iron-loaded organic phase is stripped using dilute sulfuric acid to obtain a ferric sulfate solution. The iron extractant regenerated by stripping is reused.

[0049] In this embodiment, extraction-strip extraction is used to recover the copper in the leachate, and the residual liquid after extraction and iron removal and the copper extractant enter the copper extraction and recovery unit through the residual liquid inlet and outlet after extraction and iron removal and the iron extractant inlet and outlet respectively. The copper extractant in the copper extractant storage tank is used for extraction and copper removal, the copper extraction temperature is 25-35°C, the extraction ratio O / A=1:1-2:1L / min (volume ratio), and the extraction level is 1-3. The residual copper extraction liquid finally enters the arsenic recovery unit. The organic phase loaded with copper enters the copper stripping unit and is stripped using 0.1-0.5mol / L sulfuric acid solution, the operating temperature is 25-35°C, the ratio O / A=1:1-1:3L / min (volume ratio), and the stripping level is 1-3. The copper stripping liquid (copper sulfate solution) enters the copper sulfate solution storage tank for storage. The organic phase regenerated by stripping is returned to the copper extractant storage tank. In this embodiment, extraction and iron removal are selected. Many studies have shown that for most copper extractants, Fe 3+ It will be extracted first before copper, so it is necessary to remove iron before extracting and recovering copper. 2+To stably coexist with H₃AsO₄, the leachate must maintain a high acidity, making chemical precipitation an unsuitable method for iron removal. This technology uses extraction to remove over 98% of the iron impurities in the leachate. The iron-laden organic phase is stripped with dilute sulfuric acid to produce a ferric sulfate solution. The iron extractant regenerated from the stripping is then reused.

[0050] After the copper extraction is completed, SO2 is introduced into the copper raffinate from 18 at a rate of 100 to 300 ml / min, and the duration is 60 to 120 minutes. It also includes a filtrate storage tank, in which the solution after reduction enters the second filtering unit to obtain crude As2O3 and filtrate, and the filtrate enters the filtrate storage tank for use in the copper electrolytic refining unit. The second filtering unit in this embodiment is a filter press, specifically named the second filter press 7. The discharge port of the second filter press 7 is connected to the feed port of the extraction and copper removal unit 5. The mixture is separated after filtration by the filter press 7. The filtrate has a low impurity content and a high sulfuric acid concentration, and can be returned to the copper extraction unit for reuse.

[0051] The specific implementation process is as follows: copper-arsenic-rich solid waste is added to the reactor 1, and O2 is added during the leaching process. After the leaching is completed, the first filter press 2 is used for leaching and filtration, and the filter residue is removed. The filtrate generated at the same time enters the heat exchanger 3 for heat exchange with the leaching agent. The leaching agent is heated and then enters the reactor 1. The cooled filtrate then enters the extraction and iron removal unit 4. After extraction-strip iron removal, a ferric sulfate solution is obtained. The residual iron extraction liquid enters the copper extraction unit and is extracted and stripped to obtain a copper sulfate solution. The residual copper extraction liquid enters the reduction and arsenic precipitation unit 6, where HAsO3 is reduced to HAsO2 with SO2 and spontaneously hydrolyzed into As2O3 crystals. The mixture is separated after filtration by the second filter press 7, and the filtrate re-enters the copper extraction unit for reuse. The filtrate formed by the first filter press 2 after the leaching reaction is heated and the filtrate is cooled, thereby avoiding the problem of wasting heat energy in the filtrate and causing additional energy consumption for cooling. At the same time, the leaching agent is preheated in advance, accelerating the reaction speed and reducing the consumption of heating resources required for the reaction, saving energy. The filtrate passed through the second filter press 7 is returned to the copper extraction unit for reuse, saving costs. The purification of the mixed copper electrolyte will produce black copper enriched in arsenic. Some literature reports on alkaline and acid treatment processes for black copper. Chemical precipitation or concentrated crystallization methods are generally used to achieve the separation and productization of copper and arsenic. There are no reports on the separation of copper and arsenic by extraction. Therefore, the present invention uses an extraction method to separate copper and arsenic, which can achieve efficient separation of copper and arsenic and significantly shorten the process flow.

[0052] The above is only an embodiment of the present invention, and the common knowledge such as the specific technical solutions and / or characteristics in the solution are not described in detail here. It should be pointed out that for those skilled in the art, several variations and improvements can be made without departing from the technical solution of the present invention. In the present invention, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. The scope of protection claimed by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A comprehensive treatment method for copper-arsenic-rich solid waste, comprising a leaching unit and a first filtration unit, characterized in that: Also includes: Step 1: adding copper-arsenic-rich solid waste and a leaching agent into a reactor for leaching to obtain a leachate, the leaching temperature is 110-150° C., the leaching time is 1-3 hours, and the leaching agent is black acid; Step 2: filtering the leaching liquid using a first filter press to obtain a filtrate; Step 3: Add the filtrate to the heat exchanger to preheat the leaching agent, and discharge the cooled filtrate into the extraction iron removal unit; Step 4: adding an iron extractant to the extraction and iron removal unit to extract and remove iron from the filtrate; Step 5: adding a copper extractant to the extraction and copper removal unit to remove copper from the iron extraction residual solution; Step 6: Add the copper extraction residual solution to the arsenic reduction precipitation unit, and then filter press to obtain As2O3; In the leaching process of step 1, P O2 =0.1~0.4MPa, pH=0~2, leachate-solid ratio 10:1~15:1ml / g; further comprising stripping the iron-loaded organic phase in step 4 to remove iron, and storing the organic phase after stripping and iron removal in an iron-containing stripping liquid storage tank of an iron extractant.

2. The comprehensive treatment method for copper-arsenic-rich solid waste according to claim 1, characterized in that: The iron-loaded organic phase in step 4 is stripped and iron removed by using a sulfuric acid solution with a concentration of 1 to 3 mol / L, wherein the phase ratio is O / A=1:1 to 1:3 L / min and the stripping stage is 1 to 3 stages.

3. The comprehensive treatment method for copper-arsenic-rich solid waste according to claim 1, characterized in that: The method further includes stripping the copper-loaded organic phase in step 5 to remove copper, and storing the organic phase after stripping to remove copper in a copper sulfate solution storage tank of a copper extractant.

4. The comprehensive treatment method for copper-arsenic-rich solid waste according to claim 3, characterized in that: The copper-loaded organic phase in step 5 is stripped and copper removed by using a sulfuric acid solution with a concentration of 0.1-0.5 mol / L, wherein the phase ratio is O / A=1:1-1:3 L / min, the operating temperature is 25-35° C., and the stripping stage number is 1-3.

5. The comprehensive treatment method for copper-arsenic-rich solid waste according to claim 1, characterized in that: In step 4, the extraction temperature of iron is 25-35° C., the extraction phase ratio is O / A=1:1-2:1 L / min, and the extraction stage is 1-3.

6. The comprehensive treatment method for copper-arsenic-rich solid waste according to claim 1, characterized in that: In step 5, the extraction temperature of copper is 25-35° C., the extraction phase ratio is O / A=1:1-2:1 L / min, and the extraction stage is 1-3.

7. The comprehensive treatment method for copper-arsenic-rich solid waste according to claim 1, characterized in that: In the step 1, oxygen is introduced to perform pressure leaching.

8. The comprehensive treatment method for copper-arsenic-rich solid waste according to claim 1, characterized in that: The step 6 specifically includes: introducing SO2 into the copper raffinate at a rate of 100-300 ml / min for 60-120 min, and the reduced solution enters a filter press to obtain As2O3.

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