Method for recycling low-grade molybdenum-containing copper concentrate

Abstract

The invention provides a method for recycling low-grade molybdenum-containing copper concentrate, which is characterized in that sulfuric acid is used as a leaching agent, a two-stage countercurrent leaching mode is adopted, the copper leaching rate is more than 95%, strong alkali and weak acid salt is used as a leaching agent, high-pressure oxygen molybdenum leaching is adopted, the molybdenum leaching rate is more than 85%, and copper concentrate smelting slag is produced; extracting copper from the first-section leaching solution through electrodeposition, and recycling the electrodeposition mother solution to produce acid in the second-section leaching; and enriching molybdenum in the third-section leachate through ion exchange, and carrying out acid precipitation to obtain a pure ammonium tetramolybdate product. According to the method, existing resources are further recycled, a large number of resources can be developed, the current situation of resource shortage in China is effectively relieved, pollution of valuable metal to the environment is avoided, and the method is safer and more environmentally friendly; meanwhile, the method is simple in principle, reasonable in process, high in yield and product grade and low in cost, so that development of China and improvement of comprehensive power can be promoted, the trend of low carbon, environmental protection and resource utilization is met, and the method has great practical significance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metallurgy, and relates to a method for recycling low-grade molybdenum-containing copper concentrate. BACKGROUND

[0002] Copper and molybdenum are important non-ferrous metal resources, and in nature, they are mostly associated with each other. Copper-molybdenum ore widely existing in China has high economic value. In the traditional copper-molybdenum ore, a beneficiation process is generally used to separate qualified molybdenum concentrate and copper concentrate, and the copper content in the molybdenum concentrate is strictly controlled. After the molybdenum concentrate is roasted to obtain industrial molybdenum oxide, it is used to produce molybdenum iron or ammonium molybdate through ammonia leaching. In the roasting process of the molybdenum concentrate, MoS2 is oxidized to MoO3, and when the copper content is high, it is easy to generate molybdate which is difficult to dissolve, thereby seriously affecting the recovery rate of molybdenum. However, it is difficult to separate qualified molybdenum concentrate from some copper-molybdenum ore, and in order to ensure the recovery rate of copper and molybdenum, only copper-molybdenum mixed ore can be produced, which is difficult to be treated by using the traditional process, and therefore, it is urgent to develop a new copper-molybdenum ore smelting process.

[0003] The low-grade molybdenum-containing copper concentrate comes from an industrial solid waste produced by alkaline leaching of copper-molybdenum mixed ore, and the molybdenum content is 0.5% to 2.0%, and the copper content is 1.0% to 10.0%. If the molybdenum and copper in the low-grade molybdenum-containing copper concentrate are not recycled, a large amount of mineral resources will be wasted. The stacking and leaching of the slag will not only occupy a large amount of land, but also seriously damage the ecological environment of China, cause serious pollution relief, and have certain safety hazards. SUMMARY

[0004] The application aims to provide a method for recycling low-grade molybdenum-containing copper concentrate, which uses low-grade molybdenum-containing copper concentrate as raw material, extracts copper and molybdenum therefrom by using a wet smelting process, and processes the copper and molybdenum to form valuable products, thereby meeting the trend of low-carbon environmental protection and resource utilization.

[0005] To achieve the above-mentioned purpose, the technical scheme adopted by the application is as follows:

[0006] A method for recycling low-grade molybdenum-containing copper concentrate, comprising the following steps:

[0007] 1) The low-grade molybdenum-containing copper concentrate is put into a first leaching tank, and a first leaching agent is added, the solid-liquid ratio is 1:3 to 1:8, the pH of the slurry is 2.0 to 3.0, the heating temperature is 65 to 85 DEG C, and after stirring and reaction for 1 to 4 hours, the first leaching liquid is filtered, concentrated sulfuric acid is added to the first leaching liquid, and cathode copper is obtained after electro-deposition;

[0008] 2) The first leaching residue is put into a second leaching tank, hydrogen peroxide is added to the electro-deposition mother liquor and then added to the second leaching tank, the solid-liquid ratio is 1:3 to 1:8, the pH of the slurry is 1.0 to 2.0, the heating temperature is 65 to 85 DEG C, and after stirring and reaction for 1 to 4 hours, the second leaching liquid is filtered, and the second leaching liquid is returned to the first leaching and used as the first leaching agent;

[0009] 3) The second stage leaching residue is put into a high-pressure reaction kettle, Na2CO3 solution is added into the high-pressure reaction kettle, the solid-liquid ratio is 1:3-1:5, the heating temperature is 200-250°C, the oxygen partial pressure is 0.8-1.2 MPa, and after stirring for 3-6 hours, filtration is performed, the third stage leaching liquid is used for ion exchange enrichment of molybdenum, and the collected ammonium molybdate solution is acid precipitated to obtain pure ammonium tetramolybdate.

[0010] Preferably, in step 1), the low-grade molybdenum-containing copper concentrate contains: Mo: 0.5%-2%, Cu: 1.0%-10.0%, SiO2: 25%-30%, and Ca: 1.0%-3.0%.

[0011] Preferably, in step 1), 98wt% concentrated sulfuric acid is supplemented to the first stage leaching liquid according to a sulfuric acid concentration of 50-60g / L.

[0012] Preferably, in step 1), three-stage cyclone electrodeposition in a constant current mode is used, and the current density is set to 600A / m 2 , 400A / m 2 , and 200A / m 2 , respectively.

[0013] Preferably, in step 2), the electrodeposition mother liquor is supplemented with 27wt% hydrogen peroxide according to a volume ratio of 5000:1, and then added to the second stage leaching tank.

[0014] Preferably, in step 2), the second stage leaching liquid is supplemented with 98wt% concentrated sulfuric acid according to a sulfuric acid concentration of 120-180g / L to prepare a first stage leaching agent.

[0015] Preferably, in step 3), 120-180g / L Na2CO3 solution is added to the high-pressure reaction kettle.

[0016] Preferably, in step 3), acrylic polyamine-based weak alkaline ion exchange resin is used for adsorption, the pre-exchange liquid is adjusted to a pH of 2.0-6.0 using H2SO4, adsorption, washing, and desorption are performed at a linear speed of 2-10m / h, adsorption is stopped when the Mo concentration of the column effluent is >20mg / L, industrial water is used to rinse the resin, 4%-10% NH3·H2O-4%-10% NH4Cl is used to desorb Mo, and an ammonium molybdate solution with a molybdenum concentration of 100-150g / L is obtained.

[0017] Preferably, in step 3), at a temperature of 20-40°C, the collected ammonium molybdate solution is added to 20wt%-36wt% hydrochloric acid for acid precipitation, centrifugal filtration is performed when the acid is added to a pH of 2-3 and no longer changes, pure ammonium tetramolybdate product is obtained, and the acid precipitation mother liquor can be reused for ion exchange desorption.

[0018] Preferably, in step 3), the carbon dioxide tail gas produced in the flow is absorbed by 150-200 g / L NaOH solution, and is used for the three-stage leaching.

[0019] For the comprehensive recovery of valuable metals in the low-grade copper concentrate containing molybdenum, the present application uses sulfuric acid as the leaching agent, adopts two-stage countercurrent leaching, realizes the copper leaching rate of >95%, uses strong alkali weak acid salt as the leaching agent, adopts high-pressure oxygen leaching of molybdenum, realizes the molybdenum leaching rate of >85%, and produces copper concentrate smelting slag; the first-stage leaching liquid is used for copper electrowinning, the second-stage leaching liquid is used for producing acid by recycling the mother liquor of the electrowinning, and the third-stage leaching liquid is used for enriching molybdenum by ion exchange, and pure ammonium tetratungstate product is obtained by acid precipitation.

[0020] The advantages of the present application mainly include:

[0021] (1) In the process design, the step-by-step extraction of copper and molybdenum by acid leaching and alkali leaching is innovatively adopted, the mutual interference between metals in the traditional method is avoided, and the extraction efficiency and purity are improved.

[0022] (2) Two-stage countercurrent acid leaching is adopted, the leaching rate of the obtained copper metal is high, the silicon leaching rate is <1%, and the purity of the cathode copper product is high.

[0023] (3) High-pressure oxygen leaching of sodium carbonate is adopted, the leaching rate of the obtained molybdenum metal is high, the molybdenum content in the slag is <0.1%, and the full utilization of molybdenum resources is realized.

[0024] (4) The ion exchange method is used for extracting and purifying the molybdenum metal in the leaching liquid, the purity of the molybdenum product is high, and the molybdenum recovery rate is high.

[0025] (5) The process focuses on environmental protection, realizes the recycling and recycling of carbon dioxide, ammonium chloride and other auxiliary materials through reasonable treatment, and reduces pollution.

[0026] (6) Compared with the traditional gravity separation and flotation, the process has the advantages of simple flow, low equipment requirement, low energy consumption and low cost.

[0027] The present application not only further recovers existing resources, but also develops a large amount of resources, effectively alleviates the current situation of resource shortage in China, avoids the pollution of valuable metals to the environment, is safer and more environmentally friendly, and has the advantages of simple principle, reasonable process, high yield and product grade, low cost, and the like, thereby promoting the development of China and the improvement of the comprehensive national strength, meeting the trend of low-carbon environmental protection and resource utilization, and having great practical significance. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is a process flow chart of the method for the resource utilization of the low-grade copper concentrate containing molybdenum. DETAILED DESCRIPTION

[0029] The application will be described in detail below with reference to specific embodiments, which are helpful for those skilled in the art to further understand the application, but do not limit the application in any form.

[0030] In combination Figure 1 , the method of the application mainly includes the following aspects:

[0031] I. Extraction of copper

[0032] The two-stage atmospheric acid leaching mode of one-stage weak acid leaching for directional silicon precipitation and two-stage low-acid leaching for deep copper leaching is adopted to realize the goals of efficient copper leaching, directional silicon precipitation and efficient separation of copper and silicon, etc. The one-stage weak acid leaching solution is used for producing cathode copper by cyclone electrowinning, and copper products are obtained through a short process.

[0033] The main components of the low-grade molybdenum-containing copper concentrate are as follows: Mo: 0.5% to 2%, Cu: 1.0% to 10.0%, SiO2:

[0034] 25% to 30%, and Ca: 1.0% to 3.0%.

[0035] 1.1 One-stage leaching

[0036] The low-grade molybdenum-containing copper concentrate is put into a one-stage leaching tank, the two-stage leaching solution is supplemented with concentrated sulfuric acid (Wt98%) to prepare one-stage leaching agent with a sulfuric acid concentration of 120 to 180 g / L, the prepared one-stage leaching agent is added to the one-stage leaching tank, the solid-liquid ratio is controlled at 1:3 to 1:8, the pH of the slurry is controlled at 2.0 to 3.0, the heating temperature is controlled at 65 to 85°C, and after stirring for 1 to 4 hours, filtration is performed. The one-stage leaching filtrate enters the electrowinning step, and the one-stage leaching residue enters the two-stage acid leaching.

[0037] 1.2 Two-stage leaching

[0038] The one-stage leaching residue is put into a two-stage leaching tank, the electrowinning mother liquor is supplemented with hydrogen peroxide (Wt27%) at a volume ratio of 5000:1, the prepared electrowinning mother liquor is added to the two-stage leaching tank, the solid-liquid ratio is controlled at 1:3 to 1:8, the pH of the slurry is controlled at 1.0 to 2.0, the heating temperature is controlled at 65 to 85°C, and after stirring for 1 to 4 hours, filtration is performed. The two-stage leaching filtrate is returned to the one-stage leaching and used as one-stage leaching agent, and the two-stage leaching residue enters the three-stage leaching.

[0039] The total copper leaching rate is ≥95%, the silicon leaching rate is <1%, and the copper content in the two-stage leaching residue is <0.6%.

[0040] 1.3 Electrowinning

[0041] The copper is electrodeposited from the solution to form cathode copper by electrodeposition process to realize the extraction and productization of copper. The main components of the first stage leaching solution are copper, the copper concentration is about 15-25 g / L, and the Si concentration is <200 mg / L. Concentrated sulfuric acid (Wt 98%) is added to the first stage leaching solution according to the sulfuric acid concentration of 50-60 g / L to increase the electrolyte concentration and reduce the power consumption. Three-stage cyclone electrodeposition in constant current mode is adopted, and the current density is set to 600 A / m 2 , 400 A / m 2 , and 200 A / m 2 , respectively. After electrodeposition, the copper concentration in the solution is reduced to <1 g / L, and copper with a purity of >99.5% is obtained. The electrodeposition principle is as follows:

[0042] Anode reaction: In the process of electrodeposition of copper, titanium alloy anode is used. When direct current is passed, oxidation reaction occurs on the surface of the anode. The hydroxyl ions (OH - ) in the solution lose electrons at the anode and undergo oxidation reaction to generate oxygen and water. The electrode reaction formula is: 4OH - -4e-=O2+2H2O.

[0043] Cathode reaction: Copper ions (Cu 2+ ) in the copper-containing solution obtain electrons at the cathode surface, undergo reduction reaction to generate metallic copper, and deposit on the cathode. The electrode reaction formula is: Cu 2+ +2e - =Cu. Through this reaction, the copper ions in the solution are converted into metallic copper, realizing the extraction and recovery of copper.

[0044] II. Extraction of molybdenum

[0045] The copper concentrate contains about 0.8%-2% molybdenum. Due to its existence form mainly including calcium molybdate, copper molybdate, and molybdenum disulfide, Mo is still retained in the second stage leaching residue after two-stage acid leaching. In order to extract valuable metal molybdenum, Na2CO3 is used for pressure leaching of molybdenum in the second stage leaching residue in the third stage leaching. The slurry after the third stage leaching is filtered by a pressure filter to realize solid-liquid separation. The third stage leaching solution enters the concentration and crystallization process, and the third stage leaching residue is copper concentrate smelting slag, which is a general solid waste.

[0046] 2.1 Third stage leaching

[0047] The second stage leaching residue is put into a high-pressure reaction kettle, and a Na2CO3 solution prepared at 120-180 g / L is added to the high-pressure reaction kettle. The solid-liquid ratio is controlled at 1:3-1:5, the heating temperature is 200-250°C, the oxygen partial pressure is 0.8-1.2 MPa, and the stirring reaction is carried out for 3-6 hours. After filtration, the third stage leaching filtrate is used for ion exchange to extract molybdenum.

[0048] According to the oxidation leaching reaction mechanism of molybdenum disulfide in sodium carbonate solution under high temperature and high pressure conditions, the reaction equation is as follows:

[0049] H2MoO4 + Na2CO3→ Na2MoO4 + H2O + CO2↑

[0050] CaMoO4 + Na2CO3→ Na2MoO4 + CaCO3↓

[0051] CuMoO4 + Na2CO3→ Na2MoO4 + CuCO3↓

[0052] MoS2 + 6Na2CO3 + 9O2→ Na2MoO4 + 2Na2SO4 + 6CO2↑

[0053] The carbon dioxide tail gas is absorbed by 150-200 g / L NaOH solution and is used for the three-stage leaching.

[0054] The three-stage leaching achieves a molybdenum leaching rate of ≥85%, a silicon leaching rate of <0.5%, and a three-stage leaching residue containing <0.1% molybdenum.

[0055] 2.2 Ion exchange enrichment of molybdenum

[0056] The above three-stage filtrate is adsorbed by an acrylic polyamine-based weakly basic ion exchange resin, the pre-exchange liquid is adjusted to a pH of 2.0-6.0 by H2SO4, and adsorption, washing, and desorption are performed at a linear speed of 2-10 m / h. The adsorption is stopped when the Mo concentration of the column effluent is >20 mg / L. After the resin is rinsed with industrial water, 4%-10% NH3·H2O-4%-10% NH4Cl is used to desorb Mo, and an ammonium molybdate solution with a molybdenum concentration of 100-150 g / L is obtained. The ion exchange resin after desorption is transferred to the adsorption step.

[0057] 2.3 Acid precipitation of molybdenum

[0058] At a temperature of 20-40°C, the collected ammonium molybdate solution is added to hydrochloric acid (wt 20%-36%) for acid precipitation. When the pH is not changed at 2-3, centrifugal filtration is performed to obtain pure ammonium tetramolybdate product. The product meets the MSA-2 quality standard of GB / T 3460-2017, and the acid precipitation mother liquor can be used for ion exchange desorption.

[0059] Example 1

[0060] The main components of the low-grade molybdenum-containing copper concentrate are Mo: 1.98%, Cu: 9.25%, SiO2: 26.3%, Ca: 1.49%. The low-grade molybdenum-containing copper concentrate is leached by using a one-stage leaching agent with a sulfuric acid concentration of 120 g / L, a solid-liquid ratio of 1:8, a slurry pH of 3.0, a heating temperature of 85°C, and stirring for 4 hours. After filtration, the copper concentration of the one-stage leaching solution is about 21.5 g / L, and the Si concentration is 123 mg / L. The one-stage leaching solution is supplemented with concentrated sulfuric acid (Wt 98%) to a sulfuric acid concentration of 60 g / L, and three-stage rotating flow electrodeposition is performed in a constant current mode with current densities of 600 A / m 2 , 400 A / m 2 , and 200 A / m 2 , respectively. After electrodeposition, the copper concentration in the solution is 0.56 g / L, and the purity of the cathode copper obtained is 99.8%.

[0061] The electrodeposition mother liquor is supplemented with hydrogen peroxide (Wt 27%) at a volume ratio of 5000:1. The prepared electrodeposition mother liquor is added to the second-stage leaching tank to leach the one-stage leaching residue. The solid-liquid ratio is controlled at 1:5, the slurry pH is 1.0, the heating temperature is 85°C, and stirring is performed for 3 hours. After filtration, the total copper leaching rate of the two stages is 95.8%, the silicon leaching rate is 0.47%, and the copper content of the second-stage leaching residue is 0.51%.

[0062] A 180 g / L Na2CO3 solution is prepared to leach the second-stage leaching residue in a high-pressure reaction kettle. The solid-liquid ratio is controlled at 1:5, the heating temperature is 250°C, the oxygen partial pressure is 0.8 MPa, and stirring is performed for 6 hours. After filtration, the molybdenum leaching rate is 86.5%, the silicon leaching rate is 0.45%, and the molybdenum content of the third-stage leaching residue is 0.08%.

[0063] The above-mentioned three-stage filtrate is adjusted to a pH of 6.0 using H2SO4, and a propylene acid-based polyamine-based weak alkaline ion exchange resin D630 resin is used for adsorption. The adsorption, washing, and desorption are performed at a linear speed of 10 m / h. 10% NH3·H2O-8% NH4Cl is used to desorb Mo, and an ammonium molybdate solution with a molybdenum concentration of 148.5 g / L is obtained. Hydrochloric acid (Wt 36%) is added to the ammonium molybdate solution for acid precipitation. When the pH of the slurry does not change after adding acid, centrifugal filtration is performed to obtain pure ammonium tetramolybdate. The product meets the MSA-2 quality standard of GB / T 3460-2017.

[0064] The carbon dioxide tail gas produced in the process is absorbed by a 200 g / L NaOH solution and is recycled for three-stage leaching.

[0065] Example 2

[0066] The main components of the low-grade molybdenum-containing copper concentrate are Mo: 0.58%, Cu: 1.81%, SiO2: 27.9%, Ca: 2.75%. The low-grade molybdenum-containing copper concentrate is leached by using a one-stage leaching agent with a sulfuric acid concentration of 180 g / L, a solid-liquid ratio of 1:3, a slurry pH of 2.0, a heating temperature of 65°C, and stirring for 1 hour. After filtration, the copper concentration of the one-stage leaching solution is about 22.9 g / L, and the Si concentration is 101 mg / L. The one-stage leaching solution is supplemented with concentrated sulfuric acid (Wt 98%) to a sulfuric acid concentration of 50 g / L, and three-stage rotating flow electrodeposition is performed in a constant current mode with current densities of 600 A / m 2 , 400 A / m 2 , 200 A / m 2 , respectively. After electrodeposition, the copper concentration in the solution is 0.68 g / L, and the purity of the cathode copper obtained is 99.6%.

[0067] The electrodeposition mother liquor is supplemented with hydrogen peroxide (Wt 27%) at a volume ratio of 5000:1. The prepared electrodeposition mother liquor is added to the second-stage leaching tank to leach the one-stage leaching residue. The solid-liquid ratio is controlled at 1:3, the slurry pH is 2.0, the heating temperature is 65°C, and stirring is performed for 4 hours. After filtration, the total copper leaching rate of the two stages is 96.2%, the silicon leaching rate is 0.44%, and the copper content of the second-stage leaching residue is 0.49%.

[0068] A 120 g / L Na2CO3 solution is prepared to leach the second-stage leaching residue in a high-pressure reaction kettle. The solid-liquid ratio is controlled at 1:3, the heating temperature is 200°C, the oxygen partial pressure is 1.2 MPa, and stirring is performed for 3 hours. After filtration, the molybdenum leaching rate is 86.8%, the silicon leaching rate is 0.40%, and the molybdenum content of the third-stage leaching residue is 0.07%.

[0069] The above-mentioned three-stage filtrate is adjusted to a pH of 2.0 with H2SO4 and adsorbed using an acrylic polyamine-based weak alkaline ion exchange resin. Adsorption, washing, and desorption are performed at a linear speed of 2 m / h. Mo is desorbed using 4% NH3·H2O-4% NH4Cl to obtain an ammonium molybdate solution with a molybdenum concentration of 106.9 g / L. Hydrochloric acid (Wt 36%) is added to the ammonium molybdate solution for acid precipitation. When the slurry pH no longer changes after adding acid, centrifugal filtration is performed to obtain pure ammonium tetramolybdate. The product meets the MSA-2 quality standard of GB / T 3460-2017.

[0070] The carbon dioxide tail gas produced in the process is absorbed using a 150 g / L NaOH solution and is recycled for three-stage leaching.

[0071] Example 3

[0072] The main components of the low-grade molybdenum-containing copper concentrate are Mo: 1.41%, Cu: 5.77%, SiO2: 26.2%, Ca1.98%. The low-grade molybdenum-containing copper concentrate is leached by using a one-stage leaching agent with a sulfuric acid concentration of 150 g / L, a solid-liquid ratio of 1:6, a slurry pH of 2.5, a heating temperature of 75°C, and stirring for 3 hours. After filtration, the copper concentration of the one-stage leaching solution is about 23.5 g / L, and the Si concentration is 134 mg / L. The one-stage leaching solution is supplemented with concentrated sulfuric acid (Wt 98%) to a sulfuric acid concentration of 55 g / L, and three-stage rotating flow electrodeposition is performed in a constant current mode with current densities of 600 A / m 2 , 400 A / m 2 , 200 A / m 2 , respectively. After electrodeposition, the copper concentration in the solution is 0.86 g / L, and the purity of the cathode copper obtained is 99.7%.

[0073] The electrodeposition mother liquor is supplemented with hydrogen peroxide (Wt 27%) at a volume ratio of 5000:1. The prepared electrodeposition mother liquor is added to the second-stage leaching tank to leach the one-stage leaching residue. The solid-liquid ratio is controlled at 1:4, the slurry pH is 1.5, the heating temperature is 75°C, and stirring is performed for 1 hour. After filtration, the total copper leaching rate of the two stages is 96.1%, the silicon leaching rate is 0.41%, and the copper content of the second-stage leaching residue is 0.47%.

[0074] A 180 g / L Na2CO3 solution is prepared to leach the second-stage leaching residue in a high-pressure reaction kettle. The solid-liquid ratio is controlled at 1:4, the heating temperature is 230°C, the oxygen partial pressure is 1.0 MPa, and stirring is performed for 4 hours. After filtration, the molybdenum leaching rate is 87.2%, the silicon leaching rate is 0.40%, and the molybdenum content of the third-stage leaching residue is 0.07%.

[0075] The above-mentioned three-stage filtrate is adjusted to a pH of 4.0 with H2SO4, and a propylene acid-based polyamine-based weak alkaline ion exchange resin is used for adsorption. The adsorption, washing, and desorption are performed at a linear speed of 6 m / h. 7% NH3·H2O-7% NH4Cl is used to desorb Mo, and an ammonium molybdate solution with a molybdenum concentration of 131 g / L is obtained. Hydrochloric acid (Wt 36%) is added to the ammonium molybdate solution for acid precipitation. When the slurry pH does not change after adding acid to 2.5, centrifugal filtration is performed to obtain pure ammonium tetramolybdate. The product meets the MSA-2 quality standard of GB / T 3460-2017.

[0076] The carbon dioxide tail gas produced in the process is absorbed by a 180 g / L NaOH solution and is recycled for three-stage leaching.

[0077] Obviously, the above embodiments of the present application are merely exemplary and are not intended to limit the embodiments of the present application. Based on the above description, other different forms of changes or variations can be made by those skilled in the art, and all the embodiments cannot be enumerated here. Any obvious changes or variations derived from the technical solutions of the present application are still within the protection scope of the present application.

Claims

1. A method for resource utilization of low-grade molybdenum-bearing copper concentrate, comprising: 1) Add low-grade molybdenum-containing copper concentrate to a first-stage leaching tank and add a first-stage leaching agent. The solid-liquid ratio is 1:3 to 1:8, the slurry pH is 2.0 to 3.0, the heating temperature is 65 to 85°C, and after stirring and reacting for 1 to 4 hours, filter. Add concentrated sulfuric acid to the first-stage leaching solution, and obtain cathode copper after electrowinning. 2) Add the first stage leaching residue into the second stage leaching tank. Add hydrogen peroxide to the electrowinning mother liquor and then add it to the second stage leaching tank. The solid-liquid ratio is 1:3 to 1:8, the pH of the slurry is 1.0 to 2.0, the heating temperature is 65 to 85℃, and after stirring and reacting for 1 to 4 hours, filter. The second stage leaching liquid is returned to the first stage leaching tank and used as the first stage leaching agent. 3) The second-stage leaching residue is put into a high-pressure reactor, and Na2CO3 solution is added into the high-pressure reactor. The solid-liquid ratio is 1:3 to 1:

5. The heating temperature is 200 to 250°C, the oxygen partial pressure is 0.8 to 1.2 MPa, and the reaction is stirred for 3 to 6 hours. Then the mixture is filtered. The third-stage leaching solution is used for ion exchange to enrich molybdenum. The collected ammonium molybdate solution is acid-precipitated to obtain pure ammonium tetramolybdate.

2. The method according to claim 1, characterized in that, In step 1), the low-grade molybdenum-containing copper concentrate contains: Mo: 0.5%–2%, Cu: 1.0%–10.0%, SiO2: 25%–30%, and Ca: 1.0%–3.0%.

3. The method according to claim 1, characterized in that, In step 1), 98wt% concentrated sulfuric acid is added to a section of the leachate at a sulfuric acid concentration of 50-60 g / L.

4. The method according to claim 1, characterized in that, In step 1), a three-stage swirl electrowinning process is used in a constant current mode, with current densities of 600 A / m. 2 400A / m 2 200A / m 2 Set the current.

5. The method according to claim 1, characterized in that, In step 2), the electrowinning mother liquor is added to a two-stage leaching tank at a volume ratio of 5000:1 with 27wt% hydrogen peroxide.

6. The method according to claim 1, characterized in that, In step 2), 98wt% concentrated sulfuric acid is added to the second-stage leachate at a sulfuric acid concentration of 120-180 g / L to prepare the first-stage leachate.

7. The method according to claim 1, characterized in that, In step 3), a Na2CO3 solution of 120–180 g / L is added to the high-pressure reactor.

8. The method according to claim 1, characterized in that, In step 3), an acrylic polyamine-based weakly basic ion exchange resin is used for adsorption. The pH of the pre-exchange solution is adjusted to 2.0–6.0 using H2SO4. Adsorption, washing, and desorption are performed at a linear velocity of 2–10 m / h. Adsorption is stopped when the Mo concentration in the effluent is >20 mg / L. After rinsing the resin with industrial water, Mo is desorbed using 4%–10% NH3·H2O-4%–10% NH4Cl to obtain an ammonium molybdate solution with a molybdenum concentration of 100–150 g / L.

9. The method according to claim 1, characterized in that, In step 3), at a temperature of 20–40°C, the collected ammonium molybdate solution is added to 20 wt%–36 wt% hydrochloric acid for acid precipitation. When the pH no longer changes at 2–3, the solution is centrifuged and filtered to obtain pure ammonium tetramolybdate product. The mother liquor from the acid precipitation can be reused for ion exchange desorption.

10. The method according to claim 1, characterized in that, In step 3), the carbon dioxide tail gas produced by the reaction is absorbed by a 150-200 g / L NaOH solution and reused in the three-stage leaching process.

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