Method for reducing solid content of high-calcium copper oxide leachate and increasing leaching rate

Abstract

The invention discloses a method for reducing the solid content of high-calcium copper oxide leachate and increasing the leaching rate, which comprises the following steps of: blending high-calcium copper oxide ore and disseminated porphyry type copper ore, ball-milling, settling and separating in a thickening pool, controlling the concentration of underflow to be 55-60%, conveying the underflow of ore pulp to a presoaking tank, introducing sulfuric acid, reacting in the presoaking tank, and leaching to obtain the high-calcium copper oxide leachate. Leached ore pulp is subjected to leaching dense separation, leaching dense underflow is subjected to four-stage countercurrent washing, raffinate is adopted as washing water, CCD1 supernate and leaching dense supernate are mixed and then enter a clarification dense pool, and after clarification, the mixture enters an extraction-electrodeposition procedure to produce electrodeposited copper. According to the technology, the reaction degree of calcium salt is controlled through presoaking, then the leaching rate of copper is effectively increased through six-stage continuous leaching, CCD1 supernate and leaching dense supernate are combined and then clarified through a dense pool, a filtering system in a traditional technology is replaced, the solid content of leachate is effectively reduced, and meanwhile the technology has the advantages of being short in process, high in efficiency and low in implementation difficulty.

Description

Technical Field

[0001] The invention relates to the technical field of chemical metallurgical processing, and in particular to a method for reducing the solid content of copper oxide leaching solution in the field of hydrometallurgy. Background Art

[0002] The material composition and ore structure of copper oxide ore vary greatly, and there are many types of copper minerals. At present, the domestic reserves of copper oxide are relatively small. With the increase in mining efforts, the grade of copper oxide has gradually decreased. The grade of most copper oxide ores has dropped from 17% to about 3%, and even some combined copper oxide grades have dropped to less than 1%. High-calcium copper oxide is mainly marble-type copper oxide, in which calcium carbonate accounts for a high proportion. The commonly used treatment method for copper oxide ore is leaching-extraction-electrodeposition process, but the calcium in high-calcium copper oxide mainly exists in the form of calcium carbonate, which leads to the production of calcium sulfate and carbon dioxide during the reaction. On the one hand, the produced calcium sulfate will wrap copper and unreacted calcium carbonate, and on the other hand, the carbon dioxide generated by the reaction will cause "bubbling".

[0003] In addition, the incomplete reaction of calcium carbonate leads to the production of carbon dioxide during the CCD countercurrent washing process, resulting in a significantly higher solid content in the dense supernatant. In severe cases, floating objects can be clearly seen, and the highest solid content can reach 800ppm. Traditionally, fiber balls are mainly used for adsorption, but the increase in solid content will cause the filtration equipment to be blocked, making it difficult to continue using, and the maintenance cost of the filtration equipment will increase significantly. Disseminated porphyry oxidized copper ore is a low-calcium oxidized copper ore with a calcium content of about 0.863%, which is equivalent to a calcium carbonate content of 0.92%. However, the oxidation rate of disseminated porphyry oxidized copper ore is low and it is not easy to leach. The two ores were subjected to particle size screening, and the calcium carbonate in the two ores was mainly concentrated in the +100 mesh and +200~-325 mesh particle sizes. Using traditional leaching-dense washing, the solid content of the obtained leachate is 800-1000ppm. After the leachate is adsorbed by fiber balls, the solid content is still 100-150ppm, and the leaching rate is only 72-73%. During the countercurrent washing process of the thickener, the supernatant line is less than 1m, and the clarification effect is poor.

[0004] Therefore, in order to reduce the solid content in the leachate and increase the leaching rate of copper, it is of great practical significance and economic benefit to develop a method that can reduce the solid content of high-calcium copper oxide leachate and increase the leaching rate. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a method with short process, high efficiency, low implementation difficulty, which can reduce the solid content of high-calcium copper oxide leaching solution and improve the copper leaching rate.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solution: a method for reducing the solid content of high-calcium copper oxide leaching solution and improving the leaching rate, characterized in that the method is carried out according to the following steps: Step 1: Mix high calcium copper oxide and disseminated porphyry copper oxide in a mass ratio of 1:1.8-2.2, and then control the mixed ore particle size to -200 mesh, accounting for 60%-65%, and the ball milling concentration to 60%-70% by ball milling; Step 2: The slurry obtained in step 1 is transported to the ore thickening tank for solid-liquid separation, and the underflow concentration is controlled to be 55%-60%; the dense underflow slurry is transported to the pre-leaching tank, concentrated sulfuric acid is added, and after reacting for half an hour, it is transported to the leaching tank, the reaction time is 3.5-4.5h, the amount of sulfuric acid added is 130-170kg / t. ore, the leached slurry concentration is 16%-25%, and the sulfuric acid concentration at the leaching end point is 15-20g / L; Step 3: The slurry obtained in step 2 is transported to the leaching and thickening tank, and the thickening bottom flow is pumped into the CCD1 thickening tank, and countercurrent washing is performed between the CCD1-CCD4 thickening tanks, wherein the washing water is the raffinate; the supernatant of the CCD1 thickening tank and the leaching and thickening supernatant are combined and overflowed to the clarification thickening tank, and the supernatant of the clarification thickening tank is transported to the extraction-electrodeposition process to produce copper.

[0007] In step 1, the main components of high-calcium copper oxide are: Cu 1%-2%, and the CaCO3 content is 60-70%, wherein the main phases of copper are: free oxidation copper accounts for 75-80%, combined oxidation copper accounts for 6.5-7%, primary copper sulfide accounts for 0.5-1%, and secondary copper sulfide accounts for 15-20%; the main components of disseminated porphyry copper oxide are: Cu 0.5-1%, and the CaCO3 content is 0.5-1%, wherein the main phases of copper are: free oxidation copper accounts for 35-45%, combined copper sulfide accounts for 1.5-2%, primary copper sulfide accounts for 35-40%, and secondary copper sulfide accounts for 20-25%.

[0008] In step 2, the aspect ratio of the prepreg tank is 5:1, and the slurry level is controlled below 2 / 3, and a double-layer paddle is used for stirring.

[0009] In step 3, the concentration of the thickening underflow of the leaching fraction is controlled to be 35%-37%, the concentration of the thickening underflow of the CCD1 thickening tank is controlled to be 45%-55%, and the concentration of the thickening underflow of the CCD2-CCD4 thickening tanks is controlled to be 30%-40%.

[0010] The main components of the concentrated supernatant in step 3 include: Cu 3.5-4g / L, Fe 1.5-2g / L, and sulfuric acid concentration of 15-20g / L; the main components of the concentrated supernatant in the CCD1 thickening tank include: Cu 2-2.5g / L, Fe 1.5-2g / L, and sulfuric acid concentration of 20-25g / L; the main components of the raffinate include: Cu 0.05-1g / L, Fe 1.5-2g / L, and sulfuric acid concentration of 20-25g / L.

[0011] The main components of the supernatant in the clarified thickening tank in step 3 are: Cu 2.5-3g / L, Fe 1.5-2g / L, sulfuric acid concentration of 15-20g / L, and solid content of 50-60ppm.

[0012] Wherein, the leaching tank is a 6-stage continuous leaching tank.

[0013] Compared with the traditional method of reducing solid content, the process of the present invention has the following advantages: First, the present invention combines the supernatant of the leaching and thickening tank and the CCD1 thick supernatant and then transports them to the clarifying and thickening tank for sedimentation, and controls the concentration of the leaching and thickening bottom flow to 35%-37%, controls the concentration of the CCD1 thickening bottom flow to 45%-55%, and the remaining CCD2-CCD4 thickening bottom flow concentrations to 30%-40%. The bottom flow concentration is adjusted according to the change of the calcium carbonate reaction slag rate, the CCD countercurrent washing efficiency is improved, and it is helpful for solid-liquid separation, so that the solid content is achieved within 50ppm, and the solid content in the leachate is effectively reduced, which has obvious cost advantages over traditional fiber ball filtration.

[0014] Second, calcium carbonate and sulfuric acid are reacted to generate calcium sulfate, the characteristics of calcium sulfate wrapping, and the characteristics of slow reaction of the wrapped calcium carbonate in the CCD concentration tank. By mixing high-calcium copper oxide and impregnated porphyry copper oxide in a mass ratio of 1:2, the grinding characteristics of the two minerals and the distribution characteristics of copper and calcium carbonate particle size are used to control the grinding particle size of -200 mesh to account for more than 60%, so that calcium carbonate is distributed between +100 mesh particle size and -200 mesh~+325 mesh particle size, and the unwrapped copper is exposed as much as possible during the reaction in the reaction tank. At the same time, the sulfuric acid concentration of the concentrated supernatant of the leaching is controlled to be 15-20g / L, and the sulfuric acid concentration of the raffinate is controlled to be 20-25g / L. The sulfuric acid concentration of the raffinate as washing water is slightly higher than that of the concentrated supernatant of the leaching, so that the wrapped calcium sulfate slowly disperses, further improving the leaching rate of Cu in the package. In practice, the leaching rate of copper can be increased by 0.5-1.6%, which effectively improves the leaching rate.

[0015] In addition, the present invention adds a prepreg tank with a length-to-diameter ratio of 5:1 to the original leaching process. By controlling the slurry level below 2 / 3 and using double-layer paddle stirring, 80% of the calcium carbonate reacts preferentially in the prepreg tank, effectively reducing the phenomenon of "bubbling" during the leaching tank reaction process. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0017] The following is combined with Figure 1 The present invention is further described by specific embodiments: Example 1: The main components of high-calcium copper oxide are: Cu 1.3%, CaCO3 content is 62%, and the main phases of copper are: free oxidation copper accounts for 76%, combined oxidation copper accounts for 6.8%, primary copper sulfide accounts for 0.7%, and secondary copper sulfide accounts for 16%. The main components of disseminated porphyry copper oxide are: Cu 0.7%, CaCO3 content is 0.6%, and the main phases of copper are: free oxidation copper accounts for 37%, combined sulfide copper accounts for 1.7%, primary copper sulfide accounts for 37%, and secondary copper sulfide accounts for 22%.

[0018] Follow these steps: Step 1: Mix high calcium copper oxide and disseminated porphyry copper oxide in a mass ratio of 1:2, and then control the mixed ore particle size to -200 mesh, accounting for 63%, and the ball milling concentration to 64% by ball milling; Step 2: The slurry obtained in step 1 is transported to the ore thickening tank for solid-liquid separation, and the underflow concentration is controlled to be 55%; the thick underflow slurry is transported to the pre-leaching tank, concentrated sulfuric acid is added, and after half an hour of reaction, it is transported to the 6-stage continuous leaching tank, the reaction time is 4h, the amount of sulfuric acid added is 150kg / t. ore, the leached slurry concentration is 16%, and the sulfuric acid concentration at the leaching end point is 15g / L; Step 3: The slurry obtained in step 2 is transported to the leaching and thickening tank, and the thickening bottom flow is pumped into the CCD1 thickening tank. The CCD1-CCD4 are countercurrently washed, and the washing water uses the raffinate, and the main components of the raffinate are: Cu 0.05g / L, Fe 1.6g / L, and the sulfuric acid concentration is 23g / L. The CCD1 supernatant and the leaching and thickening supernatant are combined and overflowed to the clarified thickening tank. The supernatant of the clarified thickening tank is transported to the extraction-electrowinning process to produce copper.

[0019] In step 2, the aspect ratio of the prepreg tank is 5:1, and the slurry level is controlled below 2 / 3, and a double-layer paddle is used for stirring.

[0020] In step 2, the concentration of the dense underflow of the leaching fraction is controlled to be 35%, the concentration of the dense underflow of CCD1 is controlled to be 45%, and the concentration of the dense underflow of the remaining CCD2-CCD4 is 30%-40%.

[0021] result: The main components of the concentrated supernatant of the leaching are: Cu 3.5g / L, Fe 1.5g / L, and sulfuric acid concentration is 15g / L. The main components of the concentrated supernatant of CCD1 include: Cu 2g / L, Fe 1.5g / L, and sulfuric acid concentration is 20g / L. The main components of the supernatant of the clarified thickening tank are: Cu 2.9g / L, Fe 1.5g / L, sulfuric acid concentration is 18g / L, and the solid content is 50-60ppm.

[0022] The solid content in the produced concentrated supernatant meets the extraction-electrodeposition requirements.

[0023] Leaching rate = [Cu metal content in concentrated supernatant / Cu metal content in mixed ore)] * 100%, the copper leaching rate is 74.55%.

[0024] Example 2: The main component of high-calcium copper oxide is 1.8%, and the CaCO3 content is 69%. The main phases of copper are: free oxidation copper accounts for 78%, combined oxidation copper accounts for 6.7%, primary copper sulfide accounts for 0.9%, and secondary copper sulfide accounts for 18%. The main component of disseminated porphyry copper oxide is 0.87%, and the CaCO3 content is 0.89%. The main phases of copper are: free oxidation copper accounts for 44%, combined sulfide copper accounts for 1.7%, primary copper sulfide accounts for 38%, and secondary copper sulfide accounts for 23%.

[0025] Follow these steps: Step 1: Mix high calcium copper oxide and disseminated porphyry copper oxide in a mass ratio of 1:2.2, and then control the mixed ore particle size to -200 mesh, accounting for 65%, and the ball milling concentration to 70% by ball milling; Step 2: The slurry obtained in step 1 is transported to the ore thickening tank for solid-liquid separation, and the underflow concentration is controlled to be 60%; the dense underflow slurry is transported to the pre-leaching tank, concentrated sulfuric acid is added, and after half an hour of reaction, it is transported to the 6-stage continuous leaching tank, the reaction time is 4.5h, the amount of sulfuric acid added is 170kg / t. ore, the leached slurry concentration is 25%, and the sulfuric acid concentration at the leaching end point is 20g / L; Step 3: The slurry obtained in step 2 is transported to the leaching and thickening tank, and the thickening bottom flow is pumped into the CCD1 thickening tank. Countercurrent washing is performed between CCD1-CCD4, and the washing water is the raffinate. The main components of the raffinate are: Cu 0.9g / L, Fe 2g / L, and the sulfuric acid concentration is 24g / L.

[0026] The supernatant of CCD1 and the concentrated supernatant of the leaching fraction are combined and overflowed to the clarified concentrated tank. The supernatant of the clarified concentrated tank is transported to the extraction-electrowinning process to produce copper.

[0027] In step 2, the aspect ratio of the prepreg tank is 5:1, and the slurry level is controlled below 2 / 3, and a double-layer paddle is used for stirring.

[0028] In step 2, the concentration of the dense underflow of the leaching fraction is controlled to be 37%, the concentration of the dense underflow of CCD1 is controlled to be 55%, and the concentration of the dense underflow of the remaining CCD2-CCD4 is controlled to be 40%.

[0029] result: The main components of the concentrated supernatant of the leaching process include: Cu 3.6g / L, Fe 1.54g / L, and sulfuric acid concentration of 15.6g / L. The main components of the concentrated supernatant of CCD1 include: Cu 2.3g / L, Fe 1.45g / L, and sulfuric acid concentration of 22g / L. The main components of the supernatant of the clarified thickening tank are: Cu 3g / L, Fe 1.5g / L, sulfuric acid concentration of 18g / L, and solid content of 54ppm.

[0030] The solid content in the produced concentrated supernatant meets the extraction-electrodeposition requirements.

[0031] Leaching rate = [Cu metal content in concentrated supernatant / Cu metal content in mixed ore)] * 100%, the copper leaching rate is 76.34%.

[0032] The present invention has been described in detail above. The above description is only a preferred embodiment of the present invention and should not limit the scope of implementation of the present invention. That is, all equivalent changes and modifications made within the scope of this application should still fall within the scope of the present invention.

Claims

1. A method for reducing the solid content of a high-calcium copper oxide leachate and improving the leaching rate, characterized in that: Follow these steps: Step 1: Mix high calcium copper oxide and disseminated porphyry copper oxide in a mass ratio of 1:1.8-2.2, and then control the mixed ore particle size to -200 mesh, accounting for 60%-65%, and the ball milling concentration to 60%-70% by ball milling; Step 2: The slurry obtained in step 1 is transported to the ore thickening tank for solid-liquid separation, and the underflow concentration is controlled to be 55%-60%; the dense underflow slurry is transported to the pre-leaching tank, concentrated sulfuric acid is added, and after reacting for half an hour, it is transported to the leaching tank, the reaction time is 3.5-4.5h, the amount of sulfuric acid added is 130-170kg / t. ore, the leached slurry concentration is 16%-25%, and the sulfuric acid concentration at the leaching end point is 15-20g / L; Step 3: The slurry obtained in step 2 is transported to the leaching and thickening tank, and the thickening bottom flow is pumped into the CCD1 thickening tank, and countercurrent washing is performed between the CCD1-CCD4 thickening tanks, wherein the washing water is the raffinate; the supernatant of the CCD1 thickening tank and the leaching and thickening supernatant are combined and overflowed to the clarification thickening tank, and the supernatant of the clarification thickening tank is transported to the extraction-electrodeposition process to produce copper.

2. The method for reducing the solid content of high-calcium copper oxide leachate and improving the leaching rate according to claim 1, characterized in that: In step 1, the main components of high-calcium copper oxide are: Cu 1%-2%, and the CaCO3 content is 60-70%, wherein the main phases of copper are: free oxidation copper accounts for 75-80%, combined oxidation copper accounts for 6.5-7%, primary copper sulfide accounts for 0.5-1%, and secondary copper sulfide accounts for 15-20%; the main components of disseminated porphyry copper oxide are: Cu 0.5-1%, and the CaCO3 content is 0.5-1%, wherein the main phases of copper are: free oxidation copper accounts for 35-45%, combined copper sulfide accounts for 1.5-2%, primary copper sulfide accounts for 35-40%, and secondary copper sulfide accounts for 20-25%.

3. The method for reducing the solid content of high-calcium copper oxide leachate and improving the leaching rate according to claim 1, characterized in that: In step 2, the aspect ratio of the prepreg tank is 5:1, and the slurry level is controlled below 2 / 3, and a double-layer paddle is used for stirring.

4. The method for reducing the solid content of high-calcium copper oxide leachate and improving the leaching rate according to claim 1, characterized in that: In step 3, the concentration of the thickening underflow of the leaching fraction is controlled to be 35%-37%, the concentration of the thickening underflow of the CCD1 thickening tank is controlled to be 45%-55%, and the concentration of the thickening underflow of the CCD2-CCD4 thickening tanks is controlled to be 30%-40%.

5. The method for reducing the solid content of high-calcium copper oxide leachate and improving the leaching rate according to claim 1, characterized in that: The main components of the concentrated supernatant in step 3 include: Cu 3.5-4g / L, Fe 1.5-2g / L, and sulfuric acid concentration of 15-20g / L; the main components of the concentrated supernatant in the CCD1 thickening tank include: Cu 2-2.5g / L, Fe 1.5-2g / L, and sulfuric acid concentration of 20-25g / L; the main components of the raffinate include: Cu 0.05-1g / L, Fe 1.5-2g / L, and sulfuric acid concentration of 20-25g / L.

6. The method for reducing the solid content of high-calcium copper oxide leachate and improving the leaching rate according to claim 1, characterized in that: The main components of the supernatant in the clarified thickening tank in step 3 are: Cu 2.5-3g / L, Fe 1.5-2g / L, sulfuric acid concentration of 15-20g / L, and solid content of 50-60ppm.

7. The method for reducing the solid content of high-calcium copper oxide leachate and improving the leaching rate according to claim 1, characterized in that: The leaching tank is a 6-stage continuous leaching tank.

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