A self-pressurized closed leaching process for improving the leaching rate of refractory copper oxide ore

Abstract

The present invention belongs to the field of hydrometallurgy technology, specifically relating to a self-pressurized closed leaching process for improving the leaching rate of difficult-to-treat copper oxide ore. Specifically, high-binding copper oxide ore powder and high-alkaline gangue copper oxide ore powder are uniformly mixed at a mass ratio of 1:9 to 9:1, then added to a closed stirred leaching reactor containing a sulfuric acid solution. Stirring is then initiated, and the copper oxide ore powder fully contacts the sulfuric acid solution in the reactor to form a copper oxide ore slurry. The copper oxide ore powder with a high alkaline gangue content reacts vigorously with the sulfuric acid solution to release a large amount of carbon dioxide gas and heat, thereby achieving self-pressurized leaching of the high-binding copper oxide ore powder and the high-alkaline gangue copper oxide ore powder in the closed stirred leaching reactor. This process does not require the introduction of other reagents and can achieve pressurized leaching of copper oxide ore at low temperatures. It is clean, efficient, has a high copper leaching rate, and is highly practical.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrometallurgy, and in particular relates to a self-pressurized closed leaching process for improving the leaching rate of refractory copper oxide ore. Background Art

[0002] Copper ore resources primarily include three categories: copper oxide, copper sulfide, and mixed copper ores. In recent years, with the continued mining and utilization of high-quality copper sulfide and copper oxide ores, the development and utilization of complex and difficult-to-process copper oxide ores has attracted considerable attention, and the development of related technologies is urgent.

[0003] Currently, copper companies both domestically and internationally generally use a wet process called "acid leaching-extraction-electrodeposition" to treat copper oxide ore. This process features a short process flow, mature technology, simple operation, and low capital investment. The process begins with crushing and grinding copper oxide ore (copper grade 2-5%) to a desired particle size. Sulfuric acid is then added to the leaching process in a stirring leaching process. Leaching is a crucial unit process in the wet treatment of copper oxide ore, significantly impacting subsequent extraction, purification, and electrodeposition steps. Therefore, improving the leaching rate of copper oxide ore in the stirring leaching process is crucial for copper recovery in the wet treatment process.

[0004] Copper oxide ores often exhibit complex ore properties, finely embedded particles, and susceptibility to mudification. For copper oxide ores with high bound copper content, copper-bearing minerals are often found within minerals such as limonite and kaolinite clay, resulting in copper leaching rates of less than 60% during sulfuric acid agitation leaching, making them difficult to process. For copper oxide ores with high carbonate alkaline gangue content, the reaction between carbonate gangue and sulfuric acid forms CaSO₄·H₂O precipitates on the ore surface, coating the surface of the ore particles. Consequently, the copper leaching rate of these ores during sulfuric acid agitation leaching can only reach approximately 90%, and further improvement is impossible due to the poor permeability of the leachate. Furthermore, during actual production, the agitation and acid leaching reaction is very intense, leading to problems with agitator tank overflow, making these copper oxide ores somewhat difficult to process.

[0005] Therefore, in the process of treating copper oxide ore using the wet process of "acid leaching-extraction-electrodeposition", especially when using the sulfuric acid stirring leaching process to leach copper oxide ore with a high copper content or copper oxide ore with a high alkaline gangue content, there are still production problems such as low copper leaching rate or easy overflow of the stirring tank, which need to be solved urgently. Summary of the Invention

[0006] To overcome the shortcomings and defects of the prior art, the present invention provides a self-pressurized closed leaching process for improving the leaching rate of difficult-to-treat copper oxide ores. This process does not require the introduction of other reagents and can achieve pressurized leaching of copper oxide ores at low temperatures. It is clean and efficient, has a high copper leaching rate, and is highly practical. The technical solution of the present invention is:

[0007] A self-pressurized closed leaching process for improving the leaching rate of difficult-to-treat copper oxide ore comprises the following steps: uniformly mixing high-binding copper oxide ore powder and high-alkaline gangue content copper oxide ore powder in a mass ratio of 1:9 to 9:1, adding the mixture to a closed stirred leaching reactor containing a sulfuric acid solution, and immediately starting stirring. The copper oxide ore powder is fully contacted with the sulfuric acid solution in the reactor to form a copper oxide ore slurry. The copper oxide ore powder with a high alkaline gangue content reacts violently with the sulfuric acid solution to release a large amount of carbon dioxide gas and heat, thereby achieving self-pressurized leaching of the high-binding copper oxide ore powder and the high-alkaline gangue content copper oxide ore powder in the closed stirred leaching reactor. That is, copper or copper minerals encapsulated by gangue minerals in the copper oxide ore are opened in a closed self-pressurized manner, and the leaching process of the copper oxide ore is intensified under pressurized conditions, thereby improving the leaching rate of complex copper oxide ore with a high bound copper content to above 98.00%.

[0008] The above-mentioned self-pressurized closed leaching process for improving the leaching rate of difficult-to-treat copper oxide ore has a preferred embodiment in which the mineral phase structure of the high-binding rate copper oxide ore is complex, and its main copper minerals are one or more of malachite, malachite, cuprite, azurite, chalcanthite or hydrochalcanthite, and some copper minerals are present in one or more gangue minerals of limonite, kaolinite-clay or pyrolusite.

[0009] The above-mentioned self-pressurized closed leaching process for improving the leaching rate of difficult-to-treat copper oxide ore has a preferred embodiment in which the copper oxide ore with a high alkaline gangue content contains at least one alkaline gangue mineral selected from calcite, dolomite, Iceland spar, aragonite, limestone or limestone minerals.

[0010] The above-mentioned self-pressurized closed leaching process for improving the leaching rate of difficult-to-treat copper oxide ore has a preferred embodiment in which the particle size requirement of the high-binding copper oxide ore powder and the copper oxide ore powder with a high alkaline gangue content is that more than 70 wt% of the powder has a particle size of less than 0.074 mm.

[0011] The preferred embodiment of the self-pressurized closed leaching process for improving the leaching rate of refractory copper oxide ore is that the initial concentration of the copper oxide ore slurry is 15% to 40%.

[0012] The above-mentioned self-pressurized closed leaching process for improving the leaching rate of difficult-to-treat copper oxide ore is preferably as follows: the initial sulfuric acid concentration in the copper oxide ore slurry is 2.0 to 6.0 mol / dm 3 .

[0013] The above-mentioned self-pressurized closed leaching process for improving the leaching rate of difficult-to-treat copper oxide ore has a preferred embodiment in which, during the stirring leaching process, the leaching temperature is controlled at 20°C to 100°C, the stirring speed is 200 to 600 r / min, and the leaching time is 15 min to 120 min.

[0014] The above-mentioned self-pressurized closed leaching process for improving the leaching rate of difficult-to-treat copper oxide ore has a preferred embodiment in which the pressure in the closed stirred leaching reactor is 0.20 MPa to 2.00 MPa during the stirring leaching process.

[0015] The advantages and beneficial effects of the present invention are:

[0016] (1) The present invention utilizes only the large amount of carbon dioxide gas and heat released by the vigorous reaction of the alkaline gangue components (calcite, dolomite, etc.) in the copper oxide ore with the sulfuric acid solution without adding or introducing other reagents or gases, and combines closed operation to increase the pressure in the copper oxide ore stirring leaching reactor to 0.20 MPa ~ 2.00 MPa, that is, through self-pressurization to enhance the leaching process, to achieve green and efficient leaching of high-binding rate difficult-to-treat copper oxide ores. Through the closed self-pressurized leaching process, the leaching rate of high-binding rate complex copper oxide ores can be increased from less than 60.00% under conventional stirring acid leaching conditions to more than 98.00%, with significant results;

[0017] (2) While achieving green and efficient leaching of high-binding-rate difficult-to-treat copper oxide ores, the present invention simultaneously improves the leaching effect of copper oxide ores with a high alkaline gangue content, increasing the leaching rate from 90.00% to over 98.00%, and completely solving the production problems of such copper oxide ores during the sulfuric acid stirring leaching process, such as the proneness of the stirring tank to overflow due to the violent reaction;

[0018] (3) This process has the characteristics of simple process, short flow, and green environmental protection. It can simultaneously process complex copper oxide ores with high binding rate and copper oxide ores with high alkaline gangue content, and achieve efficient leaching of two types of difficult-to-treat copper oxide ores. DETAILED DESCRIPTION

[0019] To facilitate understanding of the present invention, the present invention is described in more comprehensive and detailed manner in conjunction with preferred embodiments. However, the scope of protection of the present invention is not limited to the following specific embodiments. Unless otherwise defined, all professional terms used in the examples have the same meanings as those generally understood by those skilled in the art. The professional terms used are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0020] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the examples can be purchased from the market or prepared by existing methods.

[0021] The high-binding rate copper oxide ore raw material used in the following examples and comparative examples has a copper content of 3.90% and an iron content of 26.80%. The high-binding rate copper oxide is mainly copper-containing limonite, and its copper content accounts for more than 79.00%, which is a typical complex and difficult-to-process copper oxide ore.

[0022] The copper oxide ore raw material with a high alkaline gangue content used in the following examples and comparative examples has a copper content of 3.20% and a calcium content of 25.20%. The main mineral components are quartz, calcite, etc., and the conventional stirred acid leaching process is prone to production problems such as slurry overflow. This is a typical difficult-to-process copper oxide ore with a high alkaline gangue content. Example 1

[0023] A self-pressurized closed leaching process for improving the leaching rate of difficult-to-treat copper oxide ore, the specific process is as follows:

[0024] (1) The high-binding rate copper oxide ore and the copper oxide ore with a high alkaline gangue content are ground separately until the portion of the copper ore with a particle size less than 0.074 mm accounts for 70 wt%;

[0025] (2) After the high binding rate copper oxide ore powder and the high alkaline gangue content copper oxide ore powder are mixed evenly in a mass percentage of 1:9, they are added into a closed stirring reactor for closed self-pressurized leaching. The leaching conditions are: initial slurry concentration of 25%, initial sulfuric acid concentration of 4.0 mol / dm 3 , the leaching temperature was 100°C, the mechanical stirring speed was 400 r / min, and the leaching time was 60 min.

[0026] (3) During the closed self-pressurized leaching process, the maximum pressure in the reactor reached 1.72 MPa. After solid-liquid separation, the copper leaching rate was 99.59%. Example 2

[0027] A self-pressurized closed leaching process for improving the leaching rate of difficult-to-treat copper oxide ore, the specific process is as follows:

[0028] (1) The high-binding rate copper oxide ore and the copper oxide ore with a high alkaline gangue content are ground separately until the portion of the copper ore with a particle size less than 0.074 mm accounts for 70 wt%;

[0029] (2) After the high binding rate copper oxide ore powder and the high alkaline gangue content copper oxide ore powder are mixed evenly in a mass percentage of 3:7, they are added into a closed stirring reactor for closed self-pressurized leaching. The leaching conditions are: initial slurry concentration of 40%, initial sulfuric acid concentration of 6.0 mol / dm 3 , the leaching temperature was 80°C, the mechanical stirring speed was 500 r / min, and the leaching time was 120 min.

[0030] (3) During the closed self-pressurized leaching process, the maximum pressure in the reactor reached 2.00 MPa. After solid-liquid separation, the copper leaching rate was 99.75%. Example 3

[0031] A self-pressurized closed leaching process for improving the leaching rate of difficult-to-treat copper oxide ore, the specific process is as follows:

[0032] (1) The high-binding rate copper oxide ore and the copper oxide ore with a high alkaline gangue content are ground separately until the portion of the copper ore with a particle size less than 0.074 mm accounts for 70 wt%;

[0033] (2) After the high binding rate copper oxide ore powder and the high alkaline gangue content copper oxide ore powder are mixed evenly in a mass percentage of 5:5, they are added into a closed stirred reactor for closed self-pressurized leaching. The leaching conditions are: initial slurry concentration of 30%, initial sulfuric acid concentration of 5.0 mol / dm 3 , the leaching temperature was 60°C, the mechanical stirring speed was 600 r / min, and the leaching time was 45 min.

[0034] (3) During the closed self-pressurized leaching process, the maximum pressure in the reactor reached 1.31 MPa. After solid-liquid separation, the copper leaching rate was 99.00%. Example 4

[0035] A self-pressurized closed leaching process for improving the leaching rate of difficult-to-treat copper oxide ore, the specific process is as follows:

[0036] (1) The high-binding rate copper oxide ore and the copper oxide ore with a high alkaline gangue content are ground separately until the portion of the copper ore with a particle size less than 0.074 mm accounts for 70 wt%;

[0037] (2) After the high binding rate copper oxide ore powder and the high alkaline gangue content copper oxide ore powder are mixed evenly in a mass percentage of 7:3, they are added into a closed stirring reactor for closed self-pressurized leaching. The leaching conditions are: initial pulp concentration of 20%, initial sulfuric acid concentration of 3.0 mol / dm 3 , the leaching temperature was 40°C, the mechanical stirring speed was 300 r / min, and the leaching time was 30 min.

[0038] (3) During the closed self-pressurized leaching process, the maximum pressure in the reactor reached 0.82 MPa. After solid-liquid separation, the copper leaching rate was 98.31%. Example 5

[0039] A self-pressurized closed leaching process for improving the leaching rate of difficult-to-treat copper oxide ore, the specific process is as follows:

[0040] (1) The high-binding rate copper oxide ore and the copper oxide ore with a high alkaline gangue content are ground separately until the portion of the copper ore with a particle size less than 0.074 mm accounts for 70 wt%;

[0041] (2) After the high binding rate copper oxide ore powder and the high alkaline gangue content copper oxide ore powder are mixed evenly in a mass percentage of 9:1, they are added into a closed stirred reactor for closed self-pressurized leaching. The leaching conditions are: initial pulp concentration of 15%, initial sulfuric acid concentration of 2.0 mol / dm 3 , the leaching temperature was 20°C, the mechanical stirring speed was 200 r / min, and the leaching time was 15 min.

[0042] (3) During the closed self-pressurized leaching process, the maximum pressure in the reactor reached 0.20 MPa. After solid-liquid separation, the copper leaching rate was 98.02%. Comparative Example 1

[0043] The leaching process of the high binding rate copper oxide ore of this comparative example is as follows:

[0044] (1) Grinding the copper ore raw material until the portion of the copper ore raw material with a particle size of less than 0.074 mm accounts for 70 wt%;

[0045] (2) The copper oxide ore powder was subjected to acid leaching under normal pressure stirring. The leaching conditions were: initial slurry concentration of 25%, initial sulfuric acid concentration of 4.0 mol / dm 3 The leaching temperature was 100°C, the mechanical stirring speed was 400 r / min, and the leaching time was 60 min. After solid-liquid separation, the leaching rate of the copper ore was 59.97%. Comparative Example 2

[0046] The leaching process of the copper oxide ore with a high alkaline gangue content in this comparative example is as follows:

[0047] (1) Grinding the copper ore raw material until the portion of the copper ore raw material with a particle size of less than 0.074 mm accounts for 70 wt%;

[0048] (2) The copper oxide ore powder was subjected to acid leaching under normal pressure stirring. The leaching conditions were: initial slurry concentration of 25%, initial sulfuric acid concentration of 4.0 mol / dm3 The leaching temperature was 100°C, the mechanical stirring speed was 400 r / min, and the leaching time was 60 min. After solid-liquid separation, the leaching rate of the copper ore was 90.02%.

Claims

1. A self-pressurized closed leaching process for improving the leaching rate of refractory copper oxide ore, characterized in that: After uniformly mixing high-binding rate copper oxide ore powder and high-alkaline gangue content copper oxide ore powder in a mass ratio of 1:9 to 9:1, the mixture is added to a closed stirring leaching reactor filled with sulfuric acid solution, and stirring is immediately started. After the copper oxide ore powder is fully contacted with the sulfuric acid solution in the reactor, a copper oxide ore slurry is formed. The copper oxide ore powder with high alkaline gangue content and the sulfuric acid solution react violently to release a large amount of carbon dioxide gas and heat, thereby achieving self-pressurized leaching of the high-binding rate copper oxide ore powder and the high-alkaline gangue content copper oxide ore powder in the closed stirring leaching reactor; The main copper minerals of the high-binding rate copper oxide ore are one or more of malachite, malachite, cuprite, azurite, chalcanthite or hydrochalcanthite, and the main copper minerals are partially present in one or more gangue minerals of limonite, kaolinite-clay or pyrolusite; The copper oxide ore with a high alkaline gangue content contains at least one alkaline gangue mineral selected from the group consisting of calcite, dolomite, Iceland spar, aragonite, limestone or limestone minerals.

2. The self-pressurized closed leaching process for improving the leaching rate of refractory copper oxide ore according to claim 1, characterized in that: The particle size requirement for high-binding rate copper oxide ore powder and copper oxide ore powder with high alkaline gangue content is that the particle size of more than 70wt% of the ore powder is less than 0.074 mm.

3. The self-pressurized closed leaching process for improving the leaching rate of refractory copper oxide ore according to claim 1, characterized in that: The initial concentration of copper oxide ore slurry is 15% ~40%.

4. The self-pressurized closed leaching process for improving the leaching rate of refractory copper oxide ore according to claim 1, characterized in that: The initial sulfuric acid concentration in the copper oxide ore slurry is 2.0 ~ 6.0 mol / dm 3 .

5. The self-pressurized closed leaching process for improving the leaching rate of refractory copper oxide ore according to claim 1, characterized in that: During the stirring leaching process, the leaching temperature is controlled at 20°C~100°C, the stirring speed is 200~600 r / min, and the leaching time is 15 min~120 min.

6. The self-pressurized closed leaching process for improving the leaching rate of refractory copper oxide ore according to claim 1, characterized in that: During the stirring leaching process, the pressure in the closed stirring leaching reactor is 0.20 MPa~2.00 MPa.