Large-scale industrial development method for low-grade complex secondary copper sulfide ores

Abstract

The present invention belongs to the field of mineral engineering, and relates to a large-scale industrial development method for low-grade complex secondary copper sulfide ores. In the present invention, ores having different clay contents are classified; raw ores having a high clay content are directly heaped, so as to improve the permeability of an ore heap; and ores having a low clay content are crushed and then heaped, so as to improve the leaching efficiency of the ores. In order to address the problem of a high pyrite content, early capping is performed to control pyrite oxidation, regulation and control using a biological population are performed to inhibit pyrite oxidation, a solution is rationally dispatched to reduce acid, and copper-bearing rainwater is discharged to the bottom of a mining pit and stored therein; moreover, after dilution with the rainwater in the pit, the pH increases, and Fe3+ generates a precipitate, which settles at the bottom of the pit, thereby achieving the effect of reducing iron and acid, and also reducing environmental protection incidents.

Description

A method for large-scale industrial development of low-grade complex secondary sulfide copper deposits Technical Field

[0001] This invention belongs to the field of mining engineering, specifically relating to a method for large-scale industrial development of low-grade secondary sulfide copper ore. Background Technology

[0002] Secondary copper sulfide minerals include chalcocite, chalcocite, covellite, and bornite. These copper minerals are often associated with large amounts of pyrite, and their treatment methods mainly include flotation and bio-heap leaching. For flotation, the pyrite content and copper grade in the ore are key indicators. A process scheme of sulfur suppression and copper flotation is generally adopted. The main factors affecting copper-sulfur separation are: pyrite content, mineral type, and its floatability. When the pyrite content is high, secondary copper sulfide minerals are easily oxidized and dissolved, resulting in a large amount of copper ions in the slurry. Copper ions activate pyrite, thus worsening copper-sulfur separation during beneficiation, affecting concentrate grade and copper recovery rate. When the copper grade is low, economic indicators deteriorate, posing a significant challenge to operations. For bio-heap leaching, the pyrite content and clay content in the ore are key indicators. During the ore heap leaching process, pyrite undergoes an oxidation reaction to produce ferric iron and sulfuric acid. The heat released by oxidation and the generated ferric iron promote the leaching of secondary copper sulfide minerals. However, if the ore contains a high amount of associated pyrite and a low amount of acid-consuming gangue, the oxidation of pyrite as the solution continuously circulates in the system will lead to an excess of acidic iron accumulation. Factors such as extraction backflow and acid production from alum precipitation will further exacerbate this acid excess, reducing extraction efficiency, decreasing copper transfer, and affecting current efficiency. Ultimately, this will limit cathode copper production and increase production costs. Excessive clay content in the ore is detrimental to the permeability of the ore pile, affecting the copper ore leaching rate and hindering efficient resource utilization. Summary of the Invention

[0003] (a) Technical problems to be solved

[0004] The technical problem to be solved by this invention is how to provide a method for large-scale industrial development of low-grade complex secondary sulfide copper ore, so as to alleviate the problem of declining product yield and quality caused by excessive pyrite content and improve the utilization rate of copper resources.

[0005] (II) Technical Solution

[0006] To address the aforementioned technical problems, this invention proposes a method for large-scale industrial development of low-grade complex secondary sulfide copper deposits, comprising the following steps:

[0007] Step 1: After drilling the ore body, test the drill bit powder to determine the type of ore and classify the ore body into low clay ore and high clay ore.

[0008] Step 2: Mining different types of ore and transporting them to their respective stockpiles. Dividing the upper stockpile solution in each stockpile into raffinate and intermediate solution, and the lower stockpile solution into intermediate solution and qualified solution; and dividing the stockpiles into old stockpile area and new stockpile area according to the ore leaching time. Intermediate solution from different stockpiles is circulated among them to regulate the ore leaching environment and balance the liquid level in the stockpiles.

[0009] Step 3: There are at least two extraction electrowinning workshops and one independent electrowinning workshop. Each extraction electrowinning workshop receives qualified liquid from different stockpiles and transports its own raffinate to the old stockpile area of ​​different stockpiles. The electrorich liquid produced by each extraction electrowinning workshop flows to the independent electrowinning workshop. The electropoor liquid produced by the independent electrowinning workshop is mixed with the electropoor liquid produced by any extraction electrowinning workshop and then flows to the back-extraction section.

[0010] In step 1, the high-clay ore and low-clay ore are classified into ore types based on the different clay content in the ore. The high-clay ore is transported to stockpile #2 and directly piled up. The low-clay ore is crushed to P80 = 70mm and then transported by conveyor belt to stockpile #1 where it is piled up by a concrete placing machine.

[0011] In step 3, the raffinate produced in the extraction and electrowinning workshop is deacidified once by being fed to the old stack area, and the intermediate solution of the lower stack is deacidified again by being fed to the old stack area or the new stack area separately or simultaneously, so as to reduce the acidity of the qualified solution and increase the copper ion concentration.

[0012] In step 2 of the heap leaching process, during the rainy season, copper-containing rainwater in each heap is discharged to the bottom of the pit for storage. During the dry season, the low-acid and low-iron solution on the surface of the pit bottom is returned to the intermediate solution in the heap to compensate for evaporation and at the same time reduce the acid and iron concentration in the heap leaching solution system.

[0013] In step 2, when the average total iron concentration in each stockpile exceeds 45 g / L and the acidity exceeds 14 g / L, an inhibitor of ferrous oxide microbial activity is added to regulate the activity of ferrous oxide microorganisms and reduce the oxidation rate of pyrite.

[0014] Among these measures, for stockpiles that have reached the designed height, benign waste rock is used to seal the stockpiles, isolating the leaching residue from the external environment.

[0015] In step 3, the configuration of each workshop is as follows: the No. 1 storage yard is equipped with the No. 1 extraction electrowinning system, the No. 2 storage yard is equipped with the No. 2 extraction electrowinning system, and a No. 3 electrowinning system is set up independently.

[0016] The qualified liquid from stockpile #1 and qualified liquid from stockpile #2 are both supplied to extraction electrowinning system #1 and extraction electrowinning system #2.

[0017] The raffinate from the No. 1 extraction electrowinning system is supplied to the old pile areas of No. 1 and No. 2 stockpiles, while the raffinate from the No. 2 extraction electrowinning system is supplied to the upper pile solution of the old pile areas of No. 1 and No. 2 stockpiles.

[0018] The electrolyte rich in the extraction and electrowinning systems 1# and 2# is supplied to the electrowinning system 3#, and the electrolyte poor in the electrowinning system 3# is supplied to the back-extraction section of the extraction and electrowinning systems 1# and 2#.

[0019] (III) Beneficial Effects

[0020] This invention proposes a method for large-scale industrial development of secondary sulfide copper ore, which can effectively reduce the acid and iron concentration in the heap leaching solution system, improve the utilization rate of copper resources, ensure the yield and quality of cathode copper, and reduce environmental risks in the mining area. Attached Figure Description

[0021] Figure 1 is a process flow diagram of the present invention. Detailed Implementation

[0022] To make the objectives, contents, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0023] This embodiment provides a method for large-scale industrial development of low-grade complex secondary sulfide copper ore, including the following steps:

[0024] Step 1: After drilling the ore body, test the drill bit powder to determine the type of ore and classify the ore body into low clay ore and high clay ore.

[0025] Step 2: Mining different types of ore and transporting them to their respective stockpiles. Dividing the upper stockpile solution in each stockpile into raffinate and intermediate solution, and the lower stockpile solution into intermediate solution and qualified solution; and dividing the stockpiles into old stockpile area and new stockpile area according to the ore leaching time. Intermediate solution from different stockpiles is circulated among them to regulate the ore leaching environment and balance the liquid level in the stockpiles.

[0026] Step 3: There are at least two extraction electrowinning workshops and one independent electrowinning workshop. Each extraction electrowinning workshop receives qualified liquid from different stockpiles and transports its own raffinate to the old stockpile area of ​​different stockpiles. The electrorich liquid produced by each extraction electrowinning workshop flows to the independent electrowinning workshop. The electropoor liquid produced by the independent electrowinning workshop is mixed with the electropoor liquid produced by any extraction electrowinning workshop and then flows to the back-extraction section.

[0027] In step 1, the high-clay ore and low-clay ore are classified into ore types based on the different clay content in the ore. The high-clay ore is transported to stockpile #2 and directly piled up. The low-clay ore is crushed to P80 = 70mm and then transported by conveyor belt to stockpile #1 where it is piled up by a concrete placing machine.

[0028] In step 3, the raffinate produced in the extraction and electrowinning workshop is deacidified once by being fed to the old stack area, and the intermediate solution of the lower stack is deacidified again by being fed to the old stack area or the new stack area separately or simultaneously, so as to reduce the acidity of the qualified solution and increase the copper ion concentration.

[0029] In step 2 of the heap leaching process, during the rainy season, copper-containing rainwater in each heap is discharged to the bottom of the pit for storage. During the dry season, the low-acid and low-iron solution on the surface of the pit bottom is returned to the intermediate solution in the heap to compensate for evaporation and at the same time reduce the acid and iron concentration in the heap leaching solution system.

[0030] In step 2, when the average total iron concentration in each stockpile exceeds 45 g / L and the acidity exceeds 14 g / L, an inhibitor of ferrous oxide microbial activity is added to regulate the activity of ferrous oxide microorganisms and reduce the oxidation rate of pyrite.

[0031] Among these measures, for stockpiles that have reached the designed height, benign waste rock is used to seal the stockpiles, isolating the leaching residue from the external environment.

[0032] In step 3, the configuration of each workshop is as follows: the No. 1 storage yard is equipped with the No. 1 extraction electrowinning system, the No. 2 storage yard is equipped with the No. 2 extraction electrowinning system, and a No. 3 electrowinning system is set up independently.

[0033] The qualified liquid from stockpile #1 and qualified liquid from stockpile #2 are both supplied to extraction electrowinning system #1 and extraction electrowinning system #2.

[0034] The raffinate from the No. 1 extraction electrowinning system is supplied to the old pile areas of No. 1 and No. 2 stockpiles, while the raffinate from the No. 2 extraction electrowinning system is supplied to the upper pile solution of the old pile areas of No. 1 and No. 2 stockpiles.

[0035] The electrolyte rich in the extraction and electrowinning systems 1# and 2# is supplied to the electrowinning system 3#, and the electrolyte poor in the electrowinning system 3# is supplied to the back-extraction section of the extraction and electrowinning systems 1# and 2#.

[0036] Example 1:

[0037] (1) "Geological-Mining Linked Open-Pit Mining". After drilling the ore body, the geologists analyze the drill bit powder to determine the type of ore by analyzing the grade, liquid limit, and plasticity index of the drill bit ore powder. Subsequently, the ore body is divided into easily leached ore and difficult-to-leach ore. The mining professionals design and produce mining schedules based on the ore body model.

[0038] (2) "Mining-Benefitting Linked Heap Leaching". The mining team extracts and transports different types of ore separately, storing them in their respective heaps. The beneficiation team divides the leaching solution in each heap into two types: raffinate and intermediate solution. The leaching solution in the lower heap is also divided into two types: intermediate solution and qualified solution. The heaps are further divided into old heap areas and new heap areas according to the ore leaching time. All raffinate from the extraction workshop is deacidified once in the old heap area, while the intermediate solution in the lower heap can be deacidified again by being processed in either the old or new heap areas, either separately or simultaneously. During the rainy season, copper-containing rainwater in the heaps is discharged to the bottom of the pit for storage. After being diluted by rainwater in the pit, the pH rises, and Fe3+ precipitates and settles at the bottom of the pit, achieving iron and acid reduction effects and reducing the occurrence of environmental accidents. During the dry season, the low-acid, low-iron solution on the surface of the pit bottom is returned to the intermediate solution in the heaps to compensate for evaporation and simultaneously reduce the acid and iron concentrations in the heap leaching solution system. Intermediate solutions from different stockpiles can circulate among them, allowing for targeted control of the ore leaching environment and equilibrium liquid levels. When the average total iron concentration in the stockpile exceeds 45 g / L and the acidity exceeds 14 g / L, ferrous oxide microbial activity inhibitors are added to regulate ferrous oxide microbial activity and reduce the pyrite oxidation rate. For stockpiles that have reached the design height, benign waste rock is used for sealing to isolate the leaching residue from the external environment, thus stopping the continuous oxidation of pyrite at its source.

[0039] (3) The “Mineral Processing-Smelting Integration” plan includes at least two extraction-electrowinning workshops and one independent electrowinning workshop. The two extraction-electrowinning workshops use a “two-stage tandem extraction-one-stage back-extraction-one-stage washing-electrowinning copper extraction” process, while the independent electrowinning workshop only has an electrowinning copper extraction process. Each extraction-electrowinning workshop can receive qualified liquid from different stockpiles and can transport its own produced raffinate to the old stockpile area of ​​different stockpiles. Wastewater from the washing section within the extraction-electrowinning workshop is directly discharged into the intermediate liquid for use as makeup water for heap leaching. Electrolyte rich in liquid produced by each extraction-electrowinning workshop can flow to the independent electrowinning workshop, and electrolyte lean in liquid produced by the independent electrowinning workshop can be mixed with electrolyte lean in liquid produced by any extraction-electrowinning workshop and flow to the back-extraction section.

[0040] Taking a copper mine with an annual cathode copper production of 50,000 tons as an example, a certain biological heap leaching copper mine has an annual mining output of 20 million tons of ore with an average grade of 0.38%. The ore mainly contains chalcopyrite, covellite, pyrite, quartz, alunite, feldspar, pyrophyllite, etc., with pyrite content as high as 20%. As acid and iron accumulate in the heap leaching system, the average acid concentration in the heap solution rises to 10 g / L, and the average iron concentration rises to 45 g / L, which affects the extraction rate and cathode copper production to a certain extent. In order to efficiently utilize copper resources and maximize cathode copper production, the following "mining-benefiting-smelting" linkage scheme was adopted, achieving an annual (330-day) cathode copper production of 55,836 tons, eliminating the environmental risks during the rainy season. First, the ore is classified into high-clay ore and low-clay ore according to the different clay contents. High-clay ore is directly transported by truck to the No. 2 stockpile and directly piled by truck, while low-clay ore is crushed to P 80 After reaching 70mm, the solution is transported by conveyor belt to stockpile #1, where it is piled up using a concrete placing machine. Stockpiles #1 and #2 with a leaching cycle exceeding 300 days are designated as old stockpiles, while those with a leaching cycle of 300 days or less are designated as new stockpiles. Stockpile #1 is equipped with an extraction electrowinning system #1, and stockpile #2 is equipped with an extraction electrowinning system #2. A separate electrowinning system #3 is also provided. Under production conditions, qualified solution from stockpile #1 can supply extraction electrowinning systems #1 and #2, and qualified solution from stockpile #2 can supply extraction electrowinning systems #1 and #2. Intermediate solutions from stockpiles #1 and #2 can be exchanged. Raffinate from extraction electrowinning system #1 can supply the old stockpile area of ​​stockpiles #1 and #2, and raffinate from extraction electrowinning system #2 can also supply the old stockpile area of ​​stockpiles #1 and #2. Electrolyte rich in solution from extraction electrowinning systems #1 and #2 can supply electrowinning system #3, and electrolyte lean in solution from electrowinning system #3 can supply the back-extraction section of extraction electrowinning systems #1 and #2. When the rainy season arrives, a portion of the intermediate liquid from the stockpile is directly discharged into the open-pit mine, forming high-acid, high-iron copper-containing rainwater. Due to rainfall, the acidity of the copper-containing rainwater in the mine drops to 2.5 g / L, and the total iron concentration drops to 17 g / L, forming low-acid, low-iron copper-containing rainwater. During the dry season, the low-acid, low-iron rainwater from the surface layer of the mine is fed back into the stockpile. Each year, when the average total iron concentration in the stockpile exceeds 45 g / L and the acidity exceeds 14 g / L, a ferrous oxide microbial activity inhibitor is added to the intermediate liquid in the stockpile, maintaining a concentration of no less than 100 mg / L to regulate ferrous oxide microbial activity and reduce the pyrite oxidation rate. Since stockpile #3 has reached its design height, the solution is no longer piled up, and it is completely sealed with benign waste rock to isolate the leaching residue from the external environment, stopping the continuous oxidation of pyrite at its source. Specific process operation parameters and process indicators for the extraction and electrowinning processes are shown in Table 1 below:

[0041] Table 1: Process Operating Parameters and Process Indicators

[0042] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A large-scale industrial development method of a low-grade complex secondary copper sulfide ore, characterized by, Includes the following steps: Step 1: After drilling the ore body, test the drill bit powder to determine the type of ore and classify the ore body into low clay ore and high clay ore. Step 2: Mining different types of ore and transporting them to their respective stockpiles. Dividing the upper stockpile solution in each stockpile into: raffinate and intermediate solution, and the lower stockpile solution into: intermediate solution and qualified solution. The stockpile is divided into old stockpile area and new stockpile area according to the ore leaching time. Intermediate liquid is circulated between different stockpile areas to regulate the ore leaching environment and balance liquid level in the stockpile. Step 3: There are at least two extraction electrowinning workshops and one independent electrowinning workshop. Each extraction electrowinning workshop receives qualified liquid from different stockpiles and transports its own raffinate to the old stockpile area of ​​different stockpiles. The electrorich liquid produced by each extraction electrowinning workshop flows to the independent electrowinning workshop. The electropoor liquid produced by the independent electrowinning workshop is mixed with the electropoor liquid produced by any extraction electrowinning workshop and then flows to the back-extraction section.

2. The method for large-scale industrial development of low-grade complex secondary copper sulfide ores according to claim 1, characterized in that, In step 1, the high-clay ore and low-clay ore are classified into ore types based on the different clay content in the ore. The high-clay ore is transported to stockpile #2 and directly piled up. The low-clay ore is crushed to P80 = 70mm and then transported by conveyor belt to stockpile #1 where it is piled up by a concrete placing machine.

3. The method for large-scale industrial development of low-grade complex secondary copper sulfide ores according to claim 1, characterized in that, In step 3, the raffinate produced in the extraction and electrowinning workshop is deacidified once by being fed to the old stack area, and the intermediate solution of the lower stack is deacidified again by being fed to the old stack area or the new stack area separately or simultaneously, so as to reduce the acidity of the qualified solution and increase the copper ion concentration.

4. The method for large-scale industrial development of low-grade complex secondary copper sulfide ores according to claim 1, characterized in that, During the heap leaching process in step 2, during the rainy season, copper-containing rainwater in each heap is discharged to the bottom of the pit for storage. During the dry season, the low-acid, low-iron solution on the surface of the pit bottom is returned to the intermediate solution in the heap to compensate for evaporation and at the same time reduce the acid and iron concentrations in the heap leaching solution system.

5. The method for large-scale industrial development of low-grade complex secondary copper sulfide ores according to claim 1, characterized in that, In step 2, when the average total iron concentration in each stockpile exceeds 45 g / L and the acidity exceeds 14 g / L, an inhibitor of ferrous oxide microbial activity is added to regulate the activity of ferrous oxide microorganisms and reduce the oxidation rate of pyrite.

6. The method for large-scale industrial development of low-grade complex secondary copper sulfide ores according to claim 1, characterized in that, For stockpiles that have reached the designed height, benign waste rock is used to seal the stockpiles, isolating the leaching residue from the external environment.

7. The method for large-scale industrial development of low-grade complex secondary copper sulfide ores according to claim 1, characterized in that, In step 3, the configuration of each workshop is as follows: the No. 1 storage yard is equipped with the No. 1 extraction electrowinning system, the No. 2 storage yard is equipped with the No. 2 extraction electrowinning system, and a No. 3 electrowinning system is set up independently.

8. The method for large-scale industrial development of low-grade complex secondary copper sulfide ores according to claim 7, characterized in that, The qualified liquid from both the No. 1 and No. 2 stockpiles is supplied to the No. 1 extraction electrowinning system and the No. 2 extraction electrowinning system, respectively.

9. The method for large-scale industrial development of low-grade complex secondary copper sulfide ores according to claim 7, characterized in that, The raffinate from the No. 1 extraction and electrowinning system is supplied to the old stack areas of No. 1 and No. 2 stockpiles, while the raffinate from the No. 2 extraction and electrowinning system is supplied to the upper stack solution of the old stack areas of No. 1 and No. 2 stockpiles.

10. The method for large-scale industrial development of low-grade complex secondary copper sulfide ores according to claim 7, characterized in that, The electrolyte rich in the extraction and electrowinning systems 1# and 2# is supplied to the electrowinning system 3#, and the electrolyte poor in the electrowinning system 3# is supplied to the back-extraction section of the extraction and electrowinning systems 1# and 2#.

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