Pretreatment method for sulfide polymetallic ore containing pyrrhotite

Abstract

The present invention discloses a method for pretreating sulfide polymetallic ores containing pyrrhotite. The method comprises: subjecting the raw ore to heavy medium separation to obtain a first mineral; the heavy medium separation comprises jig heavy medium separation and cyclone heavy medium separation; subjecting the first mineral to a first grinding and magnetic separation to obtain a magnetic concentrate; subjecting the magnetic concentrate to a second grinding and flotation separation to obtain a pyrrhotite concentrate; wherein the heavy medium separation uses the pyrrhotite concentrate as a heavy medium. This method pretreats the ore using a combination of heavy medium separation, magnetic separation, and flotation, and uses the pyrrhotite obtained within the process as the heavy medium in the heavy medium separation process. While ensuring the main metal recovery rate, this method significantly reduces the amount of ore selected, significantly improves the selected grade of sulfide polymetallic ores with a high pyrrhotite content, reduces ore processing costs, and improves the economic benefits of this type of ore.

Description

Technical Field

[0001] The present invention relates to the technical field of mineral processing, in particular to a pretreatment method for pyrrhotite-containing sulfide polymetallic ore. Background Art

[0002] With the development of mineral resources, the increasing depletion of ores, and increasing environmental protection requirements, ore pretreatment processes have become increasingly important in the green and sustainable development of the mining industry. Among them, heavy media separation technology, with its advantages of a wide separation particle size range, high waste disposal efficiency, and pollution-free separation, is a green, environmentally friendly, and efficient pre-separation method, and has been widely used in the pre-treatment of sulfide ores.

[0003] The inventors of this application have discovered that existing heavy medium beneficiation processes can present problems such as high pyrrhotite content in the ore. For sulfide polymetallic ores with high pyrrhotite content, such as those with a pyrrhotite content greater than 10%, and especially those with a pyrrhotite content greater than 15%, in addition to a large amount of gangue minerals, pyrrhotite can also have a significant adverse effect on the separation of sulfide ores such as copper, lead, and zinc. For this type of ore, the use of magnetic separation can reduce the interference of pyrrhotite with the separation of other sulfides. However, there are currently no reports on the development of a systematic and comprehensive pretreatment process specifically for this type of ore. Through further research, the inventors of this application have developed a systematic and comprehensive pretreatment method for sulfide polymetallic ores containing pyrrhotite. Summary of the Invention

[0004] According to one embodiment of the present invention, an object is to provide a method for pretreating pyrrhotite-containing sulfide polymetallic ores. This object can be achieved by implementing the following technical solutions:

[0005] The present invention provides a method for pretreating pyrrhotite-containing sulfide polymetallic ores, comprising: subjecting the raw ore to heavy medium separation to obtain a first mineral; the heavy medium separation comprises jig heavy medium separation and cyclone heavy medium separation; subjecting the first mineral to a first grinding and magnetic separation to obtain a magnetic concentrate; subjecting the magnetic concentrate to a second grinding and flotation to obtain a pyrrhotite concentrate; wherein the heavy medium separation uses the pyrrhotite concentrate as a heavy medium.

[0006] Optionally, the raw ore is subjected to heavy medium separation to obtain a first mineral; the process includes: performing a first crushing and a first screening on the raw ore, performing jig heavy medium separation on the mineral on the screen to obtain a jig concentrate, wherein the screening particle size of the first screening is 12 mm; performing a second crushing on the jig concentrate, mixing it with the undersize mineral obtained by the first screening, performing a second screening, performing a cyclone heavy medium separation on the mineral on the screen to obtain a cyclone concentrate, wherein the screening particle size of the second screening is 0.5 mm; mixing the cyclone concentrate with the undersize mineral obtained by the second screening to obtain a first mineral, wherein the particle size of the first mineral is ≤0.5 mm.

[0007] Optionally, the first crushing is to a particle size of less than 100 mm; and / or the second crushing is to a particle size of less than 12 mm.

[0008] Optionally, the first grinding to -0.074 mm accounts for 65% to 75%; and / or, the particle size of the second grinding is determined according to the particle size of the heavy medium and the effect of the flotation operation.

[0009] Optionally, the second grinding to -0.074 mm accounts for 80% to 90%.

[0010] Optionally, the method further comprises: thickening the magnetic separation tailings and flotation foam to obtain underflow and overflow; and returning the overflow as a heavy medium configuration clear liquid to heavy medium separation.

[0011] Optionally, the underflow has a concentration of 30% to 35%, becoming the final selected ore.

[0012] Optionally, during magnetic separation, the magnetic separation field strength is 4000 to 6000 Oe; and / or, during flotation, calcium oxide is added and the pH value of the pulp is adjusted to 11 to 12.

[0013] Optionally, a collector is added during flotation, and the collector is one or more of ethyl xanthate, isopropyl xanthate, and ethyl thiocyanate.

[0014] Optionally, the pyrrhotite content in the raw ore is higher than 10%, for example, higher than 15%.

[0015] According to one embodiment of the present invention, ore pretreatment is carried out by combining heavy medium beneficiation, magnetic separation and flotation, and pyrrhotite obtained within the process is used as the heavy medium in the heavy medium separation process. Under the premise of ensuring the main metal recovery rate, the amount of ore to be selected is greatly reduced, the grade of sulfide polymetallic ores with high pyrrhotite content is greatly improved, the ore processing cost is reduced, and the economic benefits of this type of ore are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1It is a schematic flow chart of a method for pretreating pyrrhotite-containing sulfide polymetallic ore in one embodiment of the present invention. DETAILED DESCRIPTION

[0017] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, rather than all embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0018] One embodiment of the present invention provides a method for pretreating sulfide polymetallic ores containing pyrrhotite, comprising: using pyrrhotite concentrate obtained through subsequent flotation as a heavy medium to perform heavy medium beneficiation on the raw ore to obtain a first mineral; magnetically separating the first mineral to obtain a magnetic concentrate; and flotating the magnetic concentrate to obtain a pyrrhotite concentrate and using it as a heavy medium for heavy medium beneficiation. This embodiment pretreats the ore by combining heavy medium beneficiation, magnetic separation, and flotation, and uses pyrrhotite obtained within the process as the heavy medium in the heavy medium beneficiation process. While ensuring the recovery rate of the main metals, this embodiment significantly reduces the amount of ore to be selected and significantly improves the grade of the sulfide polymetallic ores with a high pyrrhotite content. The heavy medium used in the heavy medium beneficiation during pretreatment is an in-process product, eliminating the heavy medium procurement cost and medium consumption pressure, thereby reducing the ore processing cost and improving the economic benefits of this type of ore.

[0019] Figure 1 The following schematically illustrates the process of pre-processing a pyrrhotite-containing sulfide polymetallic ore according to an embodiment. Figure 1 Shown, including:

[0020] 1) The raw ore is crushed for the first time to a particle size of less than 100 mm, and the crushed product is screened for the first time to a screening particle size of 12 mm. Particles above 12 mm enter the heavy medium jig equipment for heavy medium separation, and the jig concentrate enters the second crushing operation to be crushed to less than 12 mm. The heavy separation tailings of the heavy medium jig equipment are the final waste rock. The processed raw ore is a sulfide polymetallic ore containing pyrrhotite, such as copper-lead-zinc ore, copper-zinc ore, lead-zinc ore, etc., wherein the pyrrhotite mineral content is about 20%, which can reduce the amount of ore selected and improve the grade of the final selected ore while ensuring the recovery rate of the main metal.

[0021] 2) The second crushing product is mixed with the undersize product of the first screening and then screened for the second time, with a screening particle size of 0.5mm. Minerals with a particle size of 0.5mm or larger enter the heavy medium cyclone for cyclone heavy medium separation; the cyclone concentrate and the undersize product of the second screening enter the first grinding operation as the first mineral (particle size ≤ 0.5mm), and the grinding fineness of the first grinding operation is -0.074mm, accounting for 65-75%. The sorting tailings of the heavy medium cyclone are the final waste rock. The heavy medium ore dressing adopted by the present invention, in addition, adopts the method of "heavy medium jig separation first, heavy medium cyclone separation later". The coarse particle size of the jigging treatment is relatively large, which can discard large gangue with low useful mineral content, play the role of preliminary waste disposal, reduce crushing energy consumption and subsequent operation processing volume; after the preliminary waste disposal, the heavy medium cyclone is used for heavy medium cyclone separation, which can efficiently discard minerals with finer particle sizes. By combining the above two pre-selection methods, the effect of early throwing and efficient pre-selection can be achieved.

[0022] 3) The ore products from the first grinding process are subjected to magnetic separation at a magnetic separation intensity of 4000-6000 Oe. The magnetic concentrate undergoes a second grinding operation, with a grinding fineness of -0.074 mm (80-90%). The magnetic tailings are then subjected to thickening. The second grinding fineness is determined based on the particle size of the heavy medium and the reverse flotation effect. The appropriate particle size can improve both the heavy medium separation effect and the flotation effect.

[0023] 4) The slurry from the second grinding process undergoes reverse flotation to remove intergrown and entrained useful sulfide minerals from the magnetic concentrate, minimizing sulfide loss. The resulting underflow, the pyrrhotite product, is then returned to the heavy medium separation process, specifically the heavy medium cyclone and heavy medium jig, to provide the heavy medium. During flotation, calcium oxide, such as lime, is added to adjust the slurry pH to 11-12. Collectors such as ethyl xanthate, isopropyl xanthate, and ethyl thiocyanate may be added. A frother, such as No. 2 oil, may also be added.

[0024] 5) The flotation foam and magnetic tailings are sent to the thickener for dehydration. The underflow concentration of the thickener is 30-35%, which becomes the final selected ore. The overflow supernatant returns to the heavy medium separation, that is, returns to the heavy medium cyclone and heavy medium jig equipment, providing clear liquid for the preparation of heavy medium in heavy medium separation.

[0025] Some embodiments of the present invention also have the following advantages and beneficial effects: 1) A combination of heavy medium, magnetic separation, and reverse flotation is used for ore pre-selection, which greatly reduces the amount of ore to be selected while ensuring the recovery rate of the main metal. 2) The heavy medium used in the heavy medium jig equipment and the heavy medium cyclone is the pyrrhotite concentrate obtained from the magnetic separation and flotation of the ore, which reduces the adverse effect of pyrrhotite on the selection of sulfide ores such as copper, lead, and zinc, and improves the selection grade of sulfide polymetallic ores with high pyrrhotite content. There is no heavy medium procurement cost and medium consumption pressure, and it has the cost advantage of repeated recycling and no need for external purchase. 3) The final selected ore product is obtained through thickening treatment, and its thickened supernatant is returned to the heavy medium for preparation and use. That is, the heavy medium preparation supernatant in the heavy medium ore separation process comes from the thickener overflow supernatant, which not only saves process water, but also reduces the dehydration of the thickener and greatly reduces the impact of flotation residual reagents (reagents contained in the flotation foam) on subsequent selection operations. 4) The regrinding particle size (i.e., the second grinding fineness) of the flotation operation is determined by taking into account both the flotation operation effect and the optimal particle size of the heavy medium. The above particle size improves the heavy medium separation effect and the flotation effect at the same time, achieving a good effect of killing two birds with one stone.

[0026] The pretreatment method and effects of the present invention are further described below in conjunction with specific embodiments:

[0027] Example 1

[0028] A certain lead-zinc mine contains 2.38% lead, 3.05% zinc, and 17% pyrrhotite mineral content.

[0029] After crushing the ore to 100 mm, it is screened using a 12 mm sieve. The oversize material is then discarded by heavy media jigging. The ore is then crushed to 12 mm and mixed with the undersize product from the 12 mm sieve before undergoing a second screening process to a particle size of 0.5 mm. The material above 0.5 mm is discarded by a heavy media cyclone. The resulting product is then mixed with the undersize material from the 0.5 mm sieve and then ground to a particle size of -0.074 mm, representing 70% of the total particle size. The resulting slurry undergoes magnetic separation at a field strength of 5000 Oe. The magnetically separated concentrate undergoes a second grinding process, achieving a particle size of -0.074 mm, representing 90% of the total particle size. The product from the second grinding process is subjected to flotation, with calcium oxide added to adjust the pH to 12. Ethyl thiocyanate is used as the collector, and No. 2 oil is used as the frother. The flotation underflow yields pyrrhotite, which is used as the heavy media for heavy media separation. The flotation foam and magnetic separation tailings are combined and sent to the thickener. The underflow concentration of the thickener is 35%, which becomes the final selected mineral; the supernatant provides clear liquid for heavy medium separation.

[0030] Through the above-mentioned pre-treatment process, the lead content of the final selected ore increased from 2.38% to 3.56%, and the zinc content increased from 3.05% to 4.54%. The losses of lead and zinc were 2.47% and 2.84% respectively, and the total amount of selected ore was reduced by 34.68%.

[0031] Example 2

[0032] A copper-zinc mine contains 1.45% copper, 4.07% zinc, and 25% pyrrhotite mineral content.

[0033] By adopting the above pretreatment method, the copper content of the final selected ore increased from 1.45% to 2.34%, and the zinc content increased from 4.07% to 6.54%. The losses of copper and zinc were 2.73% and 3.12% respectively, and the total amount of selected ore was reduced by 39.68%.

[0034] Example 3

[0035] A copper-lead-zinc mine contains 0.82% copper, 1.52% lead, 2.43% zinc, and 22% pyrrhotite mineral content.

[0036] By adopting the above-mentioned pretreatment method, the copper content of the final selected ore increased from 0.82% to 1.25%, the lead content increased from 1.52% to 2.32%, and the zinc content increased from 2.43% to 3.68%. The losses of copper, lead and zinc were 3.08%, 2.86% and 3.57% respectively, and the total amount of selected ore was reduced by 36.24%.

[0037] It can be seen from the above Examples 1-3 that: by adopting the above-mentioned pretreatment method, the ore pre-selection treatment is carried out by combining heavy medium, magnetic separation and reverse flotation, and the pyrrhotite obtained in the treatment process is used as the heavy medium in the heavy medium separation process. After the thickening treatment, the total amount of selected ore is reduced, and the selected grade of the sulfide polymetallic ore with a high pyrrhotite content is greatly improved.

[0038] The description of the present invention has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the form disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles of the invention and its practical application and to enable those skilled in the art to understand the invention and design various embodiments with various modifications as are suited for specific applications.

Claims

1. A method for pretreating pyrrhotite-containing sulfide polymetallic ore, characterized in that: include: The raw ore is subjected to heavy medium beneficiation to obtain a first mineral; The heavy medium separation includes jigging heavy medium separation and cyclone heavy medium separation; These include: The raw ore is crushed and screened for the first time, and the minerals on the screen are separated by heavy medium jigging to obtain jig concentrate; wherein the screening particle size of the first screening is 12mm; The jigging concentrate is crushed for the second time and mixed with the undersize minerals obtained from the first screening, and then screened for the second time. The oversize minerals are separated by a cyclone heavy medium to obtain a cyclone concentrate; wherein the screening particle size of the second screening is 0.5 mm; Mixing the cyclone concentrate with the undersize mineral obtained by the second screening to obtain a first mineral, wherein the particle size of the first mineral is ≤0.5 mm; performing a first grinding and magnetic separation on the first mineral to obtain a magnetic separation concentrate; performing a second grinding and flotation on the magnetic separation concentrate to obtain pyrrhotite concentrate; Wherein, the heavy medium beneficiation adopts the pyrrhotite concentrate as heavy medium.

2. The method for pretreating pyrrhotite-containing sulfide polymetallic ores according to claim 1, characterized in that: The first crushing to particle size below 100mm; and / or, crushing for the second time to a particle size of less than 12 mm.

3. The method for pretreating pyrrhotite-containing sulfide polymetallic ores according to claim 1, wherein: The first grinding to -0.074mm accounts for 65% to 75%; And / or, the particle size of the second grinding is determined according to the particle size of the heavy medium and the effect of the flotation operation.

4. The method for pretreating pyrrhotite-containing sulfide polymetallic ores according to claim 1, characterized in that: The second grinding to -0.074mm accounts for 80% to 90%.

5. The method for pretreating pyrrhotite-containing sulfide polymetallic ores according to claim 1, characterized in that: Also includes: The magnetic separation tailings and flotation foam are thickened to obtain underflow and overflow; The overflow is used as the heavy medium configuration clear liquid and returned to the heavy medium beneficiation.

6. The method for pretreating pyrrhotite-containing sulfide polymetallic ores according to claim 5, characterized in that: The bottom flow has a concentration of 30% to 35% and becomes the final selected ore.

7. The method for pretreating pyrrhotite-containing sulfide polymetallic ores according to claim 1, characterized in that: During magnetic separation, the magnetic field strength is 4000~6000Oe; And / or, calcium oxide is added during flotation and the pH value of the pulp is adjusted to 11-12.

8. The method for pretreating pyrrhotite-containing sulfide polymetallic ores according to claim 1, characterized in that: During flotation, a collector is added, wherein the collector is one or more of ethyl xanthate, isopropyl xanthate, and ethyl thiocyanate.

9. The method for pretreating pyrrhotite-containing sulfide polymetallic ores according to claim 1, characterized in that: The pyrrhotite content in the raw ore is higher than 10%.

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