Treatment method of low-grade oxidized ore

Abstract

The invention provides a treatment method of low-grade oxidized ore. The treatment method comprises the steps that low-grade minerals to be treated are subjected to ore grinding and / or mineral separation treatment, and treated oxidized minerals are obtained; the treated oxidized ore is subjected to low-temperature roasting, and roasted sand is obtained; carrying out post-treatment on the roasted product, wherein the post-treatment comprises acid leaching, purification and electrodeposition treatment; the low-grade minerals to be treated are carbonate type oxidized minerals, and the low-temperature roasting temperature is not higher than 850 DEG C. According to the dressing and smelting combined treatment process for the complex low-grade oxidized ore, carbonate type materials can be well treated, use of reducing agents and the like can be avoided, acid consumption and the content of organic matter in leachate are reduced, production operability and the recovery rate of valuable metal are improved, the production cost and energy consumption are effectively reduced, and the comprehensive utilization rate of resources is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of non-ferrous metal metallurgy, and particularly relates to a method for treating low-grade oxidized ore. Background Art

[0002] Zinc plays an important role in economic development. With the sharp increase in demand, the supply of sulfide ore resources has been seriously insufficient, and oxidized ore has become an important replacement. At present, medium and low-grade oxidized lead-zinc ore accounts for a quite large proportion, and zinc oxide deposits have been successively discovered in many places. For example, the reserves of the Lanping lead-zinc mine in Yunnan are very large, and the refractory oxidized lead-zinc ore accounts for one-third of the total reserves of the Lanping lead-zinc mine. Due to the complex mineral composition and high calcium and magnesium content, it is generally considered that the efficient utilization of this part of the ore is a major problem. At present, the refractory oxidized lead-zinc ore stored in Lanping has reached 38 million tons, with a comprehensive lead grade of about 1.50%, a comprehensive zinc grade of about 6.00%, and a lead + zinc metal content of 2.6 million tons. Zinc mainly exists in the form of carbonate, and part of it exists in the form of sulfide. The direct leaching of minerals has high acid consumption, low metal recovery rate, and difficult filtration. The inferred lead-zinc resources discovered in the Huoshaoyun lead-zinc mine in Xinjiang have reached 18.75 million tons, with an average lead + zinc grade of 31.8%. It is also a typical carbonate-type lead-zinc mine. The mining area is located in a remote area, and the transportation of raw and auxiliary materials is difficult, which brings difficulties to the development of the mine.

[0003] Currently, research work on the beneficiation and metallurgy of low-grade zinc oxide ore mainly includes the development and selection of reagents and the preferential flotation of minerals in the beneficiation aspect. In the smelting aspect, it mainly includes two categories: pyrometallurgy and hydrometallurgy. Pyrometallurgy mainly uses a rotary kiln or a fuming furnace for reduction volatilization (1000 - 1250 °C), and lead and zinc are produced in the form of zinc oxide fume dust. After leaching, it is incorporated into the traditional roasting-leaching system or separately purified to produce electrolytic zinc. However, 40% - 55% of anthracite or coke needs to be added during the reduction volatilization process, resulting in high energy consumption. Hydrometallurgy is divided into acid leaching and alkali leaching. Direct acid leaching mainly has problems such as high acid consumption, serious overflow, and difficult filtration, making the production operation difficult. Alkali leaching mainly uses ammonia water-ammonium carbonate or sodium hydroxide for leaching, but there are certain technical difficulties in solution treatment and it is not easy to combine with traditional processes. Sulfide is relatively difficult to leach during the direct leaching of minerals. The combination of beneficiation and smelting can effectively improve the recovery rate of sulfide and oxide and reduce acid consumption. However, when the selected zinc oxide ore is directly leached, the organic matter content is high, which is likely to cause problems such as burning of the electrolytic plate, and the grade of the selected ore is relatively low. It is mostly recommended to use the rotary kiln reduction volatilization method for treatment, which also has the problem of large consumption of anthracite or coke, high production cost, and serious environmental pollution. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides a method for treating low-grade oxidized ore. The method provided by the present invention for treating low-grade carbonate-type zinc oxide ore by a combined beneficiation and smelting process to recover valuable metals such as zinc, lead, and silver. In the smelting process, direct roasting is adopted to avoid the use of reducing agents, which can effectively reduce energy consumption, reduce the content of organic matter in the leaching solution, and improve the production operability and the recovery rate of valuable metals.

[0005] Specifically, the method for treating low-grade oxidized ore provided by the present invention includes the following steps: 1) Grinding and / or beneficiating the low-grade ore to be treated to obtain the treated oxidized ore.

[0006] 2) Subjecting the treated oxidized ore to low-temperature roasting to obtain roasted ore.

[0007] 3) Post-treating the roasted ore; the post-treatment includes acid leaching, purification, and electrowinning.

[0008] The low-grade ore to be treated is a carbonate-type oxidized ore, and the temperature of the low-temperature roasting is not higher than 850 °C.

[0009] In the present invention, aiming at the problems of low direct leaching recovery rate, high acid consumption, and high organic matter content in the oxidized ore produced after beneficiation for low-grade carbonate-type zinc oxide ore coexisting with sulfides and oxides, the oxidized ore (mainly composed of carbonate) produced by beneficiation in the present invention is directly roasted, and no reducing agent or oxidizing agent is added during the process. The method provided by the present invention for complex low-grade oxidized ore is ground, and the enriched oxidized ore is separated by beneficiation, and the enriched oxidized ore is directly roasted at a specific low temperature, and the roasted ore is acid-leached. This method can better target the treatment of carbonate-type materials, avoid the use of reducing agents, etc., reduce energy consumption and acid solution consumption, and greatly reduce the content of organic matter in the leaching solution. In addition, sulfide ore can also be treated by traditional smelting or pressure leaching process. At the same time, the method of the present invention can also directly treat other carbonate materials, which can greatly reduce the production cost and improve the comprehensive utilization rate of resources.

[0010] Preferably, the grade of the oxidized ore obtained by beneficiation treatment is not less than 10%, preferably 10% - 35%. The above minerals at the preferred grade can be better applicable to the treatment method of the present invention. During the beneficiation process, parameters such as metal recovery rate, oxidized ore grade, acid consumption of oxidized ore, and treatment cost need to be comprehensively evaluated.

[0011] Preferably, the ore to be treated includes one or more of carbonate-type zinc oxide ore, zinc carbonate smelting slag, carbonate-type copper ore, carbonate-type cobalt-nickel ore, and copper carbonate smelting slag.

[0012] Preferably, the ore to be treated is low-grade zinc oxide ore; preferably, zinc mainly exists in the form of carbonate and a small amount exists in the form of sulfide.

[0013] In some embodiments of the present invention, when the grade of the low-grade mineral to be processed is ≥ 10% and the acid consumption for leaching is low, ore dressing treatment may not be carried out. Preferably, after grinding treatment, it is directly subjected to the low-temperature roasting in step 2). When the content of alkaline gangue is high and the acid consumption is high, the gangue can be separated by flotation to increase the grade of the oxidized ore, and then low-temperature roasting is carried out.

[0014] Preferably, in step 2), the temperature of the low-temperature roasting is 150 - 850 °C, and the time is 0.5 - 5 h.

[0015] More preferably, in step 2), the temperature of the low-temperature roasting is 200 - 650 °C, preferably 400 - 450 °C; the time is 0.5 - 3 h, preferably 0.5 - 2 h. For example, 250, 300, 350, 400, 450, 500, 550, 600, 630 °C, etc., such as 0.8, 1, 1.2, 1.5, 2 h, etc.

[0016] In the present invention, the further preferred range of the low-temperature roasting temperature can better control the formation of oxides, promote the decomposition of carbonates, and the volatilization of organic substances, avoid the formation of minerals such as ferrites and silicates at high temperatures from reducing the leaching efficiency, and at the same time increase the grade of zinc, reduce the processing energy consumption and equipment investment.

[0017] Preferably, in step 1), the grinding treatment includes finely grinding 70% - 90% of the low-grade mineral to be processed to less than -0.074 mm.

[0018] Preferably, in step 1), ore dressing is also carried out by adding flotation reagents, and the flotation reagents include foaming agents and / or collectors. The types and addition amounts of foaming agents and collectors in the present invention can be set conventionally in the art.

[0019] Preferably, the foaming agent is selected from one or more of BK201, BK204, MIBC, and pine oil, and the addition amount of the foaming agent is 0 - 25 g / t; the collector is selected from one or more of butyl xanthate, amyl xanthate, ethyl thionocarbazide, aniline black medicine, 25# black medicine, BKBA, and BK418, and the addition amount of the collector is 50 - 200 g / t.

[0020] The present invention does not limit the specific ore dressing method, and the ore dressing can be carried out by conventional methods in the art.

[0021] Preferably, in step 1), in the low-grade mineral to be processed, when the proportion of the main metal sulfide ore > 10%, the sulfide ore, high-grade oxidized ore, and tailings are separated by ore dressing; when the proportion of the main metal sulfide ore ≤ 10%, the oxidized ore or sulfur-oxygen mixed ore and tailings are directly separated by flotation to increase the grade of the oxidized ore and reduce the gangue content.

[0022] Preferably, in step 1), treated oxidized ore, sulfide ore and tailings are obtained; the sulfide ore is treated by traditional boiling roasting or pressure leaching. In the present invention, sulfide ore and tailings are also obtained after ore dressing. Treating the sulfide ore by traditional roasting leaching or pressure leaching can be incorporated into the existing zinc smelting system for ore blending treatment, and finally electrolytic zinc is produced by electrowinning.

[0023] Preferably, in step 3), the acid leaching treatment uses concentrated sulfuric acid and / or waste electrolyte solution, the leaching temperature is 20-95 °C, the liquid-solid ratio is 2-10:1, and the leaching time is 0.5-6 h.

[0024] More preferably, the concentration of the concentrated sulfuric acid is 70%-99%, and the waste electrolyte solution is obtained by electrowinning treatment.

[0025] In the present invention, by treating the calcine with the above-mentioned concentrated sulfuric acid, etc., zinc can be recovered more effectively, the impurity content in the solution can be reduced by process control, while valuable metals such as lead and silver are enriched, and lead, silver, etc. are recovered from the smelting slag. By combining the ore dressing-smelting and low-temperature roasting-leaching processes, the acid consumption is reduced, the comprehensive metal recovery rate is increased, the influence of organic matter on electrowinning is reduced, the comprehensive utilization rate of resources is improved, the production cost is reduced, and the economic, environmental protection and social benefits of the enterprise are improved.

[0026] Preferably, it further includes purifying and removing impurities and electrowinning treatment of the leaching solution obtained by acid leaching treatment. Purifying and removing impurities mainly reduces the content of impurities such as copper, cadmium, cobalt and nickel in the zinc solution. The solution can be treated separately or jointly with the traditional roasting-leaching system.

[0027] The beneficial effects of the present invention are at least as follows: The present invention conducts low-temperature direct roasting treatment on oxidized ore, reduces production energy consumption and cost, improves the comprehensive recovery rate of valuable metals, overcomes multiple problems existing in the existing treatment methods, and has excellent comprehensive effects. The present invention provides a combined ore dressing and smelting treatment process for complex low-grade oxidized ore. The low-grade oxidized ore is ground, and the enriched oxidized ore is separated by ore dressing. The enriched oxidized ore is directly roasted at a specific low temperature, and sulfuric acid is added to the calcine for leaching, which is beneficial to the recovery of valuable metals such as zinc. This method can directly treat various carbonate materials, such as Yunnan Lanping lead-zinc ore and Xinjiang Huoshaoyun lead-zinc ore, can effectively reduce production costs and improve the comprehensive utilization rate of resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0029] Figure 1 This is the process flow diagram for the treatment of complex low-grade oxidized ore provided in Embodiment 1 of the present invention. Detailed implementation manners

[0030] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0031] In the ranges disclosed in the present invention, the endpoints and any values are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed in the present invention.

[0032] For those not specified with specific technologies or conditions in the embodiments of the present invention, they shall be carried out according to the technologies or conditions described in the literature in the field or according to the product specifications. For those devices, instruments, reagents, etc. not specified with the manufacturer, they are all conventional products that can be obtained through regular channels. The experimental reagents and raw materials involved are all commercially available products, and the reagents are all of analytical purity.

[0033] Embodiment 1 This embodiment provides a method for treating complex low-grade zinc oxide ore, and the process is as Figure 1As shown below, the specific steps are as follows (processing of low-grade oxidized ore - low-temperature roasting - leaching). The main components of the low-grade zinc oxide ore in this example are: Zn 4.64%, S 2.67%, Pb 0.78%, CaO 16.71%. Among them, more than 20% of the zinc exists in the form of sulfide ore, and the rest mainly exists in the form of smithsonite, i.e., zinc carbonate, etc. The acid consumption for direct leaching is high and the metal recovery rate is low. After beneficiation and separation of this ore, products such as zinc sulfide concentrate, zinc oxide ore and tailings are produced. The main components of the zinc sulfide concentrate are: Zn 23.70%, Pb 2.78%, and the main components of the zinc oxide ore are: Zn 18.98%, Pb 1.06%. The oxidized ore produced by beneficiation is directly subjected to sulfuric acid leaching, controlling the reaction temperature at 80°C, the reaction time at 2h, the end point pH = 1.5, the zinc leaching rate is 96.41%, the sulfuric acid consumption is 557 kg / t-ore. The addition of acid during the process is slow, serious overflow occurs, it takes a long time, and the organic matter content in the solution is high, which is likely to cause burning of the electrowinning plate. However, when the beneficiated oxidized ore is roasted at 450°C for 1h with a weight loss rate of 40%, and the roasted ore is subjected to sulfuric acid leaching under the same conditions, the zinc leaching rate is 97.13%, the sulfuric acid consumption is 483 kg / t-ore, and there are no bubbles produced during the process, the operation is relatively convenient, the organic matter content is greatly reduced, and the influence on electrowinning is avoided. The sulfide ore is sent to the traditional smelting process for ore blending treatment.

[0034] Example 2 This example provides a method for treating complex low-grade zinc oxide ore. The difference from Example 1 is that: the main components of the low-grade zinc oxide ore are: Zn 6.34%, S 3.89%, Pb 0.81%, CaO 27.20%. Among them, 23% of the zinc exists in the form of zinc sulfide, and 60% exists in the form of carbonate. After beneficiation, zinc sulfide ore, zinc oxide ore and tailings and other products are separated. The main components of the zinc oxide ore are Zn 11.78%, Pb 0.81%. The high-grade zinc oxide ore produced by beneficiation is roasted at 600°C for 1h, and sulfuric acid is added for leaching at a reaction temperature of 80°C. The zinc leaching rate is 97.67%, the sulfuric acid consumption is 823.50 kg / t ore, and there are no obvious bubbles produced during the acid addition process.

[0035] Comparative Example 1 The main components of a certain zinc oxide ore used in this comparative example are: Zn 35.35%, Pb 2.24%, CaO 8.71%. The ore is added with 40% anthracite coal and roasted at 1250 °C for 2 h. The volatilization rates of lead and zinc are both above 99%. The produced zinc oxide soot contains 55% - 60% zinc. The zinc oxide soot is sold externally or zinc is recovered by leaching. When the calcium and magnesium contents in the oxidized ore are relatively low, the ore is directly roasted at 450 °C for 1 h, with a loss-on-ignition rate of 35%. The zinc grade in the roasted ore reaches over 55%, and the lead grade reaches 3.45%. The reaction temperature and the dosage of the reducing agent (anthracite coal) in this comparative example are greatly increased, and it causes pollution to the environment. When the calcium and magnesium contents in the oxidized ore are relatively high, the gangue minerals can be separated by reverse flotation to reduce the final acid consumption for leaching.

[0036] Example 3 This example provides a method for treating complex low-grade zinc oxide ore. The difference from Example 1 is that: the roasting temperature of the oxidized ore after beneficiation in step 1) is changed to 600 °C, and the roasted ore is subjected to sulfuric acid leaching at 80 °C and an end-point pH of 1.5 for 2 h. The zinc leaching rate is 95.96%, and the sulfuric acid consumption is 524 kg / t-ore.

[0037] Example 4 This example provides a method for treating complex low-grade zinc oxide ore. The difference from Example 1 is that: the roasting temperature of the oxidized ore after beneficiation in step 1) is changed to 800 °C, and the roasted ore is subjected to sulfuric acid leaching at 80 °C and an end-point pH of 1.5 for 2 h. The zinc leaching rate is 81.54%, the sulfuric acid consumption is 438.33 kg / t-ore, the zinc leaching rate is significantly reduced, and the zinc content in the residue is relatively high.

[0038] Example 5 This example provides a method for treating complex low-grade zinc oxide ore. The difference from Example 1 is that: the roasting temperature of the oxidized ore after beneficiation in step 1) is changed to 500 °C, and the roasted ore is subjected to sulfuric acid leaching at 80 °C and an end-point pH of 1.5 for 2 h. The zinc leaching rate is 96.92%, and the sulfuric acid consumption is 486.42 kg / t-ore.

[0039] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing examples, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the present invention in each example.

Claims

1. A method for treating low-grade oxide ore, characterized in that: The following steps are involved: 1) Grinding and / or beneficiating the low-grade mineral to be processed to obtain processed oxidized ore; 2) roasting the treated oxidized ore at low temperature to obtain roasted sand; 3) post-processing the roasted sand; The post-treatment includes acid leaching, purification and electrowinning; the low-grade mineral to be treated is a carbonate-type oxide mineral, and the temperature of the low-temperature roasting is not higher than 850°C.

2. The processing method according to claim 1, characterized in that: The mineral to be processed includes one or more of carbonate-type zinc oxide ore, carbonate zinc smelting slag, carbonate-type copper ore, carbonate-type cobalt-nickel ore, and carbonate copper smelting slag.

3. The processing method according to claim 1 or 2, characterized in that: In step 2), the low-temperature calcination temperature is 150-850° C. and the time is 0.5-5 h.

4. The processing method according to claim 3, characterized in that: In step 2), the low-temperature calcination is carried out at a temperature of 200-650° C. and a time of 0.5-3 h.

5. The processing method according to any one of claims 1 to 4, characterized in that: In step 1), the ore grinding includes grinding 70% to 90% of the low-grade mineral to be processed to a particle size of less than -0.074 mm.

6. The processing method according to any one of claims 1 to 5, characterized in that: In step 1), flotation reagents are also added to carry out mineral separation, and the flotation reagents include frothers and / or collectors.

7. The processing method according to any one of claims 1 to 6, characterized in that: In step 1), in the low-grade mineral to be processed, when the proportion of main metal sulfide ore is greater than 10%, sulfide ore, oxide ore and tailings are separated by beneficiation; when the proportion of main metal sulfide ore is ≤10%, flotation of oxide ore and / or sulfide-oxygen mixed ore and tailings is adopted.

8. The processing method according to any one of claims 1 to 7, characterized in that: In step 1), treated oxide ore, sulfide ore and tailings are obtained; the sulfide ore is treated by conventional fluidized bed roasting or pressure leaching.

9. The processing method according to any one of claims 1 to 8, characterized in that: In step 3), concentrated sulfuric acid and / or waste electrolyte are used for acid leaching, the leaching temperature is 20-95° C., the liquid-to-solid ratio is 2-10:1, and the leaching time is 0.5-6 h.

10. The processing method according to any one of claims 1 to 9, characterized in that: The leaching solution obtained by the acid leaching treatment is purified, impurities are removed and electrolytically treated.

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