Method and system for comprehensive utilization of high-magnesium nickel sulfide ore by low-temperature oxygen enrichment method

Abstract

The application discloses a method and system for comprehensively utilizing high-magnesium nickel sulfide ore by a low-temperature oxygen-rich method. The method comprises the following steps: obtaining pre-leaching residue by pre-leaching and magnesium removal with high-magnesium nickel sulfide ore as raw material; obtaining activated ore slurry by mechanically activating the pre-leaching residue; and obtaining a nickel-containing leaching solution by low-temperature oxygen-rich leaching of the activated ore slurry. The application has wide application range, is simple and reliable, easy to control, and low in investment cost, and can convert metals into corresponding products, so that high-magnesium nickel sulfide concentrate can be treated at low cost and high efficiency.

Description

Technical Field

[0001] This invention relates to the field of nickel sulfide ore processing technology, and in particular to a method and system for the comprehensive utilization of high-magnesium nickel sulfide ore using a low-temperature oxygen-enriched method. Background Technology

[0002] Nickel sulfide ore is characterized by its complex composition, low grade, abundant associated gangue, and status as a refractory material, making its processing relatively complex. Currently, there are two main production processes:

[0003] One approach is a combined pyrometallurgical and hydrometallurgical process. First, nickel sulfide ore is pyrometallurgically smelted and blown to concentrate valuable metals into nickel matte. Then, nickel, copper, and cobalt in the high-nickel matte are separated and refined. This combined process suffers from drawbacks such as a lengthy process flow, low direct metal recovery rate, and high investment costs. Furthermore, and most importantly, the inventors of this application have discovered that when processing high-magnesium nickel sulfide ore, this combined process requires further magnesium reduction treatment of the ore before pyrometallurgical smelting. Therefore, this combined process cannot directly process high-magnesium nickel sulfide ore.

[0004] Second, the wet direct leaching process. Utilizing the differences in the reaction behavior of various substances in nickel sulfide ore under different conditions in sulfuric acid solution, multi-stage atmospheric and pressurized leaching is carried out. Nickel, cobalt, magnesium, etc. enter the leaching solution, while iron, sulfur, etc. enter the leaching residue. The leaching solution is then purified, extracted, and refined to obtain refined products of each metal. Compared with the above-mentioned combined pyrometallurgical and wet process, this wet process has advantages such as a shorter process flow and lower investment cost. However, the inventors of this application have found through research that the wet process still has the following problems: (1) Magnesium in the raw material is not pre-removed before leaching. When processing high-magnesium nickel sulfide ore, all the magnesium enters the leaching solution during the leaching process and enters the extraction process as impurity ions, resulting in an increase in the number of extraction stages and increased operational difficulty. (2) The raw material is directly leached without activation. To ensure the leaching rate, leaching needs to be carried out under high acid, high temperature, and high pressure, which places high demands on the operation and equipment materials and consumes a lot of energy. High magnesium can also cause scaling during the leaching process. (3) High-magnesium nickel sulfide concentrate has a high sulfur content. In the high-temperature one-step leaching process, most of the sulfur is oxidized to sulfuric acid, making it difficult to achieve a balance between heat, sulfuric acid, and sulfur. A large amount of neutralizing agent is required. At the same time, most of the impurity ions are leached out, resulting in high pressure for subsequent impurity removal.

[0005] Based on the above findings, the inventors of this application, through further research, have obtained the process for the comprehensive utilization of high-magnesium nickel sulfide ore using the low-temperature oxygen-enriched method described in this application. Summary of the Invention

[0006] According to one embodiment of the present invention, the objective is to provide a method and system for the comprehensive utilization of high-magnesium nickel sulfide ore using a low-temperature oxygen-enriched process. This objective can be achieved through the following technical solutions:

[0007] According to one aspect of the present invention, a method for the comprehensive utilization of high-magnesium nickel sulfide ore using a low-temperature oxygen-enriched process is provided, comprising: using high-magnesium nickel sulfide ore as raw material, pre-leaching to remove magnesium, obtaining a magnesium-containing pre-leaching solution and a pre-leaching residue; mechanically activating the pre-leaching residue by ball milling to obtain an activated slurry; leaching the activated slurry using a low-temperature oxygen-enriched process to obtain a nickel-containing leaching solution and a leaching residue; and post-processing the nickel-containing leaching solution to convert the metal therein into corresponding products.

[0008] Optionally, during pre-leaching for magnesium removal, sulfuric acid is used as the leaching reagent with a concentration of 60 g / L to 100 g / L; during mechanical activation, wet ball milling is used, with a ball-to-material ratio of 5:1 to 35:1 and a milling intensity of 5 G to 25 G; during low-temperature oxygen-enriched leaching, the reaction temperature is controlled at 100 °C to 140 °C.

[0009] Optionally, during pre-leaching for magnesium removal, sulfuric acid is used as the leaching reagent, and the liquid-solid separation is performed after stirring and leaching at room temperature for 0.5h to 3h; wherein, the concentration of sulfuric acid is 80g / L to 100g / L; the amount of sulfuric acid added is determined according to the magnesium oxide content of the high magnesium nickel sulfide ore, and the liquid-solid ratio is controlled to be 2:1 to 5:1.

[0010] Optionally, after pre-leaching to remove magnesium, the leaching rate of magnesium oxide is ≥90%, and the leaching rates of nickel, cobalt, and copper in the magnesium-containing pre-leaching solution are all <5%, and the leaching rate of iron is <7%.

[0011] Optionally, mechanical activation is performed using wet ball milling, wherein the ball-to-material ratio is 5:1 to 35:1, the milling intensity is 5G to 25G, and the milling time is 0.5h to 5h. Preferably, the ball-to-material ratio is 25:1 to 35:1, and the milling intensity is 15G to 25G.

[0012] Optionally, during low-temperature oxygen-enriched leaching, oxygen or oxygen enrichment is introduced as the leaching oxidant, the reaction temperature is controlled at 100℃~130℃, the reaction pressure is 0.3MPa~1.0MPa, the liquid-solid ratio is 3:1~6:1, and the liquid-solid separation is performed after stirring and oxygen-enriched leaching for 0.5h~5h.

[0013] Optionally, a nickel-containing leachate is obtained by low-temperature oxygen-enriched leaching, wherein the leaching rate of nickel is ≥95%, the leaching rate of cobalt is ≥95%, the leaching rate of copper is ≥90%, and the leaching rate of iron is <40%.

[0014] Optionally, the high-magnesium nickel sulfide ore contains 5% to 15% nickel and 6% to 20% magnesium oxide.

[0015] Optionally, the nickel-containing leaching solution is used for post-treatment, including: sequentially removing copper, removing iron, and extracting nickel and cobalt.

[0016] Optionally, during copper removal, an iron powder replacement method is used to remove copper from the nickel-containing leaching solution to obtain sponge copper and copper-removed solution; the amount of iron powder added is 1 to 3 times the theoretical amount of copper, and the mixture is stirred at room temperature for 0.5 to 2 hours.

[0017] Optionally, during iron removal, the goethite method is used to remove iron from the copper-removed liquid, resulting in iron-removed liquid and iron slag. The iron removal process using the goethite method for the copper-removed liquid includes: adjusting the pH of the copper-removed liquid to 3-4, using nickel carbonate as a pH adjuster; introducing oxygen or oxygen-enriched solution as an iron-removing oxidant; controlling the reaction temperature at 70℃-90℃; stirring; and separating the liquid and solid after reacting for 2-10 hours.

[0018] Optionally, the iron-removed liquid is extracted to obtain magnesium sulfate, cobalt sulfate, and nickel sulfate products, and the magnesium sulfate is sent to evaporation crystallization; wherein, during extraction, P204 is used to extract nickel and P507 is used to extract cobalt.

[0019] Optionally, the method further includes: using sodium carbonate to precipitate nickel in the iron removal liquid to generate nickel carbonate and sodium sulfate, and sending the nickel carbonate as a pH adjuster in the goethite process to the iron removal step.

[0020] Optionally, the method further includes: neutralizing the magnesium-containing pre-leaching solution with a neutralizing agent, separating the solid and liquid, evaporating and crystallizing to obtain magnesium sulfate product, and sending the neutralized residue obtained from neutralization into a low-temperature oxygen-enriched leaching step; wherein the neutralizing agent is one or two of magnesium oxide and magnesium carbonate.

[0021] Optionally, the method further includes: flotation of the leaching residue to obtain sulfur concentrate and tailings.

[0022] Optionally, the method further includes: pyrometallurgically treating the tailings and iron slag after iron removal to obtain iron ore products, and using the sulfur dioxide flue gas generated to produce acid as a leaching reagent for pre-leaching demagnesification.

[0023] According to another aspect of the present invention, a system for the comprehensive utilization of high-magnesium nickel sulfide ore using a low-temperature oxygen-enriched method is provided, comprising:

[0024] The pre-leaching demagnesification unit is used to pre-leach demagnesize high-magnesium nickel sulfide ore as raw material to obtain magnesium-containing pre-leaching solution and pre-leaching residue.

[0025] Mechanical activation device, including ball mill, is used to mechanically activate the pre-leaching residue obtained from the pre-leaching demagnesification device to obtain activated slurry;

[0026] The low-temperature oxygen-enriched leaching device is used to leach activated slurry using a low-temperature oxygen-enriched method to obtain nickel-containing leaching solution and leaching residue.

[0027] A nickel leaching solution post-treatment device is used to post-treat nickel leaching solutions, converting various metals into corresponding products.

[0028] Optionally, the pre-impregnation magnesium removal device includes a tank, a stirrer, and a first filter device. Sulfuric acid is added to the tank as a leaching reagent, with a sulfuric acid concentration of 60 g / L to 100 g / L. During pre-impregnation magnesium removal, the liquid-to-solid ratio is 2:1 to 5:1, and the stirring and leaching is carried out at room temperature for 0.5 h to 3 h.

[0029] Optionally, the mechanical activation device uses a wet grinding method for its ball mill, with a ball-to-material ratio of 5:1 to 35:1, a grinding intensity of 5G to 25G, and a grinding time of 0.5h to 5h.

[0030] Optionally, the low-temperature oxygen-enriched leaching device includes a vertical high-pressure reactor and a second filtration device. The vertical high-pressure reactor has an inlet for leaching oxidant, the temperature inside the reactor is 100℃~130℃, the pressure is 0.3MPa~1.0MPa, and the liquid-solid ratio during leaching is 3:1~6:1, with stirring and oxygen-enriched leaching for 0.5h~5h.

[0031] Optionally, the nickel-containing leaching solution post-treatment device includes: a copper removal unit, a goethite iron removal unit, a third filtration device, and an extraction unit arranged sequentially; wherein, the copper removal unit is used to remove copper from the nickel-containing leaching solution using an iron powder replacement method to obtain sponge copper and copper-removed solution; the goethite iron removal unit is used to remove iron from the copper-removed solution using a goethite method, and after filtration by the filtration unit, iron-removed solution and iron slag are obtained; the extraction unit uses P204 to extract nickel and P507 to extract cobalt to obtain nickel-cobalt products;

[0032] Optionally, the nickel-containing leaching solution post-treatment device further includes: a nickel precipitation device, which is connected to the filtration unit and the goethite iron removal unit respectively, for precipitating nickel in the iron removal solution using sodium carbonate to generate nickel carbonate and sodium sulfate, and sending the nickel carbonate into the goethite iron removal unit as a pH adjuster for the goethite process.

[0033] Optionally, the system further includes: a magnesium-containing pre-leaching solution treatment device connected to the first filtration device, the magnesium-containing pre-leaching solution treatment device including a neutralization unit, a fourth filtration device, and an evaporation crystallization unit arranged in sequence, wherein the fourth filtration device is also connected to a low-temperature oxygen-enriched leaching device for sending the neutralized residue obtained from the neutralization unit into the low-temperature oxygen-enriched leaching device for treatment.

[0034] Optionally, the system further includes a flotation unit connected to a second filtration device for flotating the separated leaching residue to obtain sulfur concentrate and tailings.

[0035] Optionally, the system further includes: a pyrometallurgical processing unit, which is connected to the flotation unit and the third filtration device, respectively, for pyrometallurgical processing of tailings and iron slag after iron removal to obtain iron ore products; the pyrometallurgical processing unit is also connected to an acid-producing device, which is connected to a pre-leaching demagnesium removal device, for producing sulfur dioxide flue gas generated during the pyrometallurgical processing into acid and sending it to the pre-leaching demagnesium removal device as a leaching reagent.

[0036] Beneficial Effects: According to one embodiment of the present invention, high-magnesium nickel sulfide concentrate is used as raw material. First, it undergoes pre-leaching to remove magnesium, followed by mechanical activation. Then, based on the activated slurry, a low-temperature oxygen-enriched leaching method is used to obtain a nickel-containing leachate. This nickel-containing leachate can be further processed, such as through copper removal, iron removal, and extraction, to obtain refined products containing various metals. The above embodiment has low requirements for raw materials, a wide range of process applicability, and can process high-magnesium nickel sulfide ore. The processing method is simple, reliable, and easy to control. Moreover, the investment cost is low, and the process flow is short, achieving low-cost and high-efficiency processing of high-magnesium nickel sulfide concentrate. The above embodiment is relatively flexible, with few restrictions on product formulations, and can meet a wide range of market demands.

[0037] In addition, in the optional scheme, intermediate products such as magnesium removal solution, leaching residue, copper slag, and iron slag can be processed into products such as magnesium sulfate, sulfur concentrate, sponge copper, and iron ore, thereby converting all metals into corresponding products, realizing the comprehensive utilization of high magnesium sulfide nickel ore, bringing high economic benefits and high metal recovery rate. Attached Figure Description

[0038] Figure 1 This is a process flow diagram of a method for the comprehensive utilization of high-magnesium nickel sulfide ore using a low-temperature oxygen-enriched method in one embodiment of the present invention.

[0039] Figure 2 This is a schematic diagram of the connection structure of a system for the comprehensive utilization of high-magnesium nickel sulfide ore using a low-temperature oxygen-enriched method according to an embodiment of the present invention. Detailed Implementation

[0040] The technical solution of the present invention will be clearly and completely described below with reference to embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0041] Figure 2 The diagram schematically illustrates the connection structure of a system for the comprehensive utilization of high-magnesium nickel sulfide ore using a low-temperature oxygen-enriched method according to an embodiment of the present invention. For example... Figure 2As shown, the system includes a pre-leaching demagnesification unit, a mechanical activation unit, a low-temperature oxygen-enriched leaching unit, and a nickel-containing leaching solution post-treatment unit. When using this system for the comprehensive utilization of high-magnesium nickel sulfide ore using the low-temperature oxygen-enriched method, the ore is used as raw material. First, it undergoes pre-leaching demagnesification, followed by mechanical activation and low-temperature oxygen-enriched leaching to obtain a nickel-containing leaching solution. This solution is then subjected to post-treatment processes such as copper removal, iron removal, and extraction to convert the metals into corresponding products. The system has advantages such as low requirements for raw materials, wide applicability, excellent suitability for high-magnesium nickel sulfide ore, simplicity, reliability, easy process control, and low investment cost, achieving low-cost and high-efficiency processing of high-magnesium nickel sulfide ore.

[0042] In addition, such as Figure 2 As shown, the system may also include a magnesium pre-leaching solution treatment device, a flotation unit, and a pyrometallurgical treatment unit, used to process intermediate products such as magnesium removal solution, leaching residue, copper slag, and iron slag into products such as magnesium sulfate, sulfur concentrate, sponge copper, and iron ore, thereby converting all metals into corresponding products and further improving economic efficiency.

[0043] Figure 1 The diagram illustrates a process flow chart of a low-temperature oxygen-enriched method for the comprehensive utilization of high-magnesium nickel sulfide ore according to an embodiment of the present invention. Figure 1 As shown, this embodiment specifically includes the following steps:

[0044] Step S10 involves using high-magnesium nickel sulfide concentrate as raw material, pre-leaching to remove magnesium, followed by solid-liquid separation to obtain magnesium-containing pre-leaching solution and pre-leaching residue. The pre-leaching and magnesium removal device includes a tank, a stirrer, and a first filter. The raw material, high-magnesium nickel sulfide concentrate, is a sulfide ore with a nickel content ranging from 5% to 15% and a magnesium oxide content ranging from 6% to 20%, such as 6%, 10%, 15%, 18%, and 20%. Other metals may include one or more of copper, iron, zinc, cobalt, and rare and precious metals, and are not limited to the listed items. This method has low requirements for raw materials, a wide range of applications, and is highly suitable for high-magnesium nickel sulfide ore.

[0045] By pre-leaching nickel sulfide ore, magnesium is separated before oxygen-enriched leaching, avoiding the difficulty of subsequent extraction caused by a large amount of magnesium entering the process system. This method is particularly suitable for high-magnesium nickel sulfide ores that are difficult to process with current processes. At the same time, the amount of neutralizing agent used in the subsequent magnesium-containing pre-leaching solution treatment is relatively small, reducing the pressure on the process to remove impurities.

[0046] In addition, in a preferred embodiment, during pre-leaching for magnesium removal, sulfuric acid is used as the leaching reagent, with a sulfuric acid concentration of 60 g / L to 100 g / L, preferably 80 g / L to 100 g / L. The sulfuric acid is added according to the magnesium oxide content of the high-magnesium nickel sulfide ore, with a liquid-to-solid ratio of 2:1 to 5:1. The mixture is stirred at room temperature and leached for 0.5 h to 3 h. The liquid and solid components are separated using a first filtration device to obtain a pre-leaching solution containing magnesium and a pre-leaching residue.

[0047] By using sulfuric acid of the above concentration as the leaching reagent for pre-leaching demagnesium removal, and by optimizing the liquid-solid ratio and leaching time, the leaching rate of magnesium oxide was improved, thereby effectively preventing magnesium from entering subsequent processes and reducing the pressure of subsequent impurity removal. When using sulfuric acid of the preferred concentration (80 g / L to 100 g / L) for pre-leaching demagnesium removal, the leaching rate of magnesium oxide was ≥90%, the leaching rate of nickel was <5%, the leaching rate of cobalt was <5%, the leaching rate of copper was <5%, and the leaching rate of iron was <7%.

[0048] In an optional embodiment, a magnesium-containing pre-leaching solution treatment device is used to neutralize the magnesium-containing pre-leaching solution, perform solid-liquid separation, and evaporate and crystallize to obtain magnesium sulfate product. The magnesium-containing pre-leaching solution treatment device is connected to a first filtration device and includes a neutralization unit, a fourth filtration device, and an evaporation and crystallization unit arranged sequentially; wherein the fourth filtration device is also connected to a low-temperature oxygen-enriched leaching device. The pre-acidification solution is the magnesium-containing pre-leaching solution neutralization, in which the neutralizing agent is magnesium oxide, magnesium carbonate, or a combination of both, and magnesium oxides that do not introduce new impurities into the system. Depending on the type of impurities and the final production requirements of the magnesium salt, one-step impurity removal, multi-step impurity removal, and solution concentration steps can be used.

[0049] For example, the treatment of magnesium-containing pre-leaching solution may include the following steps: 1) adding a neutralizing agent to the magnesium-containing pre-leaching solution for neutralization, filtering using a fourth filtration device to obtain a magnesium sulfate solution and filter residue, i.e., neutralization residue. The neutralizing agent is magnesium oxide. 2) further evaporating and crystallizing the magnesium sulfate solution in an evaporation crystallization unit to obtain magnesium sulfate product, and adding the neutralization residue to the oxygen-enriched leaching process. The neutralization residue produced in the neutralization process mainly consists of hydroxides of nickel, cobalt, copper, iron, etc. Adding the neutralization residue to the oxygen-enriched leaching process avoids the loss of valuable metals and further improves the metal recovery rate.

[0050] Step S20 involves mechanically activating the pre-leaching residue using ball milling to obtain activated slurry. Mechanical force alters the material properties, improving ore leaching performance and creating conditions for subsequent selective leaching. This also allows leaching to proceed under mild conditions, specifically oxygen-enriched leaching at low temperatures.

[0051] Furthermore, in a preferred embodiment, mechanical activation is performed using wet ball milling, wherein the ball-to-material ratio is 5:1 to 35:1, the ball milling intensity is 5G to 25G, and the ball milling time is 0.5h to 5h.

[0052] By using the above-mentioned wet ball milling to activate the pre-leached residue after magnesium removal, and by controlling the ball-to-material ratio, ball milling intensity, and ball milling time, the ore leaching performance can be further improved. This allows for oxygen-enriched leaching at a low temperature of no more than 140℃, with a high leaching rate.

[0053] Step S30: The activated slurry is leached using a low-temperature oxygen-enriched method, followed by solid-liquid separation to obtain a nickel-containing leaching solution and leaching residue. The low-temperature oxygen-enriched leaching device is used, which includes a vertical autoclave and a second filtration device. The vertical autoclave has an inlet for the leaching oxidant.

[0054] The activated slurry obtained from the ball milling activation step can be selectively leached under relatively low temperature conditions, allowing nickel, cobalt, and copper to enter the leaching solution, while iron and sulfur remain in the leaching residue. This results in a readily treatable solution containing valuable metals (i.e., a nickel-containing leaching solution), thus reducing the pressure on subsequent processing. This method ensures the leaching rate of valuable metals, realizes the resource utilization of sulfur, inhibits sulfation, reduces the use of neutralizing agents, and minimizes the pressure on subsequent processing.

[0055] Furthermore, in a preferred embodiment, during low-temperature oxygen-enriched leaching, oxygen or oxygen enrichment is introduced as the leaching oxidant, the reaction temperature is controlled at 100℃~140℃, more preferably 100℃~130℃, the reaction pressure is 0.3MPa~1.0MPa, the liquid-solid ratio is 3:1~6:1, stirring is performed, oxygen-enriched leaching is carried out for 0.5h~5h, and liquid-solid separation is performed to obtain leachate and leaching residue.

[0056] By employing a low-temperature oxygen-enriched leaching method on the ball-milled activated slurry and controlling the leaching temperature, pressure, liquid-to-solid ratio, and leaching time, the leaching rates of nickel, cobalt, and copper were significantly improved. Furthermore, controlling the oxygen-enriched leaching temperature within the reaction range of 100℃–130℃ further reduced the iron content in the leachate; specifically, the leaching rates of nickel, cobalt, and copper were ≥95%, ≥95%, and <40%, respectively.

[0057] Step S40 involves post-processing the nickel-containing leaching solution to convert the metals therein into the corresponding products. The nickel-containing leaching solution obtained through steps S10 to S30 is an easily processed solution containing valuable metals. Post-processing based on this nickel-containing leaching solution reduces the post-processing pressure while ensuring the leaching rate of valuable metals.

[0058] In an optional embodiment, a nickel-containing leaching solution post-treatment device is used to post-treat the nickel-containing leaching solution. This device includes a copper removal unit, a goethite iron removal unit, a third filtration device, and an extraction unit arranged sequentially. The copper removal unit is used for copper removal by iron powder displacement, the goethite iron removal unit is used for iron removal by the goethite method, and the extraction unit is used for nickel-cobalt extraction. Iron powder displacement copper removal, goethite iron removal, and nickel-cobalt extraction are all mature processes and are performed using conventional methods in the art. For example, the post-treatment may specifically include the following steps:

[0059] Step S41 involves copper removal from the nickel-containing leaching solution via displacement. Further, an iron powder displacement method is used to remove copper from the nickel-containing leaching solution, yielding crude sponge copper and a copper-removed solution. The amount of iron powder added is 1–3 times the theoretical amount of copper. The mixture is stirred at room temperature for 0.5–2 hours, followed by solid-liquid separation to obtain the copper-removed solution and crude sponge copper. By employing displacement copper removal in the nickel-containing leaching solution and simultaneously controlling the amount and time of iron powder addition, the copper recovery rate is improved; the copper displacement recovery rate is ≥99%, and the obtained crude sponge copper contains ≥40% copper.

[0060] Step S42 involves removing iron from the copper-removed liquid using the goethite method. Further, the goethite method for iron removal from the copper-removed liquid includes: adjusting the pH of the solution to 3-4, using nickel carbonate as the pH adjuster; introducing oxygen or oxygen-enriched solution as the iron removal oxidant; controlling the reaction temperature at 70℃-90℃; stirring; reacting for 2-10 hours; and separating the liquid and solid to obtain the iron-removed liquid and iron slag. The iron slag contains ≥55% iron. By using the goethite method to remove iron from the copper-removed liquid, while simultaneously optimizing the solution pH and controlling the reaction temperature and time, the iron removal rate is improved, and the nickel-iron loss rate is reduced. This ensures that the vast majority of valuable nickel and cobalt metals enter the iron-removed liquid, thereby guaranteeing the subsequent recovery rate of valuable metals such as nickel and cobalt. The amount of iron slag is approximately 0.55 t / m³. 3 The iron removal rate is ≥99%, the nickel loss rate is <3%, and the cobalt loss rate is <3%. After iron removal, the nickel concentration in the liquid is 15 g / L to 25 g / L, the cobalt concentration is 0.2 g / L to 1.5 g / L, and the iron concentration is <0.02 g / L.

[0061] Step S43 involves extracting the iron-removed liquid to obtain cobalt sulfate and nickel sulfate products. During extraction, P204 is used for nickel extraction and P507 for cobalt extraction to improve the nickel-cobalt extraction rate.

[0062] In addition, the magnesium sulfate obtained after extraction is sent to the evaporation and crystallization unit of the magnesium pre-impregnation solution treatment device for evaporation and crystallization to obtain magnesium sulfate product.

[0063] Furthermore, by employing a nickel precipitation device, the liquid after iron removal can be further precipitated with sodium carbonate to produce nickel carbonate and sodium sulfate. The nickel carbonate can then be used as a pH adjuster in the goethite process and fed into the iron removal step, achieving comprehensive utilization and reducing costs. Both the sodium sulfate and the extracted sodium sulfate can be sold as products.

[0064] In an optional embodiment, a flotation unit is used to float the leaching residue generated in step S30 to obtain a sulfur concentrate product for sale, while simultaneously generating tailings. The sulfur concentrate product obtained by flotation of the leaching residue contains ≥50% sulfur.

[0065] Furthermore, a pyrometallurgical processing unit is used to mix the tailings with the iron slag obtained in step S42, add solvents and natural gas, etc., for pyrometallurgical smelting to obtain iron ore products; at the same time, the sulfur dioxide flue gas generated during the pyrometallurgical processing is sent to the acid production unit for acid production treatment, and then used as a leaching reagent in the pre-leaching demagnesification process.

[0066] Furthermore, when performing solid-liquid separation in this application, the separation methods include: thickening separation, sedimentation separation, centrifugal separation, adsorption separation, cyclone separation, and pressure filtration, and are not limited to the mentioned liquid-solid separation methods. The equipment used, i.e., the filtration device, includes thickeners, plate and frame filter presses, vertical filter presses, sedimentation tanks, centrifuges, adsorption columns, and cyclones, and is not limited to the mentioned separation equipment.

[0067] In some embodiments described above, high-magnesium nickel sulfide concentrate is used as raw material. First, it undergoes pre-leaching to remove magnesium, followed by mechanical activation and leaching using a low-temperature oxygen-enriched method to obtain a readily treatable solution containing valuable metals, namely a nickel-containing leachate. Based on this nickel-containing leachate, refined products of various metals can be obtained through copper removal, iron removal, and extraction. Furthermore, intermediate products such as the magnesium-containing pre-leaching solution, leaching residue, copper slag, and iron slag are used to produce products such as magnesium sulfate, sulfur concentrate, sponge copper, and iron ore. This process has a wide range of applications, is simple and reliable, easy to control, and has low investment costs. It converts all metals into corresponding products, achieving low-cost and high-efficiency processing of high-magnesium nickel sulfide concentrate.

[0068] In some of the embodiments described above, this application also has the following advantages and beneficial effects:

[0069] (1) Before selective leaching, magnesium in the raw material is pre-leached and separated to reduce the amount of magnesium entering the subsequent leaching process, reduce the load on subsequent processing, and shorten the production process of magnesium as a product. This is especially useful for nickel sulfide ores with high magnesium content, such as not less than 6%.

[0070] (2) A mechanical activation process was adopted to treat the material and change its properties, thus providing a guarantee for achieving low-temperature oxygen-enriched leaching. Furthermore, a wet ball milling process was adopted for activation, which further improved the oxygen-enriched leaching efficiency.

[0071] (3) High magnesium nickel sulfide concentrate has a high sulfur content. High-temperature one-step leaching makes it difficult to achieve a balance of heat, sulfuric acid and sulfur elements. This application adopts mechanical activation to achieve low-temperature leaching, which not only ensures the leaching rate of valuable metals, but also realizes the resource utilization of sulfur elements, inhibits sulfation, and reduces the use of neutralizing agents.

[0072] (4) Based on the previous process, the present invention obtains a solution containing valence metal that can be easily processed, thereby reducing the pressure of subsequent processing. At the same time, it uses a low-cost and short process flow to prepare products that can generate economic benefits.

[0073] (5) Based on the nickel-containing leachate obtained by pre-leaching demagnesium removal-mechanical activation-low temperature oxygen-enriched leaching, crude sponge copper, nickel sulfate, cobalt sulfate, iron ore and other products can be obtained by sequentially removing copper, removing iron and extracting. The process is simple, the recovery rate of each metal is high, and it has high economic benefits.

[0074] (6) Based on the pre-leaching demagnesification-mechanical activation-low temperature oxygen-enriched leaching, combined with magnesium-containing pre-leaching solution treatment, leaching slag flotation treatment, iron slag pyrometallurgical treatment, etc., all metals of the mineral are converted into corresponding products, realizing the comprehensive utilization of high magnesium sulfide nickel ore, with low investment cost, and realizing low-cost and high-efficiency processing of high magnesium sulfide nickel concentrate.

[0075] The technical solutions in this application will be further described below with reference to specific embodiments:

[0076] The raw material used in Examples 1-10 is nickel sulfide ore, and its main elemental composition is shown in Table 1.

[0077] Table 1. Main elemental composition of nickel sulfide ore raw materials

[0078] Nickel sulfide ore Ni Co Cu Fe S Mg ％ 8.5 0.4 1.9 40.1 35.7 5.2

[0079] Example 1

[0080] For 1000g of nickel sulfide ore in Table 1, a stirred tank was used, with the liquid-to-solid ratio controlled at 3:1 and the sulfuric acid concentration at 60g / L. The leaching was carried out at room temperature for 2 hours, and the leaching results are shown in Table 2.

[0081] Example 2

[0082] For 1000g of nickel sulfide ore in Table 1, a stirred tank was used, with the liquid-to-solid ratio controlled at 3:1 and the sulfuric acid concentration at 80g / L. The leaching was carried out at room temperature for 2 hours, and the leaching results are shown in Table 2.

[0083] Example 3

[0084] For 1000g of nickel sulfide ore in Table 1, a stirred tank was used, with the liquid-to-solid ratio controlled at 3:1 and the sulfuric acid concentration at 100g / L. The leaching was carried out at room temperature for 2 hours, and the leaching results are shown in Table 2.

[0085] Table 2 Results of pre-impregnation and magnesium removal

[0086]

[0087]

[0088] Examples 1-3 show that when the sulfuric acid concentration reaches 80 g / L, approximately 90% of the magnesium in the nickel sulfide is leached out, while the leaching rates of nickel, cobalt, copper, and iron are relatively low. When the sulfuric acid concentration increases to 100 g / L, the leaching rates of each metal remain essentially unchanged. Therefore, the above-mentioned sulfuric acid pre-leaching of nickel sulfide ore has a good magnesium removal effect.

[0089] Example 4

[0090] 1000g of the leaching residue obtained after pre-impregnation and demagnesification in Example 2 was wet-milled in a ball mill for 2 hours at a ball-to-material ratio of 5:1 and a ball milling intensity of 15G. Then, it was leached in an oxygen-enriched environment in a vertical autoclave for 3 hours at a liquid-to-solid ratio of 4:1, a temperature of 120℃, and an oxygen partial pressure of 0.5MPa. The results are shown in Table 3.

[0091] Example 5

[0092] 1000g of the leaching residue obtained after pre-impregnation and demagnesification in Example 2 was wet-milled in a ball mill for 2 hours at a ball-to-material ratio of 20:1 and a ball milling intensity of 15G. Then, it was leached in an oxygen-enriched environment in a vertical autoclave for 3 hours at a liquid-to-solid ratio of 4:1, a temperature of 120℃, and an oxygen partial pressure of 0.5MPa. The results are shown in Table 3.

[0093] Example 6

[0094] 1000g of the leaching residue obtained after pre-impregnation and magnesium removal in Example 2 was wet-milled in a ball mill for 2 hours at a ball-to-material ratio of 35:1 and a ball milling intensity of 15G. Then, it was leached in an oxygen-enriched environment in a vertical autoclave for 3 hours at a liquid-to-solid ratio of 4:1, a temperature of 120℃, and an oxygen partial pressure of 0.5MPa. The results are shown in Table 3.

[0095] Table 3 Results of mechanical activation-oxygen-enriched leaching

[0096] Leaching rate (%) Ni Co Cu Fe Ball to feed ratio 5:1 64.4 57.3 63.8 50.1 Ball to feed ratio 20:1 97.1 95.5 92.4 36.7 Ball to feed ratio 35:1 96.7 95.8 91.6 44.1

[0097] Examples 4-6 show that when using wet ball milling activation treatment, the leaching rates of valuable metals such as nickel, cobalt, and copper are high when the ball-to-material ratio reaches 20:1, while the leaching rate of iron is relatively low. When the ball-to-material ratio is increased to 35:1, the leaching rate of valuable metals remains basically unchanged, while the leaching rate of impurity iron increases significantly. Therefore, appropriately increasing the ball-to-material ratio can effectively improve the leaching rate of valuable metals and control the leaching rate of impurity iron at a low level.

[0098] Example 7

[0099] 1000g of the leaching residue obtained after pre-impregnation and magnesium removal in Example 2 was wet-milled in a ball mill for 2 hours at a ball-to-material ratio of 20:1 and a milling intensity of 5G. Then, it was leached in an oxygen-enriched autoclave for 3 hours at a liquid-to-solid ratio of 4:1, a temperature of 120℃, and an oxygen partial pressure of 0.5 MPa. The results are shown in Table 4.

[0100] Example 8

[0101] 1000g of the leaching residue obtained after pre-impregnation and magnesium removal in Example 2 was wet-milled in a ball mill for 2 hours at a ball-to-material ratio of 20:1 and a milling intensity of 15G. Then, it was leached in an oxygen-enriched autoclave for 3 hours at a liquid-to-solid ratio of 4:1, a temperature of 120℃, and an oxygen partial pressure of 0.5 MPa. The results are shown in Table 4.

[0102] Example 9

[0103] 1000g of the leaching residue obtained after pre-impregnation and magnesium removal in Example 2 was wet-milled in a ball mill for 2 hours at a ball-to-material ratio of 20:1 and a milling intensity of 25G. Then, it was leached in an oxygen-enriched autoclave for 3 hours at a liquid-to-solid ratio of 4:1, a temperature of 120℃, and an oxygen partial pressure of 0.5 MPa. The results are shown in Table 4.

[0104] Table 4 Results of mechanical activation-oxygen-enriched leaching

[0105] Leaching rate (%) Ni Co Cu Fe Ball milling strength 5G 72.4 45.2 76.6 51.3 Ball milling strength 15G 97.1 95.5 92.4 36.7 Ball milling strength 25G 96.6 94.4 92.2 37.1

[0106] As can be seen from Examples 7-9, when wet ball milling activation treatment is used, the leaching rates of valuable metals such as nickel, cobalt, and copper are high when the ball milling intensity is 15G, while the leaching rate of iron is relatively low; when the ball milling intensity is 25G, the leaching rates of each metal remain basically unchanged. Therefore, appropriately increasing the ball milling intensity can significantly increase the leaching rate of valuable metals while retaining most of the impurity iron in the slag.

[0107] Example 10

[0108] 1000g of the leaching residue obtained after pre-impregnation and magnesium removal in Example 2 was wet-milled in a ball mill for 2 hours at a ball-to-material ratio of 20:1 and a milling intensity of 15G. Then, it was leached in an oxygen-enriched autoclave for 3 hours at a liquid-to-solid ratio of 4:1, a temperature of 100℃, and an oxygen partial pressure of 0.5 MPa. The results are shown in Table 5.

[0109] Example 11

[0110] 1000g of the leaching residue obtained after pre-impregnation and magnesium removal in Example 2 was wet-milled in a ball mill for 2 hours at a ball-to-material ratio of 20:1 and a milling intensity of 15G. Then, it was leached in an oxygen-enriched autoclave for 3 hours at a liquid-to-solid ratio of 4:1, a temperature of 120℃, and an oxygen partial pressure of 0.5 MPa. The results are shown in Table 5.

[0111] Example 12

[0112] 1000g of the leaching residue obtained after pre-impregnation and magnesium removal in Example 2 was wet-milled in a ball mill for 2 hours at a ball-to-material ratio of 20:1 and a milling intensity of 15G. Then, it was leached in an oxygen-enriched autoclave for 3 hours at a liquid-to-solid ratio of 4:1, a temperature of 140℃, and an oxygen partial pressure of 0.5 MPa. The results are shown in Table 5.

[0113] Table 5 Results of mechanical activation-oxygen-enriched leaching

[0114] Leaching rate (%) Ni Co Cu Fe 100℃ immersion 88.9 86.7 89.2 30.2 120℃ immersion 97.1 95.5 92.4 36.7 140℃ immersion 97.3 95.8 92.7 63.2

[0115] As can be seen from Examples 10-12, mechanical activation of the pre-leached magnesium-removed slurry by wet ball milling allows for oxygen-enriched leaching at lower temperatures, resulting in a beneficial leaching rate. However, when the temperature exceeds 140°C, the increase in leaching rate decreases, but the iron content increases. Therefore, the oxygen-enriched leaching temperature is selected as 100°C to 140°C, more preferably 110°C to 130°C.

[0116] The description of this invention is given for illustrative and descriptive purposes only and is not intended to be exhaustive or to limit the invention to the forms 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 and practical application of the invention and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A method for the comprehensive utilization of high-magnesium nickel sulfide ore using a low-temperature oxygen-enriched process, characterized in that, The method includes: Using high-magnesium nickel sulfide ore as raw material, pre-leaching is performed to remove magnesium, resulting in magnesium-containing pre-leaching solution and pre-leaching residue. Sulfuric acid is used as the leaching reagent, with a concentration of 80 g / L to 100 g / L. The amount of sulfuric acid added is determined based on the magnesium oxide content of the high-magnesium nickel sulfide ore. The liquid-solid ratio is controlled at 2:1 to 5:

1. After stirring at room temperature for 0.5 h to 3 h, liquid-solid separation is performed. The pre-impregnated slag was mechanically activated by ball milling to obtain activated slurry; wherein, wet ball milling was used, with a ball-to-material ratio of 5:1 to 35:1, a ball milling intensity of 5G to 25G, and a ball milling time of 0.5h to 5h. The activated slurry was leached using a low-temperature oxygen-enriched method to obtain a nickel-containing leaching solution and leaching residue. Oxygen or oxygen-enriched leaching was introduced as the leaching oxidant, the reaction temperature was controlled at 100℃~130℃, the reaction pressure at 0.3MPa~1.0MPa, the liquid-solid ratio at 3:1~6:1, and the liquid-solid separation was performed after stirring and oxygen-enriched leaching for 0.5h~5h. The nickel-containing leaching solution is used to remove copper to obtain sponge copper and copper-removed liquid. Iron is removed from the copper-removed liquid to obtain iron slag and iron-removed liquid. Based on the iron-removed liquid, nickel and cobalt are extracted to obtain magnesium sulfate, nickel sulfate product and cobalt sulfate product. The magnesium sulfate is then sent to evaporation crystallization. The leaching residue is floated to obtain sulfur concentrate and tailings; the tailings and iron slag are pyrolyzed to obtain iron ore products, and the sulfur dioxide flue gas generated is used to produce acid and then sent to the pre-leaching demagnesification reagent. The magnesium-containing pre-leaching solution is neutralized with a neutralizing agent, and the solid and liquid are separated and evaporated to crystallize, resulting in magnesium sulfate product. The neutralized residue obtained from neutralization is then sent to a low-temperature oxygen-enriched leaching step. The neutralizing agent is one or both of magnesium oxide and magnesium carbonate.

2. The method for comprehensive utilization of high-magnesium nickel sulfide ore using low-temperature oxygen-enriched process according to claim 1, characterized in that, After pre-leaching and demagnesification, the leaching rate of magnesium oxide is ≥90%, and the leaching rates of nickel, cobalt, and copper in the magnesium-containing pre-leaching solution are all <5%, while the leaching rate of iron is <7%.

3. The method for comprehensive utilization of high-magnesium nickel sulfide ore using a low-temperature oxygen-enriched process according to claim 1, characterized in that, The low-temperature oxygen-enriched leaching method yields a nickel-containing leachate with a leaching rate of ≥95% for nickel, ≥95% for cobalt, ≥90% for copper, and <40% for iron.

4. The method for comprehensive utilization of high-magnesium nickel sulfide ore using low-temperature oxygen-enriched process according to claim 1, characterized in that, The high-magnesium nickel sulfide ore contains 5%–15% nickel and 6%–20% magnesium oxide.

5. The method for comprehensive utilization of high-magnesium nickel sulfide ore using a low-temperature oxygen-enriched process according to claim 1, characterized in that, During copper removal, the nickel-containing leaching solution is subjected to copper removal by iron powder replacement method to obtain sponge copper and copper-removed solution; the amount of iron powder added is 1 to 3 times the theoretical amount of copper, and the mixture is stirred at room temperature for 0.5 to 2 hours.

6. The method for comprehensive utilization of high-magnesium nickel sulfide ore using a low-temperature oxygen-enriched process according to claim 1, characterized in that, During iron removal, the goethite method is used to remove iron from the copper-removed liquid, resulting in iron-removed liquid and iron slag. The goethite method for removing iron from the copper-removed liquid includes: adjusting the pH of the copper-removed liquid to 3-4, using nickel carbonate as a pH adjuster; introducing oxygen or oxygen-enriched solution as an iron-removing oxidant; controlling the reaction temperature at 70℃-90℃; stirring; and separating the liquid and solid after 2-10 hours of reaction.

7. The method for comprehensive utilization of high-magnesium nickel sulfide ore using a low-temperature oxygen-enriched process according to claim 1, characterized in that, During extraction, P204 was used for nickel extraction and P507 for cobalt extraction; And / or, the method further includes: using sodium carbonate to precipitate nickel in the iron removal liquid to generate nickel carbonate and sodium sulfate, and sending the nickel carbonate as a pH adjuster in the goethite process to the iron removal step.

8. A system used in the method for the comprehensive utilization of high-magnesium nickel sulfide ore using a low-temperature oxygen-enriched process according to any one of claims 1-7, characterized in that, include: A pre-leaching demagnesification device is used to pre-leach demagnesize high-magnesium nickel sulfide ore to obtain magnesium-containing pre-leaching solution and pre-leaching residue; it includes a tank, a stirrer and a first filter device, and sulfuric acid is added to the tank as a leaching reagent. Mechanical activation device, including ball mill, is used to mechanically activate the pre-leaching residue obtained from the pre-leaching demagnesification device to obtain activated slurry; A low-temperature oxygen-enriched leaching device is used to leach activated ore slurry using a low-temperature oxygen-enriched method to obtain nickel-containing leaching solution and leaching residue; it includes a vertical high-pressure reactor and a second filtration device, wherein the vertical high-pressure reactor has an inlet for leaching oxidant. A nickel-containing leaching solution post-treatment device is used to post-treat nickel-containing leaching solutions and convert various metals into corresponding products; it includes: a copper removal unit, a goethite iron removal unit, a third filtration device, and an extraction unit arranged in sequence. A magnesium-containing pre-leaching solution treatment device is connected to a first filtration device. The magnesium-containing pre-leaching solution treatment device includes a neutralization unit, a fourth filtration device, and an evaporation crystallization unit arranged in sequence. The fourth filtration device is also connected to a low-temperature oxygen-enriched leaching device for sending the neutralized residue obtained from the neutralization unit into the low-temperature oxygen-enriched leaching device for treatment. The flotation unit, connected to the second filtration device, is used to flotate the separated leaching residue to obtain sulfur concentrate and tailings; The pyrometallurgical processing unit is connected to the flotation unit and the third filtration device, respectively, and is used to process the tailings and iron slag after iron removal to obtain iron ore products. The pyrometallurgical processing unit is also connected to an acid production device, which is connected to the pre-leaching demagnesification device, and is used to process the sulfur dioxide flue gas generated during the pyrometallurgical processing into acid and send it to the pre-leaching demagnesification device as a leaching reagent.

9. The system according to claim 8, characterized in that, In the nickel-containing leaching solution post-treatment device, the copper removal unit is used to remove copper from the nickel-containing leaching solution using an iron powder replacement method to obtain sponge copper and copper-removed solution; the goethite iron removal unit is used to remove iron from the copper-removed solution using a goethite method, and after filtration by the third filtration device, iron-removed solution and iron slag are obtained; the extraction unit uses P204 to extract nickel and P507 to extract cobalt to obtain nickel-cobalt products. And / or, it also includes: a nickel precipitation device, which is connected to the third filtration device and the goethite iron removal unit respectively, for precipitating nickel in the iron removal liquid with sodium carbonate to generate nickel carbonate and sodium sulfate, and sending the nickel carbonate into the goethite iron removal unit as a pH adjuster for the goethite process.

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