Laterite-nickel ore hydrometallurgy post-treatment fine control system and method

Abstract

The present invention relates to a laterite-nickel ore hydrometallurgy post-treatment fine control system and method. Said system comprises a plurality of reaction devices connected in order and a plurality of pH value adjusting devices in one-to-one correspondence with the plurality of reaction devices. Each reaction device has a preset pH value, and the preset pH values of any two reaction devices are different. Each pH value adjusting device comprises a pH value adjusting module, a pH value online measurement module and a feedback control module, the feedback control module being connected to the pH value adjusting module and the pH value online measurement module. The present invention solves the following problems: during the process of introducing a neutralization solution into a mixed solution to adjust a pH value, local over-alkalinity may occur at the position where the neutralization solution is added, thus causing generation of non-target precipitates; during an early stage of adjustment, the pH difference value between the neutralization solution and the mixed solution may be large, thus causing the generated non-target precipitates to redissolve; and during a final stage of adjustment, the pH difference value between the neutralization solution and the mixed solution may be small, thus making it difficult for the non-target precipitates to dissolve, thereby reducing the final nickel and cobalt recovery rate.

Description

A refined control system and method for hydrometallurgical post-processing of laterite nickel ore Technical Field

[0001] The present invention relates to the technical field of laterite nickel ore processing, and in particular to a refined control system and method for hydrometallurgical post-processing of laterite nickel ore. Background Art

[0002] Nickel and cobalt are part of the raw materials for battery production. With the rapid development of the battery industry, the demand for nickel and cobalt has increased sharply. Currently, laterite nickel ore can be treated with high-pressure acid leaching process to obtain nickel and cobalt raw materials.

[0003] For example, the invention patent with application number CN201910765616.0 proposes a method for treating laterite nickel ore acid leaching residue, wherein the laterite nickel ore is subjected to pressurized acid leaching treatment, and iron-containing acid leaching residue and acid leaching liquid are obtained after solid-liquid separation; the acid leaching liquid is pre-neutralized, and gypsum slag and pre-neutralized liquid are obtained after solid-liquid separation; at 70-80°C, the pH value of the pre-neutralized liquid is adjusted to 3.2-3.5 using calcium hydroxide to perform a stage of iron-aluminum removal, and after solid-liquid separation, a stage of iron-aluminum slag and a stage of iron-aluminum removal liquid are obtained; the stage of iron-aluminum slag and the iron-containing acid leaching residue are subjected to a magnetization roasting process. The method comprises the following steps: treating a mixture of the first stage iron-aluminum slag and the second stage iron-aluminum de-ironing solution to obtain an iron concentrate and harmless tailings, wherein the weight content of the first stage iron-aluminum slag in the mixture is less than 25%; adjusting the pH value of the first stage iron-aluminum de-ironing solution to 4.2-4.5 using calcium hydroxide at 70-80° C. to perform a second stage iron-aluminum de-ironing, and obtaining a second stage iron-aluminum slag and a second stage iron-aluminum de-ironing solution after solid-liquid separation; subjecting the second stage iron-aluminum de-ironing solution to nickel and cobalt precipitation to obtain a nickel-cobalt precipitation barren solution and a nickel-cobalt precipitate; subjecting the nickel-cobalt precipitation barren solution to manganese and magnesium precipitation in steps to obtain manganese slag and magnesium slag in sequence; and returning the second stage iron-aluminum slag to the pressure acid leaching process.

[0004] However, in the process of introducing the neutralizing solution into the mixed solution to adjust the pH value, there will be local over-alkalinity at the location where the neutralizing solution is added, resulting in the generation of non-target precipitates. In the early stage of adjustment, the pH difference between the neutralizing solution and the mixed solution is large, and the generated non-target precipitates are redissolved. At the end of the adjustment, the pH difference between the neutralizing solution and the mixed solution is small, and the non-target precipitates are difficult to dissolve, resulting in a decrease in the final nickel and cobalt recovery rate.

[0005] Summary of the Invention

[0006] In view of this, it is necessary to provide a refined control system and method for hydrometallurgical post-processing of laterite nickel ore to solve the problem that in the process of introducing neutralizing solution into the mixed solution to adjust the pH value, local over-alkalinity occurs at the location where the neutralizing solution is added, resulting in the generation of non-target precipitates. In the early stage of adjustment, the pH difference between the neutralizing solution and the mixed solution is large, and the generated non-target precipitates are redissolved. At the end of the adjustment, the pH difference between the neutralizing solution and the mixed solution is small, and the non-target precipitates are difficult to dissolve, resulting in a lower final nickel and cobalt recovery rate.

[0007] The present invention provides a refined control system for hydrometallurgical post-processing of laterite nickel ore, comprising a plurality of sequentially connected reaction devices and a plurality of pH adjustment devices corresponding one to one with the plurality of reaction devices; wherein each of the reaction devices has a preset pH value, and the preset pH values ​​of any two of the reaction devices are different; each of the pH adjustment devices comprises a pH adjustment module, a pH online detection module and a feedback control module, wherein the pH adjustment module is used to adjust the pH value of a reaction liquid in the corresponding reaction device, the pH online detection module is used to detect the actual pH value of the reaction liquid in the corresponding reaction device, and the feedback control module is connected to the pH adjustment module and the pH online detection module, and is used to control the adjustment rate of the pH adjustment module according to the difference between the actual pH value of the corresponding reaction device and the preset pH value.

[0008] Furthermore, the multiple reaction devices include a first-stage iron and aluminum removal device, a second-stage iron and aluminum removal device, a first-stage nickel and cobalt precipitation device and a second-stage nickel and cobalt precipitation device. The preset pH value of the first-stage iron and aluminum removal device is a first preset pH value, the preset pH value of the second-stage iron and aluminum removal device is a second preset pH value, the preset pH value of the first-stage nickel and cobalt precipitation device is a third preset pH value, and the preset pH value of the second-stage nickel and cobalt precipitation device is a fourth preset pH value. The first preset pH value, the second preset pH value, the third preset pH value and the fourth preset pH value gradually increase.

[0009] Furthermore, the pH value adjustment module includes multiple neutralization liquid input ends connected to the corresponding reaction devices, the pH values ​​of the neutralization liquids in the multiple neutralization liquid input ends are different from each other, and the feedback control module is connected to the multiple neutralization liquid input ends to control the opening and closing of the multiple neutralization liquid input ends.

[0010] Furthermore, the pH values ​​of the neutralization solutions in the plurality of neutralization solution input ends are set in a stepped manner.

[0011] Furthermore, the pH value adjustment module also includes a plurality of adjustment ends corresponding one-to-one to the plurality of neutralization liquid input ends, and the plurality of adjustment ends are connected to the corresponding neutralization liquid input ends to adjust the delivery rate of the neutralization input ends.

[0012] Furthermore, the pH value adjustment module also includes a plurality of dilution ends respectively connected to the plurality of neutralization liquid input ends, and the plurality of dilution ends are used to dilute the concentration of the neutralization liquid in the corresponding neutralization liquid input ends.

[0013] Furthermore, the pH value online detection module includes a plurality of detection units, which are arranged in the reaction liquid of the corresponding reaction device to detect the actual pH measurement value at different positions of the reaction liquid, and also includes a plurality of stirring devices, wherein the stirring ends of the plurality of stirring devices are respectively built into the reaction liquid of the plurality of reaction devices to stir the reaction liquid in the reaction device;

[0014] One of the detection units is located at the neutralization liquid adding position of the reaction device, another detection unit is located at the overflow port of the reaction device, and the remaining detection units are evenly arranged in the reaction device.

[0015] The present invention also provides a method for fine control of laterite nickel ore hydrometallurgical post-processing, comprising the above-mentioned fine control system for laterite nickel ore hydrometallurgical post-processing, and further comprising the following steps:

[0016] The laterite nickel ore is subjected to pressure acid leaching, and after solid-liquid separation, iron-containing acid leaching residue and acid leaching liquid are obtained, and the acid leaching liquid is pre-neutralized, and after solid-liquid separation, a reaction liquid is obtained;

[0017] The reaction solution is sequentially introduced into a plurality of the reaction devices, and the pH value of the reaction solution in each of the reaction devices is adjusted; wherein the pH value of the reaction solution in each of the reaction devices is adjusted as follows:

[0018] The actual pH value of the reaction liquid in the reaction device is detected, and the pH adjustment rate of the reaction liquid in the reaction device is controlled based on the difference between the preset pH value and the actual pH value of the reaction device.

[0019] Furthermore, the controlling the pH adjustment rate of the reaction liquid in the reaction device based on the difference between the preset pH value and the actual pH value of the reaction device includes:

[0020] The feedback control module compares the actual pH value of the reaction liquid in the corresponding reaction device with the preset pH value and calculates the pH difference;

[0021] The greater the pH difference, the greater the adjustment rate of the pH adjustment module; the smaller the pH difference, the smaller the adjustment rate of the pH adjustment module.

[0022] Furthermore, the step of sequentially inputting the reaction solution into a plurality of reaction devices and adjusting the pH value of the reaction solution in each reaction device comprises:

[0023] The pH value of the reaction solution is adjusted by a pH adjusting device, and a stage of iron and aluminum removal treatment is performed to obtain a stage of iron and aluminum slag and a stage of iron and aluminum removal liquid after solid-liquid separation;

[0024] The pH value of the first-stage iron-aluminum removal liquid is adjusted by a pH adjustment device, and a second-stage iron-aluminum removal treatment is performed, and after solid-liquid separation, a second-stage iron-aluminum slag and a second-stage iron-aluminum removal liquid are obtained, and the second-stage iron-aluminum slag is returned to the pre-neutralization treatment process;

[0025] The pH value of the second-stage iron removal and aluminum removal solution is adjusted by a pH adjusting device, and a nickel-cobalt precipitation treatment is performed, and after solid-liquid separation, a mixed nickel-cobalt precipitate and a nickel-cobalt precipitation solution are obtained;

[0026] The pH value of the nickel-cobalt precipitation solution is adjusted by a pH adjusting device, and a two-stage nickel-cobalt precipitation treatment is performed. After solid-liquid separation, a two-stage mixed nickel-cobalt precipitate and a barren solution are obtained, and the two-stage mixed nickel-cobalt precipitate is returned to the pre-neutralization treatment process.

[0027] Furthermore, the pH value adjustment module is used to output strong base, neutral base and weak base. In the early stage of adjustment, the pH difference is large, and the pH value adjustment module outputs strong base. In the middle stage of adjustment, the pH difference is moderate, and the pH value adjustment module outputs neutral base. At the end of adjustment, the pH difference is small, and the pH value adjustment module outputs weak base.

[0028] Furthermore, the pH value adjustment module is used to output a diluent. At the end of the adjustment period, the pH value adjustment module outputs a weak base and the diluent.

[0029] Compared with the prior art, the embodiment of the present invention provides a refined control system for hydrometallurgical post-processing of laterite nickel ore, wherein the laterite nickel ore is subjected to pressurized acid leaching and solid-liquid separation to obtain an acid leaching liquid, the acid leaching liquid is pre-neutralized, and a reaction liquid is obtained after solid-liquid separation. The neutralized liquid is passed through multiple reaction devices in sequence through an acid leaching process. When located in different reaction devices, the pH value therein is adjusted to a preset pH value by a corresponding pH adjustment device, and the desired nickel-cobalt precipitate is obtained after the reaction. In the process of adjusting the pH value of the reaction liquid by the above-mentioned pH adjustment device, first, the actual pH value of the reaction liquid in the corresponding reaction device is detected by a pH online detection module, and secondly, the actual pH value of the reaction liquid in the corresponding reaction device is compared with the preset pH value by a feedback control module. Compare and obtain the pH difference, the feedback control module controls the adjustment rate of the pH adjustment module according to the size of the pH difference, and finally, the pH adjustment module is used to adjust the pH value of the reaction liquid in the corresponding reaction device. In the early stage of adjusting the pH value of the reaction liquid in the reaction tank, the non-target precipitate generated by the over-alkalinity phenomenon will re-dissolve due to the large pH difference. Therefore, at this time, the adjustment rate of the pH adjustment module can be set to a larger value to speed up the entire adjustment rate. In the later stage of adjusting the pH value of the reaction liquid in the reaction tank, the non-target precipitate generated by the over-alkalinity phenomenon is difficult to dissolve due to the large pH difference. By setting the adjustment rate of the pH adjustment module to a smaller value, the over-alkalinity phenomenon can be reduced, and the amount of non-target precipitate generated can be reduced, so as to realize the function of fine processing and increase the output of nickel and cobalt. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] FIG1 is a schematic diagram showing the connection of multiple reaction tanks in a refined control system for hydrometallurgical post-processing of laterite nickel ore provided by an embodiment of the present invention;

[0031] FIG2 is a schematic structural diagram of a pH value regulating device in a refined control system for hydrometallurgical post-processing of laterite nickel ore provided by an embodiment of the present invention;

[0032] FIG3 is a flow chart of a refined control method for hydrometallurgical post-processing of laterite nickel ore provided by an embodiment of the present invention;

[0033] FIG4 is a control flow chart of controlling the pH adjustment rate of the reaction liquid in the reaction device in the refined control method for hydrometallurgical post-processing of laterite nickel ore provided by an embodiment of the present invention;

[0034] FIG5 is a flow chart showing the sequential input of reaction liquid into a plurality of reaction devices in the refined control method for hydrometallurgical post-processing of laterite nickel ore provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0035] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, and are not used to limit the scope of the present invention.

[0036] As shown in Figures 1-2, an embodiment of the present invention provides a refined control system for hydrometallurgical post-processing of laterite nickel ore, including multiple reaction devices 100 and multiple pH adjustment devices 200 corresponding to the multiple reaction devices 100; wherein each reaction device 100 has a preset pH value, and the preset pH values ​​of any two reaction devices 100 are different, each pH adjustment device 200 includes a pH adjustment module 210, a pH online detection module 220 and a feedback control module 230, the pH adjustment module 210 is used to adjust the pH value of the reaction liquid in the corresponding reaction device 100, the pH online detection module 220 is used to detect the actual pH value of the reaction liquid in the corresponding reaction device 100, and the feedback control module 230 is connected to the pH adjustment module 210 and the pH online detection module 220, and is used to control the adjustment rate of the pH adjustment module 210 according to the difference between the actual pH value of the corresponding reaction device 100 and the preset pH value.

[0037] During implementation, the laterite nickel ore is subjected to pressure acid leaching and an acid leaching solution can be obtained after solid-liquid separation. The acid leaching solution is pre-neutralized, and a reaction solution is obtained after solid-liquid separation. The neutralized solution is sequentially passed through a plurality of reaction devices 100 through an acid leaching process. When located in different reaction devices 100, the pH value therein is adjusted to a preset pH value by a corresponding pH adjustment device 200. After the reaction, the required nickel-cobalt precipitate is obtained. In the process of adjusting the pH value of the reaction solution by the above-mentioned pH adjustment device 200, first, the actual pH value of the reaction solution in the corresponding reaction device 100 is detected by the pH online detection module 220. Secondly, the feedback control module 230 compares the actual pH value of the reaction solution in the corresponding reaction device 100 with the preset pH value and obtains the pH difference. The feedback control module 230 is used to compare the actual pH value of the reaction solution in the corresponding reaction device 100 with the preset pH value and obtains the pH difference. Module 230 controls the adjustment rate of the pH adjustment module 210 according to the size of the pH difference. Finally, the pH adjustment module 210 is used to adjust the pH value of the reaction liquid in the corresponding reaction device 100. In the early stage of adjusting the pH value of the reaction liquid in the reaction tank, the non-target precipitate generated by the over-alkalinity phenomenon will re-dissolve due to the large pH difference. Therefore, at this time, the adjustment rate of the pH adjustment module 210 can be set to a larger value to speed up the entire adjustment rate. In the later stage of adjusting the pH value of the reaction liquid in the reaction tank, the non-target precipitate generated by the over-alkalinity phenomenon is difficult to dissolve due to the large pH difference. By setting the adjustment rate of the pH adjustment module 210 to a smaller value, the over-alkalinity phenomenon can be reduced, and the amount of non-target precipitate generated can be reduced, so as to realize the function of fine processing and increase the output of nickel and cobalt.

[0038] The reaction pool in this embodiment provides support for multiple reactions in the acid leaching process of laterite nickel ore. The reaction liquid after the acid leaching process flows through multiple reaction devices 100 in sequence. The pH values ​​of the multiple reaction liquids are set to preset pH values, and the multiple preset pH values ​​are different from each other. After the laterite nickel ore reacts with the reaction liquids in the multiple reaction devices 100, nickel and cobalt precipitates are obtained.

[0039] In one embodiment, multiple reaction devices 100 include a first-stage iron and aluminum removal device 110, a second-stage iron and aluminum removal device 120, a first-stage nickel and cobalt precipitation device 130 and a second-stage nickel and cobalt precipitation device 140, the preset pH value of the first-stage iron and aluminum removal device 110 is a first preset pH value, the preset pH value of the second-stage iron and aluminum removal device 120 is a second preset pH value, the preset pH value of the first-stage nickel and cobalt precipitation device 130 is a third preset pH value, the preset pH value of the second-stage nickel and cobalt precipitation device 140 is a fourth preset pH value, and the first preset pH value, the second preset pH value, the third preset pH value and the fourth preset pH value gradually increase.

[0040] The laterite nickel ore is subjected to pressure acid leaching and solid-liquid separation to obtain an acid leaching solution. The acid leaching solution is pre-neutralized, and after solid-liquid separation, a reaction solution is obtained. The neutralized solution is introduced into a first-stage iron-aluminum removal device 110. The pH value of the reaction solution is adjusted by a pH adjustment device 200, and a first-stage iron-aluminum removal treatment is performed. After solid-liquid separation, a section of iron-aluminum slag and a section of iron-aluminum removal liquid are obtained. At this point, the iron-aluminum slag contains only iron and aluminum, while the iron-aluminum removal liquid contains iron, aluminum, nickel, and cobalt. Further treatment of the iron-aluminum removal liquid is required.

[0041] Therefore, the first-stage deironing aluminum liquid is introduced into the second-stage deironing aluminum device 120, where the pH value of the first-stage deironing aluminum liquid is adjusted by the pH adjustment device 200, and a second-stage deironing aluminum treatment is performed. After solid-liquid separation, a second-stage iron-aluminum slag and a second-stage deironing aluminum liquid are obtained. At this time, the second-stage deironing aluminum slag contains iron, aluminum, nickel, and cobalt. In order to achieve fine collection of nickel and cobalt, the second-stage deironing aluminum slag is returned to the pre-neutralization process. At the same time, the second-stage deironing aluminum liquid contains nickel, cobalt, magnesium, zinc, and magnesium, and further treatment of the second-stage deironing aluminum liquid is required to obtain a pure nickel-cobalt product.

[0042] The second-stage iron-removed aluminum solution is introduced into the first-stage nickel-cobalt precipitation device 130. The pH value of the second-stage iron-removed aluminum solution is adjusted by the pH adjustment device 200, and a first-stage nickel-cobalt precipitation process is performed. After solid-liquid separation, a mixed nickel-cobalt precipitate and a nickel-cobalt precipitation solution are obtained. At this point, the first-stage mixed nickel-cobalt precipitate contains only nickel and cobalt elements, and therefore, this product is the final product desired by this system and has a high purity. However, the nickel-cobalt precipitation solution contains nickel and cobalt elements. To avoid waste of nickel and cobalt, the nickel-cobalt precipitation solution needs to be further processed.

[0043] Finally, the nickel-cobalt precipitation solution is introduced into the second-stage nickel-cobalt precipitation device 140, and the pH value of the nickel-cobalt precipitation solution is adjusted by the pH value adjustment device 200, and the second-stage nickel-cobalt precipitation treatment is carried out. After solid-liquid separation, a second-stage mixed nickel-cobalt precipitate and a lean solution are obtained. The second-stage mixed nickel-cobalt precipitate is returned to the pressurized acid leaching process. At this time, the second-stage mixed nickel-cobalt precipitate contains nickel, cobalt, magnesium, zinc and magnesium. The nickel and cobalt content in the second-stage mixed nickel-cobalt precipitate is large, but not pure, so it is returned to the pre-neutralization process.

[0044] The waste liquid contains manganese and zinc elements. Therefore, the pH value of the barren liquid is adjusted by the pH adjusting device 200, and manganese precipitation treatment is carried out. After solid-liquid separation, manganese slag and manganese precipitation solution are obtained. The pH value of the manganese precipitation solution is adjusted by the pH adjusting device 200, and magnesium precipitation treatment is carried out. After solid-liquid separation, magnesium slag and magnesium precipitation solution are obtained.

[0045] The above process is a process for extracting nickel and cobalt by an acid leaching process in an embodiment of the present invention, wherein multiple liquid products need to be converted in two reaction devices 100. After the conversion, the pH value of the liquid product needs to be adjusted. This embodiment is achieved by setting a pH value adjustment device 200. Specifically, the multiple pH value adjustment devices 200 each include a pH value adjustment module 210, a pH value online detection module 220, and a feedback control module 230. The pH value adjustment module 210 is used to adjust the pH value of the reaction liquid in the corresponding reaction device 100. The pH value online detection module 220 is used to detect the actual pH value of the reaction liquid in the corresponding reaction device 100. The feedback control module 230 compares the actual pH value of the reaction liquid in the corresponding reaction device 100 with the preset pH value and obtains a pH difference. The feedback control module 230 controls the adjustment rate of the pH value adjustment module 210 according to the size of the pH difference. The larger the pH difference, the greater the adjustment rate of the pH value adjustment module 210, and the smaller the pH difference, the smaller the adjustment rate of the pH value adjustment module 210.

[0046] In order to control the pH adjustment rate and reduce non-target precipitation in the over-alkali phenomenon, in one embodiment, the pH adjustment module 210 includes multiple neutralizer input terminals connected to the corresponding reaction device 100, and the pH values ​​of the neutralizers in the multiple neutralizer input terminals are different from each other. The feedback control module 230 is connected to the multiple neutralizer input terminals and controls the opening and closing of the neutralizer input terminals according to the size of the pH difference. When the pH difference is large, the neutralizer input terminal corresponding to the neutralizer with a larger pH value is opened, and the other neutralizer input terminals are closed. When the pH difference is small, the neutralizer input terminal corresponding to the neutralizer with a smaller pH value is opened, and the other neutralizer input terminals are closed.

[0047] To facilitate understanding of the above scheme, further examples are given below. For example, the number of multiple neutralizing liquid input ends is three, and the three neutralizing liquid input ends are used to output strong base, neutral base and weak base respectively. The pH of strong base, neutral base and weak base decreases successively. In the early stage of adjustment, due to the large pH difference, non-target precipitates generated due to over-alkalinity can be redissolved. By adding strong base, the strong base reacts with the reaction liquid and neutralizes quickly, thereby increasing the adjustment rate. In the middle stage of adjustment, due to the moderate pH difference, non-target precipitates generated due to over-alkalinity can be redissolved. By adding neutral base, it is adapted to the reaction liquid with the corresponding pH value, thereby increasing the adjustment rate. In the late stage of adjustment, due to the small pH difference, non-target precipitates generated due to over-alkalinity are difficult to dissolve. If strong base or neutral base is added, a large amount of non-target precipitates are easily generated. Therefore, by adding weak base, the pH value of the reaction liquid is used to slowly and accurately adjust to the preset pH value to reduce non-target precipitates in the over-alkalinity phenomenon.

[0048] Of course, the number of the neutralizing liquid input terminals can also be four, five, or six, etc., to achieve the function of gradually adjusting the pH value of the reaction solution, and this embodiment of the present invention is not limited thereto. The pH values ​​of the neutralizing liquids in the multiple neutralizing liquid input terminals are set in a stepped manner. Of course, the pH values ​​of the neutralizing liquids in the multiple neutralizing liquid input terminals can also be set in a random manner, and this embodiment of the present invention is not limited thereto.

[0049] It should be noted that the neutralizing liquid in the neutralizing liquid input end should use the neutralizing solvent compatible with the corresponding reaction device 100. For example, in the process of the first stage of iron and aluminum removal, the neutralizing liquid can use calcium hydroxide, calcium carbonate, calcium oxide, slaked lime, sodium carbonate, etc. to adjust the pH value of the neutralizing solvent with a pH value of 1.8 to 4.0; in the process of the second stage of iron and aluminum removal, the neutralizing liquid can use calcium hydroxide and potassium hydroxide to adjust the pH value of the first stage of iron and aluminum removal liquid to 5.0; in the process of the first stage of nickel and cobalt precipitation, the neutralizing liquid can use calcium hydroxide and potassium hydroxide to adjust the pH value of the second stage of iron and aluminum removal liquid to 7.0; in the process of the second stage of nickel and cobalt precipitation, the neutralizing liquid can use calcium hydroxide and potassium hydroxide to adjust the pH value of the nickel and cobalt precipitation solution to 8.0.

[0050] To further reduce the formation of unintended precipitation, in one embodiment, the pH adjustment module 210 further includes multiple adjustment terminals corresponding to the multiple neutralizing liquid input terminals. The multiple adjustment terminals are connected to the corresponding neutralizing liquid input terminals to adjust the delivery rate of the neutralizing liquid input terminals. A feedback control module 230 is connected to the adjustment terminals and controls the power of the adjustment terminals based on the pH difference. A greater pH difference increases the delivery rate of the neutralizing liquid input terminals, while a smaller pH difference decreases the delivery rate of the neutralizing liquid input terminals.

[0051] In the process of adjusting the pH value of the neutralizing solvent from 1.8 to 4.0 and adjusting the pH value of the second-stage iron removal and aluminum solution from 5.0 to 7.0, the pH difference changes significantly, and the pH adjustment module 210 can be implemented using the solutions in the first embodiment and / or the second embodiment. However, in the process of adjusting the pH value of the first-stage iron removal and aluminum solution from 4.0 to 5.0 and adjusting the pH value of the nickel-cobalt precipitation solution from 7.0 to 8.0, the pH difference changes slightly, and the adjustment effect of the neutralizing solution input end and adjustment end used by the pH adjustment module 210 in the above-mentioned embodiment is not obvious.

[0052] To address the above issues, the pH adjustment module 210 in this embodiment also includes multiple dilution ports connected to the multiple neutralizing solution input ports. These dilution ports are used to dilute the concentration of the neutralizing solution in the corresponding neutralizing solution input ports. A feedback control module 230 is connected to the dilution ports and controls the delivery rate of the second neutralizing solution input port based on the pH difference. A larger pH difference results in a smaller flow rate at the dilution port, and a smaller pH difference results in a larger flow rate at the dilution port. By diluting the concentration of the neutralizing solution, the pH adjustment rate range is expanded, making it suitable for pH adjustment processes with smaller pH difference fluctuations.

[0053] In order to enable the neutralizing liquid to react quickly with the reaction liquid and ensure the accuracy of the pH value online detection module 220, in one embodiment, the pH value online detection module 220 includes a plurality of detection units, which are arranged in the reaction liquid of the corresponding reaction device 100 to detect the actual pH measurement values ​​at different positions of the reaction liquid. The module also includes a plurality of stirring devices, and the stirring ends of the plurality of stirring devices are respectively built into the reaction liquid of the plurality of reaction devices 100. The feedback control module 230 is connected to the stirring device. If the plurality of actual pH measurement values ​​are different, the feedback control module 230 drives the stirring device to operate. If the plurality of actual pH measurement values ​​are the same, the feedback control module 230 drives the stirring device to stop, and the actual pH measurement value is the actual pH value of the reaction liquid. When the difference between the plurality of actual pH measurement values ​​is greater, the feedback control module 230 controls the stirring speed of the stirring device to increase. When the difference between the plurality of actual pH measurement values ​​is greater, the feedback control module 230 controls the stirring speed of the stirring device to increase. Specifically, one of the detection units is located at the neutralization liquid adding portion of the reaction device 100 , another detection unit is located at the overflow port of the reaction device 100 , and the remaining detection units are evenly arranged in the reaction device 100 .

[0054] When multiple actual pH measurement values ​​are different, it indicates that the neutralization liquid in the reaction device 100 is not mixed evenly. At this time, the reaction liquid is stirred by the stirring end of the stirring device to quickly mix the neutralization liquid and the reaction liquid. When multiple actual pH measurement values ​​are the same, it indicates that the neutralization liquid and the reaction liquid are mixed evenly, and the measured actual pH value of the reaction liquid is relatively accurate.

[0055] At the same time, in order to realize an intelligent stirring process, when the difference between the multiple actual pH measurement values ​​is greater, the corresponding stirring rate is greater, and when the difference between the multiple actual pH measurement values ​​is smaller, the corresponding stirring rate is smaller.

[0056] As shown in FIG3 , an embodiment of the present invention further provides a method for fine control of laterite nickel ore hydrometallurgical post-processing, comprising the above-described fine control system for laterite nickel ore hydrometallurgical post-processing, further comprising the following steps:

[0057] S100, performing pressure acid leaching on the laterite nickel ore, obtaining iron-containing acid leaching residue and acid leaching liquid after solid-liquid separation, pre-neutralizing the acid leaching liquid, and obtaining a reaction solution after solid-liquid separation;

[0058] S200, sequentially inputting the reaction solution into the plurality of reaction devices, and adjusting the pH value of the reaction solution in each reaction device; wherein the pH value adjustment method of the reaction solution in each reaction device is as follows:

[0059] The actual pH value of the reaction liquid in the reaction device is detected, and the pH adjustment rate of the reaction liquid in the reaction device is controlled based on the difference between the preset pH value and the actual pH value of the reaction device.

[0060] As shown in FIG4 , in step S200 , controlling the pH adjustment rate of the reaction liquid in the reaction device based on the difference between the preset pH value and the actual pH value of the reaction device includes:

[0061] S210, the feedback control module compares the actual pH value of the reaction solution in the corresponding reaction device with the preset pH value, and calculates the pH difference;

[0062] S220 , the greater the pH difference, the greater the adjustment rate of the pH adjustment module, and the smaller the pH difference, the smaller the adjustment rate of the pH adjustment module.

[0063] As shown in FIG5 , in step S200 , the step of sequentially inputting the reaction solution into the plurality of reaction devices and adjusting the pH value of the reaction solution in each reaction device includes:

[0064] S230, adjusting the pH value of the reaction solution by a pH adjusting device, and performing a stage of iron and aluminum removal treatment, to obtain a stage of iron and aluminum slag and a stage of iron and aluminum removal liquid after solid-liquid separation;

[0065] S240, adjusting the pH value of the first-stage iron-aluminum removal liquid by a pH adjustment device, and performing a second-stage iron-aluminum removal process, obtaining a second-stage iron-aluminum slag and a second-stage iron-aluminum removal liquid after solid-liquid separation, and returning the second-stage iron-aluminum slag to the pre-neutralization process;

[0066] S250, adjusting the pH value of the second-stage iron removal aluminum solution by a pH adjusting device, and performing a first-stage nickel-cobalt precipitation treatment, to obtain a mixed nickel-cobalt precipitate and a nickel-cobalt precipitation solution after solid-liquid separation;

[0067] S260, adjusting the pH value of the nickel-cobalt precipitation solution by a pH adjusting device, and performing a two-stage nickel-cobalt precipitation process, obtaining a two-stage mixed nickel-cobalt precipitate and a barren solution after solid-liquid separation, and returning the two-stage mixed nickel-cobalt precipitate to the pre-neutralization process.

[0068] In S230 , the neutralized solution is introduced into a first-stage iron and aluminum removal unit. The pH of the reaction solution is adjusted using a pH adjustment unit, and a first-stage iron and aluminum removal process is performed. After solid-liquid separation, a first-stage iron and aluminum slag and a first-stage iron and aluminum removal liquid are obtained. At this point, the first-stage iron and aluminum slag contains only iron and aluminum, while the first-stage iron and aluminum removal liquid contains iron, aluminum, nickel, and cobalt. Further treatment of the first-stage iron and aluminum removal liquid is required.

[0069] In S240, the first-stage deironing liquid is introduced into the second-stage deironing device, where its pH is adjusted by a pH adjustment device. A second-stage deironing treatment is then performed, resulting in a second-stage deironing slag and a second-stage deironing liquid after solid-liquid separation. The second-stage deironing slag contains iron, aluminum, nickel, and cobalt. To achieve precise collection of the nickel and cobalt, the second-stage deironing slag is returned to the pre-neutralization process. Furthermore, the second-stage deironing liquid contains nickel, cobalt, magnesium, zinc, and magnesium, requiring further treatment to produce a pure nickel-cobalt product.

[0070] In S250, the second-stage iron-removal aluminum solution is introduced into the first-stage nickel-cobalt precipitation device. The pH value of the second-stage iron-removal aluminum solution is adjusted by a pH adjustment device, and a first-stage nickel-cobalt precipitation process is performed. After solid-liquid separation, a mixed nickel-cobalt precipitate and a nickel-cobalt precipitation solution are obtained. At this point, the first-stage mixed nickel-cobalt precipitate contains only nickel and cobalt elements, and therefore, this product is the final product desired by this system and has high purity. However, the nickel-cobalt precipitation solution contains nickel and cobalt elements. To avoid waste of nickel and cobalt, the nickel-cobalt precipitation solution needs to be further processed.

[0071] In S260, the nickel-cobalt precipitation solution is introduced into the second-stage nickel-cobalt precipitation device, the pH value of the nickel-cobalt precipitation solution is adjusted by the pH value adjusting device, and the second-stage nickel-cobalt precipitation treatment is carried out. After solid-liquid separation, a second-stage mixed nickel-cobalt precipitate and a lean liquid are obtained, and the second-stage mixed nickel-cobalt precipitate is returned to the pressurized acid leaching process. At this time, the second-stage mixed nickel-cobalt precipitate contains nickel, cobalt, magnesium, zinc and magnesium elements. The nickel and cobalt content in the second-stage mixed nickel-cobalt precipitate is large, but not pure, so it is returned to the pre-neutralization treatment process.

[0072] Since the waste liquid contains manganese and zinc elements, the pH value of the barren liquid is adjusted by a pH regulating device, and manganese precipitation treatment is carried out. After solid-liquid separation, manganese slag and manganese precipitation solution are obtained. The pH value of the manganese precipitation solution is adjusted by a pH regulating device, and magnesium precipitation treatment is carried out. After solid-liquid separation, magnesium slag and magnesium precipitation solution are obtained.

[0073] In order to facilitate understanding of the specific method of refined control in the present invention, different embodiments are described below.

[0074] In the first embodiment, a first stage of iron and aluminum removal is first performed, and the pH value of the reaction solution is 1.8. In this process, it is pre-adjusted to 4.0, that is, the preset pH value is 4.0. In the early stage of adjustment, sodium hydroxide can be added to the reaction solution, wherein the sodium hydroxide delivery rate is 20L / min and the diluent addition rate is 0L / min. In the middle stage of adjustment, calcium hydroxide can be added to the reaction solution, wherein the calcium hydroxide delivery rate is 20L / min and the diluent addition rate is 0L / min. At the end of adjustment, calcium carbonate can be added to the reaction solution until the pH value of the reaction solution reaches 4.0, wherein the calcium carbonate delivery rate is 20L / min and the diluent addition rate is 0L / min. At the same time, the pH value adjustment process of the second stage of iron and aluminum removal, the first stage of nickel and cobalt precipitation, and the second stage of nickel and cobalt precipitation is the same as above.

[0075] In the second embodiment, a first stage of iron and aluminum removal is first performed, and the pH value of the reaction solution is 1.8. In this process, it is pre-adjusted to 4.0, that is, the preset pH value is 4.0. In the early stage of adjustment, calcium hydroxide can be added to the reaction solution, wherein the delivery rate of calcium hydroxide is 20L / min and the addition rate of diluent is 0L / min. In the middle stage of adjustment, calcium hydroxide can be added to the reaction solution, wherein the delivery rate of calcium hydroxide is 10L / min and the addition rate of diluent is 0L / min. At the end of adjustment, calcium hydroxide can be added to the reaction solution until the pH value of the reaction solution is 4.0, wherein the delivery rate of calcium hydroxide is 5L / min and the addition rate of diluent is 0L / min. At the same time, the pH value adjustment process of the second stage of iron and aluminum removal, the first stage of nickel and cobalt precipitation, and the second stage of nickel and cobalt precipitation is the same as above.

[0076] In the third embodiment, a first stage of iron and aluminum removal is first performed, and the pH value of the reaction solution is 1.8. In this process, it is pre-adjusted to 4.0, that is, the preset pH value is 4.0. In the early stage of adjustment, calcium hydroxide can be added to the reaction solution, wherein the calcium hydroxide delivery rate is 20L / min and the diluent addition rate is 5L / min. In the middle stage of adjustment, calcium hydroxide can be added to the reaction solution, wherein the calcium hydroxide delivery rate is 20L / min and the diluent addition rate is 10L / min. At the end of adjustment, calcium hydroxide can be added to the reaction solution until the pH value of the reaction solution is 4.0, wherein the calcium hydroxide delivery rate is 20L / min and the diluent addition rate is 15L / min. At the same time, the pH value adjustment process of the second stage of iron and aluminum removal, the first stage of nickel and cobalt precipitation, and the second stage of nickel and cobalt precipitation is the same as above.

[0077] In the fourth embodiment, the pH value adjustment processes of the first-stage iron and aluminum removal, the second-stage iron and aluminum removal, the first-stage nickel and cobalt precipitation, and the second-stage nickel and cobalt precipitation can all be any one of the embodiments 1-3.

[0078] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A refined control system for laterite nickel ore hydrometallurgical post-processing, characterized in that: It comprises a plurality of reaction devices connected in sequence and a plurality of pH value adjusting devices corresponding to the plurality of reaction devices one by one; wherein each of the reaction devices has a preset pH value, and the preset pH values ​​of any two of the reaction devices are different; Each of the pH value adjusting devices comprises a pH value adjusting module, a pH value online detection module and a feedback control module. The pH value adjusting module is used to adjust the pH value of the reaction liquid in the corresponding reaction device. The pH value online detection module is used to detect the actual pH value of the reaction liquid in the corresponding reaction device. The feedback control module is connected to the pH value adjusting module and the pH value online detection module, and is used to control the adjustment rate of the pH value adjusting module according to the difference between the actual pH value of the corresponding reaction device and the preset pH value.

2. The laterite nickel ore hydrometallurgical post-processing refined control system according to claim 1 is characterized in that: The multiple reaction devices include a first-stage iron and aluminum removal device, a second-stage iron and aluminum removal device, a first-stage nickel and cobalt precipitation device and a second-stage nickel and cobalt precipitation device. The preset pH value of the first-stage iron and aluminum removal device is a first preset pH value, the preset pH value of the second-stage iron and aluminum removal device is a second preset pH value, the preset pH value of the first-stage nickel and cobalt precipitation device is a third preset pH value, and the preset pH value of the second-stage nickel and cobalt precipitation device is a fourth preset pH value. The first preset pH value, the second preset pH value, the third preset pH value and the fourth preset pH value gradually increase.

3. The refined control system for laterite nickel ore hydrometallurgical post-processing according to claim 1 is characterized in that: The pH value adjustment module includes multiple neutralization liquid input ends connected to the corresponding reaction devices, the pH values ​​of the neutralization liquids in the multiple neutralization liquid input ends are different, and the feedback control module is connected to the multiple neutralization liquid input ends to control the opening and closing of the multiple neutralization liquid input ends.

4. The refined control system for laterite nickel ore hydrometallurgical post-processing according to claim 3 is characterized in that: The pH values ​​of the neutralizing solutions in the plurality of neutralizing solution input ends are set in a step-by-step manner.

5. The refined control system for laterite nickel ore hydrometallurgical post-processing according to claim 3, characterized in that: The pH value adjustment module also includes a plurality of adjustment ends corresponding to the plurality of neutralization liquid input ends one by one, and the plurality of adjustment ends are connected to the corresponding neutralization liquid input ends to adjust the delivery rate of the neutralization input ends.

6. The refined control system for laterite nickel ore hydrometallurgical post-processing according to claim 5 is characterized in that: The pH value adjustment module further includes a plurality of dilution ends respectively connected to the plurality of neutralization liquid input ends, and the plurality of dilution ends are used to dilute the concentration of the neutralization liquid in the corresponding neutralization liquid input ends.

7. The refined control system for laterite nickel ore hydrometallurgical post-processing according to claim 1 is characterized in that: The pH value online detection module includes a plurality of detection units, which are arranged in the reaction liquid of the corresponding reaction device to detect the actual pH measurement value at different positions of the reaction liquid, and also includes a plurality of stirring devices, and the stirring ends of the plurality of stirring devices are respectively built in the reaction liquid of the plurality of reaction devices to stir the reaction liquid in the reaction device; One of the detection units is arranged at the neutralization liquid adding position of the reaction device, another detection unit is arranged at the overflow port of the reaction device, and the remaining detection units are evenly arranged in the reaction device.

8. A method for fine control of hydrometallurgical post-processing of laterite nickel ore, characterized in that: The method comprises the refined control system for laterite nickel ore hydrometallurgical post-processing as claimed in any one of claims 1 to 7, further comprising the following steps: The laterite nickel ore is subjected to pressure acid leaching treatment to obtain iron-containing acid leaching residue and acid leaching liquid after solid-liquid separation, the acid leaching liquid is pre-neutralized, and a reaction liquid is obtained after solid-liquid separation; The reaction liquid is sequentially introduced into a plurality of the reaction devices, and the pH value of the reaction liquid in each of the reaction devices is adjusted; wherein the pH value adjustment method of the reaction liquid in each of the reaction devices is as follows: Detect the actual pH value of the reaction liquid in the reaction device, and based on the predicted pH value of the reaction device The difference between the pH value and the actual pH value is used to control the pH adjustment rate of the reaction solution in the reaction device.

9. The method for fine control of laterite nickel ore hydrometallurgical post-processing according to claim 8, characterized in that: The step of controlling the pH adjustment rate of the reaction liquid in the reaction device based on the difference between the preset pH value and the actual pH value of the reaction device comprises: The feedback control module compares the actual pH value of the reaction liquid in the corresponding reaction device with the preset pH value, and calculates the pH difference; The greater the pH difference, the greater the adjustment rate of the pH adjustment module, and the smaller the pH difference, the smaller the adjustment rate of the pH adjustment module.

10. The method for fine control of laterite nickel ore hydrometallurgical post-processing according to claim 8, characterized in that: The step of sequentially inputting the reaction solution into a plurality of reaction devices and adjusting the pH value of the reaction solution in each reaction device comprises: The pH value of the reaction solution is adjusted by a pH adjusting device, and a stage of iron and aluminum removal treatment is performed to obtain a stage of iron and aluminum slag and a stage of iron and aluminum removal liquid after solid-liquid separation; The pH value of the first-stage iron-aluminum removal liquid is adjusted by a pH value adjusting device, and a second-stage iron-aluminum removal treatment is performed, and a second-stage iron-aluminum slag and a second-stage iron-aluminum removal liquid are obtained after solid-liquid separation, and the second-stage iron-aluminum slag is returned to the pre-neutralization treatment process; The pH value of the second-stage iron-removal aluminum solution is adjusted by a pH value adjusting device, and a first-stage nickel-cobalt precipitation treatment is performed to obtain a first-stage mixed nickel-cobalt precipitate and a nickel-cobalt precipitation solution after solid-liquid separation; The pH value of the nickel-cobalt precipitation solution is adjusted by a pH adjusting device, and a two-stage nickel-cobalt precipitation treatment is performed. After solid-liquid separation, a two-stage mixed nickel-cobalt precipitate and a barren solution are obtained, and the two-stage mixed nickel-cobalt precipitate is returned to the pre-neutralization treatment process.

11. The method for fine control of laterite nickel ore hydrometallurgical post-processing according to claim 10, characterized in that: The pH value regulating module is used to output strong base, neutral base and weak base. In the early stage of regulation, the pH difference is large, and the pH value regulating module outputs strong base. In the middle stage of regulation, the pH difference is moderate, and the pH value regulating module outputs neutral base. In the late stage of regulation, the pH difference is small, and the pH value regulating module outputs weak base.

12. The method for fine control of laterite nickel ore hydrometallurgical post-processing according to claim 11, characterized in that: The pH value adjustment module is used to output a diluent. At the end of the adjustment period, the pH value adjustment module outputs a weak base and a diluent.

Images