Method for leaching lithium in clay type lithium ore by using recyclable solid acid

Abstract

The invention discloses a method for leaching lithium in clay type lithium ore by utilizing recyclable solid acid, which belongs to the field of lithium leaching methods and comprises the following steps: step 1, pretreatment: firstly, crushing, grinding and roasting and activating the clay type lithium ore; step 2, leaching: mixing the pretreated minerals with a solid acid solution, and carrying out leaching reaction at set temperature and pressure; thirdly, solid-liquid separation is conducted, specifically, the acid leaching solution is put into a special centrifugal machine for solid-liquid separation, and acid leaching liquid is obtained; and step 4, purification: carrying out purification treatment on the lithium leachate, removing impurities, and finally cooling and crystallizing to obtain high-purity lithium. The method is scientific and reasonable, more sufficient solid-liquid separation of the acid leaching solution is realized by improving process abortion and using a special centrifugal machine, the subsequent lithium purification concentration is improved, and the problem of low lithium purity caused by low filtration degree of the acid leaching solution in a traditional method is solved.

Description

Technical Field

[0001] The invention belongs to the field of lithium leaching methods, in particular to a method for leaching lithium from clay-type lithium ore using recyclable solid acid. Background Art

[0002] Lithium is a lightweight metallic element with a wide range of applications and important strategic significance.

[0003] Lithium occupies an important position in the battery industry due to its high energy density and light weight. Lithium batteries have been widely used in electronic products such as mobile phones, laptops, digital cameras, mobile power tools, and with the development of electric vehicle technology, the application of lithium batteries in the automotive industry is also growing rapidly.

[0004] Lithium is also widely used in the glass and ceramic industries. In glass manufacturing, lithium can reduce the melting temperature and viscosity of the melt, simplify the production process, reduce energy consumption, extend the life of the furnace, increase production, improve operating conditions, and reduce pollution. Lithium-based grease has the advantages of anti-oxidation, pressure resistance, and good lubrication performance, especially it can still maintain good stability at low temperatures, so it is widely used in aircraft, tanks, trains, automobiles, metallurgy, petrochemicals, radio detection and other equipment. As a component of light alloys, ultra-light alloys, wear-resistant alloys and other non-ferrous alloys, lithium can greatly improve the performance of alloys, so it also has a place in the metallurgical industry.

[0005] Lithium plays an indispensable role in nuclear fusion reactors. Deuterium in nuclear fusion is abundant in natural seawater, while tritium is almost non-existent in nature, but both are the main raw materials for nuclear fusion reactions. Metallic lithium plays an important role in the field of controlled nuclear fusion and is known as the "white oil" and "high-energy metal" of the 21st century.

[0006] Lithium not only plays a key role in energy storage, material science, industrial production and other fields, but also has an irreplaceable position in the development of new energy and high-tech fields. With the advancement of technology and the increase in demand for clean energy, the importance of lithium will be further enhanced, so the way to obtain lithium is becoming more and more important.

[0007] Solid acid leaching of lithium from clay-type lithium ores is a chemical treatment method for extracting lithium, which involves using solid acid as a leaching agent to extract lithium from lithium minerals. This method has some significant advantages over traditional liquid acid leaching methods, including lower environmental impact, higher resource utilization efficiency, and better economic benefits. However, the current traditional solid acid leaching method for lithium from clay-type lithium ores still has the problem of low purity of lithium crystals due to low filtration degree of the acid leaching solution.

[0008] Therefore, it is necessary to propose a method for leaching lithium from clay-type lithium ore using recyclable solid acid. Summary of the invention

[0009] In order to solve the problem of low lithium purity caused by low filtration degree of the above-mentioned acid leaching solution, the purpose of the present invention is to provide a method for leaching lithium from clay-type lithium ore using recyclable solid acid.

[0010] In order to achieve the above object, the technical scheme of the present invention is as follows: A method for leaching lithium from clay-type lithium ore using recyclable solid acid, comprising the following steps:

[0011] Step 1: pretreatment, firstly, the clay-type lithium ore is crushed, ground and roasted for activation;

[0012] Step 2: leaching, mixing the pretreated mineral with a solid acid solution and performing a leaching reaction at a set temperature and pressure;

[0013] Step 3: solid-liquid separation: putting the acid leaching solution into a special centrifuge for solid-liquid separation to obtain an acid leaching solution;

[0014] Step 4: purification: purify the lithium leaching solution to remove impurities and finally cool it to obtain high-purity lithium.

[0015] Furthermore, the crushing and grinding process in step one refers to the use of a crusher, an angle grinder and a mixer to break and grind the clay-type lithium ore. The solid matter after the crushing and grinding process is required to be less than 0.2 cm and be round or oval.

[0016] Furthermore, the roasting activation in step 1 refers to roasting and activating the crushed and ground solid matter together with calcium carbonate, with the temperature controlled at 600° C. and the time controlled at 2 hours, which helps to form lithium carbonate in the subsequent leaching step.

[0017] Furthermore, the solid acid solution in step 2 is oxalic acid, and the concentration of the oxalic acid solution is maintained at 9-15 mol / L.

[0018] Furthermore, the leaching in step 2 refers to putting the pretreated solid matter and the oxalic acid solution into a reactor for reaction, the solid-liquid separation ratio of the leaching is 5L / 1kg, the temperature is maintained at 130°C, and the leaching reaction time is 3 hours.

[0019] Furthermore, the speed of the special centrifuge used for solid-liquid separation in step three is set to 10,000 rpm, the time is 10 minutes, the temperature is maintained at 90° C., and the acid leaching solution is subjected to three solid-liquid separation processes.

[0020] Furthermore, the special centrifuge includes a box body, a box cover is detachably connected to the top of the box body, a centrifugal cavity is arranged at the center of the interior of the box body, centrifugal filter screens are arranged on the inner and outer walls of the centrifugal cavity, a cavity and a first motor are arranged below the centrifugal cavity, the first motor is fixedly connected to the center of the cavity, the output shaft of the first motor passes through the cavity and is fixedly connected to the bottom of the centrifugal cavity, three layers of elastic filter screens are arranged on both sides of the centrifugal cavity, and the redundant length below the elastic filter screen is inserted into the cavity.

[0021] Furthermore, a second motor and a cylindrical cam are provided on both sides of the inner wall of the box body, a plurality of slide grooves are provided on the cylindrical cam, the output shaft of the second motor is fixedly connected to the cylindrical cam, one section of the transmission rod is arranged in the slide groove on the cylindrical cam, and the other section of the transmission rod is fixedly connected to the top of the elastic filter screen, a flow chamber is provided between the centrifugal chamber and the box body, and a drainage outlet is opened at the bottom of the flow chamber.

[0022] Furthermore, the purification treatment in step 4 refers to adding a precipitant such as calcium sulfate to the acid leaching solution with complete solid-liquid separation, converting calcium chloride into calcium sulfate precipitate and lithium chloride, and then separating monovalent lithium and divalent ions through a nanofiltration membrane, and then precipitating metal ions by adjusting the pH value, thereby completely purifying the acid leaching solution.

[0023] Further, the acid leaching solution purified in step 4 is cooled and crystallized for purification, the temperature is controlled at 1°C to 2°C, the time is 3 hours, oxalic acid crystals are precipitated, and high-purity lithium is obtained.

[0024] The principles and beneficial effects of the basic solution are:

[0025] 1. Solid acid leaching of lithium is a chemical process for extracting lithium, in which lithium-containing solid materials react with acidic solutions to release lithium ions. Especially when dealing with coal-based lithium ores, this method is more environmentally friendly than traditional inorganic acid leaching because it can achieve the recovery and reuse of solid acid. In this process, oxalic acid is used as a solid acid to leach lithium, and after the leaching process, it can be easily recovered from the leachate through solubility engineering. This method of recycling solid acid has the advantages of simple operation, stable organic phase extraction performance, and continuous multi-stage extraction. It successfully solves the problems of high acidity and difficulty in recovering oxidizing acid in traditional acid stripping processes, and has broad application prospects. Compared with traditional acid leaching, the solid acid of the recyclable solid acid leaching method can be recycled, which reduces the consumption of chemicals, reduces production costs, simplifies the operation process, and improves production efficiency.

[0026] 2. Liquid acid catalysts used in traditional acid leaching methods, such as sulfuric acid and hydrochloric acid, are prone to produce a large amount of waste liquid and waste residue during the reaction process. These wastes need to be specially treated, which increases the environmental burden. Solid acid catalysts can reduce this situation because they will not be lost as easily as liquid acids, thereby reducing the generation of waste. Liquid acid catalysts are highly corrosive to equipment, while solid acid catalysts are relatively mild and have less corrosion to equipment, extending the service life of the equipment and reducing maintenance costs. It is relatively easy to separate solid acid catalysts from raw materials and products, which can achieve catalyst recovery and reuse, reduce resource waste, and also reduce the impact on the environment. Solid acid catalysts usually do not contain toxic and harmful components, while liquid acids used in traditional acid leaching methods often contain substances that are harmful to the human body and the environment. The use of solid acids can avoid the use of these harmful substances and is more environmentally friendly. Solid acid catalysts do not produce harmful gases during use, reducing the health risks to operators and improving the safety of the working environment. The use of solid acid catalysts can reduce energy consumption because they usually work at lower temperatures, reducing energy use and helping to achieve the goal of energy conservation and emission reduction.

[0027] 3. Special centrifuges can quickly separate solids and liquids, and are particularly suitable for processing acid leaching liquids containing a large number of solid particles after acid leaching. Special centrifuges can effectively separate fine solid particles, even micron-level particles can be effectively separated, which is very important for improving product purity and quality. Compared with other solid-liquid separation equipment, special centrifuges have a more compact structure, small footprint, and are easy to install and maintain. The centrifuge has low energy consumption during operation and can achieve continuous operation, reducing energy consumption and operating costs. The structure of the centrifuge is relatively simple, and maintenance and cleaning are relatively easy, which helps to extend the service life of the equipment. The multi-layer shaking filtration structure of the special centrifuge can fully remove chemical reaction precipitates in the acid leaching liquid, reduce impurities in the acid leaching liquid in subsequent steps, and thus increase the lithium concentration after crystallization in the purification step.

[0028] 4. Cooling crystallization can effectively reduce the components of different substances in the mixture in the solvent, while reducing the impurity components, thereby improving the purity of the product. By controlling the cooling rate, crystals of different sizes can be obtained. Rapid cooling can obtain fine crystals, while slow cooling is conducive to the formation of large crystals. The operation of cooling crystallization is relatively simple. It only needs to control the temperature and cooling rate of the solution to achieve the precipitation of crystals. Compared with evaporative crystallization, cooling crystallization does not require a large amount of evaporating solvent during the crystallization process, so it is more energy-saving and environmentally friendly. Cooling crystallization can be used in conjunction with the concentration process. First, the solution is concentrated, and then the cooling crystallization method is used to obtain the desired solid acid crystals, which improves production efficiency and economic benefits.

[0029] 5. Through roasting and activation, the lattice structure of lithium minerals can be destroyed, making lithium more easily released from the minerals, thereby increasing the lithium leaching rate. Roasting and activation can simplify the entire leaching process, reduce subsequent processing steps, and thus reduce production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of a method for leaching lithium from clay-type lithium ore using recyclable solid acid in an embodiment of the present invention.

[0031] Figure 2 It is an axonometric view of the special centrifuge in the embodiment of the present invention.

[0032] Figure 3 It is a side sectional view of a special centrifuge in an embodiment of the present invention. DETAILED DESCRIPTION

[0033] The following is further described in detail through specific implementation methods:

[0034] The figure marks in the drawings of the specification include: box body 1, box cover 2, drainage 3, transmission rod 4, cylindrical cam 5, second motor 6, elastic filter screen 7, centrifugal filter screen 8, flow cavity 9, first motor 10, drainage port 11, centrifugal cavity 12, cavity 13.

[0035] Embodiment 1, basically as attached Figure 1 As shown: A method for leaching lithium from clay-type lithium ore using recyclable solid acid, comprising the following steps:

[0036] Step 1: Pretreatment: First, the clay-type lithium ore is crushed, ground and roasted for activation. The clay-type lithium ore is broken and ground using a crusher, angle grinder and mixer. The solid matter after crushing and grinding is required to be less than 0.2 cm and is round or oval. The round or oval shape increases the reaction contact area during leaching. The solid matter after crushing and grinding is roasted and activated together with calcium carbonate. The temperature is controlled at 600°C and the time is controlled at 2 hours. This is conducive to the formation of lithium carbonate in the subsequent leaching step.

[0037] Step 2: leaching. The pretreated mineral is mixed with a solid acid solution and subjected to leaching reaction at a set temperature and pressure. Oxalic acid is used as the solid acid solution. The concentration of the oxalic acid solution is maintained at 9-15 mol / L. The pretreated solid matter and the oxalic acid solution are placed in a reactor for reaction. The solid-liquid separation ratio of the leaching is 5L / 1kg and the temperature is maintained at 130°C.

[0038] The leaching reaction time is 3 hours;

[0039] Step 3: solid-liquid separation: the acid leaching solution is put into a special centrifuge for solid-liquid separation. The speed of the special centrifuge used for solid-liquid separation is set to 10,000 rpm, the time is 10 minutes, and the temperature is maintained at 90°C. The same acid leaching solution is subjected to three solid-liquid separation processes. The special centrifuge can centrifugally filter the solid impurities in the acid leaching solution, thereby obtaining an acid leaching solution with higher purity;

[0040] Step 4: Purification: The lithium leaching solution is purified by adding a precipitant such as calcium sulfate to the acid leaching solution with complete solid-liquid separation to convert calcium chloride into calcium sulfate precipitate and lithium chloride, and then separating monovalent lithium and divalent ions through a nanofiltration membrane, and then adjusting the pH value to precipitate metal ions, thereby completely purifying the acid leaching solution. Impurities are removed and cooled and crystallized for purification. The temperature is controlled at 1°C to 2°C for 3 hours. The crystallization of oxalic acid facilitates the subsequent recovery of solid acid and obtains high-purity lithium.

[0041] Example 2

[0042] The difference from the above embodiment is that the special centrifuge includes a box body 1, a box cover 2 is detachably connected to the top of the box body 1, a centrifugal chamber 12 is arranged at the center of the box body 1, a centrifugal filter screen 8 is arranged on the inner and outer walls of the centrifugal chamber 12, a cavity 13 and a first motor 10 are arranged below the centrifugal chamber 12, the first motor 10 is fixedly connected to the center of the cavity 13 by screws, the output shaft of the first motor 10 passes through the cavity 13 and is fixedly connected to the bottom of the centrifugal chamber 12, three layers of elastic filter screens 7 are arranged on both sides of the centrifugal chamber 12, and the redundant length below the elastic filter screen 7 is inserted into the cavity 13. A second motor 6 and a cylindrical cam 5 are arranged on both sides of the inner wall of the box body 1, a plurality of slide grooves are arranged on the cylindrical cam 5, the output shaft of the second motor 6 is fixedly connected to the cylindrical cam 5, one end of the transmission rod 4 is arranged in the slide groove on the cylindrical cam 5, and the other end of the transmission rod 4 is fixedly connected to the top of the elastic filter screen 7. A flow chamber 9 is arranged between the centrifugal chamber 12 and the box body 1, and a drainage port 11 is opened at the bottom of the flow chamber 9.

[0043] The specific implementation process is as follows:

[0044] The user opens the box cover 2, puts the acid leaching solution treated by step 1 and step 2 into the centrifugal chamber 12 of the box body 1, and closes the box door. Turn on the switch of the device, the device is powered on and starts running, the first motor 10 is powered on and starts to drive the centrifugal chamber 12 to run at high speed, and the acid leaching solution is filtered through the centrifugal filter 8 by centrifugal force to complete the initial separation. The second motor 6 is powered on and starts to drive the cylindrical cam 5 to rotate, and the transmission rod 4 drives the elastic filter 7 to start up and down reciprocating motion along the running track of the cylindrical cam 5 slideway. During this period, the three elastic filter screens 7 are staggered up and down to dynamically change the filter diameter of the filter screen, completing multiple filtration of solid impurities of different sizes.

[0045] Finally, the filtered acid leaching solution flows into the flow chamber 9, and the user opens the drain port 11 to collect the acid leaching solution with complete solid-liquid separation. The device can cooperate with the solid-liquid separation in step three of the method to achieve a more complete solid-liquid separation of the acid leaching solution to increase the subsequent lithium purification concentration. The special centrifuge can cooperate with the impurity filtering operation in step three to more fully filter the acid leaching solution, thereby increasing the subsequent lithium purification concentration.

[0046] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0047] The above is only an embodiment of the present invention. The common sense such as the known specific structure and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field know all the common technical knowledge in the technical field of the invention before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent. The protection scope required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A method for leaching lithium from clay-type lithium ore using recyclable solid acid, characterized in that: The steps include: Step 1: pretreatment, firstly, the clay-type lithium ore is crushed, ground and roasted for activation; Step 2: leaching, mixing the pretreated mineral with a solid acid solution and performing a leaching reaction at a set temperature and pressure; Step 3: solid-liquid separation: putting the acid leaching solution into a special centrifuge for solid-liquid separation to obtain an acid leaching solution; Step 4: purification: purify the lithium leaching solution to remove impurities and finally cool it to obtain high-purity lithium.

2. The method for leaching lithium from clay-type lithium ore using recyclable solid acid according to claim 1, characterized in that: The crushing and grinding process in step one refers to the use of a crusher, an angle grinder and a mixer to break and grind the clay-type lithium ore. The solid matter after the crushing and grinding process is required to be less than 0.2 cm and be round or oval.

3. A method for leaching lithium from clay-type lithium ore using recyclable solid acid according to claim 2, characterized in that: The roasting activation in step 1 refers to roasting and activating the crushed and ground solid matter together with calcium carbonate, with the temperature controlled at 600° C. and the time controlled at 2 hours.

4. The method for leaching lithium from clay-type lithium ore using recyclable solid acid according to claim 3, characterized in that: The solid acid solution in step 2 is oxalic acid, and the concentration of the oxalic acid solution is maintained at 9-15 mol / L.

5. The method for leaching lithium from clay-type lithium ore using recyclable solid acid according to claim 4, characterized in that: The leaching in step 2 refers to putting the pretreated solid matter and oxalic acid solution into a reactor for reaction, the solid-liquid separation ratio of the leaching is 5L / 1kg, the temperature is maintained at 130°C, and the leaching reaction time is 3 hours.

6. The method for leaching lithium from clay-type lithium ore using recyclable solid acid according to claim 5, characterized in that: The speed of the special centrifuge used for solid-liquid separation in step 3 is set to 10,000 rpm, the time is 10 minutes, the temperature is maintained at 90° C., and the acid leaching solution is subjected to three solid-liquid separation processes.

7. The method for leaching lithium from clay-type lithium ore using recyclable solid acid according to claim 6, characterized in that: The special centrifuge includes a box body, a box cover is detachably connected to the top of the box body, a centrifugal cavity is arranged in the center of the box body, centrifugal filter screens are arranged on the inner and outer walls of the centrifugal cavity, a cavity and a first motor are arranged below the centrifugal cavity, the first motor is fixedly connected to the center of the cavity, the output shaft of the first motor passes through the cavity and is fixedly connected to the bottom of the centrifugal cavity, three layers of elastic filter screens are arranged on both sides of the centrifugal cavity, and the redundant length below the elastic filter screen is inserted into the cavity.

8. The method for leaching lithium from clay-type lithium ore using recyclable solid acid according to claim 7, characterized in that: A second motor and a cylindrical cam are provided on both sides of the inner wall of the box body, a plurality of slide grooves are provided on the cylindrical cam, the output shaft of the second motor is fixedly connected to the cylindrical cam, one section of the transmission rod is arranged in the slide groove on the cylindrical cam, and the other section of the transmission rod is fixedly connected to the top of the elastic filter screen, a flow chamber is provided between the centrifugal chamber and the box body, and a drainage outlet is provided at the bottom of the flow chamber.

9. A method for leaching lithium from clay-type lithium ore using recyclable solid acid according to claim 8, characterized in that: The purification treatment in step 4 refers to adding a precipitant such as calcium sulfate to the acid leaching solution with complete solid-liquid separation, so that the calcium chloride is converted into calcium sulfate precipitate and lithium chloride, and then the monovalent lithium and divalent ions are separated by a nanofiltration membrane, and the metal ions are precipitated by adjusting the pH value.

10. The method for leaching lithium from clay-type lithium ore using recyclable solid acid according to claim 9, characterized in that: The purified acid leaching solution in step 4 is cooled and crystallized for purification, the temperature is controlled at 1°C to 2°C, the time is 3 hours, and oxalic acid crystals are precipitated.

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