Method for extracting lithium in clay type lithium ore through screening, flotation and acid leaching

Abstract

The invention relates to a production technology for extracting high-value elements in clay type lithium ore, in particular to a method for extracting lithium in the clay type lithium ore through screening, flotation and acid leaching. The working process of the method comprises the following steps: grinding the clay type lithium ore by using a crusher, screening the clay type lithium ore by using a standard sieve, screening fractions with high lithium element content, realizing primary enrichment of the lithium element and mechanical activation at the same time, carrying out flotation on the raw ore with the enriched fractions, enriching the lithium element in a concentrate product through flotation, and separating the lithium element from the concentrate product. And leaching the enriched product with sulfuric acid. Compared with a traditional process, a screening and flotation combined process is introduced before acid leaching to carry out mineral separation and enrichment on the raw ore, and the acid consumption and the energy consumption in the subsequent acid leaching process are reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium ore production and processing, and specifically belongs to a method for extracting lithium from clay-type lithium ore through screening-flotation-acid leaching. BACKGROUND

[0002] With the surge in global demand for lithium resources, also known as sedimentary lithium ore, it is known for its wide distribution and large reserves. Clay-type lithium ore with abundant reserves has become an important development target. However, this type of ore has low lithium grade and complex mineral composition (often associated with quartz, feldspar, mica, and other gangue minerals, as well as smectite, illite, and other clay minerals), making it difficult to extract lithium.

[0003] In recent years, significant progress has been made in lithium extraction technology from clay-type lithium ore, with core breakthroughs concentrated in four types of technical paths, but challenges still remain. For example, (1) heating and strengthening acid leaching, CN103849761A patent uses high-temperature and high-concentration sulfuric acid for direct leaching, achieving more than 90% lithium leaching rate under the condition of free roasting, significantly reducing roasting energy consumption and pollution, but the strong acid environment leads to increased equipment corrosion and high waste acid treatment cost; (2) roasting-leaching combined process (such as chlorination roasting with calcium salt reducing agent, sulfuric acid curing high-temperature acidification) CN103849761A patent improves the leaching rate to more than 90% by precisely controlling mineral phase change, but it relies on high-temperature reaction above 800℃, which consumes a lot of energy and easily generates calcium silicate and other by-products to block the lithium release channel; (3) CN116020655A patent selects a combined process of smelting to pre-concentrate lithium through physical separation such as scrubbing-flotation and simultaneously recover high-purity quartz, achieving resource synergistic utilization, but the separation efficiency of fine-grained clay minerals is low, resulting in residual difficult-to-leach lithium in the quartz-recovered mud tailings, causing resource waste; the literature "Study on leaching process conditions of a clay-type lithium ore in Yibin" (2024) mentions that green leaching agents (such as oxalic acid) significantly reduce environmental risks, but the actual leaching efficiency is less than 70%, and the industrialization economic efficiency is questionable; in addition, the existing technical document CN202310706335.4 patent involves a complex lithium extraction process, including cleaning, grading, desliming, reverse flotation to remove aluminum, and reverse flotation to remove silicon, etc. multiple steps, the leaching rate of lithium element is low, the requirements for equipment and site are high, and the tailings generated are difficult to handle, improper handling may cause environmental pollution.

[0004] The above bottleneck - strong acid corrosion, high energy consumption, low efficiency of fine particle separation, tailings residual lithium loss and insufficient green process efficiency - jointly restricts the economic and green development of clay lithium resources. The present application provides a method for extracting lithium from clay-type lithium ore. Compared with the traditional process, the present method uses sulfuric acid leaching and introduces a combined process of screening and flotation before acid leaching to concentrate the raw ore. Unlike ordinary acid leaching process which requires strong acid leaching of all mineral components, the present method only leaches the concentrated mineral components, which can effectively reduce the acid consumption and energy consumption of the subsequent acid leaching process. In addition, the present method has a more simple and complete process flow. SUMMARY

[0005] The present application aims to provide a method for extracting lithium from clay-type lithium ore by screening, flotation and acid leaching, which can improve efficiency while reducing energy consumption.

[0006] The present application is realized by the following technical scheme. A method for extracting lithium from clay-type lithium ore by screening, flotation and acid leaching, comprising the following steps: Firstly, dry the clay-type lithium ore raw ore, crush the dried ore by a crusher, and then screen it by a vibrating screen, and select the screened ore powder as the raw material; Secondly, mix the screened ore powder with water to prepare a slurry, and stir to ensure uniform dispersion of the slurry; Thirdly, add a collector to the slurry to allow the collector to fully interact with the target minerals; Fourthly, add a frother to the slurry to allow the frother to fully disperse; Fifthly, pump the prepared slurry into a flotation machine, start the scraper device to collect the froth product as the flotation concentrate; Sixthly, pump the flotation concentrate into a filter press or vacuum filter for solid-liquid separation to obtain a concentrate filter cake with low water content; Seventhly, re-slurry the concentrate filter cake with water, add sulfuric acid to the leaching tank to adjust the solution acidity to 1-3 mol / L, start the stirrer, and introduce steam to heat and maintain the slurry temperature at 60-90℃, and conduct leaching reaction for 2-3 hours under this condition. After the leaching is completed, a lithium-containing leaching solution and a leaching residue are obtained.

[0007] Further, in the first step, after drying the clay-type lithium ore raw ore, screen it by a vibrating screen, and select the ore powder with a particle size of 120-160 mesh as the raw material.

[0008] Further, in the second step, mix the screened ore powder with water in a slurry tank at a solid content (mass ratio) of 5%-10% to prepare a slurry, start the stirrer to stir for 5-10 minutes to ensure uniform dispersion of the slurry.

[0009] Further, in the third step, the collector is dodecylamine, or octadecylamine hydrochloride, or dodecyloxypropylamine, or coconut ether amine, one of which.

[0010] Further, in the fourth step, a frother is added to the pulp tank, which is methyl isobutyl carbinol (MIBC), or secondary octanol, or pine oil, or polyethylene glycol ether, one of which.

[0011] Further, in the first step, the clay type lithium ore is dried in the sun for 10-15 days, and the dried ore is crushed by a crusher.

[0012] Further, after adding the collector to the ore pulp, stirring for 5-10 minutes, the collector fully acts on the target mineral.

[0013] Further, the frother is added to the pulp tank and continues to stir for 5-10 minutes, so that the frother is fully dispersed.

[0014] Further, in the seventh step, the concentrate filter cake is mixed with water in a mass ratio of 1:5 in a leaching tank, and the slurry is re-slurried, sulfuric acid (H2SO4) is added to the leaching tank, the solution acidity is adjusted to 2.5 mol / L, the stirrer is started, and steam is introduced to heat and maintain the temperature of the ore slurry at 85℃, and the leaching reaction is carried out under the above conditions for 2 hours. After the leaching is completed, a lithium-containing leaching solution and a leaching residue are obtained.

[0015] Compared with the prior art, the process method does not use cleaning, grading, magnetic separation and other processes, and reduces the use of a large amount of equipment. After direct crushing, slurry, flotation and acid leaching, most of the lithium elements are leached, which is easy to operate and improves the efficiency in production. The prior art uses reverse flotation multiple times to remove silicon, aluminum and other substances, which is complicated. The present application can directly use the frother to screen the target elements for flotation, realize the pre-concentration of lithium elements, improve the acid leaching efficiency and reduce the energy consumption. In summary, the process of the present application is simple, has obvious energy saving advantages and strong practicability. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 The flotation concentrate photo described in the process of the present application; Figure 2 The flotation tailings photo described in the process of the present application; Figure 3 The acid leaching residue photo described in the process of the present application.

[0017] From the electron microscope photos of the flotation results, the particle sizes of the flotation concentrate and the flotation tailings are relatively small, which meets the product characteristics after the flotation process, indicating that the effective crushing and screening process has been carried out, so that the mineral particles reach the appropriate size for subsequent flotation separation.

[0018] Flotation concentrate: The mineral particles are relatively regular in shape with clear edges, which may indicate the enrichment characteristics of lithium minerals after the flotation process. The particle surfaces are relatively smooth, which may be due to the interaction of lithium minerals with reagents such as collectors during the flotation process, forming a regular surface structure that makes it easier for bubbles to attach and float. After the flotation process, they are effectively collected.

[0019] Flotation tailings: The mineral particles are irregular in shape with blurred edges, which may contain more gangue minerals (such as quartz, feldspar, etc.). The particle distribution is relatively dispersed, indicating that these minerals were separated during the flotation process and did not enter the concentrate part. The particle surface is rough, indicating the characteristics of minerals that have not been effectively enriched. These minerals may not have fully interacted with the collector due to their different surface properties from lithium minerals, thus being left in the tailings during the flotation process.

[0020] Figure 3 The electron microscope image of the acid leaching residue shows the characteristics of the clay-type lithium ore after sulfuric acid leaching. The particle size is uneven, the distribution is uneven, the shape is irregular, the surface is rough, and there are pores and cracks, indicating that the dissolution and reaction of the acid leaching process on the mineral are partially effective, but there are still minerals that have not completely reacted. DETAILED DESCRIPTION

[0021] The present application will be further illustrated by specific examples.

[0022] Experimental design: Leaching rate calculation method: Leaching rate is an important indicator to measure the extraction efficiency of lithium elements from raw ore, and its calculation formula is as follows: Where: C is the concentration of lithium elements in the acid leaching solution (ppm); V is the volume of acid leaching solution (ml); M is the mass of raw ore (g); P is the content of lithium elements in raw ore (ppm).

[0023] Flotation recovery rate calculation method: The flotation mineral recovery rate is the core indicator to evaluate the separation efficiency, which represents the proportion of target minerals recovered from raw ore.

[0024] Where: is the mass of concentrate after flotation (g); is the concentrate grade after flotation (ppm); is the mass of raw ore before flotation (g); is the grade of the raw ore before flotation (ppm).

[0025] Drug source: dodecylamine (analytical pure AR, Shanghai Macklin Biotechnology Co., Ltd.), or octadecylamine hydrochloride (analytical pure AR, Delta Biotechnology Co., Ltd.), or dodecyloxypropylamine (analytical pure AR, Aladdin Biochemical Technology Co., Ltd.), or coconut ether amine (industrial grade, Shandong Yousuo Chemical Co., Ltd.), methyl isobutyl carbinol (analytical pure AR, Shanghai Macklin Biotechnology Co., Ltd.), or secondary octanol (reagent grade, Shanghai Macklin Biotechnology Co., Ltd.), or pine oil (chemical pure CP, Shanghai Yinn Chemical Technology Co., Ltd.), or polyethylene glycol ether (experimental pure LR, Shanghai Macklin Biotechnology Co., Ltd.), sulfuric acid (analytical pure AR, National Pharmaceutical Group Chemical Reagent Co., Ltd.) Example 1 A method for extracting lithium from clay-type lithium ore by screening-flotation-acid leaching, comprising the following steps: Firstly, the clay-type lithium ore is dried in the sun for 15 days, and then the dried ore is crushed by a crusher and screened by a vibrating screen. The ore powder with a particle size of 120-160 meshes is selected as the raw material. Secondly, the screened ore powder is mixed with water in a slurry tank at a solid content of 5% (mass ratio) to prepare a slurry. A stirrer is started to stir for 10 minutes to ensure uniform dispersion of the slurry. Thirdly, dodecylamine is added to the slurry as a collector and stirred for 10 minutes to ensure that the collector fully interacts with the target minerals. Fourthly, a foaming agent methyl isobutyl carbinol (MIBC) is added to the slurry tank and continues to be stirred for 10 minutes to ensure that the foaming agent is fully dispersed. Fifthly, the prepared slurry is pumped into a flotation machine, and a scraper device is started to perform continuous scraping and foaming operation for 8 minutes. The collected foam product is used as the flotation concentrate. Sixthly, the flotation concentrate is pumped into a filter press or vacuum filter for solid-liquid separation to obtain a concentrate filter cake with low water content. Seventhly, the concentrate filter cake is mixed with water in a leaching tank at a mass ratio of 1:6 to re-slurry. Sulfuric acid (H2SO4) is added to the leaching tank to adjust the solution acidity to 3 mol / L. A stirrer is started, and steam is introduced to heat and maintain the temperature of the slurry at 75°C. The leaching reaction is carried out for 3 hours under this condition. After the leaching is completed, a lithium-containing leaching solution and a leaching residue are obtained, and the leaching rate of lithium element can reach 74%.

[0026] Example 2 A method for extracting lithium from clay-type lithium ore by screening-flotation-acid leaching, comprising the following steps: First step, dry the raw clay-type lithium ore by sunning for 13 days, crush the dried ore by a crusher, then screen the crushed ore by a vibrating screen, select the 120-160 mesh size fraction of the ore powder as the raw material; Second step, mix the screened qualified ore powder with water in a slurry tank at a solid content of 8% (mass ratio), configure the mixture into a slurry, start the agitator to stir for 8 minutes to ensure the uniform dispersion of the slurry; Third step, add the collector dodecyl oxy propyl amine to the slurry, stir for 6 minutes to make the collector fully act on the target minerals; Fourth step, add the frother sec-octyl alcohol to the slurry tank, continue to stir for 9 minutes to make the frother fully dispersed; Fifth step, pump the prepared slurry into a flotation machine, start the scraper device, and perform 5 minutes of continuous froth scraping operation, collect the froth product as the flotation concentrate; Sixth step, pump the flotation concentrate into a filter press or vacuum filter for solid-liquid separation, and obtain the concentrate filter cake with low water content; Seventh step, mix the concentrate filter cake with water in a leaching tank at a mass ratio of 1:4, re-slurry, add sulfuric acid (H2SO4) to the leaching tank to adjust the solution acidity to 2 mol / L, start the agitator, and pass in steam to heat and maintain the slurry temperature at 60°C, perform the leaching reaction for 2 hours under this condition, after the leaching is completed, obtain the lithium-containing leaching solution and leaching residue, and the leaching rate of lithium element can reach 72%.

[0027] Example 3 A method for extracting lithium from clay-type lithium ore by screening-flotation-acid leaching, comprising the following steps: First step, dry the raw clay-type lithium ore by sunning for 11 days, crush the dried ore by a crusher, then screen the crushed ore by a vibrating screen, select the 120-160 mesh size fraction of the ore powder as the raw material; Second step, mix the screened qualified ore powder with water in a slurry tank at a solid content of 9% (mass ratio), configure the mixture into a slurry, start the agitator to stir for 7 minutes to ensure the uniform dispersion of the slurry; Third step, add coconut ether amine as the collector to the slurry, stir for 8 minutes to make the collector fully act on the target minerals; Fourth step, add the frother pine oil to the slurry tank, continue to stir for 8 minutes to make the frother fully dispersed; Fifth step, pump the prepared slurry into a flotation machine, start the scraper device, and perform 9 minutes of continuous froth scraping operation, collect the froth product as the flotation concentrate; Sixth step, pump the flotation concentrate into a filter press or vacuum filter for solid-liquid separation, and obtain the concentrate filter cake with low water content; Step 7, mix the concentrate filter cake with water in a mass ratio of 1:4 in the leaching tank, re-slurry, add sulfuric acid (H2SO4) to the leaching tank, adjust the solution acidity to 2 mol / L, start the stirrer, and pass in steam to heat and maintain the temperature of the ore slurry at 60℃. Under this condition, carry out a 2-hour leaching reaction. After the leaching is completed, a lithium-containing leaching solution and a leaching residue are obtained, and the leaching rate of lithium element can reach 70%.

[0028] Example 4 A method for extracting lithium from clay-type lithium ore by screening-flotation-acid leaching, comprising the following steps: Step 1, dry the clay-type lithium ore raw ore in the sun for 12 days, crush the dried ore with a crusher, and then screen it through a vibrating screen. Select the 120-160 mesh size ore powder as the raw material; Step 2, mix the screened qualified ore powder with water in a solid content of 8% (mass ratio) in the slurry tank to configure the ore slurry. Start the stirrer and stir for 6 minutes to ensure uniform dispersion of the ore slurry; Step 3, add octadecylamine hydrochloride as a collector to the ore slurry and stir for 7 minutes to allow the collector to fully interact with the target minerals; Step 4, add the foaming agent polyethylene glycol ether to the slurry tank and continue to stir for 7 minutes to allow the foaming agent to fully disperse; Step 5, pump the prepared ore slurry into the flotation machine and start the scraper device for 8 minutes of continuous scraping and foaming operation. Collect the foam product as the flotation concentrate; Step 6, pump the flotation concentrate into a filter press or vacuum filter for solid-liquid separation to obtain a concentrate filter cake with low water content; Step 7, mix the concentrate filter cake with water in a mass ratio of 1:5 in the leaching tank, re-slurry, add sulfuric acid (H2SO4) to the leaching tank, adjust the solution acidity to 2.5 mol / L, start the stirrer, and pass in steam to heat and maintain the temperature of the ore slurry at 85℃. Under this condition, carry out a 2-hour leaching reaction. After the leaching is completed, a lithium-containing leaching solution and a leaching residue are obtained, and the leaching rate of lithium element reaches 66%.

[0029] Example 5 A method for extracting lithium from clay-type lithium ore by screening-flotation-acid leaching, comprising the following steps: Step 1, dry the clay-type lithium ore raw ore in the sun for 10 days, crush the dried ore with a crusher, and then screen it through a vibrating screen. Select the 120-160 mesh size ore powder as the raw material; Step 2, mix the screened qualified ore powder with water in a solid content of 8% (mass ratio) in the slurry tank to configure the ore slurry. Start the stirrer and stir for 5 minutes to ensure uniform dispersion of the ore slurry; Step 3, add octadecylamine hydrochloride as a collector to the ore slurry and stir for 5 minutes to allow the collector to fully interact with the target minerals; Fourth step, add the frother 2-octanol into the conditioning tank, continue to stir for 8 minutes to make the frother fully dispersed; Fifth step, pump the prepared ore slurry into the flotation machine, start the scraping device, and perform continuous froth scraping operation for 9 minutes to collect the froth product as the flotation concentrate; Sixth step, pump the flotation concentrate into the filter press or vacuum filter for solid-liquid separation to obtain the concentrate filter cake with low water content; Seventh step, mix the concentrate filter cake with water in a mass ratio of 1:6 in the leaching tank to re-slurry, add sulfuric acid (H2SO4) into the leaching tank to adjust the solution acidity to 2 mol / L. Start the stirrer and input steam to heat and maintain the temperature of the ore slurry at 90℃, and perform the leaching reaction under this condition for 3 hours. After the leaching is completed, the leaching solution containing lithium and the leaching residue are obtained, and the leaching rate of lithium element reaches 68%.

[0030] The detailed comparative data of Examples 1-5 are shown in Table 1 below: Table 1 Table 1 (continued) Table 1 (continued)

Claims

1. A method for extracting lithium from clay-type lithium ore by screening-flotation-acid leaching, characterized in that it comprises the following steps: Step 1: Dry the clay-type lithium ore, crush the dried ore with a crusher, and then screen it with a vibrating screen, and select the ore powder of a certain size range as the raw material; Step 2: Mix the screened ore powder with water to form a slurry, and stir to ensure uniform dispersion of the slurry; Step 3: Add a collector to the slurry to allow the collector to fully interact with the target minerals; Step 4: Add a frother to the slurry tank to allow the frother to fully disperse; Step 5: Pump the prepared slurry into a flotation machine, start the scraper device to collect the froth product as the flotation concentrate; Step 6: Pump the flotation concentrate into a filter press or vacuum filter for solid-liquid separation to obtain a concentrate filter cake with low water content; Step 7: Re-slurry the concentrate filter cake with water, add sulfuric acid to the leaching tank, adjust the solution acidity to 1-3 mol / L, start the stirrer, and introduce steam to heat and maintain the slurry temperature at 60-90℃, and conduct leaching for 2-3 hours under these conditions, and after the leaching is completed, obtain a lithium-containing leaching solution and a leaching residue.

2. The method for extracting lithium from clay-type lithium ore by screening-flotation-acid leaching according to claim 1, characterized in that: in Step 1, after drying the clay-type lithium ore, screen it with a vibrating screen, and select the ore powder of 120-160 mesh size range as the raw material.

3. The method for extracting lithium from clay-type lithium ore by screening-flotation-acid leaching according to claim 1, characterized in that: in Step 3, the collector is dodecylamine, or octadecylamine hydrochloride, or dodecyloxypropylamine, or coconut ether amine.

4. The method for extracting lithium from clay-type lithium ore by screening-flotation-acid leaching according to claim 1, characterized in that: in Step 4, the frother added to the slurry tank is methyl isobutyl carbinol (MIBC), or sec-octyl alcohol, or pine oil, or polyethylene glycol ether.

5. The method for extracting lithium from clay-type lithium ore by screening-flotation-acid leaching according to claim 1, characterized in that: in Step 7, mix the concentrate filter cake with water in a mass ratio of 1:5 in the leaching tank to re-slurry, add sulfuric acid (H2SO4) to the leaching tank, adjust the solution acidity to 2.5 mol / L, start the stirrer, and introduce steam to heat and maintain the slurry temperature at 85℃, and conduct leaching for 2 hours under these conditions, and after the leaching is completed, obtain a lithium-containing leaching solution and a leaching residue.

6. The method for extracting lithium from clay-type lithium ore by screening-flotation-acid leaching according to claim 1, characterized in that: in Step 2, mix the screened ore powder with water in the slurry tank at a solid content of 5%-10% (mass ratio) to form a slurry, start the stirrer and stir for 5-10 minutes to ensure uniform dispersion of the slurry.

7. The method for extracting lithium from clay-type lithium ore by screening-flotation-acid leaching according to claim 1, characterized in that: in Step 1, dry the clay-type lithium ore in the sun for 10-15 days, and then crush the dried ore with a crusher.

8. The method for extracting lithium from clay-type lithium ore by screening-flotation-acid leaching according to claim 1, characterized in that: after adding the collector to the slurry, stir for 5-10 minutes to allow the collector to fully interact with the target minerals.

9. The method for extracting lithium from clay-type lithium ore by screening-flotation-acid leaching according to claim 1, characterized in that: after adding the frother to the slurry tank, continue to stir for 5-10 minutes to allow the frother to fully disperse. ​ ​ ​ ​ 4. The method for lithium extraction from clay-type lithium ores by screening-flotation-acid leaching according to claim 1, characterized in that: ​ ​ ​ ​ ​ 7. The method for extracting lithium from a clay-type lithium ore by screening-flotation-acid leaching according to claim 1 or 2, characterized in that: ​ 8. The method for extracting lithium from a clay-type lithium ore by screening-flotation-acid leaching according to claim 1 or 3, characterized in that: ​ 9. The method of extracting lithium from a clay-type lithium ore by screening-flotation-acid leaching according to claim 1 or 4, characterized in that: ​

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