阅读说明：本技术 油漆废水处理用膨润土及其制备方法 (Bentonite for treating paint wastewater and preparation method thereof ) 是由 王子军 王子力 王小立 孙海玉 李树军 张磊 李颖 于 2021-10-26 设计创作，主要内容包括：本发明提供一种油漆废水处理用膨润土及其制备方法,该膨润土是以冰醋酸酸化膨润土原矿,并经过锂化剂配合增益剂进行改性制得；上述增益剂为氯化铝。其制备方法包括：提供冰醋酸和分散剂,对含有膨润土原矿的浆料进行活化,制成浆液；对浆液进行除砂和提纯；提供锂化剂A、锂化剂B和增益剂,对提纯所得浆液进行分段式锂化改性；对锂化改性所得反应液进行干燥和过筛,制得油漆废水处理用膨润土。本发明的膨润土的制备方法,用以解决锂基膨润土在体系中悬浮性差、分层析水严重的问题,能提高锂基膨润土的吸附能力和分散稳定性,提升锂化改性反应的交换效率和改性效果,提高产品的悬浮性能、增稠性能和膨润性能,方法简单易行,生产成本低。(The invention provides a bentonite for treating paint wastewater and a preparation method thereof, wherein the bentonite is prepared by acidifying raw ore of bentonite with glacial acetic acid and modifying the raw ore by a lithifying agent and a gain agent; the gain agent is aluminum chloride. The preparation method comprises the following steps: providing glacial acetic acid and a dispersing agent, and activating the slurry containing the bentonite raw ore to prepare slurry; desanding and purifying the slurry; providing a lithiating agent A, a lithiating agent B and a gain agent, and carrying out sectional lithiation modification on the slurry obtained by purification; and drying and sieving the reaction liquid obtained by lithiation modification to prepare the bentonite for treating the paint wastewater. The preparation method of the bentonite is used for solving the problems of poor suspension property and serious layered water separation of the lithium bentonite in a system, can improve the adsorption capacity and dispersion stability of the lithium bentonite, improves the exchange efficiency and modification effect of lithiation modification reaction, and improves the suspension property, thickening property and swelling property of the product, and has the advantages of simple and easy method and low production cost.)

1. A preparation method of bentonite for treating paint wastewater is characterized by comprising the following steps:

providing glacial acetic acid and a dispersing agent, and activating the slurry containing the bentonite raw ore to prepare slurry;

desanding and purifying the slurry;

providing a lithiating agent A, a lithiating agent B and a gain agent, and carrying out sectional lithiation modification on the slurry obtained by purification; and the number of the first and second groups,

drying and sieving the reaction liquid obtained by lithiation modification to prepare the bentonite for treating the paint wastewater;

the lithiating agent A and the lithiating agent B are one or more of lithium oxide, lithium hydroxide, lithium carbonate, lithium sulfate, lithium nitrate, lithium chloride and lithium fluoride.

2. The method of claim 1, wherein: the activation operation is divided into acidification and dispersion; the acidification operation is specifically as follows: adding glacial acetic acid into the slurry containing the bentonite raw ore according to the weight ratio of 0.5-2 per mill, and then stirring for 0.5-1h to prepare the acidic slurry.

3. The method of claim 2, wherein: the dispersion operation is specifically as follows: adding a dispersing agent into the acidic slurry according to the weight ratio of 4-6 per mill, and then stirring for 0.5-1h to prepare slurry.

4. A method according to claim 1 or 3, characterized in that: the dispersing agent is one or more of sodium hexametaphosphate, sodium pyrophosphate and sodium silicate.

5. The method of claim 1, wherein: the steps of the sectional type lithiation modification are as follows: adding a lithiating agent A into the slurry obtained by purification, heating and stirring for reaction to complete primary lithiation reaction to obtain a reaction liquid A; continuously stirring the reaction solution A and heating, then adding a lithiating agent B, stirring and carrying out heat preservation reaction to complete secondary lithiation reaction to obtain reaction solution B; and adding an aluminum chloride gain agent into the reaction liquid B, stirring and reacting to obtain a reaction liquid C, and completing lithiation modification.

6. The method of claim 5, wherein: the temperature of the primary lithiation reaction is 70-75 ℃, and the time is 1-1.5 h; the addition amount of the lithiating agent A is 2.0-4.0% of the weight of the bentonite raw ore.

7. The method of claim 5, wherein: the temperature of the secondary lithiation reaction is 80-85 ℃, and the time is 1-1.5 h; the addition amount of the lithiating agent B is 1.0-2.0% of the weight of the bentonite raw ore.

8. The method of claim 5, wherein: the addition amount of the gain agent is 0.5-1.0% of the weight of the bentonite raw ore; the reaction conditions of the reaction solution C are as follows: the temperature is 80-85 ℃, and the stirring reaction time is 0.5-1.5 h.

9. A bentonite for paint wastewater treatment prepared by the method of any one of claims 1 to 8, characterized in that: the bentonite is prepared by acidifying raw bentonite ore with glacial acetic acid and modifying the raw bentonite ore by a lithifying agent and a gain agent; the gain agent is aluminum chloride.

10. The application method of the bentonite for wastewater treatment is characterized by comprising the following steps: the bentonite obtained by the method of any one of claims 1 to 8 is added with water to prepare a solution with a concentration of 3 to 4%, and then is used in combination with cationic polyacrylamide.

Technical Field

The invention relates to the technical field of bentonite manufacturing, in particular to bentonite for paint wastewater treatment and a preparation method thereof.

Background

The clay products have various unique excellent properties such as smoothness, adsorptivity and expansibility, so the clay products are widely applied to industrial departments such as agriculture, light industry, metallurgy, chemical industry, building materials, machinery, national defense, environmental protection and the like. China has abundant bentonite resources, which is the top of the world, the content of bentonite is more than 40-80%, but most products are calcium bentonite. With the development of various industries and the expansion of the application range of bentonite, the deep processing modification of bentonite is more and more emphasized. There are two main ways to modify: the first is sodium modification, and the second is organic coating modification. However, the sample obtained by the former method cannot expand in an organic solvent, and the organic bentonite obtained by modifying the latter method is widely applied but expensive.

The lithium bentonite has a unique layered magnesium aluminum silicate structure, and Li is mainly distributed among layers⁺. The modified starch can form a special 'card house type' structure when dispersed in an aqueous solution, has excellent suspension property, rheological property and colloid property, has the characteristics of high viscosity, high dispersion, no toxicity, no odor, environmental friendliness and the like, and thus has excellent suspension, anti-settling, thixotropic and thickening effects. The lithium bentonite has the characteristics of sodium bentonite and the functions of organic bentonite, and can replace organic bentonite in many fields, so the lithium bentonite has higher value and development prospect.

The research and development of the lithium-based bentonite in China are relatively late, and more than the application of the lithium-based bentonite. Because natural lithium bentonite is not found in China at present, lithium salt is usually adopted to carry out lithiation modification on natural calcium bentonite in order to obtain low-cost high-performance lithium bentonite. The common modification method comprises the following steps: the lithium bentonite is prepared by adding a certain lithifying agent into natural calcium bentonite under certain conditions. When the existing modification process is used for preparation, the modification exchange efficiency is low, and the prepared lithium bentonite has weak lithiation performance, poor suspension performance and poor application effect. Therefore, when the lithium bentonite is applied to the field of wastewater treatment, the adding amount of the lithium bentonite is not easy to master in the face of working conditions of various pollutants and uneven concentration in wastewater, and the wastewater treatment effect is easy to influence.

Therefore, it is a subject of research by those skilled in the art how to fully lithiate bentonite in a modification reaction, improve the suspension performance of lithium bentonite, and reduce the impurity content thereof.

Disclosure of Invention

The invention provides a preparation method of bentonite for treating paint wastewater, which is used for solving the problems of poor suspension property and serious layered water separation of lithium bentonite in a system, improving the adsorption capacity and dispersion stability of the lithium bentonite, improving the exchange efficiency and modification effect of lithiation modification reaction, and improving the suspension property, thickening property and swelling property of a product.

Specifically, the invention provides a preparation method of bentonite for treating paint wastewater, which comprises the following steps:

providing glacial acetic acid and a dispersing agent, and activating the slurry containing the bentonite raw ore to prepare slurry;

desanding and purifying the slurry;

providing a lithiating agent A, a lithiating agent B and a gain agent, and carrying out sectional lithiation modification on the slurry obtained by purification; and the number of the first and second groups,

drying and sieving the reaction liquid obtained by lithiation modification to prepare the bentonite for treating the paint wastewater;

the lithiating agent A and the lithiating agent B are one or more of lithium oxide, lithium hydroxide, lithium carbonate, lithium sulfate, lithium nitrate, lithium chloride and lithium fluoride.

Further setting the mass concentration of the raw bentonite ore in the slurry to be 5-7%.

Preferably, the viscosity of the bentonite raw ore is not lower than 15mp · s, and the bentonite raw ore is dried until the water content is less than 8.0%. The slurry with proper concentration is prepared according to the viscosity of the raw ore, so that the problem that the slurry has high viscosity due to overlarge concentration of bentonite and is not beneficial to later-stage purification and modification reaction can be avoided; and the problem that the solid content of the slurry is low due to the fact that the concentration of the bentonite is too low can be avoided, so that the drying cost of the reaction liquid in the later period is increased.

It is further configured that the above-mentioned activation operation is divided into acidification and dispersion. The acidification operation is specifically as follows: adding glacial acetic acid into the slurry containing the bentonite raw ore according to the weight ratio of 0.5-2 per mill, and then stirring for 0.5-1h to prepare the acidic slurry. The existence of acid can increase the specific surface area and surface acid site concentration of the bentonite, remove impurities in pore channels, loosen pore structures and improve the activation performance of the bentonite, thereby improving the adsorption capacity of the bentonite, providing a foundation for the modification and application of the bentonite and reducing the damage of pollutants to the environment.

The dispersing operation is further configured as follows: adding a dispersing agent into the acidic slurry according to the weight ratio of 4-6 per mill, and then stirring for 0.5-1h to prepare slurry. Make surperficial electric double layer outwards extend behind bentonite surface adsorption dispersant for the electronegativity on increase bentonite surface, make the increase of electrostatic repulsion force between the ore grain, make the dispersion stability of thick liquid can improve, be favorable to promoting the edulcoration purification effect of bentonite.

Further, the dispersing agent is one or more of sodium hexametaphosphate, sodium pyrophosphate and sodium silicate. Preferably, the dispersant is sodium pyrophosphate.

Further, the sand removing and purifying steps are as follows: and (3) carrying out primary desanding on the slurry through a 100-mesh screen, carrying out primary fine purification on the desanded slurry through a cyclone with the inner diameter of 100mm, carrying out secondary desanding on the purified slurry through a 150-mesh screen, and carrying out secondary fine purification through the cyclone with the inner diameter of 100 mm. The bentonite and fine impurities are easy to separate by acidification and promotion of a dispersing agent, and the impurities are largely removed after sieving and rotational flow, so that the suspension property of the bentonite is improved.

The method is further provided with the following steps of sectional lithiation modification: adding a lithiating agent A into the slurry obtained by purification, heating and stirring for reaction to complete primary lithiation reaction to obtain a reaction liquid A; continuously stirring the reaction solution A and heating, then adding a lithiating agent B, stirring and carrying out heat preservation reaction to complete secondary lithiation reaction to obtain reaction solution B; and adding an aluminum chloride gain agent into the reaction liquid B, stirring and reacting to obtain a reaction liquid C, and completing lithiation modification.

By adopting sectional type lithiation modification reaction, when the ion exchange reaction is slowed down along with the increase of the calcium ion concentration in the primary lithiation reaction system, the secondary lithiation reaction is utilized to promote the calcium ions to form precipitate, so that the calcium ion concentration in the system is reduced, the ion exchange can be carried out more fully, and the bentonite modification efficiency and modification effect are improved.

It is further provided that the components of lithiating agent a and lithiating agent B are not the same. More preferably, lithiating agent a is lithium chloride and lithiating agent B is lithium carbonate. The lithiating agent A and the lithiating agent B are matched with the gain agent for modification, so that the cation exchange capacity can be improved, the exchange efficiency and the modification effect of bentonite can be improved, the bentonite is fully lithiated and modified, the product quality is improved, and the lithium bentonite product has better suspension performance, thickening performance and expansion performance.

Further setting the temperature of the primary lithiation reaction to be 70-75 ℃ and the time to be 1-1.5 h; the addition amount of the lithiating agent A is 2.0-4.0% of the weight of the bentonite raw ore. By utilizing high temperature and mechanical stirring, the dispersion of the lithiating agent in the bentonite slurry is more uniform, the diffusion coefficient is increased, the contact area of the bentonite and lithium ions is increased, the ion exchange speed is accelerated, and the full and high-efficiency modification reaction is ensured.

Further setting the temperature of the secondary lithiation reaction to be 80-85 ℃ and the time to be 1-1.5 h; the adding amount of the lithiating agent B is 1.0-2.0% of the weight of the bentonite raw ore.

Further setting the addition amount of the gain agent to be 0.5-1.0% of the weight of the bentonite raw ore; the reaction conditions of the reaction solution C were: the temperature is 80-85 ℃, and the stirring reaction time is 0.5-1.5 h. The method is characterized in that a lithiation agent is used for lithiating the bentonite firstly, and then a gain agent with thickening and dispersing effects is added into a reaction system, so that the shearing performance of a liquid phase in the system is enhanced, the system dispersion and the lithiation effect enhancement are facilitated, a hydration film formed after the surface lithiation can be penetrated, the further lithiation of the bentonite in the system is promoted, and the lithiation modification efficiency is improved. Meanwhile, the phenomenon that the expansion performance is weakened due to distortion caused by excessive lithium ions entering crystal lattices can be effectively avoided, so that the expansion capacity of the bentonite is remarkably increased, and the expansion performance is enhanced.

Further configured, the drying and screening steps are as follows: and (3) carrying out spray drying on the reaction liquid, and then grinding until all the reaction liquid passes through a 400-mesh sieve to obtain the bentonite.

In addition, the invention provides the bentonite for treating the paint wastewater, which is prepared by the method, wherein the bentonite is prepared by acidifying raw bentonite ore by glacial acetic acid and modifying the raw bentonite ore by a lithifying agent and a gain agent; the gain agent is aluminum chloride.

According to the invention, the dispersion, suspension, expansion and thickening performances of the prepared lithium bentonite are enhanced to different degrees, so that the lithium bentonite can be used as a raw material and can be used as a wastewater treatment agent to replace sodium bentonite or organic bentonite in the fields of paint, ink, special coating and the like in practical application.

In another aspect, the present invention also provides a method of using bentonite for wastewater treatment, comprising: adding water into the bentonite to prepare a solution with the concentration of 3-4%, and then using the solution in cooperation with cationic polyacrylamide. The lithium bentonite is prepared by purifying, modifying and drying raw bentonite ore, and the formed powder and polyacrylamide have synergistic effect to decolor and clarify various waste water including paint waste water.

Specifically, the bentonite has the functions of adsorption filtration and filter aid in wastewater treatment, can efficiently capture pollutants in wastewater, realizes solid-liquid separation in a flocculation floating mode, and is convenient for manual or slag remover fishing. The mode of utilizing the bentonite to cooperate with the polyacrylamide for wastewater treatment has the advantages of good clarification effect, simple operation, low treatment cost, recycling and the like, and the bentonite has rich raw materials, low price, good chemical and biological stability and easy regeneration.

It is noted that the wastewater in the above-mentioned wastewater treatment field includes, but is not limited to, industrial wastewater, drinking wastewater, municipal wastewater, sludge, or agricultural wastewater. The above-mentioned waste water also includes waste water of brewery or other beverage industries, waste water of paper-making, paint, dye or coating industries, waste water of slaughterhouse, waste water of leather industry and so on.

According to the invention, the bentonite raw ore is acidified by glacial acetic acid, and is dispersed, purified, modified by heating and spray-dried by adding a dispersing agent, so that lithiation modification of the bentonite is realized, and the lithium bentonite and the preparation method thereof have the following beneficial effects:

1) the bentonite raw ore is activated by using the organic acid and the dispersing agent, so that the adsorption capacity and the dispersion stability of the bentonite are effectively improved, the impurity removal and purification effects of the bentonite are favorably improved, and the suspension performance of the bentonite is improved.

2) Under the liquid condition, sectional lithiation modification reaction is adopted, so that the contact area of bentonite and lithium ions is increased, the cation exchange capacity is increased, the exchange efficiency and the modification effect of the bentonite are improved, and the product has better suspension performance, thickening performance and expansion performance.

3) After the bentonite raw ore is modified, the obtained lithium bentonite has more excellent dispersing, suspending, expanding and thickening effects; the preparation method can improve the suspension property and the swelling value of the lithium bentonite, solves the problems of poor suspension property and serious stratified water separation of the lithium bentonite in a system, has no stratified water separation on the upper layer and no impurity precipitation on the bottom when being applied to a water dispersion system and a high-content metal ion water dispersion system, and obviously improves the purity and the suspension property.

4) The preparation method of the lithium bentonite is simple and easy to implement, has low cost and is suitable for popularization and application; the quality and performance of the prepared product are obviously improved, the application range of the product is favorably expanded, the economic benefit is improved, and the market prospect is expanded.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are a part of the embodiments of the present invention, but not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art based on the embodiments of the present invention without any inventive step, also belong to the scope of protection of the present invention.

Example 1:

a preparation method of bentonite for treating paint wastewater comprises the following steps:

1) selecting bentonite raw ore with viscosity not lower than 15mp & s, drying until the water content is less than 8.0%, then adding water into the bentonite raw ore and stirring to prepare slurry with mass concentration of 5%;

2) adding glacial acetic acid into the slurry according to the weight ratio of 0.5 per mill, and then stirring for 1h to prepare acidic slurry;

3) adding sodium hexametaphosphate into the prepared acidic slurry according to the weight ratio of 4 per mill, and then stirring for 0.5h to prepare slurry;

4) carrying out primary desanding on the slurry through a 100-mesh screen, carrying out primary fine purification on the desanded slurry through a cyclone with the inner diameter of 100mm, carrying out secondary desanding on the purified slurry through a 150-mesh screen, and carrying out secondary fine purification through the cyclone with the inner diameter of 100 mm;

5) adding lithium nitrate with the weight of 2.0% of that of the bentonite original ore into the purified slurry, stirring and heating, keeping the temperature and stirring for reaction for 1h after the temperature is raised to 70 ℃, and completing a lithiation reaction to obtain a reaction liquid A;

6) continuously stirring the reaction solution A, heating to 80 ℃, adding lithium sulfate accounting for 1.0 percent of the weight of the bentonite raw ore, stirring, keeping the temperature, reacting for 1 hour, and finishing a secondary lithiation reaction to obtain a reaction solution B;

7) adding an aluminum chloride gain agent accounting for 0.5 percent of the weight of the bentonite raw ore into the reaction liquid B, and stirring and reacting at 80 ℃ for 0.5h to obtain reaction liquid C;

8) and (3) carrying out spray drying on the reaction liquid C, and then grinding until all the reaction liquid C passes through a 400-mesh sieve to obtain the lithium bentonite.

Example 2:

a preparation method of bentonite for treating paint wastewater comprises the following steps:

1) selecting bentonite raw ore with viscosity not lower than 15mp & s, drying until the water content is less than 8.0%, then adding water into the bentonite raw ore and stirring to prepare slurry with mass concentration of 7%;

2) adding glacial acetic acid into the slurry according to the weight ratio of 2 per mill, and then stirring for 0.5h to prepare acidic slurry;

3) adding sodium silicate into the prepared acidic slurry according to the weight proportion of 6 per mill, and then stirring for 1h to prepare slurry;

4) carrying out primary desanding on the slurry through a 100-mesh screen, carrying out primary fine purification on the desanded slurry through a cyclone with the inner diameter of 100mm, carrying out secondary desanding on the purified slurry through a 150-mesh screen, and carrying out secondary fine purification through the cyclone with the inner diameter of 100 mm;

5) adding lithium fluoride accounting for 4.0 percent of the weight of the bentonite raw ore into the purified slurry, stirring and heating, keeping the temperature and stirring for reaction for 1.5 hours after the temperature is raised to 75 ℃, and completing a lithiation reaction to obtain a reaction liquid A;

6) continuously stirring the reaction liquid A, heating to 85 ℃, then adding lithium nitrate with the weight of 2.0 percent of that of the bentonite raw ore, stirring, keeping the temperature and reacting for 1.5 hours, and finishing a secondary lithiation reaction to obtain a reaction liquid B;

7) adding an aluminum chloride gain agent accounting for 1.0 percent of the weight of the bentonite raw ore into the reaction liquid B, and stirring and reacting at 85 ℃ for 1.5 hours to obtain reaction liquid C;

8) and (3) carrying out spray drying on the reaction liquid C, and then grinding until all the reaction liquid C passes through a 400-mesh sieve to obtain the lithium bentonite.

Example 3:

a preparation method of bentonite for treating paint wastewater comprises the following steps:

1) selecting bentonite raw ore with viscosity not lower than 15mp & s, drying until the water content is less than 8.0%, then adding water into the bentonite raw ore and stirring to prepare slurry with mass concentration of 6.5%;

2) adding glacial acetic acid into the slurry according to the weight ratio of 1 per mill, and then stirring for 0.5h to prepare acidic slurry;

3) adding sodium pyrophosphate into the prepared acidic slurry according to the weight ratio of 5 per mill, and then stirring for 0.5h to prepare slurry;

4) carrying out primary desanding on the slurry through a 100-mesh screen, carrying out primary fine purification on the desanded slurry through a cyclone with the inner diameter of 100mm, carrying out secondary desanding on the purified slurry through a 150-mesh screen, and carrying out secondary fine purification through the cyclone with the inner diameter of 100 mm;

5) adding lithium chloride accounting for 3.0 percent of the weight of the bentonite raw ore into the purified slurry, stirring and heating, keeping the temperature and stirring for reaction for 1 hour after the temperature is raised to 75 ℃, and completing a lithiation reaction to obtain a reaction liquid A;

6) continuously stirring the reaction solution A, heating to 80 ℃, then adding lithium carbonate accounting for 1.0 percent of the weight of the bentonite raw ore, stirring, keeping the temperature and reacting for 1 hour, and finishing the secondary lithiation reaction to obtain a reaction solution B;

7) adding an aluminum chloride gain agent accounting for 0.5 percent of the weight of the bentonite raw ore into the reaction liquid B, and stirring and reacting for 1h at the temperature of 80 ℃ to obtain reaction liquid C;

8) and (3) carrying out spray drying on the reaction liquid C, and then grinding until all the reaction liquid C passes through a 400-mesh sieve to obtain the lithium bentonite.

Example 4:

the preparation method of bentonite used in this example differs from that of example 3 only in that: the technical scheme of the embodiment does not add a gain agent to the lithiation modification reaction, and other steps are consistent with those of the embodiment 3. The specific different steps are as follows:

step 6) continuously stirring the reaction solution A, heating to 80 ℃, then adding lithium carbonate with the weight of 1.0% of that of the bentonite raw ore, stirring, keeping the temperature and reacting for 2 hours, and finishing a secondary lithiation reaction to obtain a reaction solution B;

and 7) carrying out spray drying on the reaction liquid B, and then grinding until all the reaction liquid B passes through a 400-mesh sieve to obtain the lithium bentonite.

Comparative example 1:

the preparation method of bentonite used in this comparative example differs from that of example 3 only in that: the technical scheme of the comparative example does not adopt sectional modification for lithiation modification reaction, only adopts a lithiating agent A, and other steps are consistent with those in example 3. The specific different steps are as follows:

step 5) adding lithium chloride accounting for 3.0% of the weight of the bentonite raw ore into the purified slurry, stirring and heating, keeping the temperature and stirring for reaction for 2 hours after the temperature is raised to 75 ℃, and completing lithiation reaction to obtain reaction liquid A;

step 6) continuously stirring the reaction solution A, heating to 80 ℃, adding an aluminum chloride gain agent accounting for 0.5 percent of the weight of the bentonite raw ore, and stirring and reacting at 80 ℃ for 1h to obtain a reaction solution B;

and 7) carrying out spray drying on the reaction liquid B, and then grinding until all the reaction liquid B passes through a 400-mesh sieve to obtain the lithium bentonite.

Comparative example 2:

the preparation method of bentonite used in this comparative example differs from that of example 3 only in that: the technical scheme of the comparative example does not adopt sectional modification for lithiation modification reaction, only adopts a lithiating agent B, and other steps are consistent with those in example 3. The specific different steps are as follows:

step 5) adding lithium carbonate accounting for 1.0 percent of the weight of the bentonite raw ore into the purified slurry, stirring and heating, keeping the temperature and stirring for reaction for 2 hours after the temperature is raised to 75 ℃, and completing lithiation reaction to obtain reaction liquid A;

step 6) continuously stirring the reaction solution A, heating to 80 ℃, adding an aluminum chloride gain agent accounting for 0.5 percent of the weight of the bentonite raw ore, and stirring and reacting at 80 ℃ for 1h to obtain a reaction solution B;

and 7) carrying out spray drying on the reaction liquid B, and then grinding until all the reaction liquid B passes through a 400-mesh sieve to obtain the lithium bentonite.

Comparative example 3:

the preparation method of bentonite used in this comparative example differs from that of example 3 only in that: the technical scheme of the comparative example does not adopt sectional modification for the lithiation modification reaction, only adopts the lithiation agent A, does not add a gain agent into the lithiation modification reaction, and has the other steps consistent with those in example 3. The specific different steps are as follows:

step 5) adding lithium chloride accounting for 3.0% of the weight of the bentonite raw ore into the purified slurry, stirring and heating, keeping the temperature and stirring for reaction for 2 hours after the temperature is raised to 75 ℃, then continuing stirring and raising the temperature to 80 ℃ for reaction for 1 hour to obtain a reaction solution;

and 6) carrying out spray drying on the reaction solution, and then grinding until all the reaction solution passes through a 400-mesh sieve to obtain the lithium bentonite.

Comparative example 4:

the preparation method of bentonite used in this comparative example differs from that of example 3 only in that: the technical scheme of the comparative example does not adopt sectional modification for the lithiation modification reaction, only adopts the lithiation agent B, does not add a gain agent into the lithiation modification reaction, and has the other steps consistent with those in example 3. The specific different steps are as follows:

step 5) adding lithium carbonate accounting for 1.0 percent of the weight of the bentonite raw ore into the purified slurry, stirring and heating, keeping the temperature and stirring for reaction for 2 hours after the temperature is raised to 75 ℃, then continuing stirring and raising the temperature to 80 ℃ for reaction for 1 hour to obtain a reaction solution;

and 6) carrying out spray drying on the reaction solution, and then grinding until all the reaction solution passes through a 400-mesh sieve to obtain the lithium bentonite.

Experimental example 1:

performance testing of Bentonite produced by different methods

Experimental samples: different lithium bentonite were prepared by the same bentonite raw ore according to the methods of examples 1 to 4 and comparative examples 1 to 4, respectively. The samples were lithium bentonite and bentonite raw ore prepared in examples 1 to 4 and comparative examples 1 to 4. Each set was provided with 3 parallels. The results are shown in Table 1.

The experimental method comprises the following steps: (1) swelling value: accurately weighing 1.5g of sample, putting the sample into a 100mL measuring cylinder with a plug, adding 5mL of 1mol/L ammonium chloride solution into the measuring cylinder, adding water into the measuring cylinder until the solution reaches 100mL, plugging the measuring cylinder, shaking up and standing, and reading the solution in the measuring cylinder after standing for 24 hours.

(2) Degree of suspension (water and ethanol): accurately weighing 3g of sample, uniformly dispersing the sample and water according to the mass ratio of 1:1, and placing the sample and water in a 500mL beaker. Firstly, adding 100g of water into a beaker, and secondly, adding 100g of absolute ethyl alcohol into the beaker. Then dispersing the solution in the beaker for 15min at a high speed of 1200r/min by using a dispersion machine, pouring the dispersed solution into a 150mL measuring cylinder with a plug, adding water or ethanol to make the solution in the measuring cylinder reach 150mL, covering the plug, placing the measuring cylinder in a constant temperature chamber at 20 ℃ for standing for 24h, and observing the height of a settlement surface, wherein the unit is mL/3 g.

(3) Colloid value: a sample of 15g was weighed accurately into a 100mL stoppered graduated cylinder containing 60mL of distilled water, and then distilled water was added to 90 mL. The stopper was stoppered and shaken for 5min to allow the sample to disperse and mix with water. The stopper was opened, 1.0g of magnesium oxide and distilled water were added to 100mL, the stopper was closed again and shaken for 3 min. The measuring cylinder is placed on a table top without vibration, the table is kept still for 24 hours, and the scale value of the gel interface is read out and expressed by mL/15 g. The sample with the colloid value of more than 100mL/15g can be tested after the dosage of the sample is reduced to 3g and the dosage of the magnesium oxide is reduced to 0.2 g.

TABLE 1 results of the performance test of the bentonites obtained by the different methods

The result shows that the swelling property, the suspension property and the thickening property of the bentonite can be obviously improved through lithiation modification; the gain agent is matched with the sectional lithiation modification reaction, so that the modification effect of the bentonite can be obviously improved, and the suspension property, thickening property and expansion property of the product lithium bentonite are improved to different degrees; meanwhile, the lithium-based bentonite product prepared by the invention retains and even further improves the thickening and gelling properties of the product, and is more beneficial to the application of the product bentonite in the fields of wastewater treatment and the like.

Experimental example 2:

drainage test of Bentonite produced by different methods

Experimental samples: different lithium bentonite were prepared by the same bentonite raw ore according to the methods of examples 1 to 4 and comparative examples 1 to 4, respectively. The samples were lithium bentonite and bentonite raw ore prepared in examples 1 to 4 and comparative examples 1 to 4. Each set was provided with 3 parallels. The results are shown in Table 2.

The experimental method comprises the following steps: 2.0g of lithium bentonite is weighed and respectively dispersed in a 1 percent distilled water dispersion system and a high-content metal ion water dispersion system (the total concentration of calcium and magnesium ions is 3.42 multiplied by 10)^-3mol/L, the preparation method refers to GB/T1603-2001 pesticide emulsion stability determination method), magnetically stirring at 2000r/min, respectively stirring and dispersing for 30min to form a dispersion liquid with 1% solid content; then sealing the measuring cylinder, and standing in a constant temperature chamber at 20 ℃ for 24 hours; and (5) observing whether the measuring cylinder has layering or water separation and bottom precipitation.

TABLE 2 results of water evolution test of bentonite prepared by different methods

Water absorption mL	1% distilled water dispersion	High metal ion content aqueous dispersion
			Raw bentonite ore	26.2	37.3
Example 1	0	3.1
			Example 2	0	3.4
Example 3	0	2.7
			Example 4	0	10.2
Comparative example 1	0	8.4
			Comparative example 2	0	8.1
Comparative example 3	3.5	16.7, bottom with a small amount of sediment
			Comparative example 4	2.7	17.3, bottom with a small amount of sediment

The result shows that the suspension property of the bentonite can be obviously improved through lithiation modification; the method adopts the gain agent and the sectional lithiation modification reaction, solves the problems of poor suspension and serious layered water separation of the lithium bentonite in a water dispersion system (especially a high-content metal ion water dispersion system), and when the method is applied to the water dispersion system and the high-content metal ion water dispersion system, the upper layer has no layered water separation, the bottom has no impurity precipitation, and the purity and the suspension of the method are obviously improved.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; while the invention has been described in detail and with reference to the foregoing embodiments, those skilled in the art will appreciate that; the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.