Background

Bentonite is a layered material with cation exchange capacity, and the main component of the bentonite is aluminosilicate. The natural bentonite is mostly calcium bentonite, and the calcium bentonite and modified products thereof have the functions of expansibility, hydrophilicity, adsorptivity, cation exchange property, catalytic activity, dispersibility, suspensibility and the like, and are widely applied to the aspects of mineral oil and animal and vegetable oil decoloration, thickening, tackifying and anti-settling of paint, modulation of oil field drilling mud, wastewater treatment, catalyst preparation and the like. However, since it does not have an anion exchange function, its use is limited. Hydrotalcite is another layered material with anion exchange capacity, can be used for treating wastewater, preparing catalysts, composite layered nano materials and the like, and is mainly prepared by an artificial synthesis method at present due to small reserves and more impurities of natural hydrotalcite. The artificially synthesized hydrotalcite compound (abbreviated as HTLds) has the advantages of less impurities, high anion exchange capacity and capability of exchanging different types of anions between layers to obtain materials with different properties, but the use of the artificially synthesized hydrotalcite compound is influenced due to the defects of small interlayer spacing, unstable skeleton under acidic conditions, high production cost and the like. In order to make the bentonite exchange capacity better, people think of a plurality of methods, namely, calcium bentonite is changed into sodium bentonite, or the calcium bentonite is changed into high-value organic bentonite, for example, the published documents report some modification methods, and the following are extracted by searching:

1. [ PROBLEMS]artificial sodium Bentonite [ authors]Korea-Xiushan [ mechanism]Jilin [ journal]petrochemical technology and application 2005, 23(1). -47-47 [ abstracts]most of Bentonite (Bentonite) in nature (70% -80% in the world, 90% in China) is calcium Bentonite, the performance of which is poorer than that of sodium Bentonite, and a production plant usually modifies the calcium Bentonite into the sodium Bentonite by an artificial sodium modification method. For convenience of application, sodium bentonite is often classified into artificial sodium bentonite and natural sodium bentonite. According to the species and content of exchangeable cations between montmorillonite layers, sodium bentonite with the alkalinity coefficient more than or equal to 1 is used, and calcium bentonite with the alkalinity coefficient less than 1 is used.

2. [ PROBLEMS]Bentonite activation treatment and its mechanism of action with basic violet [ authors]Li, Yanglu, Wei, etc. [ institution]Wuhan university resource and environmental engineering college, [ journal]mining and metallurgy engineering, 2001, 21(3)]-63-65 [ abstracts]calcium bentonite is activated by acid, heat, TiCl₄Activated, aluminum hydroxy and AlCl₃Activating, treating the basic violet dye solution and discovering with TiCl₄And AlCl₃The removal rate of the activated bentonite to the basic violet dye reaches more than 89 percent and 98 percent respectively, and the removal rate is higher than the original soil decolorization rateThe improvement is remarkable; by X-ray analysis it was found that: TiCl (titanium dioxide)₄And AlCl₃Activated bentonite has a large interlamellar spacing,and the adsorption performance is obviously improved. The modified bentonite is mainly subjected to the coprecipitation action with bentonite particles through the cation exchange action and the dye when absorbing the basic violet solution.

3. The results of research on the treatment effect of the modified bentonite on the J acid solution and the J acid waste mother liquor in 21(6) -12-14 [ abstracts]show that the treatment effect of the modified bentonite on the J acid solution is better than that of the J acid waste mother liquor, the removal effect of the modified bentonite on the J acid waste mother liquor is related to pH and sodium sulfate content, and the sodium sulfate content is lower under neutral or alkalescent conditions. The higher the removal rate of the J acid waste mother liquor is, the highest removal rate can reach about 50 percent.

4. Influence of acid and alkali on pH of sodium bentonite suspension system [ authors]zhoukai tin [ mechanism]material physicochemical research institute of university of china [ publication name]proceedings of university of china: 1998, 19(1) -40-43 [ abstracts]the change behavior of the pH value of the sodium montmorillonite-water system is researched by a method for testing the pH value and the conductivity when the sodium montmorillonite forms a suspension system with the mass fraction of 0.1% in an acid and alkali system with the pH value of 1-3. Sodium montmorillonite suspensions exhibit buffering properties and the ability to maintain the pH is determined by the pH of the suspension formed in a neutral aqueous solution. The pH value of the suspension system is stable for about 7 days, and in the aging time, the pH value of the suspension system which is acidic rises, and the pH value of the suspension system which is alkaline falls.

5. Chinese patent application (patent) No. CN88100011.6 name method for producing calcium bentonite sodium bentonite application (patentee) Zhou Yun Chen (Address) Henan province, Xinyang county, bridge and town Union headquarters (Abstract) CFS modified sodium bentonite production method belongs to the deep processing technology of bentonite materials. The method is mainly suitable for artificially modifying natural calcium bentonite into sodium bentonite. The core of the invention is that natural saturated moisture calcium bentonite ore is added with soda powder to carry out exchange reaction rapidly under the condition of pressure shearing deformation to generate sodium bentonite. Makes the rich calcium base of China expandThe method for producing sodium bentonite from the bentonite ore makes up the defects of multipurpose and rare high-quality natural sodium bentonite. The method is suitable for factory continuous production, has low cost, and is superior to the production methods adopted at home and abroad at present. [ PRIMARY]A method for producing sodium bentonite, comprising the steps of mineral separation, crushing, soda addition, stirring, extrusion, drying, grinding and packaging, and is characterized in that: (1) natural bentonite with saturated humidity, water content of 30-50%, montmorillonite content of more than 65%, and Ca content²⁺Mainly taking ions without sand, 2, reducing the particle size after crushing to less than 1 Cm, 3, adding 1-3% of soda powder, wherein the soda powder meets the GB210-63 standard and is crushed to the particle size of less than 20 meshes, 4, stirring in a double-helix stirring mixer, and 5, in the double-helix reactor, the pressure is 50-150 Kg/Cm²The exchange reaction is carried out under the shearing deformation condition to generate sodium bentonite, and the exchange reaction formula is as follows: 。

6. chinese patent application (patent) No. CN97103231.9 (name) a method for producing sodium bentonite by using calcium bentonite (patent application (patentee) man, Sun Zhong (Address) and inner Mongolia mineral experimental research institute, Calif. Nancha autonomous region and Xinte City Ling Qinglu inner Mongolia mineral research institute, abstract, the invention belongs to the deep processing technology of bentonite. The method is mainly suitable for modifying natural calcium bentonite into sodium bentonite by an artificial 'dry method'. The core is that only one Raymond mill is used for realizing two purposes of ion exchange reaction and removing impurityminerals at one time, and the sodium bentonite is quickly and conveniently generated. Completely realizes the continuous production of factories, has short working procedure, low cost and high economic value, and is superior to the production methods adopted at home and abroad at present. [ PRIOR ART]A method for producing sodium bentonite from calcium bentonite, comprising the steps of selecting materials, airing, adding alkali for grinding and packaging, characterized in that: (1) selecting natural calcium bentonite with colloid value of more than 50ml/15g and expansion capacity of more than 4 ml/g; (2) the water content of the dried raw materials is between 13 and 18 percent, and the block size is less than 1 cm; (3) adding 2-3.5% of soda ash powder, wherein the soda ash is in accordance with the GB210-89 standard, and sieving the soda ash by a 20-mesh sieve; (4) the soda powder is fully mixed with the raw material in the Raymond mill and simultaneously dissolved by residual moisture in the raw material, and the ion exchange reaction is rapidly completed under the conditions of being subjected to rolling deformation and sensing the temperature generated by the operation of equipment to generate sodium bentonite, so that the wind power capable of controlling the product granularity is conveyed into a packaging bag through air separation.

7. Chinese patent application (patent) No. cn02103804.x name method for producing organic bentonite by dry process [ application (patentee)]headquartering company [ address]rocky scenic mountain area of beijing city [ abstract]method for producing organic bentonite by dry process. The method is mainly suitable for preparing high-value organic bentonite from natural calcium bentonite through artificial modification. The core of the invention is that natural calcium bentonite is added with soda ash in mixing equipment for exchange reaction to generate sodium bentonite; then adding an activating agent, uniformly mixing and reacting; addingorganic covering agent, heating, mixing, reacting, extruding with screw extruder to obtain strip, oven drying, and grinding to obtain organobentonite powder. It has the advantages of simple process, no need of washing and dewatering, high production efficiency, low cost, convenient large-scale production, etc. [ claim 1]A method for producing organobentonite by a dry process, comprising the steps of ore dressing, crushing, fine selection, alkali addition, mixing, activating agent addition, covering agent addition, heating and mixing, extrusion, drying, grinding and packaging, and is characterized in that: adding soda into natural calcium bentonite in mixing equipment, and performing exchange reaction to generate sodium bentonite; then adding an activating agent, uniformly mixing and reacting; adding organic covering agent, heating, mixing, reacting, extruding with screw extruder to obtain strip, oven drying, and grinding to obtain organobentonite powder.

8. The title of organic bentonite is "Songyanhe" journal of agricultural Proc. 1996, 13(4) -22-25, 46 "Abstract" natural bentonite is modified with organic cationic compound or organic cationic-organic anionic compound to obtain a thixotropic additive for organic liquid as thickener, dispersant, coagulant and suspension stabilizer, mainly for petroleum drilling, paint, ink, grease, etc.

9. [ PROBLEMS]synergistic adsorption effect and mechanism of anion-cation organobentonite [ Author]Suyuhong, etc. [ institution]department of environmental science at Zhejiang university, [ publication]Chinese environmental science [ 2001, 21(5)]-408-411 [ abstracts]synthesis and research on adsorption effect and mechanism of phenol and benzene in water by a series of anion-cation organobentonites. The result shows that the anion-cation organobentonite has synergistic adsorption effect on the organic matters in water, and the action size of the anion-cation organobentonite is related to various types, compositions and proportions of the used surfactants during modification and the self character of the organic matters; the adsorption to phenol conforms to Langmuir and Freundlich adsorption isotherms and is the result of the joint action of partition action (partition) and surface adsorption (adsorption), and the contribution rate of partition action is increased along with the increase of the addition amount of the anionic surfactant during modification; the adsorption of benzene in water is mainly based on distribution effect, the distribution coefficient is greater than that of the original soil and the single-cation organic bentonite, and the adsorption is positively correlated with the content of organic carbon.

10. Chinese patent application No. CN94110894.5 entitled method for producing activated clay with sodium bentonite, the institute of Changsha chemical mine design of the department of chemical industry, the Address, the Long Sha Ming Hua Ming Ji, the south suburb Long Shih, Hunan province, the abstract is a method for producing activated clay with sodium bentonite, which is characterized in that sodium bentonite raw ore is put into a separator filled with magnesium sulfate aqueous solution, stirred and scrubbed, then the slurry is put into a reaction tank, then transferred into a stirring tank, added with proper amount of clear water for dilution, stirred, transferred into a filter press, transferred into a filter residue pulping tank, dried in a baking oven, taken out and ground to obtain the high-quality activated clay. The invention makes the activated clay produced by low grade sodium bentonite have high quality, low sand content, 100% decolorization rate and more than 220 activity, and is suitable for producing high grade petroleum products. [ PRIOR ART]A process for producing activated clay from sodium bentonite, which comprises the steps of: directly putting the sodium bentonite raw ore into a separator containing an auxiliary agent magnesium sulfate aqueous solution, stirring and scrubbing, then transferring the slurry into a reaction tank for activation reaction, then transferring into a stirring tank, adding a proper amount of clear water for dilution, stirring, filtering in a filter press, transferring the filter residue into a pulping tank for pulping and washing, filtering the obtained slurry again, then sending into a drying furnace for drying, taking out the slurry, grinding the slurry by a grinder to obtain high-quality activated clay, and supplementing a small amount of magnesium sulfate into the filtrate, wherein the filtrate can still be used as the auxiliary agent aqueous solution for recycling.

From the above search results, it is understood that the publications mainly describe the modification of calcium bentonite into sodium bentonite or the modification of sodium bentonite into organic bentonite, there is no mention of modifying bentonite into bentonite having anion exchange capacity, and the bentonite modification method described in the publications is complicated in production process, such as document 2, which requires acid activation, heat activation, TiCl activation₄Activated, aluminum hydroxy and AlCl₃Some methods, such as activation, have a large equipment investment, although they are not difficult, and documents 6 and 7 propose that a Raymond mill or a mixing device is required, and the total cost is also high. Some production processes may also produce pollution.