Ten Strategic Applications Of Kaolin

Kaolin is a natural clay mineral with a typical 1:1 layered silicate crystal structure. Due to its abundant reserves, low price and environmental friendliness, it has been widely used in hundreds of industries such as ceramic industry, paper industry, refractory materials and cement industry, petrochemical industry and medical textile industry. With the development of science and technology and the progress of the country and society, the research on kaolin has become more in-depth. In the future, kaolin will be a strategic non-metallic mineral with better application prospects in more fields.

1. Heavy metal sewage treatment

The layered structure of kaolin makes it have a very high-quality adsorption capacity. The natural kaolin material can be transformed into an adsorbent after functional modification, which can solve the problems of heavy metals, organic pollutants, and suspended solids in water. Therefore, the modified chitosan can be wrapped on the surface of the kaolin material with the help of coupling agent and crosslinking agent to form MAGIC-MRT Ⅱ heavy metal adsorbent.

Qi Xianjin from Kunming University of Science and Technology and others used FeCl3•6H2O and FeSO4•7H2O to prepare Fe3O4-containing mixture A, and Fe3O4-containing mixture A and kaolin nanomaterials to prepare Fe3O4/kaolin nanocomposites; Fe3O4/kaolin nanocomposites The material reacts with the dirty acid to remove the arsenic in the dirty acid.

2. Air pollution treatment

Mercury is a global air pollutant, and the main pollution method is direct emissions to the atmosphere. Through the use of ultraviolet light to analyze the adsorption of a variety of clay mineral materials using CVAFS technology, it is found that kaolin is very suitable for reducing the content of mercury pollutants in the atmosphere.

3. Organic sewage treatment

The kaolin is hydrothermally modified with sodium hydroxide and disodium hydrogen phosphate to obtain alkali-modified kaolin (AMK) and phosphate-modified kaolin (PMK). After application, it is found that the modified kaolin material can effectively adsorb (methylene blue) and other organic pollutants, and the best adsorption capacity is 476.19 mg/g and 434.78 mg/g.

4. Electrochemical wastewater treatment

In recent years, it has been discovered that natural kaolinite can be used to solve the problem of non-neutral sewage treatment due to its good stability. Traditional electrode materials are susceptible to corrosion under non-neutral conditions, and most industrial wastewater is not in a neutral environment. Therefore, the corrosion of electrode materials in the process of sewage treatment using the principle of electrolysis limits its treatment effect to a certain extent. Based on this, an efficient Fe-Cu/kaolin particle electrode was successfully prepared. Its performance is better than that of the original kaolin particle electrode and activated carbon particle electrode. The expected Rhodamine B removal effect can be achieved under neutral or even alkaline conditions.

5. Solar energy storage materials

Using kaolin and sodium stearate as raw materials, a new type of kaolin/sodium stearate phase change heat storage material was prepared. Compared with the same type of phase change heat storage material, the latent heat of melting and condensation of this phase change heat storage material are as high as 109.25 and 109.01 J/g, respectively.

6. Building phase change heat storage material

The intercalation modified coal series kaolin intercalation of binary organic eutectic can be used to control indoor temperature changes. Based on this characteristic, the binary organic/coal kaolin composite phase change energy storage material can be widely used in the construction industry to achieve the purpose of energy saving. Three kaolin-based composite phase change materials (Kb-CPCMs) prepared by vacuum impregnation have good heat storage, ventilation and air conditioning functions, and are suitable for heating, ventilation and air conditioning of building envelopes.

7. New material field

Molecular sieves have the advantages of adsorption separation, rapid exchange and catalysis, and can be widely used in metallurgy, petroleum, chemical, pharmaceutical and daily chemical industries. Abundant reserves, low price, and high content of aluminum and silicon make kaolin a good raw material for preparing molecular sieves. Therefore, 4A molecular sieves can be synthesized with the help of kaolin to form new materials.

8. Hemostatic material

Based on the natural hemostatic agent instead of ochre to control bleeding, a new type of iron oxide/kaolin nanoclay composite material was successfully synthesized. The oxide form has a significant impact on its hemostatic effect.

Zhang Yi from Central South University and others first pretreated, pillared and ultrasonically crushed kaolin, then mixed it with a polymer ethanol solution to obtain an electrospinning solution, and finally electrospinned to obtain a kaolin modified hemostatic material. The obtained hemostatic material has the advantages of fast hemostasis, convenient use, beneficial to wound healing, good biocompatibility, low cost and the like.

9. Drug carrier

Kaolin can be used as a carrier to realize the loading and release of drugs. Using methanol intercalated kaolin as a carrier, compared with unmodified kaolin, after loading 5-fluorouracil, a small molecule chemotherapeutic drug, it was found that the loading of modified kaolin was as high as 55.4%, which was 147.3% higher than that of kaolin before modification. . This is because the grafting of methoxy groups between the kaolin layers expands the distance between the kaolin layers, provides new active sites for drug molecules, and promotes the entry of drugs between the layers.

10. Antibacterial material

Compared with montmorillonite, kaolinite has a weaker ion exchange capacity, so the antibacterial agent is easier to release and has a better bactericidal effect. By measuring the adsorption of CPB, it is found that CPB-kaolinite has antibacterial activity when [CPB] exceeds its CMC value. When the load of CPB on kaolinite is high, the overall charge changes from positive to negative, which has the ability to adsorb bacteria and ultimately kill bacteria. Therefore, kaolin can be well used for sterilization, and in the development process of organoclay as an antibacterial agent, the amount of surfactant fixed on the clay must exceed the CMC value.

In summary, among the seven strategic emerging industries proposed in the "13th Five-Year" National Strategic Emerging Industry Development Plan, kaolin has very broad application prospects in energy conservation and environmental protection, bio-industry, and new materials.