Active white clay is made of clay (mainly bentonite) as raw material, after inorganic acidification treatment, and then by water rinsing, drying made of adsorbent, the appearance of milky white powder, adsorption performance is very strong, can absorb colored substances. Easy to absorb moisture in the air, placed too long will reduce the adsorption performance. However, heating to more than 300 degrees Celsius will begin to lose crystal water, is the structure changes, affecting the fading effect. Active clay is insoluble in water, solvents and various oils, almost soluble in hot caustic soda and hydrochloric acid, the relative density of 2.3 ~ 2.5, in water and oil swelling small. Widely used in mineral oil, animal and plant grease, wax and liquid decolorization refining. It can also be used as desiccant for water, alkali antidotes for medicine, vitamin A, B sorbent, lubricating oil contact agent, gasoline gas phase preparation, etc. It can also be used as intermediate temperature polymerization catalyst, high temperature polymerization agent and raw material for the manufacture of granular clay.

In the past, bentonite was only known as the raw material of active clay. In fact, it is not so. Mineral soils with clay properties can be used as the raw material of active clay, such as kaolinite clay, montmorillonite clay, sepiolite clay, attapulgite clay and so on.

Kaolin clay, referred to as kaolin, is a kind of fine clay with kaolinite group minerals as the main component and pure texture. The appearance is white, light gray and other colors, and yellow, gray, black and so on when containing impurities. Dense block or loose soil, with a sense of greasy, hardness less than nails. Specific gravity 2.4-2.6, water absorption after drying. Fire resistance up to 1770-1790℃. Low plasticity, low adhesion, good insulation and chemical stability.

Pure kaolin calcined white, whiteness up to 80%-90%. Montmorillonite clay, also known as bentonite, bentonite, bentonite, is a fine clay with montmorillonite as the main mineral composition. The appearance is generally white, pink, light gray, light yellow, when contaminated by impurities can be gray green, purple brown and other darker colors. Loose earthy luster is dim, dense lump is waxy luster. Hardness 1-2, soft. Blocky or earthy, slippery. The proportion of 2-3. The volume expands after absorbing water. High plasticity and good adhesion, suspension and gelation in aqueous solution, but also cation exchange characteristics. Sepiolite clay is a kind of clay with sepiolite as the main component. The appearance is yellowish-brown, dark gray, gray and other colors, the soil is massive, soft and light, hardness 1-2, specific gravity 2.4-2.65, with viscosity and plasticity, the hand touch a sense of slippery. After adding water, it can be adjusted into a paste. After drying, it can leave a hammer mark by hammering. Attapulgite clay is a kind of clay with attapulgite as the main component. It looks like - clay, similar to montmorillonite clay, and the two are often symbiosis. Its field identification mark is the appearance of soil, gray, gray, duck egg blue, fine soil, slippery, viscous and plastic when wet, dry light, shrink. Drop it into water, sizzle and burst into pieces, but do not expand. Attapulgite clay has the same properties as sepiolite clay, with thermal stability, salt resistance, adsorption and high decolorization ability. Sepiolite was used as active clay in Hunan province, b-axis disordered kaolin was also found to be active clay in Zhejiang Province, and the residue of water purification agent was successfully developed as active clay in Shandong Province. Thus the raw materials of reactive clay are more extensive. But the active clay we usually refer to the active clay with bentonite as raw material. ?

Sepiolite can be used to make active clay by cleaning and acid activation. Selection is water separation, liquid to solid ratio of 5 ~ 10. After water separation, the suspension is added with 0.5% sulfuric acid or 1.5% hydrochloric acid, boiled for 30min, and then filtered, washed, dried and ground for the product. The decolorization rate can reach 93%, and the standard decolorization rate is 90%.