Acid washing and purification method of diatomite

June.12,2023

Diatomite purification methods are mainly divided into: physical, chemical and physical and chemical comprehensive methods. Diatomaceous earth contains a small amount of Al2O3, Fe2O3, CaO, MgO, K2O, Na2O, P2O5 and organic matter. SiO2 generally accounts for more than 80%, up to 94%. The iron oxide content of high-quality diatomite is generally 1~1.5%, and the alumina content is 3~6%. The mineral composition of diatomite is mainly opal and its variants, followed by clay minerals – hydromica, kaolinite and mineral debris. Mineral debris includes quartz, feldspar, biotite and organic matter. The content of organic matter ranges from trace to more than 30%. The color of diatomite is white, off-white, gray and light taupe, etc. It has the properties of fineness, looseness, light weight, porous, water absorption and strong permeability.

Diatom ore acid leaching method

After stripping after pickling, most of the pulp with impurities such as iron and aluminum is removed, and the diatomite concentrate with a diatomite content of 91.27% is obtained in the second deposition, and the silicon content is reached through roughing, stripping, and acid leaching. The expected demand has increased from 71.86% to 91.27%, effectively removing impurities, increasing the specific surface area, and the output value of the entire process is about 40%.

The effect of acid leaching on the modification of diatom pore structure is that acid leaching not only increases the content of diatomite, but also can modify the diatom pore structure; OsmanSan et al. studied the effect of acid leaching on diatomite filtration performance and porosity, And use acid-leached diatomite to prepare diatomite filter material and porous ceramic material.

However, the conventional acid leaching method has the advantages of long purification time, high acid dose, high cost, and environmental pollution, which is not conducive to industrial production. This greatly affects its use prospects. The microwave enhanced diatomite leaching process can not only shorten the leaching time, but also increase the leaching rate.