We know that there are a lot of suspended organisms and colloidal impurities in natural water. The forms of suspended solids are different. Some large particles of suspended solids can settle under their own gravity. The other is colloidal particles, which is an important reason for the turbidity of water. Colloidal particles can not be removed by natural settlement, because colloidal particles in water are mainly clay with negative electricity The Brownian motion of colloidal particles and the hydration on the surface of colloidal particles make colloidal particles have dispersion stability. Among them, electrostatic repulsion has the greatest influence. If coagulant is added to water, it can provide a large number of positive ions and accelerate the coagulation and precipitation of colloid. Compressing the diffusion layer of micelles makes the potential change into an unstable factor, which is also conducive to the adsorption and condensation of micelles. The water molecules in the hydrated film have fixed contact with the colloidal particles and have high elastic viscosity. It is necessary to overcome the special resistance to expel these water molecules. This resistance hinders the direct contact of the colloidal particles. The existence of some hydrated films depends on the electric double layer state. If coagulant is added to reduce the zeta potential, the hydration may be weakened. The polymer materials formed after coagulant hydrolysis (the polymer materials directly added into water generally have chain structure) play an adsorption bridging role between the colloidal particles. Even if the zeta potential does not decrease or does not decrease much, the colloidal particles can not contact each other and can be adsorbed through the polymer chain Colloidal particles can also form flocs.

Scrap zinc or concentrated zinc ores are dissolved in sulfuric acid, the solution is purified and the two solutions are reacted. A heavy mixed precipitate results that is 28 to 30% zinc sulfide and 72 to 70% barium sulfate.

Calcium carbonate is a naturally occurring mineral that is found in rocks and minerals such as calcite, aragonite, and limestone. It is commonly used in industries such as paint, paper, plastics, and rubber as a filler and pigment. The manufacturing process of calcium carbonate involves extracting the mineral from quarries or mines, crushing and grinding it into a fine powder, and then purifying it through various chemical processes.

TiO₂ comes in many different forms. However, only a few of these forms are considered food-grade (acceptable to be added to food). Many studies that raised concern about the safety of TiO₂, including the concern for genotoxicity, used forms of TiO₂ that are not considered acceptable for use in food and have different properties than food-grade TiO₂. Other studies did use food-grade TiO₂, but took steps to break the material down into smaller particles than what would normally be found in food.