Surfactants have different adsorption mechanisms on particle surfaces

2022-09-28 16:28:22

Most of the grinding aids used in my country's ceramic industry are relatively expensive and have a single performance. Most of the ceramic grinding aids used are still produced from industrial raw materials, resulting in high prices and difficult for users to accept. Coupled with the shortage of sources, most of them are Petroleum or coal chemical products, so it is difficult to popularize and apply. Using industrial waste to develop new varieties of cheap grinding aids is an important way, and the development of lignosulfonate type grinding aids is one example. Some other industrial wastes, such as sodium adipate in the oil waste liquid, lanolin in the wool spinning industry, etc., have a grinding aid effect after processing. If they can be developed and utilized, they can not only reduce production costs but also prevent waste discharge, which need to be further developed.

Various surfactants have different adsorption mechanisms on particle surfaces. Ionic surfactants are mainly based on ion exchange adsorption and ion pair adsorption; non-ionic surfactants are mainly based on hydrogen bond formation adsorption and hydrophobic adsorption. Mixing various types of surface adsorbents together can strengthen the adsorption on the particle surface and improve the grinding aid effect. In addition, the grinding-aid mechanisms required for various components in the material are different, and it is obviously difficult to adapt to the grinding requirements of different ceramic raw materials by simply adding one substance for grinding-aid. Therefore, it is best to combine several grinding aids together, and use their interaction and different mechanisms to improve the effect of grinding aids, which is the development direction of grinding aids.

Ceramic grinding aids are often divided into liquids, solids, gases and mixtures. So far, the vast majority of grinding aids used in the ceramic industry are solid and liquid grinding aids. Inorganic electrolytes with grinding effect include sodium polyphosphate, water glass, etc.; ionic surfactants include sodium lignosulfonate, sodium dodecylbenzenesulfonate, sodium citrate, etc.; non-ionic surfactants include triethanolamine Wait. When sodium dodecylbenzene sulfonate is used alone, the particle size is smaller and the effect is better. The effect of sodium lignosulfonate alone is relatively poor. Usually, the above chemicals can also be used in combination, and the effect is better. For example, when triethanolamine is mixed with sodium citrate, its grinding aid effect is greatly improved. This is because the triethanolamine molecule is weakened with the same charge after the non-ionic surfactant triethanolamine is mixed with the ionic surfactant sodium citrate. The repulsion between the polar groups of sodium citrate, and the polar groups of triethanolamine may be polarized under the electric field of the adjacent surface active ions to generate further interactions, which makes the mixed micelles easy to form, thereby further Enhances the grinding aid of surfactant molecules.