Colloid (English: Colloid), also known as colloidal dispersion, is a homogeneous mixture, which contains two substances in different states, one is dispersed and the other is continuous. Part of the dispersion consists of tiny particles or droplets, and the diameter of dispersoid particles is between 1 nm and 100 nm. Colloid is a kind of dispersion system with particle size between coarse dispersion and solution, and it is a highly dispersed heterogeneous system.

I basically agree with you. For example, calcium sulfate, usually, we can't get its colloid, but get suspension. But if we mix calcium chloride solution and sodium sulfate solution through a high-speed venturi tube and add a small amount of surfactant to flowing water. I think it is very possible to get a colloidal solution.

It can't be said that all can form colloid, but that many can be obtained by similar methods. The principle is: 1. High-speed mixing; Second, micro-substances can exist stably, and surfactants or surface modifiers can do this.