How do you get pigment?

Answer 1

As in, "How is commercial pigment (for paints etc.) made?"

The process for making pigment, mostly titanium dioxide (TiO2), starts with mineral sands. This sand is mined from old (often ancient) beaches and contains high levels of TiO2 minerals, such as rutile and ilmenite.

The sand is put through various separators, most of which make use of the magnetic and conductive properties of the various minerals in the sand to do the separation. From this you get a high TiO2 ore.

The ore can then be processed using either;

• The chloride process, or
• The sulphate process.

In the chloride process, the ore is reacted with chlorine (Cl2) at very high temperatures to form titanium chloride gas (TiCl). The gas is purified and reacted with oxygen (O2) to form TiO2 again, but in a much purer form. The TiO2 is then granulated into tiny but specifically sized particles, and these particles are coated with various chemicals that make the pigment work better in whatever product it will be used for. This process is the newest and most common in developed countries.

The sulphate process instead uses large amounts of sulphuric acid as the main reactant. It is still widely used in developing countries such as China.