Chemical Process

The only major black pigments are the carbon blacks. These come in various shades and their manufacture is discussed specially under industrial carbon. Lampback, which has a larger particle size, is used for tinting to produce shades of gray. The carbon blacks are very opaque and have excellent durability, resistance to all type of chemical and light fastness. They should not be used in direct contact with iron and steel in primer coating because they stimulate metal corrosion. There are many kind of industrial carbon available: Lampblack Carbon black Activated Carbon Natural Graphite Industrial Diamond For pigment purposes, industry usually use lampblack as the base raw material. To dilute lampblack use organic dilution because lampblack can’t dilute in water.

The oldest and formerly most important of the white pigments is white lead, which is so longer permitted as a consistent of most points. Zinc oxide, another white pigment formerly widely used, is now of only minor importance. The kind of white pigments such as follows: Titanium Dioxide Zinc Oxide Lithophone Zinc sulphide Antimony oxide Lithophone Lithophone is a mixed zinc sulphide, barium sulphate pigment that contains about 30% zinc sulphide. The original light sensitiveness has been overcome by raw material purification and by addition of such agents as polythionates and cobalt sulphate. Lithophone is a brilliantly white, extremely fine, cheap, white pigment. It is particularly well adapted to interior coating. The manufacture of this substance, barium, zinc and lithopone circuits are represented by different types of lines. The barium sulphide solution is prepared by reducing barite are (BaSO 4 ) with carbon and leaching the resulting mass. The equation is: BaSO 4