Recycled Calcium Carbonate

BRIEF OVERVIEW

Calcium carbonate is known by the formula CaCO3. It comprises 4 % of the earth’s total crust and is found in egg shells, snails, mineral rocks, pearls, shells of marine organisms and so on. It is an odourless, tasteless powder used in health supplements, agricultural industry, for environmental applications and many more. Calcium carbonate is an important ingredient for agricultural lime. Agricultural lime is primarily used for making the soil easy to work with. Calcium carbonate is widely used in manufacturing health supplements, though they are good for health, anything is large quantity is hazardous.

• Reaction with acids – Calcium carbonate reacts with acids to quickly form calcium ions, carbon dioxide and water. This phenomena explains a lot about how caves are formed.
• Calcination – When calcium carbonate is heated to high temperatures, it releases carbon dioxide. This is thermal decomposition and results in the formation of quick lime CaO.
• Erosion- When calcium carbonate saturated with carbon dioxide react with water, it resulst in the formation of calcium bicarbonate.

MANUFACTURING PROCESS:

Most of calcium carbonate we use in our daily lives are obtained from mining and quarrying. Fr high grade purity, calcium carbonate is obtained from pure marble. This is used in pharmaceutical applications.

Another synthetic way to produce calcium carbonate is to dilute calcium oxide with water to get calcium hydroxide. Then carbon dioxide is passed through solution of calcium hydroxide to obtain precipitated calcium carbonate.

Construction Industry

Typically, GCC is used in the construction industry, as building material by itself, such as marble, or as an aggregate of limestone for road building. It is also a raw component of cement or as a starting material for lime which is important for materials such as glass by burning in a kiln. It is also used to make mortar for bonding, building materials such as bricks, concrete blocks, stones and tiles.

Plastic Industry

Typically, CPCC is used as filler in plastics to improve mechanical properties such as tensile strength and elongation and electrical properties such as volume resistivity. Polypropylene compounds are filled with calcium carbonate to increase rigidity, especially to withstand high temperatures. It is used as filler in thermosetting resins and is mixed with other ingredients to form compression molded poker chips.

Ceramics Industry 

Calcium carbonate is known as whiting, and it is commonly used for many glazes in its white powdered form. The whiting acts as a flux material in the glaze when the glaze is fired in a kiln. Ground calcium carbonate will not scratch most materials such as glass and ceramics and have a moderate effect on softer metals such as copper.

Other Applications

Typically, PCC is used as an extender in paints, particularly in the matte emulsion paint which has chalked or marble typically 30% by weight in the paint. PCC is used by itself as it can be used as a white pigment or with additives as white paint or in whitewashing. In the paper industry, PCC and GCC is used as a filler in paper during the alkaline paper making process to make the paper bright and smooth. It can also be used to coat the paper white.