In addition their chemical composition makes them valuable raw materials for many branches of the chemical industry, such as the plastics, rubber and fertiliser industries.
Ukongeza apho ulwakhiwo kwamachiza awenze imichako ekrwada ebalulekileyo zenzelwa amasebe amaninzi oshishino lamachiza, ezinjengeplastiki, rabha noshishino lwesichumiso somhlaba