Mineralogy, petrography and manufacturing of good quality Blackboard chalk

Abstract

Most of the Arabian countries produce bad quality and dusty blackboard chalk. Good quality and dustless blackboard chalk are usually imported from Europe, China, Taiwan and the United States of America. The essential raw materials for the production of blackboard chalk include chalk variety of limestone and gypsum or anhydrite. These materials are available in large quantities, especially in the Tertiary sediments in most of the Arabian countries. Investigations on the factors which affect chalk production indicate that the amount of water and the percentages of calcium carbonate, gypsum and binders as well as the grain size of the different components are the controlling factors in the production of blackboard chalk.