Calcium in the form of sedentary rock can be found in such minerals as calcite, dolomite, and gypsum. The most frequently used calcium isolation method for industrial purposes uses electrolysis. During this process, calcium chloride is produced by reacting hydrochloric acid with calcium carbonate. The results of this reaction include calcium chloride, water, and carbon dioxide. The liquid calcium chloride is then subject to electrolysis; the cathode calcium is separated from the anode chloride.
There are two processes that can be used to isolate a small amount of calcium. The first process uses the reducing reaction between lime, (CaO), and aluminum; the results of this reaction include pure calcium and Ca3Al2O6. The second isolation process uses the reducing reaction between calcium chloride with metal sodium; the end result of this reaction is pure calcium and sodium chloride. These processes are not frequently used as pure calcium that has been isolated for industrial purposes is easily obtained commercially.