General process flow of calcium carbonate from limestoneIt is best to use words to explain
The earlier electrolysis is the contact method, because this method raw material consumption is big, the metal calcium solubility in the electrolyte is high, the current efficiency is low, the product quality is poor (about 1%) and so on, later improved to the liquid cathode electrolysis
There are three ways to prepare calcium, such as reduction, electrolysis and calcium refiningReduction is the main method for producing metal calcium. Usually limestone as raw materials, calcined into calcium oxide with aluminum powder as reducing agent. The calcium oxide and aluminum pieces according to a certain proportion, mixing, pressing block, 0.01 reaction in vacuum and the temperature of 1050-1200 DEG C, calcium calcium vapor and aluminum, calcium vapor the reduction of crystallization at 750-400 degrees. The crystallization of calcium re melting under the protection of argon ingots obtained dense calcium spindles. The recovery rate of reduction of production of calcium is generally around 60%.
Industrial calcium by high vacuum distillation process to obtain high purity calcium. The general control of distillation temperature of 780-820, 1 * 10-4. vacuum distillation on Purification of calcium chloride in less effective, can add nitride at lower than the distillation temperature, and to form salt. By adding nitride and vacuum distillation purification, the total impurity elements of calcium in chlorine, manganese, copper, iron, silicon, aluminum and nickel can be reduced to 1000-100ppm, high purity calcium that was 99.9%-99.99%.
