The concentration of calcium and sulphate ions is much lower in food grade compared to industrial grade. Food grade is put through several mechanical filtration processes, but industrial grade doesn’t have the same quality processing controls. Industrial grade often contains toxic metal contaminants like lead and mercury, or high levels of arsenic. These contaminants can pollute the salts if they are mined, or if the salt water source was exposed to agricultural, mining, sewage or industrial waste streams in the environment. Waste salts from desalination plants also produce industrial grade. Food grade magnesium chloride should not contain mercury nor lead. Industrial grade is used mainly for agricultural fertilizers, processing magnesium metals, swimming pool salt, de-icing of roads and removal of dust from the air in mining environments. Food grade is used mainly by tofu manufacturers and by pharmaceutical companies who further refine the salt to remove all other trace minerals, and make pharmaceutical grade for intravenous use. More information is in this article…