Potassium salts, in particular potassium chloride, potassium sulfate; magnesium salts, in particular magnesium chloride, kieserite, magnesium sulfate and magnesium oxide; sodium salts, in particular rock salt, sodium chloride; mineral fertilizers, in particular potassium fertilizing salt, potassium fertilizing salt containing multi-nutrient fertilizers, all the aforesaid goods being chemical preparations for industrial purposes