Aluminium sulphate is form by reacting alumina which contains in kaolin with sulphuric acid solution in a stirred reactor. Reaction occurs in variance of different time and temperature. The result of reaction is paste aluminium which will be extracted about 3 times using hot aquadest and consentration of aluminum analized by titrimetric methode. https://www.mamapaisa.com/product-category/helmut-extra-strong-lacquer/