And after this heat treatment for 1.5-2 hours, you need to put them in a solution with a concentration of 0.5 g / liter of ammonium molybdate and boric acid.
Futhi emva ukwelashwa ukushisa okunjalo amahora 1.5-2 kuyadingeka ukuze uwafake isixazululo nge lokuhlushwa 0.5 g / ilitha ammonium molybdate futhi boric acid.