Tank construction and method of manufacture

A tank construction comprising:

• an outer shell of steel material having an internal surface, said outer shell comprised of two half members welded together, said half members formed by deep drawing;
• an inner shell of non-corrosive material having an internal surface, said inner shell of non-corrosive material being cast inside said outer shell by a rotational casting procedure with said external surface of said inner shell located adjacent said internal surface of said outer shell, said inner shell of non-corrosive material providing a substantially leak-tight liner for said outer shell to thus prevent contact between the contents of the tank and the outer shell, said rotational casting of said inner shell is accomplished by charging said outer shell with a non-corrosive material and then subjecting the outer shell to a rotational casting movement while heat is applied to the outer shell, said outer shell serving as a mold for the inner shell wherein said mold becomes a permanent part of the completed tank.