11The material in Group 6 comprises only—
(a)calcium based reaction wastes from titanium dioxide production;
(b)calcium carbonate;
(c)magnesium carbonate;
(d)magnesium oxide;
(e)magnesium hydroxide;
(f)iron oxide;
(g)ferric hydroxide;
(h)aluminium oxide;
(i)aluminium hydroxide;
(j)zirconium dioxide.