... -10 kg/m3, about 1.2 or 1.5 times that quartz sand filter of 7.8-9 ... life more than 15 years, is the 5 times or longer than that of quartz sand filters ... Fe2O3 ≤1.0 MgO ≤0.7% CaO ≤0.5 K2O+Na2O ≤4 Rare Elements Micro component 3. Technical ... HCl+50% H2SO4 solution for 14 days Alkali resistance,82.5Mixed in 10% NaOH+10% KOH solution for 14 ... days4. Product Size(mm):Φ0.5-1,Φ1-2,Φ2-3,Φ5-6,Φ6-8,Φ8-10,Φ10- ...