Walnut shell is a kind of degreasing, crushing, screening and other processing processed particle, surface pore, the adsorption effect fabric better polishing abrasive. A compressive ability strong, walnut shell grain particle size 1.25 1.60 mm, the average compressive strength limit of 0.2295 KN (23.40 KGF).Walnut shell grain particle size 0.80 1.00 mm, the average compressive strength limit of 0.165 KN (16.84 KGF). Second, stable chemical properties, does not contain toxic substances, dissolved in acid, alkali, water volume is small, loss of walnut shell in hydrochloric acid solution was 4.99%, the attrition rate was 3.8% in sodium hydroxide solution, does not cause deterioration of water quality. "Walnut shell application and indicators" 1, water filtration materials applications Walnut shell filter material products are widely used in oil field, chemical industry, leather and other industrial wastewater treatment and urban water supply and drainage engineering, is the most ideal water purification filter material of various filters.