... Polishing Material] walnut shellSuch polishing materials processed by the special process have excellent wear resistance, uniform particle size, and ultra- ... , economic and durable and so on.Uses: It is used for oil field, refining, environmental protection, chemical industry wastewater ... 1.0-2.0mm 2.0-4.0mm function:Polishing process of spectecles, jewelry, button, stamping parts, electronic parts, ...