Lead concentrate quality standard Lawn Mower Pulley,Lawn Mower Belt Pulley,Lawn Mower Idler Pulley,Lawn Mower Idler Pulley Taizhou Chenhui Machinery Manufacturing Co., Ltd , https://www.chenhuipulley.com grade The number of Pb mass molecules is not less than % Impurity mass number of molecules is not more than % Cu Zn As MgO Al 2 O 3 First grade 70 1.2 4 0.2 1.0 2.0 Second grade product 65 1.5 5 0.3 1.5 2.5 Third grade 55 2.0 6 0.4 1.5 3.0 Fourth grade 45 2.5 7 0.6 2.0 4.0 Note: Gold and silver in lead concentrate are valuable elements and should be reported as analytical data; impurities of other types of lead concentrates are required by both parties.