... with 2 factories 3.Low B&PSilicon metal:Grade:553/441/421/3303/2502/2202Size:10-100mm ,90%minPacking:in 2 ... high purity of all grade Silicon Metal ,such as #553,#441,#421,#3303,#2202#,2502 with low P&B.Should any ... -421>99.2%≤0.40.1-0.15≤0.1-441>99.0%≤0.4≤0.4≤0.1 QUALITY CONTROL ... authorized by SGS in silicon field. international grade metal silicon 441/553/3303/2202/1515/2203/2503/3103/411/421/1101