... and chemicals Silicon Metal1) 2202Si: 99.5%min, Fe: 0.2%max, Al: 0.2%max, Ca: 0.02%max, P: 0.004 ... , Al: 0.1%max, Ca: 0.1%max, P: 0.005%max4) 421Si: 99.2%min, Fe: 0.5%max, Al: 0.2 ... %max, Ca: 0.1%max, P: 0.005%max.5) 553Si: 98.5%min, Fe: 0.5%max, Al: 0.5 ... %max, Ca: 0.3%max, P: 0.005%max. Silicon Metal