1 The analysis method of ferrochromium and ferronickel samples is discussed and the mathematical model for using binary ratio technique to analyze dual samples is set up.

2 The device consists of an electromagnet moving ferronickel optical shutter interposed in a fiber gap, and it's actuation causes optical attenuation.

3 Therefore, the current domestic enterprises mainly produce ferronickel with nickel oxide ore by electric furnace smelting or blast furnace smelting.

4 The heat treatment of ferronickel submerged arc furnace slag has little effect on reducing drying shrinkage of hardened cement paste.

5 The discussion covers the theoretical behaviour of impurities, and modem industrial and developing methods for ferronickel refining.

6 The result shows that it is feasible to use the dual ratio technique to analyze the contents of alloy elements and of the main element Fe in ferrochromium and Ferronickel samples.