How could the minerals remain in the slag after smelting?

Anita Parbhakar-Fox, of the University of Tasmania, Australia, wroted (Process Mineralogy '18): "The micro-texture of the slag is highly heterogeneous and includes distinctive dendritic wurtzite and sphalerite, Zn-rich glass phases (containing up to 34 wt.% Zn) and Zn-bearing olivine and pyroxene." More

I am interested to know: 
"1. How could the minerals remain in the slag after smelting?
2. Why didn't zinc sublimation occur?
3- On which device did you perform mineralogical analysis and how much does it cost?"

Ph.D. Natalia Petrovskaya