The flotation of spodumene produces a residual fraction of quartz-feldspar mixture, which is washed, dried and sacked according to the needs of the customers. As such, the quartz-feldspar mixture is suitable to be used as fillers within various industries. The distribution of grain size in the mixture is ideal for certain purposes.  

Keliber is evaluating separation of quartz and feldspar as more specified production for the glass and ceramics industry, in which case a better price can be obtained. The upgrading of quartz and feldspar concentrate is one of the future development projects at Keliber.  

The quartz-feldspar concentrate is a by-product that provides added value, and the yield is 60–65% of the amount of ore fed for concentration.