fig19
![Recent advances in the marketing, impurity characterization and purification of quartz](https://image.oaes.cc/036f0845-0107-47fd-9d89-518c1048755f/mmm2017.fig.19.jpg)
Figure 19. (A) High-temperature and high-pressure leaching system; (B) leaching of the treated hematite ore; (C) variation of Al and K during leaching; (D) variation of the leaching efficiency of the vein minerals from different quartz feeds. CQS: Calcined quartz sand; QC: quartz concentrate; QS: quartz sand.