Purification Mechanism of Quartz Sand by Combination of Microwave Heating and Ultrasound Assisted Acid Leaching Treatment

Utilization of Sea Sand for Preparation of High-Performance CoAl2O4 Composite Pigments via a Cleaner Mechanochemistry Route

“…The existence of Fe impurities can endow quartz with varying degrees of color, resulting in a negative effect on the optical performance. Due to complex formation reasons, the Fe element can be associated with quartz in the form of isomorphism (occupying the silica lattice), single-phase solid inclusions, and dissolved salt in fluid inclusions . Compared with the latter two forms, it is more challenging to remove the Fe element in the silica lattice of quartz and the associated aluminosilicates in sea sand.…”

“…Due to complex formation reasons, the Fe element can be associated with quartz in the form of isomorphism (occupying the silica lattice), single-phase solid inclusions, and dissolved salt in fluid inclusions. 27 Compared with the latter two forms, it is more challenging to remove the Fe element in the silica lattice of quartz and the associated aluminosilicates in sea sand. Therefore, the removed Fe at a lower acid concentration may be a single-phase solid inclusion or dissolved salt, and the residual small amount of Fe in TTS is most likely in the silica or aluminosilicate lattice when the acid concentration is above 6 mol/L.…”

A comprehensive review on the ultrasound-enhanced leaching recovery of valuable metals: Applications, mechanisms and prospects

“…The leaching characteristics of Fe from various raw materials with the assistance of ultrasound are summarized and compared in Table 7 . In recent years, ultrasound has been widely applied to remove iron (Fe) from raw materials, such as silica sand, quartz, kaolin, silicon diamond-wire saw cutting waste, and boron carbide waste-scrap [68] , [120] , [123] , [140] , [141] to improve the purity. In the early years, many studies were conducted in relatively single leaching systems, such as inorganic acid, alkali, and organic solvent.…”

Experimental Study on the Damage Characteristics and Acoustic Properties of Red Sandstone with Different Water Contents under Microwave Radiation

“…After absorbing microwaves, the temperature of the rock increases, which can inevitably lead to thermal expansion and cracking. Li et al [ 19 ] studied the change in mineral structure under microwave radiation and concluded that the mechanism of microwave rock breaking makes the rock produce irreversible thermal expansion and fracture. Ali and Bradshaw [ 20 ] and Osepchuk [ 21 ] found two causes for rock damage resulted from microwave radiation: (1) tensile stress caused by thermal expansion of minerals; and (2) shear stress caused by the intergranular slip of minerals after thermal expansion [ 22 , 23 ].…”