Effect of ultrasonic pretreatment on flotation purification of quartz

Quartz sand purity dictates its applications, with current research focusing on flotation purification. To investigate the effects of ultrasonic pretreatment on quartz flotation, an RKIII single-tank flotation machine was employed at a neutral pH of 6.8, and the impacts of varying ultrasonic powers (120-300 W) and different treatment durations (0-25 min) were discussed. Additionally, ultrasonic pretreatments were carried out in acidic and alkaline environments simulated by 1%-5% solutions of hydrochloric acid and sodium hydroxide, respectively. Through the analysis of impurity content in quartz sand, it was found that under natural pH conditions and a power range of 120-300 W, the optimal purification effect was achieved by adding 100 g of quartz sand to 1200 cm3 of deionized water and subjecting it to ultrasonic treatment for 10-15 min. As the ultrasonic power increased, the purification effect was enhanced. The results showed that the removal of Fe2O3, TiO2, and Al2O3 was increased by 10.4%, 3.3%, and 1.2%, respectively, compared with that of the conventional flotation after ultrasonic pretreatment for 15 min with ultrasound power 240 W in a neutral environment. In the optimal 5% HCl solution, the removal rate of Fe2O3 was 11.2% and 21.6% higher than that of the control group and the untreated group, respectively. The removal rate of TiO2 was 4.6% and 7.9% higher, respectively. The removal rate of Fe2O3 increased by 23.2% and that of TiO2 increased by 9.1% with 240 W ultrasonic treatment in 4% NaOH solution.