Quartz sand flotation: from low grade to high purity metamorphosis journey

In the field of quartz sand processing, flotation is the key technology to achieve its purification, especially for low-grade quartz ore, flotation can effectively remove impurities, improve the quality, to meet the stringent needs of photovoltaic, glass and other industries on high-purity quartz sand.

Before flotation, the quartz ore needs to be pre-treated. The Hanzhong quartz sandstone used in the experiment was first crushed and ground, and then screened out 109μm - 212μm particle size quartz sand as raw material. This size range of quartz sand is widely used, and the subsequent flotation purification study is of great significance to it.

In the flotation process, the choice of chemicals is crucial. The capture agent is one of the core chemicals in flotation, and a variety of capture agent systems were compared in the study. Dodecylamine - sodium oleate system at pH 3, dodecylamine dosage of 500g/t, sodium oleate dosage of 400g/t, the removal rate of (Al2O3) can be up to 64.3%; dodecylamine - sodium dodecyl sulfonate system in the acidic conditions, the pH value of the flotation effect of its less impact, in a specific amount of purification can be achieved to a certain extent; and dodecylamine - sodium oleate - sodium dodecyl sulfonate ternary mixing The dodecylamine - sodium oleate - sodium dodecyl sulfonate ternary mixed collector system, combining the advantages of the first two, the removal rate of (Al2O3) can be as high as 67.8% in a strong acidic environment, but the recovery of quartz sand concentrate is not ideal when using only the collector.

In order to improve the recovery and flotation effect, inhibitors need to be added. Four kinds of inhibitors, namely soluble starch, sodium fluosilicate, sodium hexametaphosphate and calcium lignosulfonate, were experimentally studied. The results show that soluble starch has the best effect in alkaline environment, when the pH value is 10 and the dosage is 250g/t, it can make the recovery rate of quartz sand concentrate reach more than 80%, and the content of (Al2O3) is reduced from 2267ppm to 558ppm. Taken together, soluble starch is a more ideal inhibitor.

Ultrasonic pretreatment is an effective aid to enhance the flotation effect. Different power of ultrasonic treatment has different effects on quartz sand flotation. In neutral environment, 240W power ultrasonic pretreatment for 15min has obvious removal effect on (Fe2O3), (TiO2), (Al2O3); in alkaline environment, when the concentration of NaOH solution is 4%, the removal of (Fe2O3) and (TiO2) is significant; in acidic environment, the removal of (Fe2O3) and (TiO2}) is significant; in the acidic environment, the NaOH solution concentration is 4%. The effect is remarkable; in the acidic environment, the best effect is achieved when the concentration of HCl is 5%, which can effectively remove a variety of impurities.

The process flow of quartz sand flotation has been carefully studied and optimised at every step, from raw material pretreatment, to the reasonable use of trapping agents and inhibitors, to the assistance of ultrasonic pretreatment. Through the synergistic effect of these processes, the impurities in quartz sand can be effectively removed and its purity can be improved to meet the quality requirements of quartz sand in different industries, laying a solid foundation for the wide application of quartz sand.