Iron Removal and Purification, Turning Stone into Gold — A Comprehensive Analysis of the Quartz Sand Magnetic Separation Process and Jinhuan’s Core Equipment

In fields such as photovoltaic glass, electronic packaging, and high-end ceramics, the purity of quartz sand directly determines product success. Even trace amounts of iron impurities can lead to decreased light transmittance, insufficient whiteness, and even electrical performance degradation. With advantages of high efficiency, environmental friendliness, and controllable costs, magnetic separation has become an irreplaceable core process in the iron removal and purification of quartz sand.

A complete quartz sand beneficiation system typically follows the process flow of “grinding and screening—desliming—hydraulic classification—hindered settling—magnetic separation—dewatering.” After crushing and grinding, the raw ore enters screening, followed by the removal of primary and secondary slimes. Hydraulic classification is then used to separate fine and coarse sand with unqualified particle sizes. Hindered settling further ensures particle size control, and only qualified materials enter the magnetic separation and purification stage before finally obtaining refined sand products through the dewatering process. The reason magnetic separation is positioned in the middle-to-late stage of the flow is that the upstream processes have already created ideal feed conditions with uniform particle size and low mud content, allowing the effect of magnetic separation to be maximized.

Magnetic separation itself follows the strategy of “weak first, strong later, and multi-stage progression.” The occurrence forms of iron in quartz sand are complex: there is mechanical iron introduced by crushing and grinding, which is highly magnetic and easy to remove; there are also weakly magnetic iron oxides such as hematite and limonite, as well as iron-bearing silicate minerals such as biotite and chlorite, which require higher field strengths to capture. In a typical process, the first stage uses a permanent magnetic drum separator with the field strength controlled at 0.1~0.3 T, prioritizing the removal of strongly magnetic mechanical iron to reduce the load for subsequent strong magnetic separation. The second stage enters strong magnetic separation, where the field strength is increased to above 1.0 T, using a vertical ring high-gradient magnetic separator. It utilizes the local high-gradient areas generated by the internal magnetic matrix to capture micro-fine weakly magnetic particles. For scenarios with stringent quality requirements, a two-stage vertical ring strong magnetic separation of “one roughing, one cleaning” can be set up, with the field strength progressively increasing to 1.3 T to gradually reduce the Fe₂O₃ content. For the final stage of cleaning, it can be selected based on the production line form: wet lines can use slurry high-gradient magnetic separators for final control, while dry lines can install powder iron removal equipment at the conveying pipeline or packaging inlet to ensure no secondary contamination is introduced in the finished product stage.

On the equipment side, Jinhuan Magnetic Separation covers the full process requirements of quartz sand magnetic separation. The **SCT series permanent magnetic drum separator** has a simple structure and low operating costs, undertaking the first checkpoint of medium magnetic separation for removing mechanical iron. The **SLon vertical ring pulsating high-gradient magnetic separator** is the main force of strong magnetic separation. Relying on the synergistic separation mechanism of magnetic force, pulsating fluid force, and gravity, it has become the core equipment for the separation of weakly magnetic minerals and the purification of non-metallic ores. Its super-large model, the SLon-8000, can reach a processing capacity of 2500 t/h with a single-ton energy consumption of only 0.12 kWh/t, demonstrating outstanding performance in quartz sand purification. The **SJ series slurry high-gradient magnetic separator** specializes in micro-fine particle minerals, complementing the SLon series and suitable for the refined iron removal needs of wet final-stage cleaning. In addition, the **SGTF powder dry permanent magnetic separator** is designed for dry production lines, with a magnetic field strength of up to 597 kA/m. In an application at a beneficiation plant in Henan, the iron content of quartz sand was reduced to 0.06% after a single separation, meeting the standards for glass raw materials. From roughing to cleaning, from wet to dry processes, Jinhuan Magnetic Separation provides a configurable and scalable technical path for quartz sand purification with its complete equipment matrix.