Screening machines for minerals

Around 80 percent of the stone and earth goods are used in the construction industry, while around 20 percent are supplied to the chemical, steel or glass industries. In terms of volume, the largest share of quarrying is accounted for by the raw materials gravel, sand and natural stone. In recent years, recycling of construction waste has also become an emerging branch of the mineral industry. Almost 100 million tons of secondary raw materials such as mineral construction waste or by-products from industrial processes are used in the building materials industry today.

Use of screening machines in mineral extraction

The production of minerals is usually carried out close to the occurrence. The raw material is produced in the quarry by blasting extraction followed by the preparation stages of crushing or grinding and screening. The screening and crushing stages can be repeated several times until the level of fineness is reached that is required for downstream preparation into the final product. The screening of stones and soils can be performed as wet or dry screening. The selection of the screening plant and the related screen sections should aim at the lowest possible energy consumption.

Coarse separations

Due to its robust design, the linear motion screen RHEox is mainly used in the mineral processing industry. It can be used for both dry and wet screening (RHEhydrox). In this machine, the entire screen unit is excited into linear vibration by means of an unbalance motor, cardan shaft and top-mounted unbalance exciters. Depending on the application, the RHEox can be designed as a single or multi-deck machine, in which a wide variety of screening surfaces can be used, such as steel screen cloths, polyurethane screen panels, plug-in panel systems or even gratings. Feed rates between 100 t/h and 1,000 t/h with separations from 3 mm to 500 mm are no problem for this machine. This makes it ideal for classifying stones and highly abrasive material.

Separations in the medium-sized grain range

Optimum dry screening of stones and soils in the particle size range from 1 to 25 mm and feed quantities from 25 t/h per machine can also be guaranteed by the RHEduo^® double-frequency industrial screener, in which the drive principle is based on two unbalanced motors with different rotational speeds. At the inlet side, the product is loosened by applying a large oscillation amplitude, at the outlet side, the high frequency of the motor with a higher acceleration allows precise screening even of difficult-to-screen product. Our customers appreciate especially the continuous product purity that this screening machine achieves even at high screening capacities.

Fine separations

For finer separations, such as those required for dolomite, the RHEmoto^® vibratory sieve is the preferred choice. High-precision screening is achieved by direct excitation of the screen cloth through low-maintenance unbalance motors. This direct vibration transmission is not only extremely energy-efficient, but also enables high accelerations of the screening material, which result in precise classification and thus achieve the highest product purity. In addition, the static machine housing of the screen reduces wear on the machine and mesh, as no sliding motion is required.