Rotary impact mill for fine sands and dry mortar

Natural raw materials are becoming scarcer, whilst demand for high-quality building materials for infrastructure, housing construction and renovation is rising. The market is changing noticeably, particularly for sands.

Many traditional extraction sites are coming under regulatory pressure, riverbeds may no longer be used to the same extent in many places, and the construction industry is seeking alternatives to natural aggregates. At the bauma in Munich, BHS is therefore showcasing a rotor impact mill developed specifically for this shift. The focus is on the RPM-type rotor impact mill. The plant is used to produce artificial sands, fine sands and defined final grain sizes for dry mortar or other building materials. This positions the machine in a sector that is becoming increasingly strategically important for the building materials industry: the controlled processing of mineral materials with a precise grain structure. Fine sands in particular are considered technically challenging. Whilst coarse aggregates can be produced relatively easily, the manufacture of uniform fine fractions requires significantly more precise crushing processes.

BHS develops rotor impact mill for defined final grain sizes

The machine presented operates on a classic impact crushing principle, but combines this with a very high rotational speed and a specially designed grinding gap. The material is fed centrally into the rotor and initially guided vertically. The direction of movement then changes within the machine to the horizontal plane. There, the material strikes hammers and ring liners at high speed. The resulting impact forces carry out the actual crushing. The decisive factor here is not only the sheer impact force, but the controlled processing within the grinding gap. The rotor impact mill thus achieves a high degree of comminution and is particularly suitable for fine mineral products. Typical areas of application include dry mortar plants, building material processing and the production of artificial sands. Of particular interest is the role of such machines in the context of resource conservation. As natural sands are becoming scarcer in many places or are ecologically problematic, the importance of industrially produced alternatives is growing.

RPM rotor impact mill simplifies grinding gap adjustment

One technical detail of the plant concerns the adjustment of the grinding gap. According to the manufacturer, no additional tools are required for this. Instead of complex mechanical modifications, it is sufficient to reposition the hammers and manually adjust the spacers. This can be a decisive factor, particularly in industrial operations. Production plants for building materials often operate under significant time pressure, and downtime incurs considerable costs. Systems that can be quickly reconfigured or adjusted are therefore becoming increasingly important. Key features of the rotor impact mill presented:

• high degree of comminution for fine sands and dry mortar
• Production of artificial sands as an alternative to natural sands
• Impact crushing with rotor, hammers and ring armour
• Tool-free adjustment of the grinding gap
• Use in dry mortar plants and building materials production

Fine sands are becoming increasingly important for the building materials industry

The importance of such plants is growing primarily because the requirements for building materials are changing. Modern dry mortars, plasters or industrial mixtures require precisely defined particle sizes. Even small deviations can affect workability, strength or flow properties. That is why processing does not end with comminution. After the grinding process, the material is screened, separated by particle size and then stored in silos. Only then does further processing take place in mixing plants. The combination of crushing, screening and mixing technology demonstrates just how industrialised building materials production has become today. Although sand is regarded as a simple raw material, the manufacture of precise mineral products requires complex process engineering. Artificially produced fine sands, in particular, are gaining additional importance because they can be produced independently of natural deposits. This reduces transport distances and provides greater control over material properties.

Resource conservation is transforming raw material processing

The presentation at bauma also highlights a broader shift within the building materials industry. Raw materials are increasingly subject to environmental and political scrutiny. Sand extraction from rivers or coastal regions is being restricted in many places, whilst global demand for mineral building materials continues to rise. Consequently, the focus is shifting more strongly towards recycling, artificial aggregates and more efficient processing technologies. Machines such as the rotor impact mill play a central role in this, as they can produce high-quality fine products from coarser mineral feedstocks.

The trend towards industrially prefabricated building materials is also reinforcing this development. Dry mortar, special plasters or standardised mixtures require consistent material qualities, which often can no longer be reliably achieved using natural raw materials alone. BHS is thus positioning itself in a sector that is likely to grow in importance for the construction industry in the long term. For the more strictly raw materials are regulated and the more precisely building materials must be processed, the more important technologies for controlled material processing become.