Economical alternative to wet processing

Advantages compared to wet processing

• No introduction of moisture into the aggregates
• No wet sieving
• No sludge processing
• All materials are recycled, saving landfill space
• Compact system also available as a semi-mobile version
• High level of rock reclamation
• Possible to screen out material smaller than 5 mm

Advantages compared to conventional continuous mixers

• Continuous mixing process with a defined mixing time, which helps to reduce consumption of expensive burnt lime
• Three-dimensional mixing principle
• Consistently high mixture homogeneity
• High throughput rates
• Low wear

Previously, cost-intensive wet processing was necessary in order to extract valuable rock grade from contaminated input material. Dry processing with the addition of burnt lime is not possible with conventional continuous mixers due to the extremely short retention time and poor mixing effect. The patented BHS Combimix system was developed to offer an economical alternative.

The Combimix system transforms the twin-shaft batch mixer into a mixer that operates continuously according to the proven three-dimensional mixing principle.

This results in a significantly improved mixing effect compared with conventional continuous mixers. The retention time is dependent on the input material and can be varied flexibly from 30 to more than 100 seconds. The filling level is kept constant over the entire production time by means of weight sensing in the mixer. The material is extracted at the same rate as the input material is fed into the system. This procedure enables the recovery of usable rock, while also saving on water, energy and material costs.

1. The raw material is fed in.

2. Pre-separation is performed over a roller screen.

3. The coarse-grain material is transported directly to the jaw crusher and from there to the quarry plant.

4. The clay-and-rock material is fed into the BHS Combimix system and combined with burnt lime.

5. The burnt lime is delivered from the silo by way of volumetric metering into the mixer on a screw conveyor (according to the clay content in the feed material of between 1 and 5%). A weight-based approach is available on request.

6. The mixing material is fed into the screening unit.

7. Materials larger than 5 mm are made available for further processing.

8. Materials smaller than 5 mm can be used as fertilizer, for example, where appropriate.