Addition of lime on the waste rock from aggregate quarries

The dry reagent is kept at a constant level in the Arch Breaker’s hopper, which ensures high metering accuracy regardless of the quantity of powder remaining in the silo. This set provides unmatched performance for a volumetric metering screw positioned right under a silo with lime flow rates ranging from less than 1 kg / h to almost 12 T / h – regarding the screw. Why install a waste rock liming process in a quarry?

The so-called “waste” clay material can represent up to 30 % of the annual production of a quarry. These unusable rocks were disposed of in the past, which represented a net loss for the production site. The addition of lime facilitates the segregation from the particle size of the materials to be treated. The aim for quarries is to improve their profitability and the longevity of the site. With the addition of lime, the rate of unused materials extracted can potentially drop from 30% to 10%. 

As the waste rock is reprocessed, it is no longer necessary to store it, thus saving space!

Process steps:

1. Loading the crushed rocks
2. Primary scaling with a wobbler feeder
3. Materials that pass through are sent directly to the primary jaw crusher and then to the treatment facility
4. The waste clay material is sent to a mixer and mixed with quicklime
5. Quicklime, volumetrically metered via our SODIMATE Mechanical Bin Activator coupled with a screw feeder, is injected into the mixer (from 1 to 5% depending on the clay content of the incoming product)
6. The mixture is sent to the screening equipment
7. Particles larger than 5 mm are sent to the treatment facility
8. Particles smaller than 5 mm can be used as a fertilizer if they are suitable

Process diagram: (quicklime – Arch breaker – metering screw feeder – mixer – treatment plant)