by-products to beneficiate

Rocks in the raw state
- Solid blocks are extracted from quarries by separating a mass representing several hundreds of tonnes from the working face. This rock mass may have microfractures or veins that make the stone unmarketable
- The mass-yield corresponds to the ratio of the volume utilisable in a plant on the total volume quarried. It varies between 20% to 60% according to the sites. Production in the form of solid blocks that are not utilisable in plants, can be beneficiated
- For this to be done under the best conditions, these large blocks must be stored separately and broken up with a rock-breaker

Cutting
This is made up of:
- a surface part that is not very thick (1 to 3 m) and has been altered, making it impossible to beneficiate as a co-product
- a “noble” unexploited area that is amenable to beneficiation, with several banks of healthy rocks

Stone dust slurry
Water is required to saw blocks to cool the material. Limestone powder mixed with water creates slurry. It contains at least 50% of water if the plant does not use a press filter. Otherwise, slurry now contains only 15 to 20% of water, which makes beneficiation much easier. They have the grain size of a filler.

The purpose is to incorporate this slurry as a filler in concrete, plant mixes and some industrial mortars. However, it is impossible to incorporate this material in its original state because, with a water content of 20%, slurry is too difficult to mix, and when it has 50% of water, it is too liquid to maintain good homogeneity. In both cases, the water content means that all products have to be reformulated. To beneficiate this by-product, it must be dried, dispersed and milled.

Saw slurry derived from the extraction of igneous or metamorphous rocks tend to have an acidic pH. Their potential beneficiation has to be studied on a case-by-case basis.

Saw fines
Saw fines (without water) result from the cutting out of the working face or blocks. Their grain size corresponds to a 0/1.5 mm sand.

Sawing residue
The sawing of blocks into slices produces pieces of stones. Depending on their sizes and shapes, these by-products can be beneficiated in the form of aggregates or fines.

Spoil heaps
For several years now, the cutting and non-utilisable blocks have been stored to create piles that are more or less voluminous depending on the site. These spoil heaps weigh many tonnes and can be beneficiated.

Scrubbing slurry
The extraction of alluvial material results in the production of argillosiliceous slurry. Silica, which has a grain size of between 0 and 1 mm, can be separated from clay by cyclone separation and used as a draining material.

Industry waste
Clinker from household waste incineration plants and sand from foundries are by-products that can be beneficiated.