STONE SCREENING DUST. MANUFACTURED SAND

 

It is well-known that the process of production of crushed stone in the granite quarries is accompanied by the formation of large amounts of waste – stone screening dust. Furthermore, the production of large fractions of crushed stone results in formation of stone screening dust amounting up to 20-25 % of the basic material. Yet the production of cubical crushed stone of small fractions (5-15 mm) results in the increase of the amount of stone screening dust to 40%.

In general, the stone screening dust has a certain commercial value and is occasionally sold by companies to local consumers. However, full-scale sale of the stone screening dust is limited by high content of dust particles in it. Judging from our research of Ukrainian granite quarries, typical stone screening dust contains up to 30% of particles with fineness less than 140 µm with high degree of water absorption preventing from using the stone screening dust in its pure form in concrete manufacture.

However, the remaining 70% of the stone screening dust are a valuable material which, after minor additional processing, may become an additional marketable product to be used in quarries; the stone screening dust processing has good market prospects.

The implementation of the proposed processing method allows processing of the newly formed low-value production waste into products which are constantly in demand and the market price of which often exceeds the price of the main commodity items of granite quarries – crushed stones of various fractions.

The essence of the proposed processing method lies in upgrading the main processing line of a granite quarry by installing the section of dry aerodynamic dedusting of the stone screening dust in the vibrofluidized-bed separator with subsequent grading of dedusted material.

The structural diagram of the section for the stone screening dust processing depends on specific requirements and needs of the customer and, to a certain extent, allows to obtain the following:

  • one or more dust fractions of granite which can technically be used as fine aggregates or fractions that can be recycled using the standard procedure;
  • several fractions of dry dust-free granite sand which is a cheap synthetic alternative to natural high-silica sands;
  • mixture of coarse sand and fine gravel that are in demand in construction industry and landscaping.

You can find more detailed information about the products and their use below.

Moreover, the full-scale implementation of the stone screening dust processing will result in a decrease of total dust content at the production site due to the implemented aspiration of basic crushing equipment and sizing screens without the use of water.

A detailed technical and commercial proposal can be found here.

Raw material Material after dedusting
The products obtained after air vibro-separation and screening
Including: Brief description and application:
Dust fraction with a particle size of 0-160 (200 µm). The main range can be divided into two sub-ranges with an average particle size of 50-80 and 140-160 µm respectively. The relative humidity is 0.5%. The bulk density is up to 1300 kg/m3. Main scopes of application: fine aggregate for concrete and asphalt concrete, dry pack mortars, plastics, etc. Cheap substitute for quartz and marble powder
Sand fraction with a particle size of 200-2000 µm. The main range can be divided into sub-ranges with an average particle size of 200-630 µm, 630-1000 µm, 1000-2000 µm, etc. with possible formation of sand compositions with different modulus of fineness. The relative humidity is up to 0.5%. The bulk density is up to 1500 kg/m3. Main scopes of application: replacement of dry high-silica sand in all scopes of application except for the foundry industry.
Coarse sand and gravel with a particle size of 2-5 mm (depending on the grain-size distribution of the basic material). The relative humidity is up to 0.5%. The bulk density is up to 1500 kg/m3. Main scopes of application: - fine aggregate (crushed stone) for concrete and asphalt concrete; - decorative powders;
Last modified on Friday, 25 October 2013 11:03