Clear your dust stockpiles quickly and efficiently

• 
• 17th December 2008
• Quarrying
 

Quarry dust accumulates on a great many sites as a low value by-product of crushing processes. It can be very difficult to find a market for this material as the commercial value is very low in its raw form. It is therefore the case that more often than not the dust simply takes up valuable space on site as it accumulates in ever growing stockpiles.

CDE have extensive experience working with quarry dust and providing customers with a means of turning this waste into commercially viable products. The specific nature of the raw material being processed will have an impact on the final products but typically a very large proportion of the material - approximately 75% in our experience - lies in the 75 micron to 5mm range.

There is therefore potential for this material to be used as a sand substitute, for example, in concrete manufacture. This is particularly useful where no ready supply of natural sand is available for ready mix concrete batching. By using the quarry dust as a concrete sand substitute an operator can greatly reduce the cost of buying drawn in natural sand.

There have traditionally been some barriers to the processing of quarry dust which have prevented it being widely adopted as a means of producing commercially viable products. The material generally contains a high percentage of silts below 75 micron - typically between 12% and 20% of the stock. It is widely accepted that washing is therefore the best method for removing these silts with suitable accuracy.

However, within the washing options available, it is hydrocyclone technology, as used on the CDE EvoWash system that will deliver the best results. Some of the more traditional washing equipment such as screw classifiers and bucket wheels are simply not accurate enough in their removal of fine silts. It is generally the case that when using these traditional methods, ponds will fill quickly with material in the 75 micron - 150 micron range. This not only creates excess waste handling and reduces efficiency but also compromises the quality of the final washed product.

Quarry dust is generally very lean in the 75 micron to 600 micron range, so it is therefore essential that any process can recover as much of this material as possible. This is particularly true when the material is destined for use in concrete manufacture.

CDE can offer a range of options for those looking for a means of processing this waste product. Where volumes are substantial and there is a steady stream of material in this range to be processed a full turnkey CDE Dust washing plant can be provided. There are numerous options open to you in relation to the make up of this plant, which can include full closed circuit water recycling if required. There are numerous installations of plants such as this throughout Europe with varying capacities.

CDE can also now offer a solution to those with a more temporary problem. A new mobile dust washing unit allows customers to deal with stockpiles of this quarry dust on a contract basis. This removes the requirement for any significant capital outlay to initiate the project while also ensuring a quick solution to your immediate problem. CDE's new DustMax20 is fully trailer mounted and is built to handle -20mm material. The system utilises CDE's EvoWash sand washing technology as well as their recently launched AtroFeed system.

Quarry dust is by its nature very ‘sticky' due to the relatively high silt content and often the presence of clay within the stock. The AtroFeed treats the feed material with a high pressure jet of water, which provides sufficient attrition to remove the clays while also adequately separating the fine silt particles from the larger particles that will make up the commercially viable output. This process ensures maximum recovery of all the commercial grade material, thus helping you to maximise your returns.

The mobile DustMax20 is available for immediate hire from CDE. Full terms and conditions as well as contract terms can be discussed on an individual basis. For further information on this or other CDE projects contact CDE via; email: info@cdeglobal.com, visit:  http://www.cdeglobal.com/ or tel: +44 (0) 28 8676 7900.

 

Associated Links

• Hub-4 Profile of CDE Ireland Ltd
• CDE Ireland Ltd Company Website