Wet line Processing:
PICS INTERNATIONAL wet line system ensure the recycled aggregate product is free of dirt, clay, wood, plastic and organic materials. These machines break down and remove deleterious material from recycled aggregate feeds, as well as liberate fines and float out lightweight trash, such as plastics, wood, sticks and other debris.
The most rudimentary approach to C&D Waste Recycling is to Recycle and Segregate the material to produce the size fractions required for the construction sector. This cannot fully address the aforementioned contaminants usually found in such material (Paper, plastic, wood, organics etc.). In such systems it is common to reject all material < 10mm as waste as it is generally of a very poor grade due to high contaminants, soil, silt and clay content.
This fraction can ‘typically’ represent 40-50% of the incoming material and is therefore a clear potential resource. In rejecting this fraction, dry systems generally recover only 50-60% of the overall resource. Furthermore, the end products generated are typically low quality, due to notable content of the mentioned contaminants. This has an adverse effect on their utility and potential market value. Some of this is mitigated through flotation units / air separators. Whilst this does see some notable improvement it does so to a lesser degree than full ‘wet’ processes, cannot equally address the presence of clays and does not offer commercial quality sand fractions.
Washing the materials brings a number of key advantages, borne out by the increasing number of such systems installed within the EU (and some other countries) in recent years, particularly within the last decade.
The most obvious gains to the processor are in production quantities and quality. Product to waste ratios are dramatically improved versus dry systems as all viable material >0.063mm material is retained as commercial product or segregated by product. If we consider a typical UK installation, the fines (< 0.063mm) fraction may be measured as around 20% of the overall feed. This means an additional 20-30% production versus a dry system where the < 10mm is rejected as waste.
Quality gains are also highly significant with a properly specified wet process. The noted contaminants are removed through a combination of scrubbing, flotation and screening, and presented as a by-product ‘trash’ stockpile. Some operators are able to dispose of this as a waste to fuel resource, depending upon its composition. The resultant aggregate fractions are physically and visually higher quality making them suitable for a wide range of non-structural applications, whether for sale to the construction materials sector, or for use in-house in the manufacture of sellable value-added products.
Wet systems additionally offer the producer washed sand product which can also be used in non-structural concrete applications. Depending upon the chosen configuration (and raw material characteristics) the system may produce one (usually < 5mm) sand product or two grades of sand: < 5mm and < 2mm. The former has commercial value in non-structural concrete manufacture and the latter can be used as pipe bedding and for cable laying.
Feed hopper
The feed hopper features an integrated belt feeder to ensure the efficient transfer of material from the hopper to the next stage of processing.
Pre-screening:
Pre-screening and sizing solutions from PICS INTERNATIONAL provide precise particle separation for wet line processing. From pre-screening material, to rinsing and sizing the final product, to dewatering lightweight trash removed from the feed, PICS INTERNATIONAL Screens can be used during all stages of the C&D recycling process.
Washing & Aggregate cleaning:
Utilizing material-on-material scrubbing with water, Log Washers are designed to remove tough, plastic clay contaminants and other deleterious materials from gravel, stone and hard ore feeds.
PICS INTERNATIONAL Log Washers can accept a feed material up to 6″ (150mm) cubed. As the percentage of material to be removed increases, longer units should be used to increase the retention time washing action. In very severe applications, two or more Log Washers may be required.
Trash Screen for removal of light weights:
The trash containing light-weights such as wood, plastics, etc. is collected from the lower end of the system along with most of the water. It is then dewatered using our Trash DW Screen. Removal of this trash is essential as with these impurities, the product has limited applicability and thus low value.
segregation for washed Aggregate:
Sagregating is an important part of processing and is used to separate material according to its size. Material is typically fed to a single, double or triple-deck segregator to make the required sizes.
Hydro cyclone system for Sand washing:
Cyclone based washing units have become the industry benchmark over the last few years and particularly in the last 5 years. Originally more common within mineral processing environments they are now a common site in virtually all sectors of wet processing. Cyclones are based on the separation of low mass particles via centrifugal force. Their ‘forced’ separation of particles makes them significantly more efficient and accurate in removing the targeted excess fines than conventional ‘settlement based’ sand washing systems.
Water Management system for recycling of process water:
PICS INTERNATIONAL water management solutions provide a way for producers to maximize their resources and minimize their footprint. Whether it is recovering process water for reuse upstream or dewatering unwanted fines, silts and clays, PICS INTERNATIONAL can help you reduce or potentially eliminate your C&D waste settling pond.
