Washing and fines recovery

When the material is dirty and needs to be washed before use, we design, build and install complete systems of washing and selection.
We also recover fines that are dragged away by the wash water.
Washing systems, and fines recovery groups, are designed not only according to the product to be washed
but also according to what kind of material needs to be washed away.

If you need to remove very sticky/slimy sludge or clay, it is necessary to employ disaggregation machines
like drum or paddle deslimers, before washing. If there are pollutants such as plastic, wood and paper,
in the product to be treated, it is necessary to use anti-clogging screens and anti-clogging dryers.
The particles which are very small, with a diameter between a few dozen microns and a few hundred microns,
are dragged by the water flow along with the silt. To recover only the fine particles of the product,
and separate them from the silt, we use a fines recovery group.

Deslimer

To disintegrate small lumps of clay or sticky materials or to remove sticky substances from the surface of the product we use deslimers.
Deslimers can be of two kinds: rotating drum deslimers or logwasher deslimers.
The first type is a drum in which silt and clay are removed by the strong mechanical action of the paddles
positioned on the inner side of the drum and a flow of water in backwash.
The second type is a tank in which two rotating shafts, equipped with small paddles, shuffle the material continuously in a flow of water.
In both machines impurities are removed from the material as a result of two actions: the intense mechanical friction of the paddles
against the material and the flow of water that washes away the impurities that have been removed from the product.

Washing and selection

The material that has been pre-treated in the deslimer is then sent to a washing screen,
which can be of two kinds: vibrating or rotating washing screens. Here it is washed by jets of water under pressure and granular classification is made.
In the vibrating screens which have several screening decks, the screening decks beneath the first,
not only wash the material but also classify the granulomtery into different sizes.
In a rotary screen, the grids are positioned so that the dimension of the holes along the cylinder
increases from the material point of entry to its exit.

Fines recovery

The flow of washing water drags all the fine and very fine particles.
The recovery of the fine particles takes place with a centrifugal operation carried out by a hydrocyclone and dewatering carried out by a vibrating dryer.
The machine, which we employ for this purpose, is a fines recovery group.
This group is made up by a tank where wastewater is collected, a pump, a cyclone and a vibrating dryer with a reverse slope.
All the machines and equipment (pump, hydro cyclone, pipes and connections) that come into contact
with the mixture of water and fines at a high speed, are lined with anti-abrasive rubber or are made of extremely hard steel alloys.
The waste water from the washing is full of fine particles, and is sent to the collection tank.
A pump sucks the mixture of water and fines and sends it to a hydrocyclone.
Inside the hydrocyclone, a centrifugal force ejects the thickened still fluid solid particles from the conical part while the water
and the silt are expelled from the upper part. The dense mixture of particles and water falls onto the polyurethane net of the vibrating dryer,
where a bed of fines is formed over the net, and acts as a filter. The solid mass is thus dehydrated.