RECYCLING AND CRUSHING

The recycling process converts waste into resources thus saving on raw materials and energy. In agreement with the customer, we define: type and composition of waste to be recycled, hourly input flow, type, quantity and technical features of the output products, and if the materials need to be crushed, their main characteristics, like hardness, abrasiveness, homogeneity, final granulometry etc. which will need to be considered for the crushing process. After defining the industrial process, together with the client, we will choose the machines and we will proceed to designing and constructing the recycling plant.

We conceive, design, build and install recycling and crushing systems to treat:
• glass (with aluminium and steel);
• inert materials (rocks or materials coming from building demolitions);
• slag (coming from steel mills and foundries).

Recycling plants are generally complex systems where:
• magnetic separators
• induction separators
• screens
• light fractions separators
• optical separators
• crushers
connected by different conveyor types, are installed.

INDUCTION SEPARATION

The induction separator separates non-ferrous metals such as aluminium, copper and brass. It is a conveyor belt equipped with a permanent magnet rotor, coaxial to the conveyor head drum. The magnet rotor rotates at high speed and generates alternating high-frequency magnetic fields that induce currents in the non-ferrous metals.

The induced currents, in turn, generate magnetic fields opposite to the fields produced by the rotor. The opposite magnetic fields lift and expel the non-ferrous metals from the flow of inert materials, which, instead, follow the path given by the conveyor belt and fall into a different container.

It is possible that in the flow of material being sorted some ferrous metals may be present but the magnetic drum retains and discharges them into a third container underneath the machine.

CRUSHING

Crushing is the reduction of material into small pieces, by compression or impact. Crushing by compression occurs by means of crushers that can be: jaw crushers, cone crushers or roller mills. The jaw crusher [180] has two steel, wear resistant plates. The first plate is fixed and is an integral part of the machine frame. It is called a fixed jaw. The other plate is called the swing jaw. The lower part of the swing jaw is hinged by a toggle to the machine frame, while the upper part is driven by an eccentric shaft. The space between the jaws is called the crushing chamber. Each time the shaft rotates, the eccentric movement of the swing jaw increases then reduces the space in the crushing chamber, and the material is consequently broken up.

A conic mantle, eccentrically rotating around a vertical shaft, inside a concave, constitutes the cone crusher. As the cone makes a complete rotation, the space between the mantle and the concave, the crushing chamber, varies. These variations in the dimensions of the crushing chamber, caused by the eccentric rotation of the mantle, allow the material to slide down in the space between the concave and the cone and the material is consequently crushed and broken up.

 

There are different types of roller crushers, but the operating principle remains the same. The material is broken up by being compressed between two or more rollers. The rollers are normally cylindrical and can have a vertical or horizontal axis, but there are also crushers with conical rollers.

Crushing by impact is carried out by hammer mills. The hammers, supported by horizontal or vertical shafts, spin at high speed and throw the material against impact plates. The impact is very strong, material is broken up, and granulometry is reduced.