Saving Gold from Landfills

Waste Handling & Recycling

Saving Gold from Landfills

Recovery of Metals from fine Shredder Fractions
Approximately 20 grams of gold, 200 to 300 grams of silver, as well as platinum and other precious and non-ferrous metals: this multitude of resources can be hiding in one tonne of heavy non-ferrous fraction, and which until now have invariably been deposited in landfills. A new one-of-a-kind process allows to reclaim and sell these metals profitably.
(ed. WoMaMarcel - 18/9/2015)
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Layout of the Recycling Process

In the first part of the process, the input material is crushed and the lightweight materials are separated. In the second stage, the remaining material is screened and sorted by density. The final products are thus various materials and metal fractions cleanly separated according to type and grain size.

The centerpiece of the plant is the rotor impact mill of type RPMV. It crushes the brittle-hard materials and shapes the ductile, metallic ones into balls. The standard plant, which BHS offers as a complete solution, achieves a throughput of approximately 10 tonnes per hour. In addition, BHS will also design larger plants which are tailored to specific customer requirements.

The input material consists of the fine components from coarse shredding

Mechanical Crushing

To begin with, coarse materials with a grain size of over 20 mm are screened, and lightweight materials such as foam, textiles or plastics are separated and freed from dust by means of a zig-zag separator. The dust is conveyed to a covered container.

The remaining material (grain sizes between 0 and 20 mm) is crushed and disaggregated in the rotor impact mill. The machine works selectively here: brittle materials – for example mineral substances, glass or castings – are finely crushed and the composites are separated, while elastic materials such as rubber remain intact.

The result: non-magnetic metals with a grain size of 0 - 3 mm

The key effect of the sorting is that ductile metals, i.e. those which can be deformed plastically, are shaped into balls in the rotor impact mill. This is why the machine is also referred to as the “ball shaper”. It lays the foundations for the next stage, which cleanly separates the non-ferrous metals from the other materials. In order to be separated and conveyed to the downstream process stages, the non-ferrous metal parts, which are often long and flat, should have as compact and spherical a form as possible.

Every batch is passed through the mill several times; lightweight material and dust are separated out and discharged before the mill prior to each step. The speed of the rotor and the number of cycles can influence the crushing performance of the machine.


After the last cycle through the rotor impact mill (RPMV), the material passes through a hopper into a screening machine, which separates it into the three fractions. Each of these is then sorted by gravity separation into heavy and light fractions. The heavy fraction containing metallic components is conveyed to magnetic separators and split into magnetic and non-magnetic metal fractions.

The non-ferrous metal fraction can be screened again and separated into heavy and light components. This creates two non-ferrous fractions, the light fraction containing light metals such as alumini-um or magnesium and the heavy fraction containing copper and brass, for example.

The individual batches are decoupled with two hoppers – one in the circuit above the rotor impact mill and one before the separation stage – allowing for virtually continuous operation. As the rotor impact mill runs, one batch is prepared in the mill circuit and another is screened and sorted.

The resulting product: ball-shaped copper.

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