New dry process simplifies the reclamation of aluminum.
Aluminum salt cake generated during the smelting of secondary aluminum contains between 5 and 10 percent aluminum usually. The recovery of this aluminum has thus far proven difficult costly and time consuming to recover effectively. BHS-Sonthofen has developed a new process based on the selective impact crushing or this salt cake. This is a dry process ensuring better and cost effective results.
BHS-Sonthofen using its multi-functional Rotorshredder and VSI rotor centrifugal crusher completes the aluminum recovery from salt cake using a dry process. Compared to conventional jaw and impact crushers, impact crushing using BHS machines offers the following advantages: Technologically advanced designs mean that in spite of low energy consumption required by motor drive systems, materials are propelled in the machines at great velocity. This generates high impact, shock and stress forces ensuring materials are cleanly separated.
Salt cake lends itself well to an impact crushing process. Brittle slag flakes break off of the comparatively soft aluminum, when the impact forces exerted by the Rotorshredder hammers and the fixed anvil ring of the VSI rotor centrifugal crusher come into contact with the materials.
Effective processing takes place in two stages: First a BHS Rotorshredder crushes the feed stock to a grain size of 40 mm. Feedstock can contain salt cake pieces with a weight of as much as 120 kg and solid aluminum pieces as large as 80 mm. The second step employs the BHS VSI rotor centrifugal crusher of the type RSMX. At this stage materials from the secondary crushing process are screened using a screening cut of 1-3 mm, 3-10 mm and larger than 10 mm. These sized fractions are conveyed to especially tailored magnetic separators sensitive to the appropriate grain size for the removal of any captured ferrous materials. Aluminum can then be effectively separated from the slag residue using cyclone separators.
The resulting final product is a clean aluminum granulate, which can be sold and returned to the materials recycling loop. The salts are further processed and then also reused, e.g. in a smelting process. Only the fine fraction of 0 to 1 mm is dumped.
Testing in the BHS Technology Centre with materials from a German customer has shown that around 8 percent more aluminum can be recovered.
Alfred Weber, Sales Director of the Recycling Division at BHS-Sonthofen, has done a simple calculation and concluded: „With the new process a recoverable value of approximately 800,000 Euros is achievable from a feed stock volume of 10,000 t. Our new plant has proven so efficient that it is economical in many cases to process the aluminum slag where it originates – directly in the smelting plant.“
Compared to previously employed recovery process, the utilization of BHS technologies offers considerable advantages including lower power consumption, lower wear and maintenance costs as well as lower noise pollution. And very important during the processing of aluminum products: No danger of dust explosion due to the continuous dust extraction system.
Background: The machines
Rotorshredder RS
The crushing tools of the BHS Rotorshredder of type RS consist of several rugged hammers, which are flexibly mounted on a high-speed vertical shaft. They exert a high intense stress on the infeed good through impact, shock and shearing forces. The result is selective size reduction:
-Particle sizes are selectively reduced.
-Composite materials are separated.
-Brittle-hard materials are finely crushed.
-Metals are exposed and cleaned.
-Entangled materials are separated.
As soon as the infeed good has reached the nominal crushed size, it leaves the machine without force through appropriately designed grid segments. As a result, the Rotorshredder avoids unnecessary energy input. The crushing tools have a long service life and do not need to be adjusted or sharpened. The machine works continuously.
The main application in the recycling industry is the treatment of all kinds of materials containing metal. However, commercial waste, wood, paper and other waste materials can also be selectively broken up.
VSI rotor centrifugal crusher RSMX
The VSI rotor centrifugal crusher of the type RSMX is a high-capacity crusher with a vertical shaft with throughput rates of 30 to 400 t/h depending on the type. Each single particle in the infeed good is accelerated to a high speed in the patented twin-chamber rotor and then thrown against a fixed impact wall. The impact wall can either consist of an anvil ring or a rock shelf. Clogging is largely avoided through the generous dimensioning of the rotor and housing.
The wear is reduced to only a very few parts as a result of the rock-on-rock principle. The machine therefore is suitable for very hard or abrasive recycling materials, such as slag or glass. The VSI rotor centrifugal crusher also produces a constant grading curve with pronounced wear. The crushing results can be substantially influenced and optimized by selecting a suitable speed.
About BHS-Sonthofen
BHS Sonthofen GmbH is an owner-operated German group of companies in the machinery and plant engineering field, based in Sonthofen (Bavaria). The company offers technical solutions for mechanical process engineering, concentrating primarily on mixing, crushing, recycling and filtration. With more than 350 employees and several subsidiaries, BHS-Sonthofen has a global presence.
The Recycling Technology division offers a wide range of machines and systems for the recycling industry. The product spectrum covers the processing of brittle-hard waste materials such as electronic waste, slag, shredder residual fractions etc., as well as resilient materials such as tires, cables, and refuse-derived fuels.
For more information, see www.bhs-sonthofen.de.
Firmenkontakt
BHS-Sonthofen GmbH
Roland Schmid
An der Eisenschmelze 47
D-87527 Sonthofen, Germany
+49 8321 6099-231
press@bhs-sonthofen.de
http://www.bhs-sonthofen.de
Pressekontakt
VIP Kommunikation
Regina Reinhardt
Dennewartstr. 25-27
52068 Aachen, Germany
+49.241.89468-24
reinhardt@vip-kommunikation.de
www.vip-kommunikation.de
