The demand for recycled aggregate is on the rise. One of the most common examples of such products is recycled concrete. We go through some of the principles of recycling concrete with the Metso expert Jouni Hulttinen.
Usually, concrete contains rebar and other materials that strengthen it. Before being fed into a crusher such as the Metso Lokotrack LT106 or LT1213/S that ultimately process it to a certain size and shape, concrete needs to be pulverized into a suitable size that fits into the crusher. During crushing, metal is separated with a magnetic separator.
With recycling we can consume less raw materials and preserve gravel resources. Also, depending on the chosen equipment, there can be less transportation needs, which means lower fuel consumption. For example, with Metso Lokotrack mobile crushers, crushing can be done on-site and material can be used there again as filling material, for example. Cost savings come from the same aspects: less transportation means less fuel costs and eliminating the waste material means that there are no costs associated with dumping.
Sorting is crucial for a successful recycling operation. Uncrushable materials must be pulled out from feed material. For example, rebar longer than feed opening (max. rebar length about 500 mm) and thicker than the minimum setting must be removed (max. rebar diameter about 20 mm).
In some of the Metso Lokotrack models with jaw crushers, we have an ASC (Active Setting Control) system as an optional feature to protect the crusher against overloading. If an uncrushable object enters the crusher cavity and crushing forces reach the preset maximum level, oil starts to escape out of the cylinders and the setting releases. This way the uncrushable object can get out of the cavity.
The functionality enables continuous crushing and protects the Metso crusher from extreme overloads. When automated, the crusher setting is returned the original one when the uncrushable object has dropped out of the cavity.
For optimal capacity, it is also important to make sure that the feed material is of the correct size. Here the basic crushing principles with different crushers should be taken into consideration just like with any other feed material.
Team
Prime Technologies Ltd.