There are a myriad of industrial processes that require ferrous or magnetic contaminants to be removed. One example of this was a customer of ours who makes a product ground from white marble limestone to make a super fine white slurry. Most of the contaminants that can discolour the slurry are magnetic.
In processes such as these there are a couple of options, a magnetic plate and can be suspended above the white slurry to attract all the contaminants to one place.
Alternatively, a process could be set up by which the slurry pours over magnetic separator bars which would collect contaminants.