Flotation of the final product is concentrate and tailings. But in the flotation process to produce intermediate products, namely the selection of tailings and scavenging concentrate, traditionally called middlings. According to the method of treatment of middling coenobium content, useful mineral floatability and requirements of the concentrate quality and. Common treatment options are the following four:
First, return to the appropriate place in the front of the flotation. This method can be used for processing is mainly composed of a monomer dissociation of mineral particles composed of the middling, the most common is sequential return, namely after operation of middling return to previous work, the minerals can be floating in general, and more emphasis on recycling rate, the use of the sequential return, the middling subject to re-election less chance, can avoid losses. If middlings floating better to concentrate and high, must increase the number of middling recleaning, adopting middling returned to oneness is after the merger of the middling returned to the Ministry of the appropriate operations, after the merger of the middling, often need to concentrate, and then return.
Return to form middling is often varied, sometimes by the test to determine the middling return place. General rules of middling return is middling, should return to the mineral composition and floatability and taste similar to work.
Second, middling regrinding. For coenobium more middling, requireregrinding. Re grinding can be carried out separately, and can be returned to the first grinding. When there is a part of the ore body in the single dissociation of the ore, it can be returned to the grading operations. When the surface of the ore needs to be mechanically cleaned, it can also return to the mill.
Third, single flotation middling. Sometimes middlings, although there was no intergrowth, but its nature is special, such as disseminated complex, difficult to float ore grains, mud wait, floating and ore difference, return in front of the work are not appropriate. In this case, the separate flotation middling.
Fourth, other methods. If it is not good to separate the flotation method, chemical processing method can be used to deal with it.