Experimental study on recovery of kaolinite from flotation tailings through removal of iron using flotation process

For seeking more ways of comprehensive utilization of flotation tailings and realizing high value-added utilization of valuable minerals in flotation tailings, the method for recovery of kaolinite from tailings, a new mode of comprehensive utilization of tailings, is proposed.Through integration of the methods for separation of kaolinite and iron, two technical schemes are applied, i.e.bulk flotation of carbon and iron with carbon particles as carrier, and separation of kaolinite by inhibition of iron, so as to allow such processes to incorporate with existing flotation circuit of a coal preparation plant.The study is made in the paper with the flotation tailings from Tangshan Mine Coal Preparation Plant as the object, and relevant separation tests are made based on analysis of the mineral composition, element content and size composition of the tailings.Study result shows that: kaolinite occupies a dominate share of about 85% in the main crystalline minerals of the test sample; the occurrence of iron is dominantly in forms of hematite with a relatively low content of structural iron—all favorable requisite conditions for separation of kaolinite through removal of iron; the two processes as mentioned above all operate with a relatively poor selectivity when anionic fatty acids or their lipids are used as the collector, and the effect of removal of iron is still unsatisfactory even at a reduced dosage of collector and an increased dosage of inhibitor; whereas, when positive flotation is made with cationic collector at a collector dosage of 900 g/t and an inhibitor dosage of 120 g/t, there can be seen, through a single flotation process, an increase of calcination whiteness of froth product by 9 percentage points, an overall reduction of the content of iron by about 20% with a rate of removal being around 60%; and a sharp rise of product yield reaching 50%.This can lead to an reduction of volume of feed to subsequent magnetic separation link and optimization of kaolinite separation process.