Performance Evaluation And Flotation Mechanism Research On Scheelite Flotation Collector

It is a difficult problem to Separation scheelite and calcic gangue in the field of scheelite flotation, because the surface proterty and the floatability is general similar between these two minerals, in result to decrease the selective collecting of collectors to, so the improvement of collector selection for scheelite has gradually become research focus in mineral processing. By conducting single mineral flotation experiments, the thesis studied the flotation ability of scheelite with different kinds of collectors, including Medialan(MDL), sodium oleate(Na OL), octyl hydroximic acid(OHA), salicylhydroxamic acid(SHA), and Oxyparaffin Soap(731) and benzohydroxamic acid(BHA). The flotation mechanism was also studied through some modern methods such as infrared spectroscopy(IR) and electrokinetic potential testify analysis.As is indicated from single scheelite flotation experiment results, the flotation ability of scheelite is better with MDL, Na OL, OHA, and 731 as collecting regents, particularly the flotation ability of scheelite is best when using MDL as collector, when MDL collector consumption is 50mg/L, the scheelite recovery has exceeded 95%, and the flotation p H value is in wide range. However, SHA collector and BHA collector show poor flotation ability for scheelite, when the regent consumption is respectively 200mg/L, the scheelite recovery is only 20%. Only when the dosage exceeds to 600mg/L separately, scheelite recovery is only 80%, it can reach better flotation ability when enough activator is used. The flotation ability of scheelite by selecting six kinds of collectors is sorted from strong to weak in the following: MDL, OHA, Na OL, 731, BHA and SHA.The results of four pure minerals flotation tests show that MDL has weak flotability on quartz in wide p H value and could achieve effective separation between scheelite and quartz. However, the recovery of fluorite and calcite remained high at 90% when p H between 6 and 12, but sodium silicate could effectively depress fluorite, esperically when p H was 8, fluorite recovery rate is about 70% lower than the scheelite recovery, could achieve effective separation of scheelite and fluorite. odium silicate has an intensive depression effect on calcite is poor. When the dosage of sodium silicate reaches 2500mg/L, the recovery rate of calcite fell sharply and the recovery of scheelite is large, realized the separation of the two. Using OHA as collector, although a certain amount of sodium silicate could inhibit the calcite and fluorite, but compared with MDL the recovery of scheelite is low, and when the dosage of sodium silicate more than 2000mg/L, recovery of scheelite decline rapidly. Artificial mixed mineral separation test also confirmed that the flotation separation effect is better when MDL as scheelite collector.As was shown from the results of IR analysis and adsorption quanlity, the aboved six collertors had chemically adsorped on scheelite surface. The collector adsorption quanlity on the scheelite surface has close relation with pulp p H value, and its changing trend is consistent with pure scheelite flotation tests rules. Adsorption quanlity increases with collector dosage.contact angle mearsures show that surface contact angle is wider with MDL, OHA as scheelite collectors and up to the maximum angle under the condition of 8 and 7 p H value. While after adsorbing other four collectors, the contact angle is similar and generally lower than MDL. From the zeta potential measures results, the potential of scheelite surface dropped after adsorbing MDL and OHA, and it explained again that there was chemical adsorption between collector and wolframite surface. The results of zeta potential mearsures show that As MDL and OHA adsorped on scheelite surface, the zeta potential shifted to more negative position compared with no collector function and it also confirmed that collertors had chemically adsorped on scheelite surface.