| In china, more than90percent titanium resources are reserved in vanadic titano-magnetite deposit. The flotation treatment of ilmenite in this type of ore has always been the world-class problem and research emphasis in mineral processing field. In general, there are still some deficiencies needed to be improved, such as the low efficiency of resource utilization and weak theoretical research. Using various modern analysis technologies and combining theoretical investigation with experimental study, this dissertation has done detailed and systematical researches in ilmenite flotation system, including the interfacial composition and properties, the interfacial assembly of the flotation reagents and the interface interaction between particles, etc.. Basing on above-mentioned researches, this dissertation resultantly has established a novel separation principle of "ion selective migration and components controllable assembly on solid-liquid interface", and proposed innovative technical prototypes to process Panzhihua ilmenite. Main conclusions and innovations of this dissertation are listed as follows:1. Ion selective migration and collector directional adsorption on solid-liquid interfaceAdopting the surface analysis methods such as X-ray photoelectron spectroscopy(XPS), infrared spectroscopic(FTIR) and zeta potential, this dissertation has discovered the selectivity of ion migration behavior, the difference of collector adsorption location, and the connection between these two processes, well revealing the internal mechanism of the collector adsorption process in ilmenite flotation.Same elements such as Ti、Fe、Ca、Mg exist on the surface of both ilmenite and titanaugite (the gangue mineral), and the dissolution behavior of the Ca、 Mg is much more remarkable than that of Ti and Fe. In a weak acid environment, ion migration and collector adsorption on solid-liquid interface would take place. On the surface of ilmenite, surface dissolution is beneficial to the oxidation from Fe2+to Fe3+which has a much stronger reaction with oleat, therefore the adsorption is strengthened. As for titanaugite, Ca2+and Mg2+substantially transform into the pulp during surface dissolution process, while Ca2+and Mg2+are the main active points reacting with sodium oleate, so the absorption would be weakened. In a weak alkalic pulp environment, the ion migration trend becomes weakly, and Ca and Mg play a leading role in the adsorption of the both minerals.Based on the above results, to enlarge the floatability difference between these two minerals, pre-treatment methods of strengthening dissolution in lower pH environment and assistant dissolution by ultrasonic were proposed.2. Assembly mechanism of multicomponent flotation reagents on the surface of mineralsBy studying the surface activity, adsorption mechanism, and flotation performance of combined reagents, the synergistic effect of collectors and competitive adsorption of regulators were discussed, providing a basis for establishing flotation reagent system.Combining sodium oleate with some flotation reagents could enhance their collection property on ilmenite, such as chelating agent, anionic surfactant and nonionic surfactant. Although the combination of benzyl hydroxamic acid and sodium oleate would weaken the ability for reducing the surface tension, both of them could form chemical absorption on the mineral surface, which could fasten the absorption. Sodium dodecyl sulfate could slightly enhance the ability for reducing the surface tension, and it can be absorbed on the mineral surface together with sodium oleate by electrostatic interaction. TX-100can’t be adsorbed on the surface of ilmenite by itself, but coadsorption could occur when it is combined with sodium oleate, and TX-100could significantly improve the efficiency for reducing the surface tension.Under certain condition, competitive absorption would take place on the two mineral surfaces when waterglass, CMC and sodium oleate are in coexistence. The intensity sequence of absorption ability on surface of ilmenite is:sodium oleate>CMC>waterglass; while for titanaugite, the sequence would be:waterglass> CMC> sodium oleate.3. Interface interaction and regulation between homophase/ heterogeneous particlesBy flotation and sedimentation test, particle size analysis and scanning electron microscope (SEM) combining the interaction energy calculation, heterocoagulation, selective flocculation and carrier effect were studied, and the relationship with the enhancement of fine particles flotation was also analysed.Heterocoagulation between fine titanaugite particles and ilmenite particles, having an adverse impact on the floatability of ilmenite, could be dispersed by waterglass. Selective flocculation flotation could be realized by the combination of water glass and CMC. Hydrophobic agglomeration would be observed when sodium oleate is added, as for ilmenite, it is found that autogenous-carrier effect exerts between fine and coarse particles, and the floatability of fine particles could be increased significantly when carrier proportion is well controlled.The calculations from DLVO and EDLVO theory show that, the essence of generation and dispersion of heterocoagulation is the regulation of surface electricity, and the precondition of autogenous-carrier effect is the regulation of surface wettability, which brings about the hydrophobic property among particles.4. Flotation technology of Panzhihua ilmeniteTwo novel flotation technologies developed for Panzhihua ilmenite ore, greatly enhance the resource utilization of Panzhihua ilmenite.The Panzhihua ilmenite with TiO2grade about9.00%is used as raw material for flotation tests. By open circuit test of "Whole size fraction flocculation flotation" technology process, the grade and recovery of obtained concentrate (calculated by TiO2) are47.90%and35.07%, respectively, the grade of TiO2in tailing as low as2.07%. By close circuit test of "coarse and fine particles classification, respective magnetic separation, and mixed flotation" technology process, the grade and recovery of obtained concentrate (calculated by TiO2) are47.93%and52.11%, respectively. |
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