Manufacturers Of Old Tailing Recovery Key Technologies

The research was derived from the nation's "tenth five" science and technology tackling key subject----the key industrial technologies' research on development and utilization of copper, lead, zinc, tin from tailings (2003 BA612A-18), the aim of the special subject is to recover valued components comprehensively in tailings.Cassiterite-polymetallic sulfide ores of Dachang in Guang Xi, including zinc, sulfur arsenic, lead and antimony, are typical complex refractory sulfide ores. At present, the tailings produced from polymetallic sulfide ores have accumulated about 30 million tons, containing rich tin, lead, zinc, antimony and sulfur, arsenic. Because of the limit of technical level and the condition of production, technical index of recycling metals was lower. A lot of metals, especially fine metals, lossed seriously in tailings. There were many useful minerals not being recovered. The loss of these tailings caused both a waste of resources and the hidden danger of polluting external environment of mines in Dachang. With increasing depleted resources and the ongoing large-scale production in Dachang, when the exploitation of the original ores was carried on, the secondary development and utilization of tailings and comprehensive recovery of a variety of valuable elements can generate very substantial economic and social benefits, be of great significance and value.This study aiming at recycling minerals comprehensively from polymetallic sulfide ores' tailings, a detailed study was made about the flotation performance of jamesonite, iron sphalerite, arsenopyrite and pyrite. Through adsorption determination,ξpotential of mineral and spectra analysis for testing the surface composition, the flotation separation mechanisms of four minerals were explored. On the basis of mineralogy study in the old tailings, a new type of efficient equipment was applied, a small-scale pilot test and continuous separation test were made. Efficient and economic process suitable for the comprehensive recovery of valuable elements in the tailings was proposed and the following results were achieved:(1) Pre-throwing tailings' technology: Using jig and ionic spiral chute in Pre-throwing tailings, 49.57% of the tailings can discarded, it greatly reduced the harmful effects of the sludge and carbon quality, while reduced energy consumption and unnecessary grinding. At the same time, it enhanced selected grade. The grade of lead, antimony, zinc, tin, sulfur and arsenic increased from 0.22%, 0.15%, 3.27%, 0.57%, 5.70% to 0.87%, 0.33%, 0.237%, 4.971%, 0.878%, 8.944% and 1.474%.(2) Separation technology of lead and antimony: After pre-throwing tailings, ZnSO₄, NaCN and Na₂S₂O₃ were used as combined inhibitors, HN-1 and YC-1 were used as combined collector. The lead-antimony crude concentrate of Pb7.47% and Sb4.96% by flotation can be enriched. But it was very difficult to raise the index by flotation further, so the new efficient equipment "Ion Waveform shaker" was used. That is, through the "flotation-weight" joint, the effective separation of lead-antimony minerals in Dachang's tailings was realized successfully. This technology is the key of success in comprehensive recovery from tailings.(3) separation technology between zinc, sulfur and arsenic: As sulfur, arsenic can be floated better, the separation between zinc, arsenic and sulfur was mineral processing problems. In the project, it is necessary to depress sulfur and arsenic in order to float zinc. To depress sulfur and arsenic selectively, using combined inhibitors CS-2 and sodium humate efficiently can realize separation of zinc with sulfur and arsenic, and separation of sulfur and arsenic. According to the difference of oxidation degrees between sulfur and arsenic, it can strengthen further inhibition on arsenic by K₂Cr₂O₇ to float sulfur. Qualified sulphur concentrate was attained with the grade of 36.17% and the recovery of 52.00%. However, when activing and electing arsenic, residual sulphur in the tailings will be activated with arsenic into the flotation concentrate. Thus it was very difficult to separate arsenic by flotation still. According to the specific gravity difference in minerals, "Ion waveform shaker " was used to cleaning arsenic in this study. That the combined technology of flotation and gravity separation was attained arsenic concentrate with grade of 35.32% and recovery of 55.97%.(4) Fine-grained mineral recovery technology: During the study course of the project, we used a self-developed particularly suitable for separation of fine-grained minerals equipment - a new type of Ion waveform shaker. The surface of the equipment had been brushed a special coating that we developed. The flow film processing occurred, according to different electric, magnetic and weight of minerals under the composite field of gravity, magnetic, electrical, mechanical force and so on. Separation results were better than ordinary shaker, particularly fine-grained, micro-fine particles. In flotation and gravity separation process, the cleaning of rough concentrate of lead and antimony, the cleaning of arsenic rough concentrate and the election of tin from the ultimate flotation tailings all belonged to fine, fine-grained particles' re-election. Good separation effects were achieved by ion-wave shaker.(5) ZnSO₄+NaCN+Na₂S₂O₃ were the fine combined depressants of marmatite. The mechanism of combined depressants, ZnSO₄+NaCN+Na₂S₂O₃,was mainly the formation of hydrophilic membrane or particles on mineral surface and dissolution of hydrophobic collector's membrane on minerals surface, these functions complemented each other to enhance the inhibitory effect.(6)The collecting capacity of YC-1 was greater than HN-1 , and the selectivity of HN-1 was superior to YC-1. YC-1 + HN-1 were the good collectors of jamesonite. The mechanism of combined collectors was coadsorption, increasing density of collector's adsorption layer on mineral surface. The surface of the minerals in different regions had different activity. When combining and using HN-1 with YC-1, HN-1 with small activity can adsorb on the high active surface of minerals, however the mineral surface with low activity was relatively suitable for fixation of YC-1 with high activity. The results were the collector's adsorption capacity increased. The Pharmacies adsorbed on mineral surface were more homogeneously distributed. IR spectra showed that the main adsorption products of combination collectors HN-1 + YC-1 on jamesonite surface were: Pb(DTC)₂, Pb(DTP)₂, (DTC)₂ and (DTP)₂. Pb(DTC)₂ and Pb(DTP)₂ were Four-ring metal chelates. The chelates were stable and highly hydrophobic, they can adsorb on the surface of minerals by chemical adsorption and can improve minerals floating. (DTC)₂ and (DTP)₂ are collector's bimolecular generated in the process of adsorption, they had good drainage too, and they can adsorb on the surface of minerals with physical adsorption by intermolecular force so that causing mineral hydrophobic.(7)oxidant CS-2 and sodium humate can be as good depressors of arsenopyrite and pyrite, they can achieve selective inhibition of pyrite and arsenopyrite in different combinations and dosage forms. As the flotation test results and the adsorption capacity of potential as can be seen, CS-2 can oxide pyrite and arsenopyrite, so that they have a hydrophilic surface of the oxide film. Sodium Humate can complex and eliminate active ions on the surface of arsenopyrite and pyrite. It not only reduced the collector adsorption, but also covered the hydrophobic collector absorbed, thus it attained the purpose of depressing mineral. With the presence of inhibitors,ξpotential did not play an important role for the xanthate collector charged negative. The main reason that sulphide ore was depressed was not competition between oxidants and xanthate, was rather not xanthate's adsorption capacity reduction on the mineral surface. That may be due to oxidation on surface and the formation of a hydrophilic oxide film. From the infrared spectra of pyrite and arsenopyrite we know, when CS-2 and sodium humate existed, there were oxides both on the two mines' surface. But the oxidation products were different. The oxidation degree of arsenopyrite was more deep than pyrite. The oxidation product on arsenopyrite surface was mainly FeAsO₄ and that of pyrite was mainly more closer FeS₂O₃.With the oxidation reaction, pyrite can be oxided and generated to FeSO₄ further.During the whole study, not only the new equipment ion-wave shaker was used but also pre-throwing tailings technology was raised. flotation and gravity separation combined technology separating lead and antimony, technology of depressing sulfur and arsenic to float zinc, gravity separation combined technology to exclude arsenic and recovering cassiterite by Ion Waveform shaker were raised and got successful recovery of the valuable minerals from the old tailings in Dachang. By studying the impact and mechanism of different flotation reagents for minerals, rational combination and use of flotation pharmacy can be as an effective solution method to solute the problem of mineral that is difficult to float and be low index. This was the key to get success in the project. In addition, the technology study of lowing down arsenic could reduce the quantity of arsenic in tailings so as to meet requirements of the following use for manufacturing cement.