Collectors beneficiation

Flotation was carried out at an alkaline pH, controlled by lime. A xanthate collector with cyclic alcohol further (pine oil, cresylic acid) was shown to be the most effective. The use of small quantities of a dithiophosphate-type collector, together with xanthate was beneficial. 

This method is the most commonly used in beneficiation if oxide copper-bearing ore. The reagent schemes used to treat oxide copper ores, mixed copper sulphide oxide ores and oxide copper cobalt ores varies from one ore type to the next, mainly by type of collector and sulphidizer used. 

The choice of reagent scheme depends largely on the type of natural ore to be treated. The three main groups of reagents used in beneficiation of oxide copper and copper cobalt ores include (a) sulphidizers, (b) collectors and (c) modifiers and depressants. 

Xanthated fatty acid mixture is a new line of collectors, specifically designed for beneficiation of oxide copper ores that contain dolomitic and carbonaceous gangue minerals [19]. This collector was developed after extensive laboratory development testwork. The effectiveness of this collector was compared to a standard xanthate collector in a series of continuous locked cycle tests (Table 19.5). 

The chemistry of cassiterite flotation has been a subject of considerable research for many years. The findings that sulphosuccinamates, phosphonic acid and arsonic acid were selective collectors for cassiterite flotation lead to the introduction of flotation as a complementary recovery process to gravity concentration at most primary tin mill concentrators in the early 1970s. In spite of continued research, subsequent progress in development has been rather limited. Cassiterite flotation still remains a secondary tin recovery process in most plants, for beneficiation of cassiterite below 40 pm size. 

In the case of carbonatite ores, a beneficiation process involves preflotation followed by reactivation and flotation of pyrochlore. In the case of pegmatitic ores that contain silicates, biotite, albite and limonite, as the gangue minerals, direct flotation of pyrochlore can be achieved with a variety of different collectors. 

Collectors from the PM series were specifically developed for beneficiation of niobium ores that contain nepheline/cyanite as the major gangue minerals. The collector is composed of a mixture of phosphate ester collector (SM15, Clariant) and phosphonic acid treated with octanol. From an ore that assays 0.5% Nb20s, a concentrate grade of 49% Nb205 at a recovery of 73% was achieved. 

The ore used in this example contained a mixture of pyrochlore and columbite as the major niobium minerals. The tantalum is mainly associated with columbite. The major gangue minerals present in this ore were soda and potassium feldspars with small amounts of mica and quartz. Beneficiation of this ore using cationic flotation, normally employed for flotation of niobium, was not applicable for this particular ore, since most of the mica and feldspar floated with the niobium and tantalum. The effect of amine on Ta/Nb flotation is illustrated in Figure 23.9. The selectivity between Ta/Nb and gangue minerals using a cationic collector was very poor. 

Most recently, development testwork was performed on a large perovskite deposit (Powderhom) located in the USA. An effective beneficiation process was developed, where a concentrate assaying >50% Ti02 was achieved in the pilot plant confirmation tests [7]. During this development testwork, a number of different collectors were examined at different pH values. Figure 25.5 shows the effect of the different collectors on perovsikte flotation. The most effective collector was phosphoric acid ester modified with either fatty alcohol sulphate or petroleum sulphonate. 

Method 3 - It involves bulk titanium/zircon flotation using succinamate collector followed by bulk concentrate pretreatment and selective zircon flotation. This method was developed for beneficiation of the Wimmera heavy mineral sand from Australia [12], The beneficiation flowsheet with type and level of reagents is shown in Figure 25.17. 

Frothing Agents are intended to stabilize the particle (mineral)-air mixture (foam) at the surface of the flotation tank. Alkyl or amyl alcohols in the C5 to C12 range are typical frothers. They lower ysv which is beneficial to the stability of the foam to some extent collectors and frothers may counteract in their effects so that compromise conditions must be selected. 

Lower original potential in grinding is beneficial to flotation selectivity of galena. Thus, collectors should be added into the mill directly. Table 10.12 is the results of flotation separation of Beishan concentrator of PbS-ZnS ore for collector addition in different places. It shows that the recovery and grade of galena concentrate are improved obviously when collectors are added in mill compared to in agitator. 

The flotation responses of the kaolin samples to the various flotation collectors were measured using the separation efficiency (SE) index. This index combines both grade and recovery to describe the efficiency of the beneficiation process. The mathematical expression used to compute the separation efficiency is the following ... 

R.H. Yoon and J. Yordan, Beneficiation of Kaolin Clay by Froth Flotation Using Hydroxamate Collectors , Minerals Engineering, 1992,5(3-5), pp. 457-467. 

Reentrainment from the bottom of the cyclone can be prevented in several ways. If a typical long-cone dry cyclone is used and liquid is kept continually drained, vortex entrainment is unlikely. However, a vortex breaker baffle in the outlet is desirable, and perhaps a flat disk on top extending to within 2 to 5 cm (0.8 to 2 in) of the walls may be beneficial. Often liquid cyclones are built without cones and have dished bottoms. The modifications described earlier are definitely needed in such situations. Stern, Caplan, and Rush (Cyclone Dust Collectors, American Petroleum Institute, New York, 1955) and Rietema and Verver (in Tengbergen, Cyclones in Industry, Elsevier, Amsterdam, 1961, chap. 7) have discussed liquid-collecting cyclones. 

The general equipment used can range from very simple columns and test tubes to elaborate pumps, columns, detectors, and fraction collectors automatically controlled by a computer with an appropriate human interface. Minimal equipment is sufficient for exploratory work or one-time development cycles more sophisticated equipment is beneficial for laboratories engaged in more intensive development. A modest set of useful equipment includes 1) peristaltic pump 2) end-over-end tube rotator 3) fraction collector and 4) spectrophotometer (UV visible). 

Within a given line of battery technology, energy and power density typically are inversely related. Increasing the energy density requires maximization of active electrode material mass per battery mass and thus requires minimization of the amount of additional components (such as current collector, conductive additives, or void space for optimizing electronic and ionic connectivity within an electrode material, see Section 3.5.5), most of which are beneficial for increased power densities. 

From a fundamental point of view, insertion electrochemistry deals with the thermodynamics and kinetics of intercalation processes starting at the electrodesolution and current collector-electrode interfaces, and occurring (propagating) into the electrodes interior. Very often (but not mandatory) intercalation processes into host electrodes occur in the form of first-order phase transition, and thus the classical galvanostatic charging of the electrode can be beneficially combined with simultaneous in situ XRD characterization. The latter allows the distinction between solid-solution and the two-phase coexistence paths of the intercalation process. 

Flotation is commonly employed for beneficiation of minerals. Frothers are added to the vigorously agitated mixture. Air bubbles attach to the collector-mineral particles, which then rise and are removed along with the froth or foam. The valuable components are separated from the waste or gangue by preferential floating of one of the components to the top while the other sinks to the bottom. 

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