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The adsorption of anionic collectors (xanthate) on the surface of galena was studied using diffuse reflectance FTIR (DRIFT) and scanning electron micrograph (SEM) techniques. The effect of sulphite interaction with galena on the mechanism of potassium amyl xanthate (KAX) adsorption onto galena surfaces has been studied in situ using electrochemical potential, FTIR spectra and SEM have been used to identify the mechanism of interaction between sulphite and galena surfaces. Activated galena with copper sulfate (10-4M) has been investigated at pH 9.5 and potassium amyl xanthate (3.10-2M) concentration. Potential (Eopt (PbS) = +55mV); Adsorbed colloidal (Pb-AX, 1109-1384Cm-1) is found even at high xanthate concentration, colloidal lead oxide/hydroxide particles have been imaged after 10-4M lead sulfate addition at pH 9.5. The behaviour of this system is consistent with ion exchange between xanthate and hydroxide followed by oxidation to dixanthogen (X2, 1276Cm-1) and diffusion of this species across the surface

The flotation of sulphide minerals and their modulation has been a subject of investigation for many years. The influence of pH, Dp, Db and xanthate concentration on the sulfide minerals floatability of is well known and it is usually used as one of the flotation control parameters. In this study, we propose to make a theoretical and experimental study concerning the use of xanthate in the sulfides flotation processes (PbS-ZnS-FeS2). Sphalerite (Dp= 0,4443mm, Db=0,1530mm) floted in pH range from 7-10.5 but galena (Dp= 0,3705mm, Db=0.2000 mm) floted better only from pH 8 to 9.5

A lot of industries (chemical, mining) developed numerous processes based on the use of the adsorption, From then on, the resolution of practice problems pass inevitably by the understanding of fundamental concepts governing the phenomena of flotation and the interaction in the solid- liquid or solid - gas interface. In this study, we suggest proceeding to a theoretical and experimental study concerning the organic synthesis of an organo metallic product (KEX) by intermittent method and their use in the processes of sulphides flotation. Searches showed that the surface state after grinding resulted from a combination of oxidized sorts of sulfur treat type with copper sulphate and lead oxy-hydroxide thickness of which is very superior to 200 nm. The addition of an organometallic molecule sulphurated (Potassium ethyl xanthate KEX) in available concentrations of 1g/l (6, 24.10 -3 M) is going to lead the forming of an organometallic layer mixed in the galena surface. From weak concentrations in collector, the organometallic layer present in the mineral surface is mixed. It is formed by a complex xanthate type of lead (PbX, bandages IR in 1200 cm -1 ), of dixanthogene (X2 forms oxidized with the molecule of xanthate, bandages IR in 1262 cm -1 ), of elementary sulfur and a certain proportion of initial superficial oxidized phases. The mechanism leading to the forming of PbX is the type of ionic exchanges. On the other hand, two types of different mechanisms can be at the origin of dixanthogene forming (X2). A first type consists of a catalytic oxidation in the mineral surface with reduction of the dissolved oxygen. This type of mechanism depends essentially on the potential redox of the system. A second type brings in the forming of xanthate salts of lead by a mechanism of Ionic exchange (eq. 1) then their catalytic degradation (eq. 2): Pb n + + n X - → (Pb X) n Equation 1: independent from the potential redox. Pb(X) n (catal. by PbS) + 1/2 O2 + n/2 H2O → Pb (OH) n + n/2 X2 Equation 2: dependent on the redox potential.