Our recent studies revealed that the ground SULPHIDE minerals in contact with water generate H2O2 but its effect on the oxidation of pulp components and hence in deteriorating the concentrate grade and recovery in flotation has not been explOREd yet. The use of Na2S reductant at the grinding stage is thought to control the deleterious effects of H2O2 in the pulp liquid. TherefORE, the effect of Na2S addition during grinding stage on the formation of H2O2 and its influence on SULPHIDE complex ORE flotation was investigated. The results showed that the presence of Na2S increases the formation of H2O2 but decreases the dissolved oxygen. An increase in Na2S dosage in grinding, the Pb grade and recovery in Cu-Pb concentrate is decreased while pyrite is depressed marginally better. These changes in flotation response of SULPHIDEs have been discussed and explained with the formation of H2O2 quantitatively.

Tappehsorkh Zn-Pb-(Ag) deposit, hosted by Lower Cretaceous siltstone, tuff and dolomite, is located in the northern part of the Irankuh mountain range, south of Esfahan. SULPHIDEs in this ORE have a relatively simple mineralogy including sphalerite, galena, tetrahedrite, pyrite and to a lesser extent, chalcopyrite, marcasite and bornite. Gangue minerals are predominantly dolomite, quartz and barite. Based on zoning in the SULPHIDE mineralization, texture and structure and location of ORE facies relative to syn-sedimentary normal faults, theses ORE facies are classified as vein-veinlet, laminated and massive. Dolomitic-silicic alteration is among the major processes concomitant with SULPHIDE mineralization. The greatest degrees of alteration and related ORE mineralization occur at the vicinity of the normal faults and decrease away from it. Geochemical studies indicate that the ORE-bearing fluids were of oxidized composition, which were reduced once reaching favorable host rocks and consequently deposited SULPHIDE minerals. Minor and trace element studies in the various sulfide ORE facies demonstrate that the ORE-bearing fluid in all the ORE facies has a similar composition. Textures such as framboidal pyrite, contemporaneous folding of organic matter along with SULPHIDE lamination in the laminated ORE facies, and diagenetic structures such as load casts in the host siltstone indicate that SULPHIDE mineralization has occurred in the sedimentary-diagenetic stage. However, SULPHIDE mineralization in the regional dolomite is considered to have occurred in a shallow diagenetic environment because of replacement of regional dolomite by hydrothermal dolomite. Based on features of ORE mineralization such as the extensional tectonic setting, siltstone and carbonate host rocks, and occurrence of various SULPHIDE facies such as vein-veinlet, laminated and massive, the Tappehsorkh deposit is very similar to Sedex-type deposits.

The Ab-Bagh Zn-Pb deposit is located in the central part of the Sanandaj-Sirjan zone (SSZ) and at the southeastern part of the Malayer-Esfahan metallogenic belt. This deposit is hosted by Upper Jurassic-Lower Cretaceous sedimentary sequence. Zinc and lead mineralization occurred within two horizons. The ORE horizon 1 is hosted by Late Jurassic-Early Cretaceous black shale and siltstone. The ORE body displays a wedge-like shape and is located close to syn-sedimentary fault. The ORE horizon 2 occurs in lower Cretaceous carbonates and includes a massive ORE facies that is concordant with host rock layering. It is also underlain by a stockwork facies. Weathering processes led to a supergene ORE stage at Ab-Bagh deposit in parts toward the surface. Based on geology, mineralogy and geochemistry, two types of non-sulfide ORE were distinguished: the white ORE and the red ORE. The white ORE is a wall-rock replacement mineralization that contains high Zn, low Fe and a very low concentration of Pb. To the opposite, the red ORE formed after the direct replacement of sulfide protORE and it typically contains low Zn, high Fe and medium Pb± As concentrations. Supergene ORE consists of smithsonite and hydrozincite. Minor cerussite, Zn-rich clays, greenockite, covellite and Fe-Mn oxides were also identified. The supergene part of the Ab-Bagh deposit formed as a consequence of long time weathering of a SEDEX-type sulfide protORE. Oxidation of sulfide minerals (mainly pyrite and sphalerite), carbonate buffering reactions and precipitation of secondary Zn-bearing minerals are the main geochemical process involved. The REE patterns of the white non-sulfide ORE are similar to that recorded in the host rocks but REE patterns of red ORE, is similar to sulfide ORE. The comparison with other major non-sulfide Iranian deposits suggests that Ab-Bagh deposit is very similar to Kolahdarvazeh and Mehdiabad deposits, it also shows lots of similarities with other worldwide examples (e.g. Moroccan non-sulfide ORE deposits).

Ball mills are common grinding equipment in mineral processing industries. Ball wear results from three mechanisms namely impact, abrasion and corrosion. Of these, the corrosion mechanism is the least investigated, due to its chemical-electrochemical nature. TherefORE, the aims of this research were to investigate the grinding chemistry influence (slurry pH, solid percentage, water chemistry and gas purging) on corrosive wear of steel balls and to determine the contribution of corrosion mechanism to total wear of steel balls. The results indicated that the mass losses of steel balls could be reduced considerably by controlling the pulp chemistry inside the mill. In addition, the results showed that 73.51% of the corrosion products are generated from the oxidation of steel balls. It was also estimated that the corrosion mechanism accounts for 26.68% of the total wear of steel balls.

Nanoclusters of nickel SULPHIDE (NiS)n and iron SULPHIDE (FeS)n for n=3–5 are studied using B3LYP exchange correlation function with 6-31G as a basis set.The structural stability of different isomers of NiS and FeS is analysed with the optimized energy, binding energy and vibrational studies. The electronic properties of isomers are discussed in terms of HOMO–LUMO gap, ionization potential, electron affinity, and embedding energy of different clusters. Based on the calculated energy, planar ring, linear ladder and bipyramidal cube of NiS and FeS nanoclusters are found to be mORE stable. The increase in number of atoms in the clusters leads to increase in its stability. The dipole moment is high for planar rhombus and linear ladder structures of NiS and FeS nanoclusters.The ionization potential and electron affinity are high for planar ring structure of NiS and FeS clusters. The value of energy gap of linear ladder NiS nanocluster and cube and bipyramidal cube structures of FeS is found to be low. The binding energy for cube structure of NiS and FeS clusters is found to be high. Hexagonal ring structure of NiS and FeS clusters has low embedding energy value. The other parameters such as dipole moment and point symmetry are also discussed. The structural stability and electronic properties will provide an insight for experimentalist to tailor new materials that have potential importance in engineering applications.

The Mehdi Abad zinc-lead deposit, which is located in central Iran, is one of the largest zinc deposits of the region. The OREbody consists of primary SULPHIDE as well as supergene non-SULPHIDE ORE. The deposit comprises a main SULPHIDE/nonSULPHIDE OREbody below a valley floor and of the so-called Calamine Mine (exclusively non-SULPHIDEs), on the flank of a mountain, separated by faults from the fonner. The non-SULPHIDE ORE of the Calamine Mine is hosted within Cretaceous (Albian) strata of the regional Abkou Formation, and occurs as a matrix of fault- and karst breccias. .ORE minerals are composed of hemimorphite, hydrozincite, smithsonite, goethite, as well as small amounts of mimetite, hetaerolite, and sauconite. Texturally, hemimorphite occurs as two different types. Type-l displays sub- to anhedral shapes and is commonly associated with goethite and/or hydrozincite. This type-l hemimorphite is commonly altered and partly dissolved to relict box work textures on a microscopic scale. Type-2 hemimorphite is euhedral and has grown in fractures and open spaces of the host rock and in breccias. At least three different stages are proposed for the genesis of the hemimorphite mineralisation: (i) formation of type-l hemimorphite from supergene ORE fluids, (ii) the partial dissolution and alteration of type-l hemimorphite to hydrozincite, probably accompanied by the precipitation of goethite due to a change in Eh-pH conditions, and fmally (iii) the precipitation of type-2 hemimorphite within fractures and open spaces.

Background and Objective: Existing of fine clay in mines and small particles of copper have caused reduction in chemical and biologicalreactions of these source, also using them makes it impossible to used in mass leaching operation in hydrometallargy of copper.Materials and Methods: In this study colum bioleaching of minus 1 mm fraction size of agglomeration of column bioleaching operation were evaloated.Results: A column bioleaching test of agglomerated ORE was run for 105 days along with a negative control using thymol as bactericide. At this stage,about 77.5% of copper was recovered while this amount in non-inoculated column was only 57%.Conclusion: The result showed that this procedure can be successfully used to obtain biologic copper in these resources.