mineral processing technology and mineral processing equipment

In mineral processing plant ,a number of organic and inorganic reagents are used in flotation and auxiliary processes to achieve separation, including collectors, frothers, extenders, activators, depressants, deactivators, flocculants, and dispersants. Collectors, frothers, and extenders are surfactants added to impart hydrophobicity to the minerals and to make selective adsorption of the collector possible or to eliminate interference to flotation by various dissolved or colloidal species. We discuss collectors this time. Collectors The primary role of the collector is to adsorb selectively, which imparts hydrophobicity to particles of the mineral to be floated. If it is to have the dual ability to adsorb and to impart hydrophobicity, the collector molecule must contain at least two functional parts, a nonpolar group of sufficient hydrophobicity and a polar or ionic group that will be electrostatically or chemically reactive toward species on the mineral surface. The nonpolar pa

In mineral processing plant , Almost all minerals show some degree of conductivity. An electrostatic separation process uses the difference in the electrical conductivity or surface charge of the mineral species of interest. The electrostatic separation process has generally been confined to recovering valuable heavy minerals from beach-sand deposits. However, the growing interest in plastic and metal recycling has opened up new applications in secondary material recovery. When particles come under the influence of an electrical field, depending on their conductivity, they accumulate a charge that depends directly on the maximum achievable charge density and on the surface area of the particle. These charged particles can be separated by differential attraction or repulsion. Therefore, the important first step in electrostatic separation is to impart an electrostatic charge to the particles. The three main types of charging mechanisms are contact electrification or triboelectrificat

In beneficiation plant , High magnetic fields (up to 2 tesla) are generated by passing current through a resistive coil or by permanent magnets. The development, through the use of finite element analysis techniques, of newer computer models has helped to achieve higher magnetic force. However, there is a logical maximum magnetic field for both the resistive coil and permanent magnet. Resistive coils are limited by the intrinsic resistance applied by the windings; the field strength of existing permanent magnets can be increased only marginally by modifying the magnet geometry. In the future, new magnetic materials may help to overcome this limitation. Currently, superconducting magnets are the only economically and technically viable way to achieve field strengths as high as 5 tesla. Fundamental requirements of superconducting magnets are a suitable conductor and a cryogenic system. During the last decade, extensive research in material science has resulted in new alloys that are s

In beneficiation plant , Most of the weakly magnetic minerals, such as garnet, ilmenite , and magnetic impurities in silica sand , can be effectively separated with a magnetic separator that has a flux density greater than 6,000 gauss. For nearly a century, induced-roll magnetic separators were the only economically viable unit operation in these applications. In spite of their considerable success, induced-roll separators have certain limitations in their selectivity and application. The development of permanent-magnet technology during the last two decades has reestablished the importance of magnetic separation and has increased the efficiency of fine-particle separations that were not successful with induced-roll magnets. Principle and Design In the last decade, magnetic separation technology has undergone a revolution. Research in material science and ceramic technology has culminated in the development of new permanent rare-earth magnets and superconducting alloys that can b

In beneficiation plant like hematite , Separating paramagnetic or weakly magnetic particles requires a higher flux density. This higher density is achieved by designing electromagnetic circuitry that can generate a magnetic force of up to 2 tesla. For example, in a silica sand processing plant , these separators are used to remove weakly magnetic iron-bearing particles. Induced-roll Magnetic Separator Induced-roll dry magnetic separators are widely used to remove trace impurities of paramagnetic substances from feedstocks such as quartz, feldspar, and calcite. The machine contains laminated rolls of alternating magnetic and nonmagnetic discs. A magnetic flux on the order of 2 tesla is obtained, and very high gradients are obtained where the flux converges on the sharp edges of the magnetic laminations. A thin stream of granular material is fed to the top of the first roll. The magnetic particles are attracted to the roll and are deflected out of their natural trajectory (Figure 1

In mineral processing plant , Low-intensity magnetic separators have flux densities up to 2,000 gauss. These separators are mainly used to remove ferromagnetic materials, such as iron, to protect downstream unit operations, such as conveyor belts, or to scalp ferromagnetic materials to improve the performance of permanent or electromagnetic separators used to separate weakly magnetic materials. Low-intensity separators can treat wet slurry or dry solids. Protective Magnets The device most widely used to protect downstream operations from tramp iron is a magnetic pulley installed in the head of the belt conveyor (Figure1). These devices remove tramp metals from dry solids. They contain either a permanent magnet or an electromagnet. Many types of magnets can be used—for example, plate magnets, cross-belt magnets, cobbing magnets, grate magnets, magnetic humps, and magnetic filters. The arrangement of magnetic drum separators is shown in Figures 2 A and 2 B . Wet Magnetic

In beneficiation palnt , Jig is one of important gravity equipments . The essence of a jig is captured in Figure 1, which shows a Harz Jig. The downward movement (called the pulsion stroke) of a plunger fluidizes the bed of particles on a sieve plate so that heavy particles move to the bottom and light particles to the top of the bed. As the plunger then moves upward, it creates a suction stroke that collapses the jig bed. The capacity of jigs, usually given as tons per square meter of bed area per hour (t/m 2 /h), is so variable as to be meaningless unless the jig type and conditions are closely specified. Capacity is a function of the jig type and size, the particle size and nature of the feed, the amount of the various products to be removed, and the desired quality and recovery of concentrate. Jig Types Jigs were formerly classified as movable (where the bed of particles moved up and down in a tank of  static water) and fixed sieve (where the bed is fixed and the water

In beneficiation plant , as a important way of gravity separation , Heavy media separation (HMS) has been used industrially to ---Produce a finished concentrate and a rejectable waste in one operation ---Reject a relatively coarse waste leaving an enriched product ready for further processing (a step that can greatly reduce expensive grinding costs) ---Produce a finished concentrate and a lower-grade product ready for further processing ---Produce two finished products of differing composition Ordinarily, HMS is used for the first two of these functions—the first for coal, the second for ores. The most successful way to achieve a float – sink separation has been to use a quasi-stable suspension of a solid that is appreciably heavier than the mineral to be floated. Various solids have been employed to make an aqueous heavy media suspension (Table 1). Silica sand in an inverted conical vessel is used in the Chance Cone system,. Because this suspension is relatively unsta