High-intensity wet magnetic separators have been successfully introduced into, the mineral processing field over the past ten to fifteen years, due largely to rapid advancements in magnet design. Wet magnetic separation, until recent years, was applied solely to the concentration of minerals of high magnetic susceptibility, such as magnetite, at relatively coarse sizes. Now, however, high-intensity separators are capable of treating weakly paramagnetic minerals and have extended the range of treatable particle size down to about one micrometre.
For the purpose of initially analysing the forces involved in particle capture, an idealized situation describing the separation process can be applied. A spherical paramagnetic particle in a fluid moving at constant velocity, approaches a ferromagnetic wire of circular cross section. A uniform magnetic field applied perpendicular to the wire axis magnetizes the wire and a magnetic force acting on the particle is developed. If the magnetic force is large enough to overcome the competing hydrodynamic force then the particle will adhere to the wire.
The force is thus proportional to three terms: the volume of the particle, the particle magnetization, and the field gradient over the dimensions of the particle. A brief description of how field gradients are created in an HGHS follows.
Competing forces acting on the spherical particle include hydrodynamic drag, gravity and interparticle affects such as electrostatic attraction, friction and magnetic attraction. However, when handling particles between about 5 and 50m in an HGMS, the predominant competing force is hydro dynamic drag. If a Stokesian regime is assumed for the simplified case, then the drag is given by:
A model capable of predicting HGMS performance from readily obtainable test data would be invaluable as an initial guide to applicability of this separation technique. For this reason an empirical model of capture was developed.
In order to closely control particle size and magnetic susceptibility, samples with narrow size and susceptibility ranges were prepared. Pure samples of hematite and ilmenite (98% Fe2O3 or FeTiO3) with narrow susceptibility ranges were obtained from mines in Quebec.
A magnetic response curve of a given material can be generated by passing the material through the Frantz several times at a set side slope and at successively higher currents. Each non-magnetics product becomes the feed for the succeeding pass. A plot of cumulative weight % reporting to the magnetics vs current describes the magnetic susceptibility distribution of the material.
The size distribution of the sample is easily determined through the use of the Warman Cyclosizer, which divides the sample into five distinct size increments. Application of the magnetic susceptibility distribution is not as straight forward. As was previously demonstrated, the Frantz can be employed to produce a magnetic response curve of a mineral-bearing sample.
For the unimineral samples used in the testwork, the response curves were very steep, indicating that each sample had a narrow range of susceptibility. A sample such as a concentrate, however, will often contain several minerals, each with a distinct magnetic susceptibility. Also, because of interlocking of mineral particles, many particles will exhibit susceptibilities in between those of the individual minerals; (the net volume susceptibility of a particle containing two or more different minerals is the sum of the products of the volume susceptibility and volume fraction of each mineral). Thus, the magnetic response curve for the concentrate may have a relatively low slope with a wide range of susceptibility, a curve with no discrete increments.
The above technique can be performed on all particle size increments, since each size increment may have a unique response curve. For simplification, however, the response curves for the different size increments can be averaged so that the whole sample can be represented by a single curve.
An iron ore sample from the Carol Lake deposit in Quebec was made suitable for preliminary testing of the model through the following sample preparation: (1) sequential grinding to -400 mesh (2) magnetite removal with the Davis Tube and (3) classification with a laboratory cyclone. The cyclone underflow consisted mainly of hematite and silica with a size range compatible to that which the model was developed (8 to 35 m).
A tin concentrate containing mainly pyrrhotite (Fe7S8) and cassiterite (SnO2) was obtained from a gravity concentration circuit at the Sullivan Concentrator, Cominco Ltd, Kimberley, B.C. To produce a sample with a size distribution within the range of the model the concentrate was screened at 325 mesh.
Various studies have been conducted in high-gradient magnetic separation (HGMS) technology over the past few years. The major advantages of this technology are obvious when processing highly complex feedstocks, such as blood. The current state-of-the-art technology for protein fractionation is liquid chromatography, which needs several time-consuming and costly upstream purification steps to be able to process the feedstock. In contrast, HGMS allows the extraction of one protein fraction directly from the non-purified complex feedstock. With HGMS technology, the efforts of downstream processing can be decreased drastically, while the yield is increased.
The principle of the technology is to bind a specific protein fraction to magnetic beads with a highly selective functionalized surface. By using a magnetic field, it is possible to extract the magnetic beads and also the specific fraction from a non-purified feedstock together with these beads in a single unit operation. Application fields for this technology are slurries involving high downstream effort, extremely low titer, and highly valuable components like hormones, antibodies, enzymes, or simply the functionalized particles themselves.
Research was conducted on the magnetic beads, the selective binding, and the elution process. The first rotor-stator magnetic separator systems were built in order to evaluate the separation principle. The separation, particle life time as well as elution processes were evaluated and proven
To take the HGMS to the next stage, a new design concept was developed for the rotor-stator technology, a quantum leap in terms of yield and harvesting efficiency as well as cleaning and sterilization. The ANDRITZ high-gradient magnetic separator design is compliant to:
Effectively process fine, weakly-magnetic minerals with the SLon Vertically Pulsating High-gradient Magnetic Separator (VPHGMS). The unit is a wet, high-intensity magnetic separator that uses a combination of magnetic force, pulsating fluid, and gravity to process minerals. The advanced features are incorporated into a design utilizing a unique vertical configuration, jigging action, and special matrix materials to achieve the best results.
Slurry is introduced through slots in the upper yoke to the matrix, which is housed inside the vertical separating ring. The magnetic particles are attracted to the matrix and are then carried outside of the magnetic field where they are subsequently flushed to the magnetic concentrate trough. The non-magnetic or less magnetic particles pass through the matrix through slots in the lower yoke to the non-magnetic collection hoppers.
The ring is arranged in a vertical orientation as opposed to a traditional Jones-type WHIMS, which uses a horizontal carousel. The vertical nature of the carousel allows for reverse flushing, where magnetics flushing in the opposite direction of the feed allows strongly magnetic and/or coarse particles to be removed without having to pass through the full depth of the matrix volume. In addition, the magnetics flushing is accomplished near the top of rotation, a location with a low stray magnetic field to reduce any residual grip on the magnetic particles. The end result is high availability due to minimized matrix plugging.
An actuated diaphragm provides pulsation in the separation zone to assist the separation performance by agitating the slurry and keeping particles in a loose state, minimizing entrapment. This mechanism alsomaximizes the particle accumulation (trapping) on all sides of the rod matrix, creating more usable surfacearea for magnetics collection. A further benefit is to reduce particle momentum, which aids in particlecapture by the applied magnetic force. This leads to improved fine particle collection and separation.
The SLon VPHGMS utilizes a filamentary matrix constructed of steel rods to accommodate various size ranges of feeds. The rods are oriented perpendicular to the applied magnetic field to enable optimum magnetic force to be achieved while minimizing the risk for entrapment of particles, when compared to grooved plates, randomly positioned filaments (wool), or expanded metal sheets.
High Gradient Magnetic Separator HGMS series is now deironing Product developed independently by our Company. It combines the characteristics of worldwide high intensity magnetic separator so far it is the domestic high intensity Magnetic separator with the best functions and the most advanced technology. The Concentration ratio of this Product is high, and the adaptability for ore-feeding ize, ore-feeding concentration and fluctuation is strong. This product is also reliable in operation and easy to maintain.
Electro Magnetic coil is electrified with direct current and thus forms magnetic field. Magnetic line of force goes through magnetic medium producing high gradient magnetic field. When Slurry containing magnetic minerals flows through magnetic medium from the bottom to the top. Magnetic granule is absorbed by the giant magnetic field on the surface of magnetic medium. Under the control of PLC, each valve and electric element operates automatically. As a result, the iron is removed from mineral.
1. Background field is 16000 Gauss, and the surface of magnetic medium intensity is 50000 Gauss. 2. Row ore enters the magnetic medium from down to up and the pressing rinse water pulsates tailings from up to down. Our uniquye series magnetic separator uses pressing water to pulsates tailings. The Supply direction of minerals is opposite to the direction of minerals, so the coarse granular can be washed away easily, and the magnetic medium jam is effectively prevented. This product solves the magnetic medium jam problem in other high intensity magnetic separator. 3. Other high gradient magnetic separator in the world imposes strict limitation on the fineness of the minerals. We research the unique structure and optimized combination of magnetic medium, and make the upper limit of the our unique series magnetic separator for mineral fineness 2.0mm, simplify the work for grade of mineral on site, and it has more adaptability.
The high gradient magnetic separator (HGMS) is a strong magnetic separator for the screening of weakly magnetic minerals. It is a new type of strong magnetic separator developed on the basis of a general magnetic separator machine.
The high gradient magnetic separator equipment is suitable for: Separation of weak magnetic minerals, such as hematite, limonite, siderite, ilmenite, chromite, wolframite, tantalum-niobium ores, red mud and so on; Iron removal and purification of coal, non-metallic minerals, building materials, such as quartz, feldspar, nepheline, fluorite, sillimanite, spodumene, kaolin, etc; It also used for wet magnetic separation of magnetite, pyrrhotite, roasting ore, ilmenite and other materials with a particle size of 3mm or less.
The HGMS is mainly composed of a pulsating mechanism, an excitation coil, an iron yoke and a rotating ring. It is divided into dry type and wet type magnetic machine. The weak magnetic ore mainly has limonite, hematite, manganese ore, and symbiotic ore (multiple ores coexisting). These weak magnetic ores are mainly composed of ferric oxide, if you want to extract ferric oxide, you need to use high-strength magnetic equipment. Our company has developed a high-strength magnetic concentrator for this difficult mine.
There are many weak magnetic ores that are bulk and need to be crushed first, crushing, grinding then magnetic separation. The general process flow is ore analysis, jaw crusher, screen, roller crusher, ball mill, magnetic separation.
The HGMS adopts a rotating ring vertical rotation and recoil concentrate, and a high-frequency vibration mechanism. It fundamentally solves the worldwide technical problem that the magnetic material of the flat ring strong magnetic separator and the flat ring high gradient magnetic separator are easy to block.
Under the action of the water flow to the mine spout, the ore particles are loosely fed into the feed area of the tank. In the magnetic field, the magnetic ore particles are magnetically aggregated and moved toward the magnetic poles and adsorbed on the cylinder. When the magnetic ore particles rotate with the cylinder, the non-magnetic minerals such as gangues entrained in the magnetic clusters fall off during the turning, and the magnetic cluster finally attracted to the surface of the cylinder is the concentrate. The concentrate goes to the weakest point of the magnetic system at the edge of the magnetic system with the cylinder, and is discharged into the concentrate tank under the action of the flushing water sprayed from the unloading water pipe. Non-magnetic or weakly magnetic minerals are left in the slurry with the slurry exiting the trough, which is the tailings.
The magnetic system of the high gradient magnetic separator is made of high-quality ferrite material or composited with rare earth magnetic steel. The average magnetic induction intensity of the magnetic roller surface is 100-600 mT. According to the needs of users, it can provide magnetic separation of many different surface strengths such as downstream, semi-reverse flow and counterflow.
During the operation of the high gradient magnetic separator, for each group of magnetic media, the direction of the rinse concentrate is opposite to that of the ore supply, and the coarse particles can be washed out without passing through the magnetic medium stack, thereby effectively preventing the magnetic medium. Blockage; set the high-frequency vibration mechanism of the slurry to drive the slurry to generate pulsating fluid force.
Under the action of pulsating fluid force, the ore particles in the slurry are always in a loose state, which can improve the quality of the magnetic concentrate; the flat ring high gradient magnetic separator has strict requirements on the ore size, unique magnetic structure and optimized combination of magnetic The medium makes the magnetic separator upper limit of 2.0 mm, which simplifies the on-site grading operation and has wider adaptability. The multi-gradient medium technology and the liquid level stability control device improve the iron concentrate grade and recovery rate; The ring speed and the vibration frequency of the high-frequency vibration box are steplessly adjusted by the inverter; compared with the domestic similar products, its unique design effectively solves the stepping phenomenon of the rotating ring.
The brand has Slon high gradient magnetic separator, Flsmidth, Metso, etc. JXSC has always been developing the magnetic separation technique, and bring magnetic separation machines for the mining industry. Contact us to get the price and specification info.