how to use magnetic separation sulfida gold ore

magnetic separation method

magnetic separation method

Magnetic separation is a process used to separate materials from those that are less or nonmagnetic. All materials have a response when placed in a magnetic field, although with most, the effect is too slight to be detected. The few materials that are strongly affected (magnetised) by magnetic fields are known as Ferromagnetics, those lesser (though noticeably) affected are known as Paramagnetics.

Ferromagnetics require relatively weak magnetic fields to be attracted and devices to separate these materials usually have magnets that are permanently magnetised (Permanent magnets do not require electricity to maintain their magnetic fields). Paramagnetics require stronger magnetic fields and these can only be achieved and maintained by electro magnets (large wire coils around an iron frame current is continuously passed through the coils creating the magnetic field within the iron. The field is concentrated across an air gap in the circuit).

Both ferromagnetic (low intensity) and paramagnetic (high intensity) separation devices (Laboratory Magnetic Separator) may be operated with dry solids or with solids in pulp form. (A complete classification of magnetic separating devices is given in Wills Mineral Processing Technology, pp. 338-356).

(*The units given are kilogauss (kG). These are the units most commonly used. The equivalent S.I. unit is the Tesla (T) * 1 Tesla = 10 kilogauss). The extremes of field strength used are based on experience from a magnetic separation testing laboratory over many years.

magnetic separation of fine mineral sulphides

magnetic separation of fine mineral sulphides

The separation of fine sulfides becomes increasingly difficult at fine particle sizes. Potential fine size separation methods are froth flotation and magnetic separation. The mineral sulfides, with the exception of pyrrhotite, are either weakly paramagnetic (e.g. chalcopyrite) or diamagnetic (e.g. molybdenite). Those which are paramagnetic can only be separated using high-gradient magnetic separation (hgms) at high fields (up to 2 Tesla) and low flow rates (e.g. 1 cms-).

Arsenopyrite (FeAsS), chalcopyrite (CuFeS2) and marcasite (FeS2) were leached and the susceptibility of the leach product measured. From the measured sulfate in solution, the percentage of the particle that had reacted was calculated and hence the coating thickness was estimated.

Mixed Sulfidesfall into two categories, mixtures of iron-containing sulfides and non-iron-containing sulfides.The magnetic profiles for various mixtures after leaching (100C, 60 min, 930 kPa air, 0.5M NaOH). In all cases the mixtures are of equal masses. Curve 1 is for pyrite/arsenopyrite. .The magnetic fraction up to 600 mA (- 50 wt%) was primarily pyrite (by XRD); the non-mags was arsenopyrite. The calculated susceptibility of each mineral in the leached mixture is less than that of leaching a single mineral. For example, arsenopyrite in the mixture gave K = 0.8 x 10- down from 1.8 x 10- for the pure mineral.

It has been shown that the magnetic susceptibility of the iron-containing sulfide minerals, arsenopyrite, chalcopyrite, and marcasite can be enhanced by oxidative alkaline pressure leaching in a similar manner to pyrite. It is presumed that the reason is that identified for pyrite.

The magnetic susceptibility of marcasite, arsenopyrite and chalcopyrite, in addition to pyrite can be enhanced by oxidative alkaline pressure leaching. Probably all iron-containing sulfides will show a susceptibility increase under these conditions. A thin layer of magnetic iron oxides is probably the cause.

5 easily extracted gold ores and 8 processing methods - jxsc

5 easily extracted gold ores and 8 processing methods - jxsc

Easily extracted gold ore has long been a major source of gold production in countries around the world, and such resources will be declining due to long-term mining. In the paper, I list 5 Easily Extracted Gold Ores and 8 Processing Methods, lets read on to find out!

Placer gold deposits are formed by primary gold deposits broken up by mechanical and chemical weathering and transported, sorted and deposited by external forces. There are many kinds of placer gold deposit, such as eluvial gold deposit, slope gold deposit, diluvial gold deposit, riverbed alluvial gold deposit and shore gold deposit, etc.

The characteristics of this kind of deposit are soft, shallow burial depth, generally 5~10m, some 20~30m; the thickness of gold-bearing deposit is generally 1~5m, individual up to 10m; The belt width is 50~300m on average, and the length can reach several kilometers or tens of kilometers; the slope of the gold deposit is very small, generally 0.002~0.02.

The gold ore is generally simple in composition, shape mostly in granular or scaly, and the particle size is usually 0.5~2mm, average density about 17.5~18.0g/cm3. According to the particle size, gold can be divided into a large piece of gold (greater than 5mm), coarse gold (5~1.65mm), medium gold (1.65~0.83mm), fine gold (0.83~0.42mm), extra fine gold (0.42~). 0.15mm) and the most particulate gold (or floating gold, less than 0.15mm).

The basic composition of ore is quartz, with a content of more than 90%, and almost no heavy metal sulfide. Natural gold is mostly filled in the crack and cleavage surface of quartz in coarse grains, or disseminated in quartz veins in fine grains. Gold is easy to dissociate after crushing and grinding.

This ore is most common in gold-bearing quartz veins ore and generally contains 1% to 5% of metal sulfides. According to the state of gold production, it can be divided into two types: one is associated with sulphide ore, another is associated with gangue minerals such as quartz.

(1)Associate with sulphide ore The composition of such ore is relatively simple. Pyrite is the main metal sulfide, and the content of sulfides such as copper, lead, zinc and antimony is very small. The relative content of natural gold in pyrite is more than 60%, and the remaining gold is present in gangue minerals such as quartz and other metal sulfides. This type of ore is most suitable for flotation. For the very fine gold contained in the flotation tailings, tailings cyanidation can be carried out. When the grinding product contains coarse particles of free gold, it should be added with mercury or gravity separation before flotation.

(2) Associate with gangue minerals The main feature of this ore is that the metal sulfide content is low, and more than 70% of natural gold is symbiotic with quartz. The metal minerals in the ore are mainly pyrite. In addition, there is a small amount of chalcopyrite, pyrrhotite, stibnite, galena, etc., but no arsenic, antimony, clay and carbonaceous materials. Such ores are more suitable for treatment by the mercury + cyanide method or the whole mud cyanidation method.

Oxidized ores are generally present in the shallower surface oxidation zone. According to the degree of oxidation, it can be divided into partially oxidized ore and oxidized ore. Most of the natural gold is found in gangue minerals and metal oxide minerals. The gold content of the ore is high, mostly between 10 and 20 gt. The surface of the gold particles often has an iron oxide film, and the degree of pollution increases with the increase of the oxidation rate of the ore. The commonly used processing method is mercury (or gravity separation) and cyanide, partially oxidized ore can use flotation process.

When the gold practices in the ore are coarse, the surface of the gold particles is clean, and the ore is not muddy, 70%~80% of the gold can be recovered from the ore by using the single amalgamation or mixed mercury gravity separation process. When the ore with high oxidation degree, high content of mud, and series surface pollution, even though the particle size is coarse, it is not suitable to be directly treated by amalgamation. It must be gravity separated first, and the heavy sand (concentrate) is selected to be scrubbed by grinding machine to remove the surface contamination, then mix the mercury. The fine particle ore with a low oxidation degree is usually treated by flotation. As for the fine particle ore with high oxidation degree, and dispersed in non-sulfide minerals, even if the surface of the gold particles is not contaminated, the gold particles are too fine to be treated by the amalgam method. The only feasible treatment method is the whole mud cyanidation process, the gold leaching rate can reach 96%~98%.

The mineral composition of this type of ore is similar to that of a small amount of sulfide quartz vein ore. The difference is that the sulfide content is high (5% to 15%). Metal minerals include pyrite, pyrrhotite, galena, sphalerite, chalcopyrite, and porphyrite, but pyrite accounts for more than 80%. The gangue minerals are mainly quartz, followed by calcite, feldspar, chlorite, sericite and the like.

Natural gold has a very close relationship with pyrite, so this type of ore is very suitable for flotation treatment, and the recovery rate can reach 93%~96%. If the ore contains coarse particles of free gold, it should be gravity separation before the flotation. When there are refractory gold-containing sulfide mineral particles in the flotation tailings, they can be recovered by the gold shaker.

The gold beneficiation process of easy to separate gold ore consists of amalgamation, gravity separation, flotation, and cyanide. The choice of the extraction processing method depends on the nature of the ore and the requirements of the product form. The commonly used beneficiation flow as following.

This procedure is suitable for the quartz primary ore and oxidized ore containing coarse gold. Simple layout, low investment, and fast effect, which is suitable for small gold processing plant. related post:Gold Extraction Processing and Environment Consideration

Two schemes: first amalgamation and then gravity separation or first gravity separation and then amalgamation. The former one is suited for the treatment of simple gold-bearing quartz vein sulphide ore, amalgamation process can recover the coarse particle-free gold, then gravity separation to select the heavy metal sulfide concentrate containing gold. The latter scheme, first gravity separation and then amalgamation, is suited for those oxidized coarse particle ore, and placer gold ore which with a low grade.

the flotation process is commonly used to process the gold-bearing quartz vein ore which contains fine particle gold and good flotability sulfide ore, and process gold sulfide ore which contains several valuable metals (such as copper, lead, zinc). The flotation process can enrich gold and other valuable metals to the maximum extent, and waste tailings can be obtained with low production cost.

The basic premise of using this process is that the coarse gold in the ore can be recovered by amalgamation. the great feature of this process is that can achieve a higher recovery rate than a single flotation process. In addition to the ore processed by the above flotation process, gold-bearing oxidized ore and ore associated with free gold are suitable.

As for such gold ore, in the presence of a fine particle in quartz gangue minerals, which are deeply oxidized and do not contain Cu, As, Sb, Bi and carbonaceous materials, is suited for adopts cyanidation. Advantages: low cyanide consumption, high leaching rate, high efficiency and easy control.

This combination is mainly used to process gold-bearing quartz vein ore and quartz-pyrite ore those have close symbiosis relation of sulfide. Compared with the cyanidation process, the flotation cyanide process has the advantages as following: does not require a fine ground particle, saving consumption; lesser washing and mixing step; smaller area required, low investment.

It is mainly based on flotation, and is suitable for the ore that is closely symbiotic with GOL and sulfide, and can only be recovered by smelting. Due to the small amount of non-floating sulphide ore particles (mostly pyrrhotite) in the flotation tailings, it needs to be recovered by using a gold shaker table, spiral chute and cyclone.

In summary, the choice of gold processing flow is closely related to the nature of the ore. For some complex gold-bearing ores, especially refractory polymetallic gold-bearing ores, it is technically necessary to select or develop a combination of the gold processing methods in order to maximize gold recovery and efficiently recover various useful ingredients. Gold processing equipment for sale If you have questions in flowsheet design, mining machine configuration, gold plant optimization, gold processing techniques support and the like, we are here to help, just say Hi to us!

JXSC, a 35 years gold mining machine manufacturer, has been supplying effective and safety gold mining equipment for hundreds of gold mining companies around the world, Australia, USA (like California, Colorado, Georgia, Alaska), India, Congo, South Africa, Ghana, Tanzania, Ghana, and so on.

separation process of iron ore,iron ore magnetic separation machine,iron ore beneficiation design | prominer (shanghai) mining technology co.,ltd

separation process of iron ore,iron ore magnetic separation machine,iron ore beneficiation design | prominer (shanghai) mining technology co.,ltd

At present, there are about 300 kinds of iron-bearing minerals found in nature. According to their chemical composition, iron ore can be divided into magnetite, hematite, limonite and siderite; The specific magnetic susceptibility of the material is different, and iron ore is divided into strong magnetic and weak magnetic minerals, which also provides a basis for the selection. The beneficiation process of iron ore of different nature is also completely different.

Multimetal-containing magnetite gangue minerals often contain silicate and carbonate minerals, cobalt pyrite, chalcopyrite or apatite, etc. It is recommended to use a combined weak magnetic separation-flotation process, that is, use weak magnetic separation The process first recovers iron, and then uses the flotation process to recover sulfide or apatite, which is conducive to obtaining higher beneficiation indexes.

Generally, the combined process of weak magnetic separation and flotation is also divided into two types: weak magnetic separation-flotation and flotation-weak magnetic separation. The difference between these two processes lies in the destination of the conjoined magnetite and sulfide.

This shows that under the same grinding particle size, the combined process of flotation and magnetic separation can obtain iron concentrates with low sulfide content and sulfide concentrates with high recovery rate.

Single weakly magnetic iron ore mainly includes hematite, siderite, limonite, and hematite (spiegelite)-siderite ore. Due to the variety of minerals involved in this kind of minerals and a wide range of particle sizes, the beneficiation method will be more complicated, often using gravity separation, flotation, strong magnetic separation or their combined processes.

The flotation process is mainly used for the separation of fine-grained and particulate weakly magnetic iron ore, including two process flows of positive flotation and reverse flotation. Among them, the positive flotation process is suitable for quartz hematite ore without easy pumice gangue, and the reverse flotation process is suitable for ore with easy flotation gangue.

However, due to the low grade of strong magnetic separation concentrates of most weak magnetic iron ore, and the low processing capacity of the gravity separation process unit, the combined process of strong magnetic separation and gravity separation is often used, that is, the strong magnetic separation process is first used to discard a large amount of waste. Qualified tailings, and then use the gravity separation process to further process the strong magnetic concentrate to improve the grade of the concentrate.

Polymetallic weakly magnetic iron ore refers to phosphorus-containing hematite and siderite ore. Most concentrators will first use gravity separation, flotation, strong magnetic separation or a combined process to recover iron minerals, and then use the flotation process to recover phosphorus or sulfide.

It is not difficult to see that due to the large variety and complex nature, most iron ore will use multiple combined beneficiation processes to obtain ideal beneficiation indicators. It is recommended that mine owners must do a good job of beneficiation tests, and rationally choose the appropriate iron ore beneficiation process based on the final report results.

Prominer has been devoted to mineral processing industry for decades and specializes in mineral upgrading and deep processing. With expertise in the fields of mineral project development, mining, test study, engineering, technological processing.

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