beneficiation in liquid

the complete collection of copper beneficiation reagents | fote machinery

the complete collection of copper beneficiation reagents | fote machinery

In the flotation process of the copper mine, the use of flotation reagents to change the surface properties of the mineral is a flexible and effective way to control the flotation behavior. It is also an important reason why flotation can be widely used in mineral processing. This article mainly focuses on copper collectors, inhibitors, activators, foaming agents, ore-leaching bacteria, lixivium, extractants, etc.

Copper and sulfur in copper ore have strong collection properties, which is also conducive to improving the recovery of associated gold in copper sulphide ores. The flotation effect of refractory copper-sulfur ore containing secondary copper minerals is better than that with butyl xanthate, but its selectivity is worse.

As the excellent collector and foaming agent for non-ferrous metal ores, it has a special separation effect on the copper, lead, silver and activated zinc sulfide ores and refractory polymetallic ores.

It has stronger collection capacity than xanthates, especially for chalcopyrite. It has weaker collection capacity for pyrite, but better selectivity and faster flotation speed. Better separation effect than xanthate can be obtained by using it in the separation of copper-lead sulfide ore.

As the highly selective collector, it has very low solubility in water and high activity for flotation of copper, zinc, molybdenum and other sulfide ores, as well as precipitated copper, segregate copper, etc. It's often used in combination with water-soluble collectors to increase the efficacy, reduce dosage and improve selectivity.

DMDC: It has a strong collection capacity for copper and a weak collection capacity for pyrite and unactivated sphalerite. It can be used for copper and sulfur separation and its flotation index is higher than butyl xanthate.

Compared with the xanthate or aerofloat, it has higher selectivity and stability. It has a stronger collection effect on chalcopyrite and chalcocite, but a weaker collection ability on pyrite. The amount of pyrite inhibitor can be reduced during the flotation of copper sulfide.

Under the condition of alkalescence, it has good collecting ability and selectivity for chalcopyrite and other copper-bearing minerals, as well as strong collecting ability for associated precious metals such as gold and silver.

QF collector, containing thiocarbonyl functional groups, has strong collection capacity for natural gold, chalcopyrite and other minerals. Its ability to collect gold and copper is higher than that of low-grade xanthate and dithiocarbamate collectors.

PN405 has a strong selective collecting and foaming capacity for copper ore. By using this agent alone or with a small number of xanthate collectors, a better selection index can be obtained when floating the copper. It is also a high-efficiency collecting and foaming agent for copper-nickel sulfide ore to be used in conjunction with Y89 xanthate.

MOS-2 has strong new selective collecting ability for copper ore and weak collecting ability for pyrite. The separation of copper and sulfur can be realized and the dosages of collectors, lime and no. 2 oil can be reduced in lower alkaline medium by using it. Mos-2 collector also has a good foaming performance, so when using it as a collector, less or no foaming agent can be used.

It is a new class of ester collector for copper sulfide, which can preferentially collect copper in the rough selection stage with strong chemical adsorption on the surface of copper, and it is not easy to fall off.

It has good collecting performance and selectivity for copper sulfide, good selectivity for skarn copper ore with high secondary copper content, and can separate copper and sulfur in low alkaline medium.

It is a collector of copper sulfide ore, which has both foaming properties with rich and non-sticky foam, good selectivity, strong collecting property and fast flotation speed to improve concentrate grade. It has a wide PH range and can be added in stock solution.

It is a modified chalcophile chelating agent, which has no other hydration group except the groups that can form chelating compounds with copper, and can form stable hydrophobic polymers insoluble in water (or with very low solubility) with the surface of copper oxide.

It has a strong inhibitory effect on sulphide ores other than chalcopyrite. It can avoid the inhibitory effect on chalcopyrite when using too much sodium sulfide. It can be used in combination with sodium sulfite and zinc sulfate.

The combination of T-16 + zinc sulfate inhibitor can inhibit zinc, activate copper and lead, and eliminate the effect of slurry foam viscosity, which can effectively realize the flotation separation of copper-lead and zinc.

One of the development trends of mining is the application of bioleaching technology to recover important metals from various low-grade ores. Compared with traditional mineral processing technology, biological leaching technology has the characteristics of low cost, easy operation and low pollution.

The extractant can chemically react with the extract to form an extractable compound that can be dissolved in the organic phase, which is the most critical factor affecting the success of the extraction process.

In the flotation process of copper ore, the beneficiation reagent is an important factor that determines the flotation effect. It is one of the main research directions of mineral processing workers to explore a new copper flotation process and develop new cost-effective and environmentally friendly reagents to improve the utilization rate of copper resources.

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beneficiation - an overview | sciencedirect topics

beneficiation - an overview | sciencedirect topics

Beneficiation includes crushing, grinding, gravity concentration and flotation concentration. Beneficiation is followed by processing activities such as smelting and refining. The beneficiation process begins with milling, which is followed by flotation for further beneficiation. At the first stage, extracted ores undergo the milling operation to produce uniformly sized particles for crushing, grinding, wet or dry concentration. The type of milling operable in a certain plant is chosen by capital investment and economics. The degree of crushing or grinding, which is required for further beneficiation, is dependent on capital. Crushing is a dry operation which only involves dust control using water spray (Drzymala, 2007). A primary or jaw crusher is located at the mine site and reduces the particle diameter of the ores into<6 in. The crushed ore is then transported to the mill site for crushing, grinding, classification and concentration. The second stage, grinding, is a wet operation which requires initial flotation and water to make a slurry. The hydrocyclone operates between each grinding operation to classify the type of particles: fine or coarse (Long etal., 1998).

This process is used to adhere to ore mineral or a group of minerals with the air bubbles after involving chemical reagents in operation. Chemical reagents got reacted with the desired mineral in the flotation process. The effectiveness of the flotation technique is dependent on four factors: the degree of oxidation of the ore, the number of copper minerals present, the nature of the gangue and the presence of iron sulphides. There are some other important factors such as the particle size, minerals compatible with the reagents and the condition of the water. Conditioners and regulators might be used during or after the milling time for ore treatment (Drzymala, 2007). Flotation is an effective method to concentrate the targeted elements existed in minerals based on the difference in physicochemical properties of various mineral surfaces. It can easily separate copper (Feng etal., 2018b), lead (Feng etal., 2017a), zinc (Feng and Wen, 2017) and tin (Feng etal., 2017b) minerals from gangue minerals by addition of flotation reagents. The concentrates of minerals must go through pyrometallurgical methods like smelting and refining. However, before these steps, the concentrates may require roasting and sintering, which depends on the processing method. The ore concentrate undergoes partial fusion which turns it into agglomerated material suitable for processing operations (Drzymala, 2007). The sintering operation consists of blending, sintering, cooling and sizing. At first, the raw material concentrates are blended with moistures in mills, drums or pans. This step is called blending. In the next step, the concentrate feed is fired or sintered and then cooled (Long etal., 1998). The sinter gets crushed with being cool. Then the concentrate will be graded. After grading, it is crushed to produce a smaller sinter product. In roasting, gassolid reactions are involved at elevated temperatures, which purify the metal by treating it with hot air (Shedd, 2016).

Dry beneficiation has two important advantagessaving water, a valuable resource, and no tailings pond and subsequently, no leaching of the trace/toxic elements into ground water. In dry beneficiation of coal, coal and mineral matter are separated based on differences in their physical properties such as density, shape, size, luster, magnetic susceptibilities, frictional coefficient, and electrical conductivity [2325]. Dry beneficiation gives a clean coal as well as reduces some of the polluting elements associated with minerals. It cannot remove the inorganic matter in coal present as salts resulting from the marine environment during coalification. Azimi etal. [26] evaluated the performance of air dense mediumfluidized bed separator in removing trace elements, such as Hg, As, Se, Pb, Ag, Ba, Cu, Ni, Sb, Co, Mn, and Be. Their study revealed the association of Pb, Ag, Ba, Cu, Mn, and Be with ash-forming minerals. Elements such as As, Se, and Sb showed some organic bonding. High rejection of Hg was achieved through dry beneficiation of coal where Hg is mostly associated with pyrites.

The beneficiation and obtainment of raw materials often has a severe effect on the environment and generates byproducts that in many cases cannot be further processed into suitable products. The high concentration of REs (mainly in the form of oxides) in spent glass polishing material would therefore enable the easier and resource-saving production of predominantly cerium and lanthanum oxides. As a consequence, the focus of this chapter was on reviewing and investigating recovery processes for REs, whereas all mineral acids of technical relevance were taken into account. The presence of RE compounds containing fluoride made digestion with nitric and HCl more complex and achieved maximum leaching yields for lanthanum of 70%, whereas the extraction of cerium was higher than 90% using high acid concentrations and excess as well as hydrogen peroxide to some extent. However, the main advantage of these process types is that less wash water is required compared with sulfuric acid processing. On the other hand, off-gas and wastewater treatment seems to be more easily manageable in the case of H2SO4. Nevertheless, because polishing agents are usually based on noncritical REs, which in some cases (especially cerium) are even being overproduced nowadays, the economic viability of such processes has to be carefully analyzed.

Mineral beneficiation begins with crushing and grinding of mined ore for near-complete separation of ore and gangue minerals as well as between ore minerals. Each processing step is designed to increase the grade (concentration) of the valuable components of the original ore. Mined ore undergoes comminution by crushing and grinding, and gravity concentration by Dense Media Separation (DMS) removes the bulk of the rocks and gangue minerals. Installation of a DMS unit between the crusher and the grinder is extremely beneficial to eliminate large volumes of waste rocks from the ore. Consequently, the grinder, milling, and flotation unit will treat a significantly lower volume of higher-grade preconcentrate at a reduced operating cost with respect to energy, grinding media, and flotation reagents. The mineral pyrrhotite is often magnetically separated, collected, and treated to recover the minerals of PGEs and nickel. Sulfide minerals are further concentrated by froth flotation. The final concentrate upgrades the PGE content to 0.0150% (100400g/t) PGEs. The wet concentrate dewatered is thickened in large tanks, and filtered by disk or drum filters. The concentrate is dried in a spray drier or flash drier to reduce the energy requirement for smelting and the possible occurrence of explosions in the furnace. Dry concentrate is transferred pneumatically from the drier into the furnace for smelting.

Mineral beneficiation, particularly base and noble metals, is sensitive to optimum use of reagents, recovery of metals, and clean concentrate. High fluctuation of feed grade at flotation cells yields loss of metals to tailing. The offline analytical procedures discussed at Chapter 7, Section 7.5, are not appropriate under changing feed grade. The process is not capable of continuous in-stream detection and spontaneous corrective measures. This is surmounted by complete concentrator automation. The circuit is comprised of three major integrated units: probe or sensor, in-stream analyzer, and digital process control module.

The in-stream X-ray analyzer (Fig.13.5) employs sensors acting as a source of radiation, which is absorbed by the sample causing fluorescent response of each element. The analyzer probes are installed in feed, concentrates, and tailing streams. The metal content (Pb, Zn, Cu, Fe, Cd, Ag, Au, etc.) and pulp density, in the form of electrical signals from the probes (sensors), are conveyed in electronic circuits (detectors generating a quantitative output signal) to a digital computer in the control room. A continuous screen display and/or printout showing the elemental dispersion at every minute is available for manual or automatic control of reagents in the flotation process. The field instruments for the flotation circuits comprise pH and metal probes and magnetic flow meters with control valves for reagent dosing pumps. The system improves the recovery of each metal as well as concentrate grade. The regulated feed reagents, apart from improved metallurgy, result in significant savings of reagent cost.

Figure13.5. Mill sampling system by in-stream analyzer. The probe is installed in the slurry stream of feed (conditioner) and reject (tailing) for continuous sensing of metal grades and simultaneous digital process control of reagents.

The steps to be taken for proper functioning of the slurry pond, handling of coal rejects and their utilization, periodic desilting, arrangement for water recirculation, measures to prevent water pollution from slurry ponds, arrangement for surplus water overflow, etc. shall be indicated in the mine closure plan. Reject dumps should be properly benched and graded on cessation of washery/mining operations and the area should be reclaimed biologically. Similarly, slurry ponds should be dismantled and dewatered and the area reclaimed at the end of washery/mining operations.

In the beneficiation of phosphate ores the tailings generated still carry significant phosphate content. The recovery has been difficult as the tailings carry a large proportion of clay minerals, magnesium oxide and iron carbonate mineral known as ankerite, an iron carbonate. Until recently, there was no suitable method for separating phosphate from such clayey wastes.

Progress has been made to recover some fraction of phosphate from these wastes. Separation of ankerite mineral has been attempted by magnetic separation with some success (Abdel-Khalek et al., 2001). The magnetic stream enriched with phosphate is further processed by flotation to separate magnesium oxide. A product containing 3132% P2O5 by processing tailings with 20% P2O5 has been produced (Abdel-Khalek et al., 2001).

The beneficiation study of vein-type apatite from Mushgia Khudag deposit, Mongolia, wascarried out to gain knowledge for processing an extremely REE-enriched igneous-hydrothermal ore type associated with Upper JurassicLower Cretaceous, c. 140Ma, syenite magmatism.

In the field, the studied apatite veins range from centimeters to several meters in width and crosscut the syenite. The main REE carrier phase is apatite, which contains an average of 14.7% total REO, with the highest values reaching 20.8%. This is the highest concentration of REE reported in apatite to date.

Apatite is accompanied by minor amounts of other REE phases, such as cheralite, monazite, parasite, synchysite, bastnaesite, and xenotime. Apatite typically occurs as idio- to hypidimorphic grains varying from 0.1 to 4.0mm in diameter.

In the composite sample, the content of REE was calculated as 1.74%, most of which comprised light REE. Y was the only heavy REE. The ratio of heavy to light REE was found to be very low. The recovery of apatite (REE) is the main aim of the beneficiation work.

Over 90% TREE recovery was obtained at the mass recovery of 22%. After three time cleaners, the final concentrate was of the grade TREE 9.3% at the recovery of 85.0% and of the grade P2O5 22.3% at the recovery of 85.7%. The enrichment ratio of the process was 5.3 for TREE and forP2O5.

Mineralogical studies indicated that after rougher and cleaner flotation, the contents of the two REE-bearing minerals in the concentrate, apatite (REE) and monazite, had increased to 80.39% and 0.69% from the original 11.19% and 0.1%, respectively.

Apatite-hosted REE ores are expected to represent an increasingly important source for REE in the future due to the abundance of apatite and other phosphates in various geological environments including igneous, igneous-hydrothermal, and sedimentary systems.

Most ore beneficiation methods require large volume of water. It is necessary in the process of separation of various valuable and gangue minerals. The final concentrates as produced contain high proportion of moisture. Smelters, captive or custom base, are generally located at long distances from mining- beneficiation sites due to inadequate infrastructure. Shipment of concentrate in pulp form to long distances is not advisable. Pulp transport by road, rail or sea route is unsafe even at exorbitant high cost. Therefore, dewatering or solid-liquid separation is performed to generate dry concentrate. However, partial presence of water is desirable, say between 5 and 10% moisture content, for easy handling and safe transport. Metal losses are expected if the moisture content is totally dry or too low. It often becomes serious environmental issue on account of spreading air-driven concentrate in dry and dust form. Dewatering is done at successive stages of sedimentation or thickening, filtration and thermal drying.

Sedimentation is natural gravity settling of the solid portion of the concentrate pulp. It takes place in a cylindrical thickening tank in the form of layers (Fig. 12.50). Pulp is fed continuously from the top of the tank through pipe. The clear liquid overflows out of the tank. The thickened pulp settled at the bottom is taken out through a central outlet. The deposition process can be accelerated and the settled solids can be pushed toward the central outlet by rotating suspended radial arms performing as automatic rake mechanism. Sedimentation process would produce thickened pulp of 55-65% solids by weight.

Filtration is the second stage of solid-liquid separation, normally after thickening, by means of a porous medium. The most common filter media is cotton fabrics but can be extended to any one of jute, wool, linen, nylon, silk and rayon. The filter pads allow liquid to percolate and retain the solid on the outer surface. The filter media is washed and cleaned at regular interval for better performance and longevity. Several types of filter mechanisms are in use. The most widely used filters in mineral processing applications are disc, drum and horizontal type. Filtration produces moist filter cake of 80-90% solids.

Disk filters are used with vacuum filtration equipment. It is made of several large discs (Fig. 12.51). Each disk consists of sectors that are clamped together. The ribs between the sectors are designed in a radial fusion narrowing at the center. The semidry feed enters from the side. The disc rotates slowly so that cake forms on the face of the disc and semidry cakes are lifted above the slurry. The cake is suction dried. It is removed by scraper blades fitted on the side of each disc and pushed to discharge chutes. Generally, disk filters are used for heavy-duty applications such as dewatering of lead-zinc-copper concentrate, low-grade iron ore-taconite, coal, and aluminum hydrate.

Horizontal belt filter consists of a highly perforated horizontal rubber drainage conveyor deck fitted with filter media. Slurry is fed at the starting point of the deck and moves to the other end. Filtration starts partly by gravity and partly by vacuum mechanism attached to the bottom of the moving drainage deck. The cake is discharged as the belt reverses over a roller.

Drum or rotary drum filter works on the same principle as that of a disc filter. The drum is mounted horizontally and rotates in slow motion (Fig. 12.52). The surface of the drum is tightly wrapped with filter media and divided into several compartments, each one attached with drain lines. The filter is partially submerged in slurry feed. The drum rotates slowly through the slurry and produces filtered cakes while moving out of the submergence level. Partially dry cakes are removed by a combination of reversed air blast and automatic scraper knife.

Drying of concentrate is done prior to shipment. Rotary thermal dryer is widely used for production of final salable concentrate. It consists of a long cylindrical shell mounted on a roller at little slope to rotate the unit in uniform speed. Hot air at about 980 C is passed inside the cylinder through which the wet feed moves from feeding point to discharge end by gravity. Dry concentrate at 510% moisture moves on conveyer to the stockyard before being loaded onto trucks or rail wagons as required for shipment.

A simple process of beneficiation has been selected, which will be low in capital cost. As the scheme is a simple one, the cost of operation and maintenance will be minimal. The process technology is so chosen that it should be able to meet the quality parameters laid down by consumers. The flow scheme is briefly described here:

The scheme of beneficiation indicated here is a simple and effective technique that does not take into consideration either small coal or fines. This simple scheme may be applicable both for consumption in the power sector and the cement industry. However, depending upon the raw coal characteristics and needs of the consumer, total washing may be needed, as in the case of coking coal (Fig. 9.6).

application of liquid/solid fluidization technique in beneficiation of fines - sciencedirect

application of liquid/solid fluidization technique in beneficiation of fines - sciencedirect

Use of liquid/solid fluidization techniques for size classification is a common practice in mineral processing operations. Extending its application in gravity separation for finer feed particles (0.5mm) is not straightforward as these fine size particles tend to remain in a mixed state during fluidization. In this paper an effort is made to explore the possibilities of adopting liquid/solid fluidization technique to beneficiate fine-size feed. The study shows that separation is effective within a limited range of size (ratio) with proper control on superficial water velocity. This study is relevant to beneficiation of low-grade ore which typically liberates at finer size where beneficiation has been a challenge.

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