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lead and copper beneficiation

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.

As a leading mining machinery manufacturer and exporter in China, we are always here to provide you with high quality products and better services. Welcome to contact us through one of the following ways or visit our company and factories.

Based on the high quality and complete after-sales service, our products have been exported to more than 120 countries and regions. Fote Machinery has been the choice of more than 200,000 customers.

how to process copper ore: beneficiation methods and equipment | fote machinery

how to process copper ore: beneficiation methods and equipment | fote machinery

All available copper-bearing natural mineral aggregates are called copper mines. The high-grade copper concentrate can be obtained by the coarse grinding, roughing, scavenging of copper ore, then grinding and concentrating of coarse concentrate.

Due to the different types of ore, the nature of the ore is also different, so the beneficiation process needs to be customized. The specific process for selecting copper ore depends mainly on the material composition, structure and copper occurrence state of the original copper ore.

Before the beneficiation of copper ores, crushing and grinding are required. The bulk ores are crushed to about 12cm by a jaw crusher or a cone crusher. Then the crushed materials are sent to the grinding equipment, and the final particle size of the copper ore is reduced to 0.15-0.2mm.

Copper sulfide can be divided into single copper ore, copper sulfur ore, copper-molybdenum deposit, copper nickel, carrollite and so on. Basically, only flotation can be considered in its separation.

Almost all copper sulphide ores contain iron-bearing sulfides, so in a sense, the flotation of copper sulfide is essentially the separation of copper sulfide from iron sulfide. The common iron sulfide minerals in copper ore are pyrite and pyrrhotite.

1 Disseminated grain size and symbiotic relationship of copper and iron sulfide. Generally, pyrite has a coarse grain size, while copper ore, especially secondary copper sulfide, is closely associated with pyrite. Only when the copper ore is finely ground can it be dissociated from pyrite. This characteristic can be used to select copper-sulphur mixed concentrates, discard the tailings, and then grind and separate the mixed concentrate.

2 The influence of secondary copper sulfide minerals. When the secondary copper sulfide mineral content is high, the copper ions in the slurry will increase, which will activate the pyrite and increase the difficulty of Cu-S separation.

3 The influence of pyrrhotite. The high content of pyrrhotite will affect the flotation of copper sulfide. Pyrrhotite oxidation will consume the consumption of oxygen in the pulp. In severe cases, the copper minerals do not float at the beginning of flotation. This can be improved by increasing inflation.

Generally, copper is floated firstly and then sulfur. The content of pyrite in dense massive copper-bearing pyrite is quite high and high alkalinity (free CaO content> 600800g/m3) and high dosage of xanthine are often used to suppress the pyrite. There is mainly pyrite in its tailings with few gangues, so the tailings are sulfur concentrates.

For the disseminated copper-sulfur ore, the preferential flotation process is adopted, and the sulphur in the tailings must be re-floated. To reduce the consumption of sulfuric acid during the floatation and ensure safe operation, the process condition of low alkalinity should be adopted as far as possible.

It is more advantageous for copper sulfur ore containing less sulfur with copper easy to be floated. Carry out the bulk flotation firstly in the weakly alkaline pulp and then add lime to the mixed concentrate to separate the copper and sulfur in the highly alkaline pulp.

In semi-preferential bulk-separation flotation, Z-200, OSN-43 or ester-105 with good selectivity are used as collectors to float copper minerals firstly. The copper concentrate is then subjected to copper-sulfur bulk flotation and the obtained copper-sulfur mixed concentrate is subjected to separation flotation of floating copper and suppressing sulfur.

It avoids the inhibition of the easily floating copper under high lime consumption and does not require a large amount of sulfuric acid-activated pyrite. It has the characteristics of reasonable structure, stable operation, a good index and early recovery of target minerals.

3 The xanthate collector mainly plays the role of chemisorption together with the cation Cu (2 +), so minerals whose surface contains more Cu (2 +) minerals have a strong effect with the xanthate. The order of the effect is: chalcocite > covellite > porphyrite> chalcopyrite.

4 The floatability of copper sulfide minerals is also affected by factors such as crystal size, mosaic size, being original or secondary. The minerals with fine crystal and mosaic size are difficult to float. Secondary copper sulfide ore is easy to oxidize and more difficult to float than original copper ore.

As for the grinding and floating process, it is more advantageous to adopt the stage grinding and floating process for refractory copper ore, such as the re-grinding and re-separation of coarse concentrate, re-grinding and re-separation of bulk concentrate, and separate treatment of medium ore.

Copper oxide (CuO) is insoluble in water, ethanol, soluble acid, ammonium chloride and potassium cyanide solutions. It can react with alkali when slowly dissolving in ammonia solution. The beneficiation methods of oxidized copper ore mainly include gravity separatio, magnetic separation (see details on copper ore processing plant), flotation and chemical beneficiation.

Flotation is one of the commonly used mineral processing techniques for copper oxide ores. According to the different properties of copper oxide ores, there are sulphidizing flotation, fatty acid flotation, amine flotation, emulsion flotation and chelating agent-neutral oil flotation method.

Process flow: The dosage of sodium sulfide can reach 1~2kg/t during vulcanization. Because the film produced by vulcanization is not stable and is easy to fall off after vigorous stirring, and sodium sulfide itself is easily oxidized, sodium sulfide should be added in batches.

Besides, the vulcanization speed of malachite and azurite is relatively fast, so the vulcanizing agent can be directly added to the first flotation cell with no need to stir in advance during vulcanization and adjust the amount of vulcanizing agent according to the foam state.

Fatty acids and their soaps are mainly used as collectors of fatty acid floatation, also known as direct flotation. During flotation, water glass (gangue inhibitor), phosphate, and sodium carbonate (slurry regulator) are also usually added.

There is a practice of mixing vulcanization and fatty acid methods. Firstly float the copper sulfide and part of the copper oxide with sodium sulfide and xanthate, and then float the residual copper oxide with fatty acid.

For example, the ore in the Nchanga processing plant in Zambia contains 4.7% copper. The copper content achieved to 50% ~ 55% through flotation by adding 500g/t of lime (pH 9 ~ 9.5), 10g/t of cresol (foaming agent), 60g/t of ethylxanthate, 35g/t of amyl xanthate, 1kg/t of sodium sulfide, 40g/t of palmitic acid and 75g/t of fuel oil.

It is mainly to sulfurize the copper oxide mineral firstly and then add the copper accessory ingredient to create a stable oil-wet surface. Then, the neutral oil emulsion is used to cover the mineral surface, resulting in a strong hydrophobic floating state. In this way, the mineral can be attached to the foams firmly to complete the separation.

Many problems should be paid attention to in the flotation of copper ore, such as the length of the vulcanization time, whether to add sodium sulphide in batches and the proportion of chemicals. Here is a brief introduction.

1 The vulcanization time. Different ores require different vulcanization times. Generally speaking, it should be short rather than longer. The suitable vulcanization time is 1 to 3 minutes. After 6 minutes, the recovery rate and concentrate grade will decrease.

2 Add sodium sulfide in batches. The roughing time for processing the ore in the concentrator is about ten minutes, while the ore contains a large amount of carbonaceous gangue and the divalent sulfur ions disappear quickly in the slurry. So the effect of adding sodium sulfide in batches is better than that of adding it once.

3 Add sodium sulfide proportionally. Generally, copper oxide floats in the liquid at a slower speed, and reduce the number of cycles of the mineral in the flotation process can obtain a higher recovery rate. It is of great significance to study the distribution ratio of sodium sulfide among different operations to catch the mineral at the right time.

The chemical beneficiation method is often used for refractory copper oxide and mixed copper. For some copper oxide minerals with high copper content, fine mosaic size and rich sludge, the chemical beneficiation method will be used to obtain good indicators because the flotation method is difficult to realize the separation.

The solution of ammonia and ammonium carbonate in a concentration of 12.5% was used as the solvent to leach for 2.5h at a temperature of 150, a pressure of 1925175~2026500Pa. The mother liquor can be distilled by steam at 90 to separate ammonia and carbon dioxide. Copper, on the other hand, is precipitated from the solution as black copper oxide powder.

Because some copper oxide minerals are not tightly combined with iron, manganese, etc., it is difficult to separate them by using the magnetic separation method alone, and flotation has a good separation effect.

Therefore, the flotation method is used to obtain high-grade concentrates, the magnetic separation is for tailings and wet smelting is carried out finally. This process combines flotation, magnetic and wet smelting very well, which greatly increases the recovery rate and reduces the beneficiation cost.

The above are several common beneficiation methods for copper oxide minerals. For the selection of copper oxide minerals, it is best to conduct a professional beneficiation test and customize the process according to the report.

Flotation is the most widely used method in copper mine production. The copper ore pulp is stirred and aerated, and the ore particles adhere to the foams under the action of various flotation agents. The foams rise to form a mineralized foam layer, which is scraped or overflowed by the scraper. This series of flotation processes are all completed in the flotation machine. (Contact Manufacturer)

The internal magnetic system of the barrel adopts a short circuit design to ensure that the barrel skin has no magnetic resistance at high speeds, and the stainless-steel barrel skin does not generate high temperatures, extending the life of the magnetic block.

Since it adopts a dynamic magnetic system design, the roller does not stick to the material, which is conducive to material sorting. The selected grade can be increased by 3-6 times to more than 65%.

Copper mines are generally purified by flotation, but for the beneficiation of copper minerals with coarser grain size and higher density, the pre-selection by the gravity separation method will greatly reduce the cost and achieve flotation indicators.

As a leading mining machinery manufacturer and exporter in China, we are always here to provide you with high quality products and better services. Welcome to contact us through one of the following ways or visit our company and factories.

Based on the high quality and complete after-sales service, our products have been exported to more than 120 countries and regions. Fote Machinery has been the choice of more than 200,000 customers.

beneficiation - an overview | sciencedirect topics

beneficiation - an overview | sciencedirect topics

Thermal beneficiation is the use of combustion to reduce the level of carbon in the ash. Thermal beneficiation also eliminates ammonia issues and can improve fineness and uniformity. Successful thermal beneficiation technologies have been commercially deployed since 1999 (Keppeler, 2001). This technology produces more than a million tons of marketable fly ash per year in the eastern United States. There are two technologies that can be considered proven: the first is PMI's Carbon Burnout (CBO) system, based on dense phase fluidized bed combustion; and the second is SEFA Group's STAR technology, based on dilute or entrained fluidized bed combustion.

The ability of thermal beneficiation to improve ash quality is truly impressive. It is a proven, highly flexible technology that can operate on a variety of ash types with a very wide range of carbon concentrations and sizes. It produces an ash that is low or even free of carbon. It also eliminates ammonia from fly ashes impacted by nitrous oxide controls or opacity treatments. The process may improve fineness by eliminating coarse carbon and liberating ash trapped within.

Thermal beneficiation is a combustion process and may require additional air emission permitting. If not integrated into the power plant, it will also require its own emission control system. It is by far the most expensive of all the technologies considered. A facility can cost tens of millions of dollars, which suggests that it would be more attractive for larger power plants with access to large and stable markets. The construction of a thermal beneficiation facility may require significant plant modifications and systems integration; however, it does not specifically target ash fineness and uniformity.

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.

Beneficiation of copper ores is done almost exclusively by selective froth flotation. Flotation entails first attaching fine copper mineral particles to bubbles rising through an orewater pulp and, second, collecting the copper minerals at the top of the pulp as a briefly stable mineralwaterair froth. Noncopper minerals do not attach to the rising bubbles; they are discarded as tailings. The selectivity of the process is controlled by chemical reagents added to the pulp. The process is continuous and it is done on a large scale103 to 105 tonnes of ore feed per day.

Beneficiation is begun with crushing and wet-grinding the ore to typically 10100m. This ensures that the copper mineral grains are for the most part liberated from the worthless minerals. This comminution is carried out with gyratory crushers and rotary grinding mills. The grinding is usually done with hard ore pieces or hard steel balls, sometimes both. The product of crushing and grinding is a waterparticle pulp, comprising 35% solids.

Flotation is done immediately after grindingin fact, some flotation reagents are added to the grinding mills to ensure good mixing and a lengthy conditioning period. The flotation is done in large (10100m3) cells whose principal functions are to provide: clouds of air bubbles to which the copper minerals of the pulp attach; a means of overflowing the resulting bubblecopper mineral froth; and a means of underflowing the unfloated material into the next cell or to the waste tailings area.

Selective attachment of the copper minerals to the rising air bubbles is obtained by coating the particles with a monolayer of collector molecules. These molecules usually have a sulfur atom at one end and a hydrophobic hydrocarbon tail at the other (e.g., potassium amyl xanthate). Other important reagents are: (i) frothers (usually long-chain alcohols) which give a strong but temporary froth; and (ii) depressants (e.g., CaO, NaCN), which prevent noncopper minerals from floating.

Beneficiation of complex base metal sulfide ores is based on selective production of individual clean concentrates of copper, zinc, and lead. Sphalerite flotation through copper activation becomes complicated when other minerals such as pyrite can get inadvertently activated.

Adsorption density of cells of P. polymyxa was found to significantly higher on pyrite than on sphalerite irrespective of pH. Adsorption on sphalerite was the highest in acidic pH regions only (26), beyond which cell adsorption decreased steeply.

Flocculationdispersion behavior of pyrite and sphalerite was seen to be influenced by interaction with bacterial cells and their metabolic products as a function of pH, cell density, and bioreagent concentrations. For example, more than 90% of pyrite particles were observed to be flocculated and settled at pH 89 in the presence of bacterial cells, while sphalerite was preferentially dispersed. Similarly, interaction with EBP isolated from metabolites promoted selective flocculation of pyrite and dispersion of sphalerite. On the other hand, interaction with ECP was not very effective in separation of pyrite from sphalerite because the selectivity ratio was very poor. Pyritesphalerite separation can be effectively achieved through selective bioflocculation of pyrite and dispersion of sphalerite using either bacterial cells or bioproteins.

Pyrite can also be selectively depressed through bioflotation after bacterial conditioning. Flotation tests using 1:1 mixtures of pyrite and sphalerite indicated that prior bacterial interaction followed by xanthate conditioning and copper activation resulted in preferential flotation of only sphalerite, while pyrite was depressed.

Pyrite could also be similarly removed from galena because differential adsorption and surface chemical behavior of P. polymyxa cells as well as proteins and polysaccharides were also observed on pyrite and galena as well. Selective bioflocculation in the presence of either bacterial cells or extracellular proteins could selectively flocculate pyrite from pyritegalena mixtures. Galena was also found to be selectively flocculated after interaction with exopolysaccharides. Similarly selective flotation of galena along with efficient pyrite depression could be attained after interaction with extracellular proteins.

A. ferrooxidans have been used to demonstrate selective pyrite depression from a low-grade leadzinc ore. Both sphalerite recovery and zinc grade in the floated sphalerite concentrate were enhanced by bacterial cells in the absence of conventionally used cyanides [48].

Ore beneficiation refers to the selection and collection of higher-grade ore fragments or rejection of lower-grade fragments from ROM ore. The upgraded ore will have a higher grade, and therefore require a smaller-scale processing plant, perhaps with different technology, compared to ROM ore. Ore beneficiation is only worthwhile if the majority of the uranium is retained and the majority of the mass is rejected.

In the earliest times of uranium mining hand sorting was employed, based on visual appearance or simple gamma scanning. In more recent times, mechanical sorting based on physical, mineralogical, or radiometric characteristics are employed.

At the Cluff Lake uranium mine and mill in Canada, in phase 1 operations high-grade ore was fed to a gravity concentration plant with jigs and vibrating tables. The concentrate averaged over 30% U (Schnell and Corpus, 2000). The gravity concentrator rejects were stored and retreated later (see Section 6.5.1).

Flotation (sometimes spelled floatation) separates mineral grains that respond differently when air bubbles are forced through a suspension in water with chemical additives, causing certain minerals to rise with the froth, from which they can be collected in a concentrated form. It was used in some Canadian uranium mines in the 1980s (eg, Muthuswami et al., 1983) and has been investigated in India (eg, Singh et al., 2001). It is used at the Olympic Dam copperuraniumgold mine to separate sulfidic copper-bearing minerals (Alexander and Wigley, 2003) and only incidentally for uranium minerals; uranium is recovered from the reject stream of the flotation circuit. Some recent investigation of the technique for application to multimetallic ores containing uranium is described by Kurkov and Shatalov (2010).

Shatalov et al. (2001) report that the automated radiometric ore separating was widely adopted in former Eastern Bloc countries starting in 1955. Variants and improvements up to 2000 are discussed. Radiometric sorting has been used in recent times in Ukraine (OECD-NEA/IAEA, 2014, p. 426). Radiometric sorting trials at Ranger mine in Australia and Rssing in Namibia are reported by Schnell (2014), who also comments that [G]ravity separation has been applied to uranium ores in the past with some success, but this was associated with radiation issues (cf. Section 6.5.1, where it was used with very high-grade ore). Lund et al. (2007) mention radiometric sorters in use historically in Australia and South Africa.

A form of upgrading by physical means, rotary scrubbers, at the Langer Heinrich uranium mine in Namibia is described by Marsh (2014), who states that the rejected oversize Barren Solids will contain 4050% of the solids mass but only 510% of the uranium in the ROM feed.

When the price of uranium was high in the mid-2000s, there was relatively low interest in upgrading, rather treatment of low-grade ore was considered feasible and pursued (cf. Lund et al., 2007). However, with lower prices since 2010, more experimentation is being reported. For example, ablation can remove uranium-rich mineral crusts from some sandstone ores (Coates et al., 2014) with some ore types; Scriven (2014) cites the ablation technique resulting in rejection of 9095% of the unprocessed ore mass but with a loss of only 510% of the uranium originally present. Another process under development (Becker et al., 2015) is for certain low-grade, surficial ores. It can reportedly increase the ore grade by a factor of 30 times or more without the use of chemicals, producing an inert waste and providing a leach feed suitable for acid leaching, although details of this second process were not yet released at that time. To date, neither has been undertaken at a commercial scale.

In tin beneficiation, the main new technology being adopted is the high-gravity concentrator, examples being the Kelsey jig, Falcon and Knelson concentrators, and the Mozley multigravity separator. Radical change in tin smelting and refining technology is not expected. In smelting, use of the TBRC and the Sirosmelt technologies will be more widely adopted, using fuming instead of reduction smelting for second-stage processing. Economies of scale are leading to the dominance of a few large smelters in countries such as China, Malaysia, and Bolivia. Refining technology will in general continue to rely on the same chemical principles, but will see greater adoption of automated technology such as the centrifuge for dross removal, and the vacuum process. Hydrometallurgical technologies may make an impact with developments in ion exchange, solvent extraction, and biooxidation and reduction.

Microbially induced mineral beneficiation involves three strategies, namely, selective bioleaching of the undesirable mineral from an ore or concentrate, selective flotation of the mineral, or selective dispersion/flocculation. Such microbially induced beneficiation will find applications in a number of areas such as:

Besides bioleaching using Acidithiobacillus bacteria and bioremediation using SRB, many mining organisms which inhabit ore deposits find applications in mineral beneficiation such as microbially induced flotation and flocculation. Acidithiobacillus spp can be used also to bring about microbially induced flotation and flocculation of minerals. Heterotrophic bacteria such as Paenibacillus polymyxa and Bacillus subtilis, yeasts such as Saccharomyces cerevisiae, and SRB such as D. desulfuricans can be used to bring about surface chemical changes on minerals, Principles and examples of microbially induced mineral beneficiation processes are illustrated in Chapter 10, Microbially Induced Mineral Beneficiation. Experimental protocols for such applications are illustrated below: [1]

Fully grown bacterial culture is centrifuged at 10,000g for 15min at 5C. The supernatant is decanted and filtered through sterile Millipore (0.2m) filter paper to remove all insoluble materials and any remaining bacterial cells.

CFE of a fully grown culture contains different bioreagents such as proteins, polysaccharides along with trace amount of other constituents. Proteins and polysaccharides can be isolated and used as flotation and flocculation reagents.

A suitable volume of a fully grown culture is initially centrifuged, and the supernatant filtered through a sterile millipore (0.2m) filter paper. Analytical reagent grade, extra pure, and fine powdered ammonium sulfate is added slowly to a saturation level of 65% with constant shaking at 4C. The solution is allowed to stay under refrigeration for 12h at 4C. The precipitated protein is dissolved in a minimum volume of 0.1M Tris hydrochloride buffer of pH 7 and dialyzed against the same buffer for over 18h at 4C. The precipitate formed during dialysis is removed through centrifugation and disposed. The clear supernatant is lyophilized, and the resultant solids weighed, and kept at 4C for further use.

An actively grown bacterial culture is harvested by centrifugation and dissolved in lysis buffer (10mM Tris-HCl (pH 8.0), 0.1M NaCl, 1mM EDTA (pH 8.0), 5% (v/v) Triton X-l00). The suspension is sonicated and centrifuged at 10,000g for 5min. The supernatant is subjected to 65% ammonium sulfate precipitation, the solution kept in a refrigerator for 1012h, and centrifuged. The precipitated protein is dialyzed with trisbuffer at neutral pH range and then precipitated with acetone. This protein precipitate is dissolved in trisbuffer and SDS-PAGE is carried out.

A suitable volume of fully grown batch culture is centrifuged to remove bacterial cells. The supernatant containing the extracellular polysaccharide (ECP) is filtered and lyophilized. The dehydrated sample is dissolved in 10mL of distilled water and cooled to <10C. Twenty milliliter of double-distilled ethanol is added to selectively precipitate ECP and purified. It is stored in a refrigerator for 8h at 4C. The precipitate is washed with double-distilled water. The ethanol precipitation procedure is repeated two to three times further, to purify the polysaccharide, and the solution dialyzed with double-distilled water. After dialysis, ECP is stored at low temperature (4C). The concentration of ECP is determined by the phenolsulfuric acid method [40].

The spectrophotometer is switched on and the wavelength adjusted to 280nm. Absorbance is calibrated to zero with buffer and the absorbance of the protein solution measured. The wavelength is adjusted to 260nm and absorbance calibrated to zero with buffer. The absorbance of the protein solution is measured.

One vial with 5mg of BSA is taken and 1mL of distilled water added (5mg/mL), 0.2mL is pipetted out into an Eppendorf tube and 0.8mL of distilled water added (1mg/mL) (Working standard). Standards can be prepared by taking 20, 40, 60, 80, 100L of BSA working standard in test tubes and made to 200L with distilled water. Two mL of Bradford reagent is added to all including test solutions and thoroughly mixed. After 10min, readings are measured at 595nm.

4 % Phenol: Conc. H2SO4, stock standard solution: 100mg of glucose was dissolved in 100mL of double-distilled water (100g/0.1mL). Working standard solution: 10mL of stock solution was made to 100mL with double-distilled water (10g/0.1mL).

Standards are prepared by taking 20, 40, 60, 80, 100L of glucose working standard in test tubes and made to 1mL with double-distilled water. To all the tubes including unknowns, 2mL of 4% phenol and 5mL of concentrated sulfuric acid are added and mixed thoroughly. Readings are taken at 490nm.

Coal is a sedimentary rock that occurs in seams bounded by layers of rock. The generation of waste is unavoidable during coal extraction and beneficiation. Mine waste or spoils are materials that are moved from its in situ location during the mining process but are not processed to obtain the final product. Dealing with mine waste is a major part of surface mining methods, where all of the rock above the coal seam (overburden and sometimes interburden) must be removed to expose the coal seam. This is done in a systematic fashion of digging pits with most of the overburden waste being cast from above the coal to be extracted into an adjacent pit from which the coal has already been extracted. Minimizing the handling of overburden waste is one of the keys to economic success in surface coal mining. Various techniques, such as cast blasting, are used to achieve this objective.

If underground mining methods are used, the amount of out-of-seam material handled is much less than in surface mining, and minimizing that amount has multiple economic benefits as discussed in Chapter 11. When large amounts of out-of-seam material have to be removed for underground infrastructure such as ventilation overcasts and undercasts and conveyor belt transfer points, it can be gobbed or left underground in untraveled mine openings. However, most of the out-of-seam material extracted in underground mines is mixed with the coal and constitutes part of the run-of-mine (ROM) or raw coal product.

Because modern mechanized mining equipment does not distinguish between the coal seam and layers of rock that encapsulate it and because complete or full extraction of a mineable coal seam is generally the objective of any coal-mining operation, there will always be some level of out-of-seam dilution in the ROM product. In most cases, out-of-seam material extracted with the coal must be separated from the coal before shipment to satisfy customer quality requirements. This is accomplished with coal preparation plants that generate a clean coal product and a waste material referred to as coal refuse. Coal preparation plants utilize various mineral processing technologies that, with few exceptions, are slurry-based and involve the use of substantial quantities of water [1]. The efficiency of these processing systems depends on the size of material being treated. Hence, raw coal must be classified into different size fractions leading to two coal refuse products on the output side: (1) coarse coal processing waste (CCPW) and (2) fine coal processing waste (FCPW). Generally, CCPW is material larger than 150m (100 mesh) in size [2]. CCPW includes reject streams from jigs, heavy media vessels, and heavy media cyclones. FCPW includes reject streams from spirals, flotation columns and cells, desliming cyclones, and effluent streams of filter presses, screenbowl centrifuges, and other dewatering equipment. All FCPW streams are typically concentrated in a thickener whose output is a waste slurry.

Most extraction and beneficiation wastes from coal mining (i.e., mine spoils and coal refuse) are categorized as special wastes that are exempted from regulation by hazardous waste rules and laws (e.g., Subtitle C of the US Resource Conservation and Recovery Act). However, coal utilization generates another type of waste known as coal combustion residuals (CCRs), which are regulated to some degree (e.g., Subtitle D of the US Resource Conservation and Recovery Act). CCRs are categorized into four groups based on physical and/or chemical forms that derive from the combustion method and the emission control system used. A brief description of each group follows [3]:

Bottom ash is a coarse, angular, gritty material with similar chemical composition to fly ash. It is too large to be carried up by the smokestack, so it collects in the bottom of the coal furnace. It comprises 12% of all CCRs.

Boiler slag is molten bottom ash that forms into pellets in the bottom of slag tap and cyclone type furnaces. It has a smooth glassy appearance after it is cooled with water. Boiler slag comprises 4% of all CCRs.

Flue gas desulfurization (FGD) material is residue from the sulfur dioxide emission scrubbing process. It can be a wet sludge consisting of calcium sulfite or calcium sulfate, or it can be a dry powdery material that is a mixture of sulfites and sulfates. FGD material comprises 24% of all CCRs.

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).

Commercial coal cleaning or beneficiation facilities are physical cleaning techniques to reduce the mineral matter and pyretic sulfur content. As a result, the product coal has a higher energy density and less variability (compared with feedstock coal) so that power plant efficiency and reliability are improved. A side benefit to these processes is that emissions of sulfur dioxide and other pollutants including mercury can be reduced. The efficiency of this removal depends on the cleaning process used, the type of coal, and the contaminant content of coal. Basic physical coal cleaning techniques have been commercial for over 50 years. The cleaning of coal takes place in water, in a dense medium, or in a dry medium.

Physical cleaning processes are based on either the specific gravity or the surface property differences between the coal and its impurities. Jigs, concentration tables, hydrocyclones, and froth flotation cells are common devices used in current physical coal cleaning facilities.

The removal efficiency ranged from 0% to 60% with 21% as average reduction. This efficiency is highly dependent on the type of coal and chloride content of the coal. Concerning other fuels, the cleaning of crude oil occurs mostly through the residue desulfurization (RDS). However, the content of Hg in crude oil is usually very low, and RDS is an inefficient method to even lower this content.

life cycle analysis of copper-gold-lead-silver-zinc beneficiation process - sciencedirect

life cycle analysis of copper-gold-lead-silver-zinc beneficiation process - sciencedirect

Life cycle assessment of gold-silver-lead-zinc-copper beneficiation is carried out.LCA is conducted through SimaPro software using ILCD, IMPACT 2002+, and CED method.Gold-silver beneficiation are higher impact as compared to lead-zinc.Notable impact categories are ionising radiation, acidification, eutrophication, and human health.Electricity and fossil fuel consumption are the dominant factors causing the impacts.

Gold, silver, lead, zinc, and copper are valuable non-ferrous metals that paved the way for modern civilisation. However, the environmental impacts from their beneficiation stage was always overlooked. This paper analysed the life cycle environmental impacts from the beneficiation process of gold-silver-lead-zinc-copper combined production. The analysis is conducted by utilising the SimaPro software version 8.5. The life cycle assessment methodologies followed are the International Reference Life Cycle Data System (ILCD) method, the IMPACT 2002+ method, and the Cumulative Energy Demand Method (CED). The most significant impact categories are ecotoxicity, climate change, human toxicity, eutrophication, acidification, and ozone depletion among nearly 15 impact categories which are assessed in this study. The analysis results from the ILCD method indicate that there is a noteworthy impact on ionising radiation caused by the beneficiation process. Out of the five metals considered, gold and silver beneficiation impacts the most while leadzinc beneficiation impacts the least. Gold beneficiation has most impacts on the category of climate change and ecosystems. Other major impact categories are ionising radiation, terrestrial eutrophication, photochemical ozone formation, human toxicity, and acidification. The IMPACT 2002+ method shows the overall impact is on ecosystem quality and human health from this combined beneficiation process, dominantly from goldsilver beneficiation. The life-cycle inventory results show that the blasting process and the amount of electricity consumption in the beneficiation process contribute to cause significant amount of environmental impacts. The comparative impact results are presented and discussed in detail in this paper. Sensitivity analyses are presented based on various electricity grid-mix scenarios and energy-mix scenarios, and the results suggest that electricity grid mix has a dominant effect over the fossil-fuel mix. This paper also highlights the potential steps which could cut down the environmental effects by integrating renewable-energy technologies.

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