extraction iron grinding

extraction of iron from limonite - xinhai

extraction of iron from limonite - xinhai

The current international situation makes more and more people focus on iron ore. The common iron ores include magnetite, hematite, limonite and siderite. Among them, as typical refractory iron ore, limonite has the characteristics of easy-to-sliming, poor separation index, etc, but it still is a favorable backing to solve the shortage of iron mineral resources due to its abundant reserves. The common process used in the extraction of iron from limonite mainly includes a single separation process and joint separation process.

The common single separation processes used in the extraction of iron from limonite mainly include the gravity separation process, magnetic separation process and flotation process (positive flotation process and reverse flotation process).

The gravity separation is to extract the iron from limonite based on gravity. As the main process used in the extraction of iron from limonite, the gravity separation process is often used to deal with coarse grain ore in most cases.

In order to further improve the concentrate quality, most limonite concentrators usually use the washing-gravity separation process for the extraction of iron from limonite. That is, use the cylindrical screen washer, groove ore washer and scrubbing machine to wash the ore, then use the dense media separator, jigging and other gravity separators, which is mostly used for extraction of iron from limonite and pseudohematite. The process has the advantages of simple gravity separator, low cost and less power consumption, while it also the disadvantages of low recovery rate and high tailings grade, which is not conducive to the comprehensive recovery of resources.

Limonite stone containing the iron, so they are magnetic. The different iron content in the limonite also makes their magnetism different. Therefore, we can make use of the magnetic differences to the extraction of iron from limonite. Generally, the strong magnetic separation process is often used for the extraction of iron from limonite, but the recovery rate of this process is poor for the fine-grained limonite (-20 um).

The single flotation process has a good recovery effect for fine iron ore, but the flotation effect is seriously affected because limonite is easy to be sliming. So, it is very important to consider desliming or strengthening dispersed slime before flotation. Because the fine particle size is difficult to adhere to the bubble surface, a separate mineralized foam layer emerges, and easy to adhere to the coarse surface. When gangue mud was attached to the surface of coarse limonite, its selectivity and floatability decreased significantly. Slime than the surface and surface energy (activity) are large, one is adsorption (consumption) a large number of flotation agents, resulting in slurry oil drugs, viscous, reduce the selectivity and flotability of floating ore; The second is the strong hydration ability, once the slime adheres to the bubble, the hydration film on the bubble surface is not easy to remove, thus bringing serious difficulties to the concentration and filtration of the concentrate, resulting in the decrease of recovery rate.

The flotation process used in the extraction of iron from limonite can adopt positive flotation or reverse flotation process. Research and practice show that the reverse flotation is more suitable for the removal of quality and impurity of limonite. In addition, the limonite has the loose crystal particle and large specific surface area, which can absorb and consume a lot of flotation reagents, so the flotation process used in the extraction of iron from limonite need to adopt multistage dosing and multistage separation flow.

General, the extraction of iron from limonite can adopt gravity separation-strong magnetic separation process to obtain the good effect, that is, the limonite is sent to washing after the fine crushing or rod mill, then sent to screening, classifying and desliming process, the coarse grain is processed by gravity separation process to obtain concentrate, the intermediate grade adopts roller-type magnetic separator to obtain concentrate, the fine grain and slime adopt the high gradient magnetic separator to obtain concentrate.

In order to improve the recovery rate of iron metal, regrinding and reprocessing can be considered during the gravity separation process, which can obviously improve the iron grade of the concentrate, and obtain the high recovery rate because the iron ore in the fine grain and sludge is also recovered.

When the grinding fineness reaches a certain value, adding the sodium carbonate and sodium silicate in the grinding process, making the pulp achieve the good dispersion, so adopting the selective flocculation process can make the limonite flocculate selectively. But sometimes a single flocculation process is still difficult to improve the grade of limonite concentrate because a large number of coarse-grain of gangue minerals are failed to remove. Therefore, the selective flocculation-flotation process can obtain a better mineral processing index.

For low-grade and fine-grain embedded limonite, only the fine grinding can obtain the high-grade iron concentrate, but sliming phenomenon also occurs at the same time, resulting in a low recovery rate. In this case, adopting the flocculation-strong magnetic separation process can deal with the low-grade and fine-grain embedded limonite.

It is shown that the flocculation-strong magnetic separation process improves the iron recovery by 10.97-15.73% compared with the direct magnetic separation process under a similar grade of iron concentrate. The fine iron ore that lost in the strong magnetic separation process is recovered by selective flocculation because its apparent size is increased. Therefore, the flocculation-strong magnetic separation process can be used for fine-grade limonite, but it is important to control the slurry dispersion, selective flocculation process and separation conditions of the strong magnetic separator (mainly the feeding way and the volume of flushing water).

The limonite has the special output structure, and it is easy to produce mud in the grinding process, which leads to the difficulty in the extraction of iron from limonite, and the gangue mineral composition of limonite varies greatly. In view of the particularity of limonite, the composition types of main iron ore and gangue minerals in limonite shall be determined through ore dressing test, and the suitable processes used in the extraction of iron from limonite shall be formulated accordingly.

dust collection for cast iron dust

dust collection for cast iron dust

Styles come and go, but the use of cast iron in the construction business remains steady. Whether its for home, office or institutional uses, this material is used widely. Working with this metal, however, carries certain risks. As any metalworking operation understands, measures must be taken to protect workers.

Many methods exist to improve air quality in metalworking facilities. These measures yield many benefitsthey protect workers, safeguard equipment and ensure regulatory compliance. Fortunately, these solutions are affordable and easy to implement.

The Occupational Safety and Health Administration (OSHA) regulates metallic dusts and fumes with a special vigor due to their particular dangers to workers. While cast iron grinding involves far less toxicity than other metalworking processes, it is still crucial for employers to protect workers. Exposure to iron oxide, a substance sometimes encountered in cast iron grinding, is a danger, as well. This substance has been associated with cases of pulmonary siderosis, an occupational lung disease.

Iron dust is also listed by OSHA as a combustible dust. Cast iron grinding facilities must be aware of dust accumulating in a confined space. These particulates, combined in just the right proportion with oxygen in such a space, pose an ignition risk. Dust explosions can be highly destructive and can cause injury or death to workers.

Most dust concerns involved with cast iron grinding will fall under OSHAs total dust limit of 15 mg/m3. This permissible exposure limit (PEL) is a cap on a workers exposure as averaged over an 8-hour shift. The PEL for iron oxide is more strict. Workers are only allowed 10 mg/m3 during the course of a shift.

RoboVents dust collectors are unsurpassed in their effectiveness and ease of use. Our engineers have almost three decades of experience treating dusts of all kinds. RoboVents line of portable dust collectors are well suited for single grinding stations. These collectors can be outfitted with arms or hoods to capture dust at its source, protecting workers and those around them. For facility-wide solutions, RoboVents systems like the Senturion Series provide power and efficiency to clean the air while keeping costs under control.

These dust control solutions do more than just improve livesthey are crucial tools for protecting facilities and complying with safety regulations. RoboVent is passionate about its role in industry and in leading the way in air quality solutions. We offer the best service in the business, as well as the best warranties available.

We dont just sell air filtration equipmentwe design and manufacture innovative, high-performance dust collectors, fume extractors and ventilation equipment for practically any application. From source capture of weld fumes and industrial dust to ambient air filtration systems, our clean solutions are effective, efficient, and flexible to suit a variety of applications.

We manufacture facility-wide industrial air filtration systems, source capture solutions for robotic welding cells, specialized dust collection equipment for plasma and laser cutting, and portable source capture systems for manual welding, cutting and grinding. Let us match you with a RoboVent dust collector that meets your needs.

We have installation crews across the country hired, trained and certified by RoboVent. You will work with an assigned project manager to ensure everything runs smoothly and with minimal disruption to your operations. Prefer to do it on your own? Well make sure you have expert guidance, instruction and support. Ask us about your installation options.

Whether you want us to handle all monthly preventive maintenance for you or simply need regular equipment checks to make sure everything is in top condition, we can help you find a service package that meets your needs.

We offer three levels of ClientCare service. Our service packages let you leverage our expertise so you can reduce the burden on your maintenance staff, control your maintenance budget, and stay focused on your core business.

Need to get something out of the air? We can filter that. We manufacture top-of-the-line cartridge-style dust collector filters such as PleatLock and Endurex. PleatLock filters contain 35% more filter media for longer life and savings with excellent sub-micron efficiency. Reliable, economical Endurex filters are used by thousands of manufacturers today.

Find filters for all types and brands of equipment and practically any application. We have the right filters for weld fume, metalworking dust, abrasive blasting, plastics, fiberglass, silica, pharmaceutical production, chemical manufacturing and other processes. Plus, find baghouse and spray booth filters, oil mist filters, and specialty filters for odor control, HVAC and more from our Rensa Filtration sister companies. Ask us which filtration technologies are right for you!

We can help you select the right equipment for your needs or design a total air quality solution that is cost-effective, energy-efficient. Our engineering teams will work with you to define your goals, select and conduct the right kinds of testing for your facility, and design a system that meets all of your air quality goals.

Our testing services include IAQ evaluation, Dust Hazard Analysis (DHA), OSHA compliance testing, combustible dust testing and our comprehensive VentMapping service for complex needs. Learn more about our testing and system design services.

extraction systems for grinding & polishing|esta extraction technology

extraction systems for grinding & polishing|esta extraction technology

Fine dust emissions arise during grinding and polishing of surfaces (e.g. Metals or plastics). Their harmful, often toxic effects make working with these substances a problem for industry. The capture and filtering of these dusts by extraction systems is designed to protect the health of employees for one, secondly they maintain the cleanliness of production halls and machines.

fine fiberglass dust collection, grinding dust extractors & collectors

fine fiberglass dust collection, grinding dust extractors & collectors

When it comes to material processing, dust can be a concern not only for the comfort and safety of workers involved, but also for the integrity of the end product. Ambient dust can contaminate product supply, reduce efficiencies across processes and lessen the lifespan of critical equipment.

When it comes to fiberglass fine grinding, dust collection and extraction is a necessary component to any manufacturing facilityand can be one that does not have to be overwhelming or high maintenance. The ultra-fine particulates that come from fiberglass fine grinding cause problems for both workers and equipment if left unchecked.

Anyone who has insulated his or her home can understand why exposure to fiberglass needs to be limited. Respiratory concerns, as well as the irritation it can cause with contact to the skin, are just the beginning of risks that come with exposure to fiberglass dust.

With limited exposure, a worker can experience coughing, wheezing and asthma-like symptoms, and with prolonged exposure, bronchitis and even the potential for cancer. With risks like these, it is in an employers best interest to curb fiberglass dust accumulation. Doing so will protect workers and increase plant efficiency, since healthy workers are more productive.

Fiberglass dust also creates a fine powder which can find its way into delicate electronics or mechanics, thus compromising facility equipment and increasing maintenance costs across machinery. Equipment downtime is a manufacturers worst nightmare and can create compounded inefficiencies down the line.

Though the threat for exposure-related cancer is real, it has not been unequivocally confirmed through any study to date. Because of this, the Occupational Safety and Health Administration (OSHA) classifies fiberglass dust as an irritant.

Increase the efficiency of your manufacturing facility with an accurate and powerful dust-collection and extraction system. The right ventilation or filtration system will positively impact your processes on a product level as well as an employee level. RoboVent has both, ambient dust collection options for whole-facility air control, or source collection systems to achieve a more targeted solution.

We can also create a custom design that can handle your fiberglass dust-collection challenge, while still giving your budget the attention it deserves. And with our exclusive VentMapping system, we can target every problem area in your facility for the most cost-effective, clean-air solution.

Clean air improves worker health and minimizes contamination of source materials which could otherwise add up to tens of thousands of dollars per year in prevention. By installing a RoboVent dust-collection system, you can increase efficiencies without sacrificing your equipment budget.

We dont just sell air filtration equipmentwe design and manufacture innovative, high-performance dust collectors, fume extractors and ventilation equipment for practically any application. From source capture of weld fumes and industrial dust to ambient air filtration systems, our clean solutions are effective, efficient, and flexible to suit a variety of applications.

We manufacture facility-wide industrial air filtration systems, source capture solutions for robotic welding cells, specialized dust collection equipment for plasma and laser cutting, and portable source capture systems for manual welding, cutting and grinding. Let us match you with a RoboVent dust collector that meets your needs.

We have installation crews across the country hired, trained and certified by RoboVent. You will work with an assigned project manager to ensure everything runs smoothly and with minimal disruption to your operations. Prefer to do it on your own? Well make sure you have expert guidance, instruction and support. Ask us about your installation options.

Whether you want us to handle all monthly preventive maintenance for you or simply need regular equipment checks to make sure everything is in top condition, we can help you find a service package that meets your needs.

We offer three levels of ClientCare service. Our service packages let you leverage our expertise so you can reduce the burden on your maintenance staff, control your maintenance budget, and stay focused on your core business.

Need to get something out of the air? We can filter that. We manufacture top-of-the-line cartridge-style dust collector filters such as PleatLock and Endurex. PleatLock filters contain 35% more filter media for longer life and savings with excellent sub-micron efficiency. Reliable, economical Endurex filters are used by thousands of manufacturers today.

Find filters for all types and brands of equipment and practically any application. We have the right filters for weld fume, metalworking dust, abrasive blasting, plastics, fiberglass, silica, pharmaceutical production, chemical manufacturing and other processes. Plus, find baghouse and spray booth filters, oil mist filters, and specialty filters for odor control, HVAC and more from our Rensa Filtration sister companies. Ask us which filtration technologies are right for you!

We can help you select the right equipment for your needs or design a total air quality solution that is cost-effective, energy-efficient. Our engineering teams will work with you to define your goals, select and conduct the right kinds of testing for your facility, and design a system that meets all of your air quality goals.

Our testing services include IAQ evaluation, Dust Hazard Analysis (DHA), OSHA compliance testing, combustible dust testing and our comprehensive VentMapping service for complex needs. Learn more about our testing and system design services.

extraction of iron, iron mining, iron ore processing

extraction of iron, iron mining, iron ore processing

As one of the earliest, most widely used metals in the world, iron ore is an important raw material for iron and steel production. At present, iron ore resources are decreasing day by day, which is characterized by more lean ore than rich ore, more associated ore and complex ore composition. Xinhai Mining, as a mineral processing equipment manufacturer with over-20-year experience, provides responsible iron ore processing technologies by different type of iron ores.

Because of the strong magnetism of magnetite, the extraction of iron from magnetite is weak magnetic separation technology. The magnetite iron ore processing maninly includes:

It is suitable for the extraction of iron from simple single magnetite. It can be divided into successive-grinding weak magnetic separation process and stage-grinding weak magnetic separation process. Successive-grinding weak magnetic separation process is suitable for extraction of iron from magnetite with coarse grain or high grade iron. Stage-grinding weak magnetic separation process is suitable for extraction of iron from low grade magnetite with fine grain.

It mainly points at the extraction of iron ores which are difficult to increase its fineness or with many SiO2 impurities. It includes weak magnetic-cation anti-flotation separation process and magnetic-positive anion flotation separation process.

Hematite is weak magnetic ore, which can be easier separation by flotation than magnetite. In the old days, hematite was separated by gravity separation, however it was weed out for unreachable capacity. Now Hematite iron ore processing is as follows:

Commonly, weak magnetic separation can be added before strong magnetic separation to remove the strong magnetic ore or impurity in raw ore. Then strong magnetic separation is used to separating hematite, which is also the work flow of the mixture of magnetite and hematite.

Hematite is easier to floated than magnetic, which could be separated by positive flotation. As the density of iron ore is much higher than that of gangue mineral, gangue mineral is more likely to attach to the foam than iron ore. Therefore, for the extraction of iron ore, reverse flotation is more advantageous than positive flotation. When the magnetite content mixed in hematite is higher, reverse flotation is a more convenient method for the extraction of iron ore.

In the process of high intensity magnetic-flotation, a part of gangue mineral in the ore is firstly removed by high intensity magnetic separation, and then the coarse concentration of high intensity magnetic separation is sent to the flotation to obtain the final qualified concentrate.

Limonite is one of the main type of iron ores, but its iron content is lower than magnetite and hematite, and it is a secondary iron ore. At present, the industrial application of limonite iron ore processing includes:

The single separation process of lignite is mainly used for the lignite with high iron content and good selectivity, which can be divided into a single magnetic separation process and a single gravity separation process. The single gravity separation process is used to deal with the extraction of iron ore with coarser grain size, and the equipment is selected according to the grain size of the ore. Single magnetic separation process generally refers to a single strong magnetic separation process, this process has a strong adaptability to the ore, the concentrate is easy to concentrate and filter, but it is not suitable for fine grade slime.

The combined iron ore processing technology only used for limonite, includes magnetization - magnetic separation process, flotation - strong magnetic separation process, gravity separation - strong magnetic separation process, etc., which are used for the extraction of iron from limonite with relatively complex composition. The specific iron ore processing technology shall be determined after the mineral processing test has proved the ore properties.

Like limonite, siderite is a low-grade iron ore that is unstable. The iron ore processing technology used in siderite concentrator are gravity separation and strong magnetic separation. Different siderite has different iron ore processing methods. The extraction of iron from single siderite with coarse grain size is suitable to be treated with single gravity separation, single strong magnetic separation and combined process including two kinds of iron ore processing technologies. For the extraction of iron from siderite with fine grain size, effective extraction of iron include roasting magnetic separation, strong magnetic separation, flotation or magnetic flotation combined process.

Siderite containing magnetite can be separated by a combined iron ore processing method of weak magnetic separation and gravity separation, strong magnetic separation, or flotation in series, or a more complex iron ore processing method.

Iron ore processing capacity is huge, iron ore tailings account for about half of the total metal tailings, in recent years due to the increasing awareness of environmental protection and tailings accidents, whether from the perspective of comprehensive utilization of resources or from the perspective of environmental protection and safety, iron ore tailings treatment is a problem that needs attention.

To avoid resource waste and tailings accidents at the source, the main treatment methods of iron ore tailings at present are: tailings reprocessing, tailings dry stacking and full tailings consolidation and filling method.

Stage grinding(2 stages) + stage separation(6 stages magnetic separation) + iron concentrate dewatering + tailings magnetic and gravity separation + grinding + flotation separation of sulfur and titanium.

One stage grinding + two-block classification + close-circuit grinding + four-block magnetic separation + concentrate dewatering + tailings dewatering

Weak magnetic separation: two-and-half-block close circuit crushing and screening + one stage pre-magnetic separation for tail tossing + one stage close circuit grinding + two-block weak magnetic separation

Xinhai Mining has set up a mine design institute and a mine research institute, with an experienced team of experts, and has applied for many patents (some invention patents are under examination and approval). The technical indexes of mineral processing are guaranteed.

Till now, Xinhai Mining has accomplished over 2000 mine design, research and equipment supplying projects. Among them, there are over 500 mineral processing EPC+M+O projects. Xinhai Mining has technologies and experiences for over 70 kinds of ores.

Pointed at different problem during mine construction, Xinhai Mining put forward mineral processing EPC+M+O service, supplying close-circuit service from mineral processing test and mine design, equipment manufacturing and purchasing, reaching standard and production, to mine management and operation.

solvent extraction of iron

solvent extraction of iron

As indicated by equation (1) the extraction will be dependent of the pH of the aqueous phase. The distribution curves for different metals in carboxylic acids have been investigated and reported at length over the years. The extraction curves for some common metals with the Versatic 10 system are shown in Figure 1. As can be seen, the curves for zinc and ferric iron are far apart, and a very efficient separation of the two metals is thus to be expected.

Although the use of carboxylic acids as extracting agents for metals has been known for many years, they have not been applied much in commercial processes so far. The reason for this is mainly to be found in the extracting reaction itself. It will be seen that the extraction of the metal ions liberates an equivalent amount of protons from the organic acid. To obtain an efficient extraction of metal ions from the aqueous phase, an equivalent amount of alkali has thus to be added to neutralize the acid proton formed.

However, this type of extraction has one drawback in common with precipitation in requiring the addition of base (ammonia or caustic for example) in an amount sufficient to neutralize any free acid present initially, and to permit extraction of the metal ion of interest, and all metal ions preceding it in the extraction series. This means that in order to extract for instance copper, every other metal ion preceding copper in the extraction series has to be removed either by precipitation, which however, is undesirable because of co-precipitation losses, or by extraction. In any case one molecule of caustic is consumed per valency of the iron removed. In the case of trivalent iron which is invariably present in copper leach liquors this means a considerable caustic consumption, which has been shown by calculation to make carboxylic acid extraction often economically unattractive for this type of separation.

In the process presented in this paper, it will be shown, in contrast with the above quotation, that there will be no need for the addition of any external alkali, in order to extract ferric iron into the organic phase. The process makes use of the alkaline property of the calcine material itself by starting the process with organic leaching, i.e. leaching zinc oxide with the organic carboxylic acid RH.

Having formed the Versatic zinc salt of the organic acid, it will be seen that according to the distribution curves in Figure 1, the extraction of ferric iron may take place by the ion exchange reaction:

Thus by reactions (2) and (3) zinc will be brought from the calcine material into an aqueous sulphate solution via the dissolution of zinc oxide in the organic phase. By the same overall operation iron has simultaneously been removed from the aqueous sulphate solution and extracted into the organic phase as a ferric organic salt. The crucial point and net result of this combined operation of leaching and solvent extraction is that no addition and thus no cost of alkali, has been necessary to have the iron extracted into the organic phase.

The use of the exchange reaction, Equation (3), for removing ferric iron from zinc sulphate liquors was demonstrated already by Fletcher and Fleet. Their conclusion was, however, along the same lines as the above quotation from Spitzer. Thus it is concluded by Fletcher and Flett that A major factor in the economics of the use of carboxylic acids for the recovery of metals by solvent extraction is not the solvent loss but the amount of alkali required. Thus for divalent metals two moles of alkali are required for every mole of metal extracted. Indeed, the presented calculations showed that the alkali cost was more than forty times greater than the cost for solvent make-up.

Further results on the use of the zinc salt of Versatic acid for the removal of iron zinc calcine leach solutions has recently been published by Van der Zeeuw. The results obtained confirm the excellent properties of Versatic acid for the extraction of iron. The fate of some of the other contaminants such as cobalt, copper, arsenic, antimony and germanium is also discussed with the conclusion that these elements are not likely to cause any serious problem. The last quantities if iron are suggested to be precipitated as hydroxide in order to remove the undesirable contaminants by co-precipitation.

The conceptual flowsheet in Figure 2 shows how the process for extracting iron by a carboxylic acid is integrated into the hydrometallurgical processing of zinc. The neutral leach and the hot acid leach will basically be the same as in the conventional Jarosite and Goethite processes. By replacing the precipitation steps for jarosite or goethite, the iron extraction will be brought about by the following operations: the organic leach, solvent extraction of iron, and the stripping of iron from the organic phase.

In the organic leach step enough zinc salt of the organic acid has to be produced in order to 1) neutralize the free sulphuric acid in the hot acid leach and 2) extract iron by the exchange reaction (3) at pH 2-3. Before the exchange reaction between zinc and ferric iron is taking place, the free sulphuric acid will be neutralized by the organic zinc salt:

The iron concentration in the hot acid leach solution will be reduced from some 10-25 g/l Fe to 0.5-1 g/l Fe. The iron may be removed quantitatively if necessary, but it is most likely of advantage to leave a small amount for precipitation as ferric hydroxide due to its scavenging effect on trace metals impurities.

Stripping of iron from the organic phase may be done by a mineral acid or by hydrolytic stripping which will be explained in detail later. The iron product, which may be completely free from zinc and other impurities, will be an iron salt or iron oxide, depending on the stripping procedure.

iron ore processing,crushing,grinding plant machine desgin&for sale | prominer (shanghai) mining technology co.,ltd

iron ore processing,crushing,grinding plant machine desgin&for sale | prominer (shanghai) mining technology co.,ltd

After crushing, grinding, magnetic separation, flotation, and gravity separation, etc., iron is gradually selected from the natural iron ore. The beneficiation process should be as efficient and simple as possible, such as the development of energy-saving equipment, and the best possible results with the most suitable process. In the iron ore beneficiation factory, the equipment investment, production cost, power consumption and steel consumption of crushing and grinding operations often account for the largest proportion. Therefore, the calculation and selection of crushing and grinding equipment and the quality of operation management are to a large extent determine the economic benefits of the beneficiation factory.

There are many types of iron ore, but mainly magnetite (Fe3O4) and hematite (Fe2O3) are used for iron production because magnetite and hematite have higher content of iron and easy to be upgraded to high grade for steel factories.

Due to the deformation of the geological properties, there would be some changes of the characteristics of the raw ore and sometimes magnetite, hematite, limonite as well as other types iron ore and veins are in symbiosis form. So mineralogy study on the forms, characteristics as well as liberation size are necessary before getting into the study of beneficiation technology.

1. Magnetite ore stage grinding-magnetic separation process The stage grinding-magnetic separation process mainly utilizes the characteristics of magnetite that can be enriched under coarse grinding conditions, and at the same time, it can discharge the characteristics of single gangue, reducing the amount of grinding in the next stage. In the process of continuous development and improvement, the process adopts high-efficiency magnetic separation equipment to achieve energy saving and consumption reduction. At present, almost all magnetic separation plants in China use a large-diameter (medium 1 050 mm, medium 1 200 mm, medium 1 500 mm, etc.) permanent magnet magnetic separator to carry out the stage tailing removing process after one stage grinding. The characteristic of permanent magnet large-diameter magnetic separator is that it can effectively separate 3~0mm or 6~0mm, or even 10-0mm coarse-grained magnetite ore, and the yield of removed tails is generally 30.00%~50.00%. The grade is below 8.00%, which creates good conditions for the magnetic separation plant to save energy and increase production.

2.Magnetic separation-fine screen process Gangue conjoined bodies such as magnetite and quartz can be enriched when the particle size and magnetic properties reach a certain range. However, it is easy to form a coarse concatenated mixture in the iron concentrate, which reduces the grade of the iron concentrate. This kind of concentrate is sieved by a fine sieve with corresponding sieve holes, and high-quality iron concentrate can be obtained under the sieve.

There are two methods for gravity separation of hematite. One is coarse-grained gravity separation. The geological grade of the ore deposit is relatively high (about 50%), but the ore body is thinner or has more interlayers. The waste rock is mixed in during mining to dilute the ore. For this kind of ore, only crushing and no-grinding can be used so coarse-grained tailings are discarded through re-election to recover the geological grade.

The other one is fine-grain gravity separation, which mostly deals with the hematite with finer grain size and high magnetic content. After crushing, the ore is ground to separate the mineral monomers, and the fine-grained high-grade concentrate is obtained by gravity separation. However, since most of the weak magnetic iron ore concentrates with strong magnetic separation are not high in grade, and the unit processing capacity of the gravity separation process is relatively low, the combined process of strong magnetic separation and gravity separation is often used, that is, the strong magnetic separation process is used to discard a large amount of unqualified tailings, and then use the gravity separation process to further process the strong magnetic concentrate to improve the concentrate grade.

Due to the complexity, large-scale mixed iron ore and hematite ore adopt stage grinding or continuous grinding, coarse subdivision separation, gravity separation-weak magnetic separation-high gradient magnetic separation-anion reverse flotation process. The characteristics of such process are as follows:

(1) Coarse subdivision separation: For the coarse part, use gravity separation to take out most of the coarse-grained iron concentrate after a stage of grinding. The SLon type high gradient medium magnetic machine removes part of the tailings; the fine part uses the SLon type high gradient strong magnetic separator to further remove the tailings and mud to create good operating conditions for reverse flotation. Due to the superior performance of the SLon-type high-gradient magnetic separator, a higher recovery rate in the whole process is ensured, and the reverse flotation guarantees a higher fine-grained concentrate grade.

(2) A reasonable process for narrow-level selection is realized. In the process of mineral separation, the degree of separation of minerals is not only related to the characteristics of the mineral itself, but also to the specific surface area of the mineral particles. This effect is more prominent in the flotation process. Because in the flotation process, the minimum value of the force between the flotation agent and the mineral and the agent and the bubble is related to the specific surface area of the mineral, and the ratio of the agent to the mineral action area. This makes the factors double affecting the floatability of minerals easily causing minerals with a large specific surface area and relatively difficult to float and minerals with a small specific surface area and relatively easy to float have relatively consistent floatability, and sometimes the former has even better floatability. The realization of the narrow-level beneficiation process can prevent the occurrence of the above-mentioned phenomenon that easily leads to the chaos of the flotation process to a large extent, and improve the beneficiation efficiency.

(3) The combined application of high-gradient strong magnetic separation and anion reverse flotation process achieves the best combination of processes. At present, the weak magnetic iron ore beneficiation plants in China all adopt high-gradient strong magnetic separation-anion reverse flotation process in their technological process. This combination is particularly effective in the beneficiation of weak magnetic iron ore. For high-gradient strong magnetic separation, the effect of improving the grade of concentrate is not obvious. However, it is very effective to rely on high-gradient and strong magnetic separation to provide ideal raw materials for reverse flotation. At the same time, anion reverse flotation is affected by its own process characteristics and is particularly effective for the separation of fine-grained and relatively high-grade materials. The advantages of high-gradient strong magnetic separation and anion reverse flotation technology complement each other, and realize the delicate combination of the beneficiation process.

The key technology innovation of the integrated dry grinding and magnetic separation system is to "replace ball mill grinding with HPGR grinding", and the target is to reduce the cost of ball mill grinding and wet magnetic separation.

HPGRs orhigh-pressure grinding rollshave made broad advances into mining industries. The technology is now widely viewed as a primary milling alternative, and there are several large installations commissioned in recent years. After these developments, anHPGRsbased circuit configuration would often be the base case for certain ore types, such as very hard, abrasive ores.

The wear on a rolls surface is a function of the ores abrasivity. Increasing roll speed or pressure increases wear with a given material. Studs allowing the formation of an autogenous wear layer, edge blocks, and cheek plates. Development in these areas continues, with examples including profiling of stud hardness to minimize the bathtub effect (wear of the center of the rolls more rapidly than the outer areas), low-profile edge blocks for installation on worn tires, and improvements in both design and wear materials for cheek plates.

With Strip Surface, HPGRs improve observed downstream comminution efficiency. This is attributable to both increased fines generation, but also due to what appears to be weakening of the ore which many researchers attribute to micro-cracking.

As we tested , the average yield of 3mm-0 and 0.15mm-0 size fraction with Strip Surface was 78.3% and 46.2%, comparatively, the average yield of 3mm-0 and 0.3mm-0 with studs surface was 58.36% and 21.7%.

These intelligently engineered units are ideal for classifying coarser cuts ranging from 50 to 200 mesh. The feed material is dropped into the top of the classifier. It falls into a continuous feed curtain in front of the vanes, passing through low velocity air entering the side of the unit. The air flow direction is changed by the vanes from horizontal to angularly upward, resulting in separation and classification of the particulate. Coarse particles dropps directly to the product and fine particles are efficiently discharged through a valve beneath the unit. The micro fines are conveyed by air to a fabric filter for final recovery.

Air Magnetic Separation Cluster is a special equipment developed for dry magnetic separation of fine size (-3mm) and micro fine size(-0.1mm) magnetite. The air magnetic separation system can be combined according to the characteristic of magnetic minerals to achieve effective recovery of magnetite.

After rough grinding, adopt appropriate separation method, discard part of tailings and sort out part of qualified concentrate, and re-grind and re-separate the middling, is called stage grinding and stage separation process.

According to the characteristics of the raw ore, the use of stage grinding and stage separation technology is an effective measure for energy conservation in iron ore concentrators. At the coarser one-stage grinding fineness, high-efficiency beneficiation equipment is used to advance the tailings, which greatly reduces the processing volume of the second-stage grinding.

If the crystal grain size is relatively coarse, the stage grinding, stage magnetic separation-fine sieve self-circulation process is adopted. Generally, the product on the fine sieve is given to the second stage grinding and re-grinding. The process flow is relatively simple.

If the crystal grain size is too fine, the process of stage grinding, stage magnetic separation and fine sieve regrind is adopted. This process is the third stage of grinding and fine grinding after the products on the first and second stages of fine sieve are concentrated and magnetically separated. Then it is processed by magnetic separation and fine sieve, the process is relatively complicated.

At present, the operation of magnetic separation (including weak magnetic separation and strong magnetic separation) is one of the effective means of throwing tails in advance; anion reverse flotation and cation reverse flotation are one of the effective means to improve the grade of iron ore.

In particular, in the process of beneficiation, both of them basically take the selected feed minerals containing less gangue minerals as the sorting object, and both use the biggest difference in mineral selectivity, which makes the two in the whole process both play a good role in the process.

Based on the iron ore processing experience and necessary processing tests, Prominer can supply complete processing plant combined with various processing technologies, such as gravity separation, magnetic separation, flotation, etc., to improve the grade of TFe of the concentrate and get the best yield. Magnetic separation is commonly used for magnetite. Gravity separation is commonly used for hematite. Flotation is mainly used to process limonite and other kinds of iron ores

Through detailed mineralogy study and lab processing test, a most suitable processing plant parameters will be acquired. Based on those parameters Prominer can design a processing plant for mine owners and supply EPC services till the plant operating.

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.

influence of mechanical grinding on lithium insertion and extraction properties of iron silicide/silicon composites - sciencedirect

influence of mechanical grinding on lithium insertion and extraction properties of iron silicide/silicon composites - sciencedirect

Anode performances of iron silicide/Si composites were studied for Li-ion battery.We prepared the composites by mechanical grinding for mixture of ferrosilicon and Si.Crystal phase changed from FeSi to FeSi2 with increasing mechanical grinding time.Better performances were obtained for electrodes of the composites of FeSi2 and Si.

We prepared composite electrodes of iron silicide/Si by using mechanical grinding for mixtures of ferrosilicon and Si followed by gas-deposition, and investigated their electrochemical properties as Li-ion battery anode. With increasing the mechanical grinding time, the phase transformation from FeSi to FeSi2 took place more significantly, and the composite electrode showed better cycle stabilities. There was no remarkable difference in mechanical properties and electronic conductivity between FeSi and FeSi2. On the other hand, the FeSi2 electrode exhibited about three times larger capacities in comparison with the FeSi electrode. In addition, a result of our first principle calculation indicates that Li-ion can diffuse more easily in FeSi2 lattice than in FeSi lattice. It is suggested that the better cyclability of the composite electrodes was attributed to the moderate reactivity of FeSi2 with Li and the smooth Li-ion diffusion in it.

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