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iron ore mine processing process flotation process

treatment and recycling of the process water in iron ore flotation of yuanjiacun iron mine

treatment and recycling of the process water in iron ore flotation of yuanjiacun iron mine

Wen-li Jiang, Hai-feng Xu, "Treatment and Recycling of the Process Water in Iron Ore Flotation of Yuanjiacun Iron Mine", Journal of Chemistry, vol. 2017, Article ID 9187436, 8 pages, 2017. https://doi.org/10.1155/2017/9187436

Coagulating sedimentation and oxidation treatment of process water in iron ore flotation of Yuanjiacun iron mine had been studied. The process water of this mine carried residual polyacrylamide (PAM), poly(diallyldimethylammonium chloride) (PDADMAC), and Ca2+ from the flotation and caused decrease of the iron flotation recovery or grade of the concentrate. The studies on high-intensity magnetic separation (HIMS) tailings for coagulating sedimentation showed that the settling performance of coagulant (named CYH) was better than that of PDADMAC. The analyses of FTIR spectra and zeta potential demonstrated that CYH is adsorbed mainly through electrostatic attraction onto HIMS tailings. Sodium hypochlorite was adopted to oxidize the residual organics in tailings wastewater. When sodium hypochlorite is at the dosage of 1.0g/L, reaction temperature is of 20C, and reaction time is of 30 minutes, the removal rates of PAM, COD, and Ca2+ were 90.48%, 83.97%, and 85.00%, respectively. Bench-scale flotation studies on the treated tailings wastewater indicated that the iron recovery and grade of concentrate were close to those of freshwater.

Iron ore resources are extremely rich in China, but most of them belong to complex ultrafine iron ore with high content of impurities [1]. Reverse flotation has been proved to be an efficient process for economic reasons [26]. In order to ensure iron concentrate grade and iron recovery, a large number of processing reagents are selected and applied in the iron ore beneficiation. The process water carried plenty of residual processing reagents, and such wastewater with color depth and strong smell could seriously affect the environment and the local people. Prevailing campaign for a cleaner and safer environment with clean surface water and ground water has led to increased recycling of process water within the production cycle of mineral flotation [7]. Since the chemistry property of process water is entirely different from fresh water, there is a concern about the possible effects of the contained components on the efficiency of the flotation process [8]. In iron ore flotation process, a large amount of NaOH is taken to adjust the pH. The wastewater pH of iron ore is more than 9, so physicochemical treatment of iron wastewater from a certain degree is rather difficult [9]. At present, the common methods of treatment of wastewater from flotation are acid-alkali neutralization [10, 11], precipitation, coagulation, and sedimentation [1215], chemical oxidation degradation [16], constructed wetland [1719], ion exchange method [20], adsorption method [21, 22], and biological method [23, 24]. However, the single method above cannot completely clear wastewater pollution with harsh operating conditions. In addition, they may also produce secondary pollution.

Yuanjiacun iron mine of Shanxi province in China is the largest iron mine of micrograined hematite combined with magnetite in Asia. The annual processing capacity of iron ore reaches 22 million tons, and the wastewater from mineral processing is about 400 thousand m3 every day. If the dressing wastewater is directly discharged into the nature, it will not only pollute the surrounding environment but also has a great potential safety risk. Recycling of process water is a good way to solve the problem. In this study, the influence of tailings wastewater components were investigated on flotation of hematite in order to assess the practicability of recycling process water in flotation practice first. A novel coagulant CYH was introduced to coagulate HIMS tailings, and the coagulating sedimentation mechanism of CYH was investigated by FTIR spectra and zeta potential. Moreover, sodium hypochlorite was adopted to oxidize the organic pharmaceutical residues in wastewater. Besides, the effect of wastewater treatment was evaluated by recycling of tailings wastewater.

All test samples including tailings wastewater, high-intensity magnetic separation (HIMS) tailings, and flotation samples were procured from the Yuanjiacun iron mine concentrator of Shanxi province in China. The tailings wastewater was collected from flotation tailings water combined with magnetic separation tailings water, stirred evenly, and stored in plastic bottle. The wastewater quality was shown in Table 1. Test results showed that the tailings wastewater presented yellowish brown, suspended solids (SS) content and the concentration of Ca2+, Cl, and COD exceeded the standard.

The concentration of the HIMS tailings pulp was 11.93% by weight, and the main minerals were quartz (62.54%), amphibole (17.44%), chlorite (4.16%), hematite (4.75%), montmorillonite (3.82%), calcite (2.93%), and feldspar (4.36%). The XRD analysis of the sample was shown as Figure 1. The sample was classified into different size fractions as shown in Table 2. As shown in Table 2, most particle size of the sample was fine and more, even if the sample was on quiescent standing in a month, it also would not naturally subside.

The samples for flotation were taken from on-site samples of flotation, which were ground to 95% passing 0.045mm, and contained 34.90% specularite and hematite, 8.70% magnetite, 0.20% limonite, 39.40% quartz, 11.40% chlorite and hornblende, and 4.90% calcite and dolomite.

Coagulant (CYH) of the molecular weight of 80 thousands was synthesized in our lab and it was of technical grade. Amphoteric polyacrylamide (PAM) of the molecular weight of 12 million was of technical grade. Collector (named RA-715) and coagulant poly(diallyldimethylammonium chloride) (PDADMAC) were from the Yuanjiacun iron mine concentrator of Shanxi province in China and they were of all technical grade. CaCl2 and NaCl acted as sources of Ca2+ and Cl ions, respectively. Other chemical materials were bought from commercial companies and their purity was above chemical purity grade.

Use 300mL HIMS tailings pulp mentioned above at every turn to conduct coagulation contrast test. First, add the required amount of CYH into the testing pulp, and mix them up evenly; then add PAM into the testing pulp, and after a period of stirring, leave the samples standing and record the height of supernatant as a function of standing time.

Use 1.0L iron tailings wastewater mentioned above at every turn to conduct oxidation-sedimentation experiment. When the wastewater was heated to the desired temperature, sodium hypochlorite (10% of available chlorine) was added. After stirring the mixture for the desired time, FeCl2 were added to the mixture, and the KI-starch paper was used to detect the reaction progress until it did not change blue. Afterwards, the pH was adjusted to 9~10 with NaOH solution. After several hours of standing, the supernatant was separated, and then the PAM concentration, COD value, and Ca2+ content were measured.

The bench-scale flotation tests were conducted in a XFD-63 flotation cell (self-aeration) whose volume for rougher flotation and cleaning flotation was 0.5L, using 200g ore at every turn to obtain a Fe concentrate. Fatty acids (RA-715) were used as collector, NaOH was used as pH regulators, starch was used as depressant, and CaO was used as activator. The flotation flow sheet was illustrated in Figure 2.

The infrared spectra of samples were recorded by Nicolet AVATAR370 FTIR spectrometer (USA) using the KBr disk technique. The quartz samples used for this purpose were ground in an agate mortar and pestle to pass 5m. 50mg of samples was mixed with 30mL distilled water in the absence or presence of 100mg/L coagulant at pH 9 and 25C. After stirring for 3min, still standing for 4h, the solid product in the mixture was filtrated and rinsed three times and then dried in a vacuum oven and recorded infrared adsorption spectra from 400cm1 to 4000cm1.

Zeta potentials of HIMS tailings samples were measured by using a Brookhaven ZetaPlus zeta potential analyzer (USA). The samples used for this purpose were ground to less than 5m in an agate mortar and pestle. 50mg of the samples was added to 30mL aqueous solution with or without 100mg/L coagulant. After stirring for 10min, then the pH values were adjusted with HNO3 or NaOH solutions and measured. All measurements were conducted in a 0.1mol/L KNO3 background electrolyte solution. The agitated suspension was sampled to record the zeta potential. The results presented were the average of five independent measurements with a typical variation of 5mV.

Bench-scale flotation studies on the process water showed that tailings wastewater reduced the flotation iron concentrate grade and iron recovery [25]. Large doses of coagulants such as PAM and PDADMAC were used in wastewater treatment in Yuanjiacun concentrator previously. Only in the part of HIMS tailings concentration, doses of PAM and PDADMAC were several times of other similar mines [25]. In order to assess the practicability of recycling of process water in flotation practice, the influence of tailings wastewater components of PAM, PDADMAC, Ca2+, and Cl ions was investigated independently. The results were shown in Figure 3.

Figures 3(a) and 3(b) showed that an increasing PAM or PDADMAC concentration reduced the iron flotation recovery. However there was very little reduction in iron grade. When the concentration increased from 0mg/L to 3mg/L for PAM and 0mg/L to 30mg/L for PDADMAC, the recoveries of iron decreased from 74.66% to 66.74% and 74.66% to 64.63%, respectively. Figure 3(c) demonstrated that an increasing Ca2+ ions concentration reduced the iron grade and increased the iron flotation recovery obviously. When the concentration of Ca2+ ions increased from 0mg/L to 180mg/L, the iron grade of concentration decreased from 66.27% to 64.42%; the iron grade decreased sharply on addition of 360mg/L. However there was a slight increase in recovery in process water in presence of a number of Ca2+ ions. Figure 3(d) showed that, with increasing the dose of Cl, there was no change in iron grade and recovery decreased only slightly.

Single factor tests of components contained in tailings wastewater showed that PAM, PDADMAC, and Ca2+ ions reduced the flotation iron recovery or grade of the concentrate. The origins of PAM, PDADMAC, and other organic species in tailings wastewater were the coagulants, flocculants, and flotation reagents such as PAM and PDADMAC for coagulating sedimentation of concentration and wastewater treatment, starch for depressing hematite flotation, and RA-715 for flotation of activated silicate minerals. The origin of calcium species in tailings wastewater was the ore and flotation reagents such as lime for activating SiO2 and silicate minerals. The method of coagulating sedimentation was used in the process of concentration of HIMS tailings, flotation concentrate and flotation tailings, and treatment of wastewater of tailings pond in Yuanjiacun concentrator. In order to lower the content of suspended solids, PAM, and PDADMAC, coagulating sedimentation experiments were conducted with a novel coagulant CYH. Given the maximum amount of coagulants and flocculants used in HIMS tailings concentration in Yuanjiacun concentrator at present, we chose coagulating sedimentation testes of HIMS tailings concentration as a representative for detailed investigations to study the performance of CHY.

Figure 4 exhibited the effect of PDADMAC or CYH dosage on coagulation efficiency by using PAM as a flocculant at 26.88g/(t undressed ore, the same below) initial concentration. The results in Figure 4 showed that, at the coagulant dosage of 8.96g/t, the settle rate of CYH was faster than that of PDADMAC, even faster than that of PDADMAC at the dosage of 17.92g/t. The turbidity of liquid supernatant by using CYH as a coagulant at 8.96g/t initial concentration was lower than that of PDADMAC same as that of initial concentration and was rough equal to that of PDADMAC as a coagulant at 17.92g/t initial concentration. When the initial concentration of CYH increased from 8.96g/t to 17.92g/t, the settle rate and turbidity changed little. Compared with PDADMAC, CYH exhibited superior coagulating ability.

The flocculation response of PAM as a function of initial concentration by using CYH as a coagulant at 8.96g/t initial concentration was presented in Figure 5. As it could be observed from Figure 5, the settle rate rapidly increased with increasing flocculant concentration. However, increasing PAM concentration had minor influence on turbidity of liquid supernatant.

As shown in Figure 1, quartz was the highest content of mineral in HIMS tailings. So, we chose quartz as a representative for FTIR spectrum investigation to study the adsorption mechanism of quartz before and after interaction with CYH. The FTIR spectra were presented in Figure 6.

Figure 6 showed that, after interaction with CYH, the stretching and bending vibrations of saturated C-H bonds in CYH molecules appeared at around 2962.17, 2933.24, 2871.53, and 1432.15cm1 on quartz surfaces, respectively. The results of FTIR spectra exhibited that, after CYH treatment, new adsorption peaks on quartz surfaces did not appear except for CYHs adsorption bands, which inferred that CYH might adsorb onto quartz surface without the formation of new complexes.

Zeta potentials of HIMS tailings particles as a function of pH values in the absence and presence of CYH were shown in Figure 7. It indicated that the potential of HIMS tailings was high. So coagulating sedimentation treatment of HIMS tailings was rather difficult from a certain degree because of the electrostatic repulse force among particles. As it could be observed from Figure 7, CYH could lower -potential values within the scope of pH 5~12, inferring that cationic CYH might adsorb onto particles surfaces. The results of zeta potential indicated that CYH adsorbed onto HIMS tailings mainly through electrostatic attraction, which agreed with the FTIR spectra results.

CYH that is a good coagulant has strong binding force by using hydroxy. After the mixture of HIMS tailings and CYH, the stable silicate mineral groups in the wastewater were exposed; meanwhile, CYH entered into the wastewater and hydrolyzed strongly to be a polyhydroxy polymer compound. CYH adsorbed characteristically onto particles surfaces through electrostatic force, hydrogen bond, hydrophobic association, and van der Waals force, bridging the various silicate minerals in the long CYH chain, forming large flocs to reach rapid subsidence through trapping and rolling.

Table 3 showed that, by using CYH as a coagulant, the content of SS of tailings wastewater decreased obviously, and the wastewater became clear. However, the COD value and concentration of PAM in tailings water were still much higher than freshwater. The tailings water still could not meet the requirements of reuse for flotation. Thus, oxidation-sedimentation treatment was still needed in the process.

We chose removal rates of PAM and COD as representatives for detail investigations to study the effect of reaction parameters. Figure 8(a) showed the effect of dosage of sodium hypochlorite (NaClO) on the removal rates of PAM and COD. As shown in Figure 8(a), the removal rates of PAM and COD rapidly increased with increasing NaClO concentration when it was less than 1.0g/L and then slowly increased and reached 90.48% and 83.97% at 1.0g/L dosage, respectively. As it could be observed from Figure 8(b), the removal rates of PAM and COD increased with increasing reaction temperature. When the reaction temperature increased from 15C to 30C, the removal rates increased from 87.62% to 94.61% and 77.86% to 87.64% for PAM and COD, respectively. The reaction temperature is higher, the reaction rate is faster, but the decomposition of NaClO is faster. The choice of 20C as the reaction temperature can ensure NaClO has good oxidation ability, but also conform to the most of natural temperature of tailings wastewater in Yuanjiacun concentrator. Figure 8(c) demonstrated that the removal rates of PAM and COD rapidly increased with prolonging reaction time when it was less than 30min and then maintained roughly constant.

As shown in Table 4, after treatment by using oxidation-sedimentation method, pH of tailings wastewater increased from 9.12 to 9.35, suspended solids content decreased from 178mg/L to 48mg/L, and concentration of Ca2+ ions, TFe, PAM, and COD decreased from 240mg/L to 36mg/L, 4.97mg/L to 0.36mg/L, 3.15mg/L to 0.30mg/L, and 131mg/L to 21mg/L, respectively. And the removal rates of PAM, COD, and Ca2+ was 90.48%, 83.97%, and 85.00%, respectively. The water quality of treated tailings wastewater was close to the quality of freshwater.

Bench-scale flotation studies were conducted according to the procedure as shown in Figure 2. These studies would show whether oxidation-sedimentation treatment of the tailings wastewater occurring in the pilot plant had any effect on selectivity and/or recovery of minerals during flotation. Results were given in Table 5. The results showed that the concentrate yield, grade, and recovery increased by 0.95%, 1.25%, and 2.75%, respectively, by using treated tailings wastewater as flotation water compared to that of tailings wastewater without treatment. Compared to freshwater, in the case of the equivalent yield, treated tailings wastewater achieved an excellent concentration containing 65.45% Fe with 73.49% Fe recovery, and the Fe grade increased by 0.31%.

(1) Single factor tests of components contained in tailings wastewater in Yuanjiacun concentrator showed that PAM, PDADMAC, and Ca2+ ions reduced the flotation iron recovery or grade of the concentrate.

(2) When CYH was used to coagulate HIMS tailings, -potential decreased, and silicate minerals formed flocculent mass by bridging; thus suspended matters decreased effectively. This was subsequently confirmed by FTIR spectrum and zeta potential analysis. But the tailings wastewater could not reach recycling standards.

(3) Oxidation experiment showed that a 90.48% reduction in PAM, 83.97% reduction in COD, and 85.00% reduction in Ca2+ were achieved at the sodium hypochlorite dosage of 1.0g/L, reaction temperature of 20C, and reaction time of 30 minutes. Bench-scale flotation tests on the treated tailings wastewater indicated that the Fe recovery and grade of concentrate were close to those of freshwater.

The authors gratefully acknowledge the financial supports of the National Natural Science Foundation of China (no. 5160041305) and the China Postdoctoral Science Foundation (no. 2016M591382). This project is also supported by Lanxian County Mine Co., Ltd., TISCO, China.

Copyright 2017 Wen-li Jiang and Hai-feng Xu. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

iron ore processing plant, iron ore mining process, iron ore beneficiation plant, iron ore extraction process, iron ore machine

iron ore processing plant, iron ore mining process, iron ore beneficiation plant, iron ore extraction process, iron ore machine

This plant initially used stage grinding single magnetic separation - fine screening and regrinding process. Xinhai increased cationic reverse flotation process for undersize concentrate. The final concentrate was obtained after one roughing and one cleaning. The reverse flotation froth was sent to regrinding after thickening and magnetic separation, then magnetic concentrate returned to reverse flotation for reprocessing. Finally, iron concentrate was increased from 65.43% to 68.88%.

Xinhai increased anionic reverse flotation process of magnetic concentrate on the basis of the single magnetic separation process. Iron ore concentrate was obtained directly with a roughing, tailings were discarded with three scavenging, middlings returned to efficient thickener. Finally, iron concentrate was increased from 64.25% to 67.22%.

The qualified iron concentrate of this project was obtained with Xinhai round vibrating screen - Xinhai magnetic separator. Oversize middlings were sent to closed-circuit grinding system (including Xinhai wet grid type ball mill and hydrocyclone) for fine grinding. And other qualified concentrates were gained by magnetic separation - fine screen - magnetic separation, then oversize material returned to thickening and magnetic separation for reprocessing. Finally, iron concentrate was increased from 67 % to 69 %, silicon dioxide was reduced from 6.5% to 4.5 %.

Strong magnetic iron ore belongs to free-milling mine, which can get high-grade iron concentrate with weak magnetic separation process. With the improving demand of iron ore concentrate, Xinhai has speeded up the research and innovation of magnetic iron ore dressing technology and magnetic separation equipment in recent years, and achieved remarkable results.

Xinhai increases fine screening-regrinding process in two stage grinding, stage separation, single weak-magnetic separation process, which timely separates fine minerals, reduces the overgrinding and improves the processing capacity of ball mill. The iron concentrate grade increases by about 8%.

One stage closed-circuit grinding and classifying system consists of ball mill and cyclone, which not only guarantees the classification efficiency and classification size, but also separates the qualified concentrate in advance.

Magnetic separation timely separates the qualified coarse grain concentrate and tailings. And this combined process reduces more flotation processing quantity and reagents than direct flotation and saves a lot of flotation production cost.

Strong magnetic process recycles fine grained iron ore that plays a role in desliming and tailings discarding. The reverse floatation process has simple reagent system that greatly reduces reagent into the pulp.

beneficiation of iron ore

beneficiation of iron ore

Beneficiation of Iron Ore and the treatment of magnetic iron taconites, stage grinding and wet magnetic separation is standard practice. This also applies to iron ores of the non-magnetic type which after a reducing roast are amenable to magnetic separation. All such plants are large tonnage operations treating up to 50,000 tons per day and ultimately requiring grinding as fine as minus 500-mesh for liberation of the iron minerals from the siliceous gangue.

Magnetic separation methods are very efficient in making high recovery of the iron minerals, but production of iron concentrates with less than 8 to 10% silica in the magnetic cleaning stages becomes inefficient. It is here that flotation has proven most efficient. Wet magnetic finishers producing 63 to 64% Fe concentrates at 50-55% solids can go directly to the flotation section for silica removal down to 4 to 6% or even less. Low water requirements and positive silica removal with low iron losses makes flotation particularly attractive. Multistage cleaning steps generally are not necessary. Often roughing off the silica froth without further cleaning is adequate.

The iron ore beneficiation flowsheet presented is typical of the large tonnage magnetic taconite operations. Multi-parallel circuits are necessary, but for purposes of illustration and description a single circuit is shown and described.

The primary rod mill discharge at about minus 10- mesh is treated over wet magnetic cobbers where, on average magnetic taconite ore, about 1/3of the total tonnage is rejected as a non-magnetic tailing requiring no further treatment. The magnetic product removed by the cobbers may go direct to the ball mill or alternately may be pumped through a cyclone classifier. Cyclone underflows usually all plus 100 or 150 mesh, goes to the ball mill for further grinding. The mill discharge passes through a wet magnetic separator for further upgrading and also rejection of additional non-magnetic tailing. The ball mill and magnetic cleaner and cyclone all in closed circuit produce an iron enriched magnetic product 85 to 90% minus 325 mesh which is usually the case on finely disseminated taconites.

The finely ground enriched product from the initial stages of grinding and magnetic separation passes to a hydroclassifier to eliminate the large volume of water in the overflow. Some finely divided silica slime is also eliminated in this circuit. The hydroclassifier underflow is generally subjected to at least 3 stages of magnetic separation for further upgrading and production of additional final non-magnetic tailing. Magnetic concentrate at this point will usually contain 63 to 64% iron with 8 to 10% silica. Further silica removal at this point by magnetic separation becomes rather inefficient due to low magnetic separator capacity and their inability to reject middling particles.

The iron concentrate as it comes off the magnetic finishers is well flocculated due to magnetic action and usually contains 50-55% solids. This is ideal dilution for conditioning ahead of flotation. For best results it is necessary to pass the pulp through a demagnetizing coil to disperse the magnetic floes and thus render the pulp more amenable to flotation.

Feed to flotation for silica removal is diluted with fresh clean water to 35 to 40% solids. Being able to effectively float the silica and iron silicates at this relatively high solid content makes flotation particularly attractive.

For this separation Sub-A Flotation Machines of the open or free-flow type for rougher flotation are particularly desirable. Intense aeration of the deflocculated and dispersed pulp is necessary for removal of the finely divided silica and iron silicates in the froth product. A 6-cell No. 24 Free-FlowFlotation Machine will effectively treat 35 to 40 LTPH of iron concentrates down to the desired limit, usually 4 to 6% SiO2. Loss of iron in the froth is low. The rough froth may be cleaned and reflotated or reground and reprocessed if necessary.

A cationic reagent is usually all that is necessary to effectively activate and float the silica from the iron. Since no prior reagents have come in contact with thethoroughly washed and relatively slime free magnetic iron concentrates, the cationic reagent is fast acting and in somecases no prior conditioning ahead of the flotation cells is necessary.

A frother such as Methyl Isobutyl Carbinol or Heptinol is usually necessary to give a good froth condition in the flotation circuit. In some cases a dispersant such as Corn Products gum (sometimes causticized) is also helpful in depressing the iron. Typical requirements may be as follows:

One operation is presently using Aerosurf MG-98 Amine at the rate of .06 lbs/ton and 0.05 lbs/ton of MIBC (methyl isobutyl carbinol). Total reagent cost in this case is approximately 5 cents per ton of flotation product.

The high grade iron product, low in silica, discharging from the flotation circuit is remagnetized, thickened and filtered in the conventional manner with a disc filter down to 8 to 10% moisture prior to treatment in the pelletizing plant. Both the thickener and filter must be heavy duty units. Generally, in the large tonnage concentrators the thickener underflow at 70 to 72% solids is stored in large Turbine Type Agitators. Tanks up to 50 ft. in diameter x 40 ft. deep with 12 ft. diameter propellers are used to keep the pulp uniform. Such large units require on the order of 100 to 125 HP for thorough mixing the high solids ahead of filtration.

In addition to effective removal of silica with low water requirements flotation is a low cost separation, power-wise and also reagent wise. Maintenance is low since the finely divided magnetic taconite concentrate has proven to be rather non-abrasive. Even after a years operation very little wear is noticed on propellers and impellers.

A further advantage offered by flotation is the possibility of initially grinding coarser and producing a middling in the flotation section for retreatment. In place of initially grinding 85 to 90% minus 325, the grind if coarsened to 80-85% minus 325-mesh will result in greater initial tonnage treated per mill section. Considerable advantage is to be gained by this approach.

Free-Flow Sub-A Flotation is a solution to the effective removal of silica from magnetic taconite concentrates. Present plants are using this method to advantage and future installations will resort more and more to production of low silica iron concentrate for conversion into pellets.

advanced flotation technology | eriez flotation division

advanced flotation technology | eriez flotation division

Eriez Flotation is the world leader in column flotation technology with over 900 installations. Columns are used for floating well-liberated ores. Typically they produce higher grade and have lower power costs than conventional cells. Applications include Roughers Scavengers Cleaners

Eriez Flotation is the world leader in column flotation technology with over 900 installations. Columns are used for floating well-liberated ores. Typically they produce higher grade and have lower power costs than conventional cells. Applications include

The HydroFloat fluidized bed flotation cell radically increases flotation recoveries of coarse and semi-liberated ores. Applications include: Split-feed flow-sheets Flash flotation Coarse particle recovery

The StackCell uses a 2-stage system for particle collection and froth recovery. Collection is optimized in a high shear single-pass mixing canister and froth recovery is optimized in a quiescent flotation chamber. Wash water can be used.

The StackCell uses a 2-stage system for particle collection and froth recovery. Collection is optimized in a high shear single-pass mixing canister and froth recovery is optimized in a quiescent flotation chamber. Wash water can be used.

The CrossFlow is a high capacity teeter-bed separator, separating slurry streams based on particle size, shape and density. Applications include: Split-feed flow-sheets with the HydroFloat Density separation Size separation

The rotary slurry-powered distributor (RSP) is used to accurately and evenly split a slurry stream into two or more parts, without creating differences based on flow, percent solids, particle size or density. Applications include Splitting streams for feeding parallel lines for any mineral processing application

The rotary slurry-powered distributor (RSP) is used to accurately and evenly split a slurry stream into two or more parts, without creating differences based on flow, percent solids, particle size or density. Applications include

Eriez Flotation provides advanced engineering, metallurgical testing and innovative flotation technology for the mining and minerals processing industries. Strengths in process engineering, equipment design and fabrication positionEriez Flotation as a leader in minerals flotation systems around the world.

Applications forEriez Flotation equipment and systems include metallic and non-metallic minerals, bitumen recovery, fine coal recovery, organic recovery (solvent extraction and electrowinning) and gold/silver cyanidation. The company's product line encompasses flotation cells, gas spargers, slurry distributors and flotation test equipment.Eriez Flotation has designed, supplied and commissioned more than 1,000 flotation systems worldwide for cleaning, roughing and scavenging applications in metallic and non-metallic processing operations. And it is a leading producer of modular column flotation systems for recovering bitumen from oil sands.

Eriez Flotation has also made significant advances in fine coal recovery with flotation systems to recover classified and unclassified coal fines. The group's flotation columns are used extensively in many major coal preparation plants in North America and internationally.

Eriez Flotation provides advanced engineering, metallurgical testing and innovative flotation technology for the mining and minerals processing industries. Strengths in process engineering, equipment design and fabrication positionEriez Flotation as a leader in minerals flotation systems around the world. Read More

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.

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