Engineering & Mining Journal

DEC 2018

Engineering and Mining Journal - Whether the market is copper, gold, nickel, iron ore, lead/zinc, PGM, diamonds or other commodities, E&MJ takes the lead in projecting trends, following development and reporting on the most efficient operating pr

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fluidized - scale units that is article previously data obtained using this pilot The objectives o ) to provide a from a previously • Increase mill throughput by as much as 15-20% • Reduce energy & media consumption • Produce a coarse tailing stream Coarse Particle Recovery Changes Everything! EFD's HydroFloat ™ Separator radically improves the traditional sulfide processing circuit through Coarse Particle Flotation. Unlike conventional flotation, the HydroFloat Separator recovers particles as large as 800 microns with as little as 1% mineral surface expression. By rejecting the balance as "coarse" tailings, much of the recirculating load is eliminated, thus greatly increasing mill capacity… with NO loss in mineral recovery! Coarse Particle Recovery using EFD's HydroFloat Separator can: Particles approximately 850 microns Overflow Coarse Mineral Air Underflow Coarse Tails Rejects only those particles that have no hydrophobic surface expression For more details download these White Papers at www.EriezFlotation.com THE SIGNIFICANCE OF EXPOSED GRAIN SURFACE AREA IN C OARSE PARTICLE FLOTATION OF LOW - GRADE COPPER ORE WITH THE HYDROFLOAT TECHNOLOGY Jan D. Miller , C.L. Lin and Yan Wang Department of Metallurgical Engineering , College of Mines and Earth Sciences University of Utah , Salt Lake City, UT 84112 USA Phone: 801 - 581 - 5160 Email: Jan.Miller@utah.edu Michael J. Mankosa and Jaisen N. Kohmuench Eriez Flotation Division , 2200 Asbury Road , Erie, PA 16506 USA Phone: (814) 835 - 6000 Email: mmankosa@ereiz.com Gerald H. Luttrell Mining & Minerals Engineering, 100 Holden Hall Virginia Tech, Blacksburg, VA 24061 USA Phone: (540) 230 - 7112 Email: Luttrell@vt.edu ABSTRACT Conventional flotation machines are typically limited to a particle topsize of 150 - 200 microns due to inherent constraints created by the pulp and froth phases. To overcome these limitations, a novel bed flotation system called the HydroFloat Sep arator has been developed specifically for the purpose of floating coarse particles containing only minute amounts of exposed hydrophobic mineral s . Over the last decade, this technology has been successfully applied to industrial minerals with several full - installed to recover particles up to and exceeding 3 mm diameter. More recently, sulphide - based test work has shown that this novel device is also capable of recovering metalliferous values at a grind size much coarser than currently u sed in industrial concentrators . In the current study, X - ray microtomography (Figure 1) was used to experimentally quantify the degree of hydrophobic surface exposure necessary to recover particles of different sizes using the HydroFloat technology. The da ta indicate that both p mass and surface area of exposed grains are critical factors in coarse particle flotation from a low grade copper ore. Excellent recovery for multiphase particles as large as 850 microns was achieved provided there was suffic ient surface exposure of locked sulfide grains. This article provides d etailed 3D analysis of flotation products using X - ray microtomography , which define s the extent of surface area exposure necessary for recovery of each size class fed to the HydroFloat Separator . Fundamental issues of bubble attachment are also discussed as well as process strategies for improved plant operations. Figure 1 Ð Analysis of locked particles by X - ray computed tomography . KEYWORDS Coarse Particle Flotation , X - Ray Comput ed Tomography, Liberation /Exposure , HydroFloat Separator OARSE PARTICLE GRADE COPPER ORE WITH THE HYDROFLOAT TECHNOLOGY College of Mines and Earth Sciences Conventional flotation machines are typically limited to a particle topsize of 150 - 200 microns due to inherent constraints created by the pulp and froth phases. To overcome these limitations, a novel specifically for the purpose of only minute amounts of exposed hydrophobic mineral s . Over the last this technology has been successfully applied to industrial minerals with several full installed to recover particles up to and exceeding 3 mm diameter. More recently, sulphide - based test work values at a grind size . In the current study, X - ray microtomography was used to experimentally quantify the degree of hydrophobic surface exposure necessary to ta indicate that both p mass and surface area of exposed grains are critical factors in coarse particle flotation from a low grade 850 microns was achieved provided This article provides d etailed 3D analysis of the extent of surface area exposure . Fundamental issues of bubble discussed as well as process strategies for improved plant operations. RECOVERY OF VALUES FROM A PORPHORY COPPER TAILINGS STREAM Michael J. Mankosa, Jaisen N. Kohmuench, Lance Christodoulou Eriez Flotation Division , 2200 Asbury Road , Erie, PA 16506 USA Phone: (814) 835 - 6000 Email: mmankosa@ereiz.com Jaisen Hilsen and Gerald H. Luttrell Mining & Minerals Engineering, 100 Holden Hall, Virginia Tech, Blacksburg, VA 24061 USA Phone: (540) 230 - 7112 Email: Luttrell@vt.edu ABSTRACT The efficiency of the froth flotation process has long been known to be strongly dependent on particle size. For sulfide minerals, good recoveries are typically achieved in industrial flotation circuits for particles in the 10 to 200 micron size range. Particles outside this c ritical size are typically lost in the tailings streams rejected by industrial operations due to inherent constraints associated with the physical interactions that occur in the pulp and froth phases of conventional flotation equipment. In response to thes e limitations, a series of experimental studies were conducted to determine whether particles lost as tailings could be economically recovered using a suite of novel flotation technologies developed for the upgrading of ultracoarse and ultrafine particles in the industrial mineral s industry . F or the case of ultra coarse particle s , a fluidized - bed flotation system called the HydroFloat separator was tested . The novel flotation device in both laboratory and - scale trials showed that good recoveries of previously lost sulfide values up to 0.7 mm in diameter could be achieved . A sample photograph of coarse middling particles recovered by this technology is shown in Figure 1. Similarly, f or ultrafine particl es, a new high - intensity flotation system known as the StackCell was tested . This technology, which utilizes high - shear high - energy contacting of slurry and gas, was capable of recovering valuable ultrafine sulfide slimes that were previously lost as waste due to low capture efficiencies . f this article are (i) to describe the unique operating principles of these two advanced flotation technologies and associated ancillary classification equipment , (ii) to present experimental test data show ing the metallurgical benefits of this approach for upgrading coarse and fine sulfide minerals, and (ii i generic cost - benefit analysis of the proposed system for upgrading tailing streams historically rejected by sulfide mineral concentrators . Figure 1 Ð Photograph of coarse middling particles recovered as froth concentrate discarded tailing stream using the HydroFloat technology. KEYWORDS Coarse Particle Flotation, Fine Particle Flotation, HydroFloat, StackCell ABSTRACT froth flotation process has long been known to be strongly dependent on particle size. For sulfide minerals, good recoveries are typically achieved in industrial flotation circuits for particles in the 10 to 200 micron size range. Particles outside this c ritical size are typically lost in the tailings streams rejected by industrial operations due to inherent constraints associated with the physical interactions that occur in the pulp and froth phases of conventional flotation equipment. In response to thes e limitations, a series of experimental studies were conducted to determine whether particles previously lost as tailings could be economically recovered using a suite of novel flotation technologies developed for the upgrading particles in the industrial mineral s industry . F or the case of ultra coarse particle s , bed flotation system called the HydroFloat separator was tested . The data obtained using this laboratory and pilot - scale trials showed that good recoveries of previously lost sulfide values up to 0.7 mm in diameter could be achieved . A sample photograph of coarse middling particles recovered by this technology is shown in Figure 1. Similarly, f or ultrafine particl Similarly, f or ultrafine particl Similarly, f es, a new high - intensity flotation system known as the StackCell was tested . This technology, which utilizes high - shear energy contacting of slurry and gas, was capable of recovering valuable ultrafine sulfide slimes that due to low capture efficiencies . The objectives o f this article are (i) to operating principles of these two advanced flotation technologies and associated , (ii) to present experimental test data show ing the metallurgical benefits for upgrading coarse and fine sulfide minerals, and (ii i ) to provide a generic cost - benefit analysis of the proposed system for upgrading tailing streams historically rejected by sulfide mineral Photograph of coarse middling particles recovered as froth concentrate from a previously discarded tailing stream using the HydroFloat technology. KEYWORDS Coarse Particle Flotation, Fine Particle Flotation, HydroFloat, StackCell SPLIT - FEED CIRCUIT DESIGN FOR PRIMARY SULFIDE RECOVERY Michael J. Mankosa and Jaisen N. Kohmuench Eriez Flotation Division , 2200 Asbury Road , Erie, PA 16506 USA Phone: (814) 835 - 6000 Email: mmankosa@ereiz.com Gerald H. Luttrell Mining & Minerals Engineering, 100 Holden Hall, Virginia Tech, Blacksburg, VA 24061 USA Phone: (540) 230 - 7112 Email: Luttrell@vt.edu John A. Herbst Mining Engineering , 365A Mineral Resources Building Wes t Virginia University, Morgantown, WV 26506 Phone: ( 304 ) 293 - 7680 Email: jaherbst@mail.wvu.edu ABSTRACT A new generation of advanced flotation technologies has recently been developed and commercially deployed during in the industrial minerals industry. One such technology is the HydroFloat separator. This unique fluidized - bed flotation system has dramatically increased the upper particle size limit that can be successfully treated by froth flotation. Recent studies co nducted using laboratory, bench - scale and pilot - scale equipment indicate that this technology can also be used to float coarse sulfide middlings that cannot be recovered by conventional flotation machines. D ata collected from pilot - scale tests conducted at a base metal concentrator indicate that this technology can float composite middling s as large as 700 microns containing as little as 5% hydrophobic mineral. As such, the crossover of this technology into the base metals industry has the potential to offe r many advantages for recovery, selectivity and capacity through the use of split - feed circuitry. The split - feed concept, which is often used for upgrading industrial minerals, involves segregation of the feed into more than one size class followed by sepa rate upgrading of each class using separator s/ reagent s specifically optimized for that particular size class. An example of a split - feed flowsheet for sulfide flotation that includes coarse and fine processing circuits is provided in Figure 1 . In this case , a coarser grind size and correspondingly higher mill throughput can be accommodated via the use of the coarse particle flotation equipment. The objectives of this article are (i) to introduce the key features of the split - feed circuitry incorporating the HydroFloat technology, (ii) to present experimental test data showing the metallurgical benefits of this processing scheme, and (iii) to provide simulations of the split - feed circuitry illustrating the increased milling capacity that may be attained by th is approach. Figure 1 Ð Flowsheet for a split - feed sulfide flotation circuit . KEYWORDS Circuit Design, Circuit Simulation , Split - Feed Flotation, Coarse Particle Flotation Circuit Feed Primary Grinding Primary Classifiers Column Cleaner Secondary Classifiers Conventional Rougher Regrind Mill Regrind Classifiers Tails Conventional Scavenger Final Concentrate HydroFloat Split-Feed Sulfide Flotation HydroFloat Separator 1.604.952.2300 Recovers virtually all particles which exhibit greater than 1% hydrophobic surface expression

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