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By B. Y. M. Bueno

Biosorption of heavy metals can be an effective process for the removal of heavy metals ions from aqueous solutions. In this study, the adsorption properties of Rhodococcus opacus biomass for Pb(II) and Cu(II) ions was investigated. The effects of initial pH, initial metal concentration and biomass concentration on biosorption efficiency were studied in a batch system. Results showed that the initial pH would play an important role in the Pb(II) and Cu(II) ions removal by R. opacus and affected the zeta potential of R. opacus. The equilibrium adsorption was reached with 60 min. The Langmuir and Freundlich models were used for describing of adsorption isotherm data. The maxi-mum adsorption capacities of biomass were determined as 94.3mgg-1 and 32.2 mgg-1 for the Pb(II) and Cu(II) ions, respectively. The experimental data fitted to pseudo second order kinetic model. Adsorption capacity of Pb(II) ions was found to be reduced by the presence of the other competing metal ions in the system. The FT-IR results of R. opacus biomass showed that biomass has different functional groups and these groups are able to react with metal ions in aqueous solution.

Jan 1, 2014

By N. Hamlef

In this study, the effects of heat treatment on phase formation and surface morphology of the Cr-Pt coated system are investigated using X-ray diffraction and electron microscopy techniques. The CrPt andCr4Pt (Cr3Pt - A15 type) phases were formed after heat treatment of the coated samples. Heat treating at 1000°C renders a distinct island coating morphology that is non-continuous in nature. A diffusional model is proposed for this coated system with regards to the surface morphology formation after heat treatment.

Jan 1, 2014

By Henrique Kahn, Daniel Uliana, Carina Ulsen, Guilherme Nery

"Gold has been a material in high demand since the dawn of humanity. After hundreds of years of exploitation, the increasingly search for gold occurs in lower grade deposits with greater extraction difficulty. Therefore, for maximum efficiency, deep knowledge of the characteristics of these minerals and their associations is crucial, which is acquired through an accurate and rigorous routine of process mineralogy and batch extraction tests. The industrial gold process extraction occurs by gravity concentration, sulphides flotation and cyanidation. For gravity concentration, it is fundamental to establish the proportion of free or coarse gold grains and its association to heavy minerals; regarding flotation, the most relevant data are the proportion of gold associated to sulphides and their liberation by the surface area; for cyanidation, it is crucial to evaluate gold accessibility and the kinetics of leaching. Thus, the characterization of gold associations and liberation is vital to establish the plant design, to optimize operating plants and to reduce gold losses. Our aim is the characterization of gold occurrence in low-grade Brazilian deposits with complex mineralogical assemblages to support processing flowchart definition and to predict metallurgical recoveries. Gold distribution in light and heavy minerals was evaluated by heavy liquid separation and the occurrence of gold in free or locked particles was carried out on heavy products by SEM-based automated image analysis using the MLA system. All the products of heavy liquid separation were cyanidated in head samples with different milling conditions to evaluate the reaction kinetics and maximum recovery."

Jan 1, 2014

By B. Dubreuil, J. -M. Lalancette, D. Lemieux

A gold bearing pyrite concentrate was treated at the pilot scale for the extraction of gold. Mineralogical analysis of the concentrates identified gold to be mainly present in the form of a solid solution in pyrite. Gold distribution resulted in a poor extraction yield of 55 % by direct cyanidation. A piloting campaign including an oxidative pre-treatment by roasting in a fluid bed was followed by treatment with halogens for gold extraction and has led to a gold extraction yield of 94%. Sulphur removal during the oxidation was very efficient at >99.5% and gold extraction by the halogens was completed within a 1 hour contact time. The piloting was performed on a 300 kg sample and used a diluted solution of hypohalites as the oxidizing agent for gold extraction. Sulphuric acid was injected in the reactor during the halogens treatment to lower pH to 2. The diluted solution of hypohalites (1-3%) was generated by electrolysis during the piloting campaign in a diaphragm-less electrolysis cell. The extracted gold was recovered via adsorption over silica and the gold depleted brine was treated for impurities removal. This brine was recycled for further gold extraction. With the recycling of water and brine, the regeneration of hypohalites and with a barren solid that is inert and stable, the Nichromet Extraction technology is a green process where the protection of the environment does not preclude profitability.

Jan 1, 2014

By X. M. Yu

A large amount of polluted sludge is produced by a nonferrous metal factory after treating waste water with lime/ferrous salt. The concentration of arsenic in the dried sludge is high to 5.84%, a toxicity test is taken on the sludge according to GB5085.3-2007 and the extraction content is 15.75mg/L, which surpasses the arsenic extraction standard [As]=5mg/L, the sludge is categorized as hazardous waste. If put outside without disposal, it would be very harmful to environments. Here we report an optimum protocol to extract arsenic; S2- alkaline liquor is utilized to treat the arsenic sludge. At 85?, 10L 7% S2- liquor is added into 1kg dried sludge and the resulting mixture is stirred for 120min at 250r/min, then separated by centrifugation and the compressed waste residue dried naturally. The average arsenic content is 1.40mg/L, lower than GB5085.3-2007 Standard and arsenic-free residue is consistent with GB18598-2001 Standard, which can be bury safely. The extracted arsenic is transferred into copper arsensite for use as addictive in copper electrolysis and the waste water can be recycle after calcium is removed.

Jan 1, 2014

By Ibrahim Alp, Duygu Dinç, Ersin Yazici, Adularya Energy and Electricity Generation and Mining Inc., Oktay Celep, Haci Deveci

Thiosulfate leaching as an environmentally benign alternative to cyanide leaching has received particular attention in recent years. Most studies have focused on thiosulfate leaching of free milling ores and, to some extent, pregrobbing ores. In this study, leaching of gold from the refractory Kaletas ore (in which gold/silver alloy is the only mode of occurrence detected) in ammoniacal thiosulfate solutions was studied. A two-level full factorial design (23) was adopted to investigate the effects of concentration of thiosulfate (0.2-1 M Na2S2O3), ammonia (0.5-1 M NH3) and copper (0.05-0.1 M CuSO4) on the extraction of gold from a ground ore (-38 µm) over a period of 24 h. Statistical analysis confirmed the leaching of gold improved with increasing concentrations of thiosulfate and ammonia. In contrast, increasing the concentration of copper in the range tested adversely affected the extraction of gold. The magnitude of effects of parameters on the gold extraction was in the order of Na2S2O3 > NH3 > CuSO4. The maximum extraction of gold (69.6%) was obtained in the presence of 1 M Na2S2O3, 1 M NH3 and 0.05 M CuSO4. The negative influence of copper on gold extraction is most likely attributed to the decomposition of thiosulfate catalyzed by copper. Concentration of thiosulfate was also identified to be statistically the most important parameter for its consumption.

Jan 1, 2014

By C. R. Mambote

Vanadium is an important metal that is used mainly in ferrous and non-ferrous alloys due to the high tensile strength, hardness, fatigue resistance and corrosion resistance. Vanadium consumption in the steel industry represents about 85% of the vanadium-bearing products produced worldwide. The primary sources of the metal are patronite, roscoelite, and mottramite. Vanadium has also been produced as a by-product of the uranium production program which uses carnotite ores as a source of uranium. Vanadiferous magnetite iron ores are used for producing vanadium as well. In addition, it is known that vanadium can be recovered from the ashes of crude oil and petroleum coke. The process for treating boiler residues, fly ash and petroleum coke is similar to the process used to treat spent catalysts and ores. However, some of these materials may contain high carbon that must be removed at specific stage of the operation. Several processes are available for obtaining vanadium from fly ash, such as roasting vanadium bearing materials in the presence of sodium salt. The salt roasted calcine is subsequently leached with an alkaline or acidic solution. To obtain a cal-cine from which the vanadium can subsequently be recovered, the carbon in the source materials has to be eliminated prior to the roasting process. Other processes use the conventional hydrometallurgical route, in which fly ash is leached with sulphuric acid to obtain an impure vanadium pentoxide. The impure vanadium pentoxide is then treated with a sodium carbonate solution under atmospheric conditions to subsequently precipitate vanadium as ammonium metavanadate. Actually, the salt roasting process is the only process used commercially. In the present study, the progress in the technology of vanadium extraction from secondary materials is reviewed. The perspectives and the challenges for new process development are discussed.

Jan 1, 2014

By Guadalupe Sanchez, Roel Cruz, Sergio Castro, Claudia Beltrán, Isabel Lázaro

The recovery of zinc in refineries is strongly affected by the formation of zinc ferrites during the roasting of zinc concentrates. To achieve the highest zinc recovery most of these plants operate under high acidity and high temperature conditions in their leaching circuits. However, under these conditions high iron dissolution occurs. For iron control the common practice is to precipitate it as jarosite, and calcine is normally used as neutralizing agent. This practice causes a significant loss of metal values associated with the calcine, such as zinc ferrites and silver insoluble phases. These metal values are carried by the jarosite into confined waste in many plants. In order to diminish such losses, it is necessary to use a neutralizing agent that could substitute the use of calcine. An alternative neutralizing could be the basic zinc sulfate (BZnS). This work presents the results of a laboratory analysis on the required conditions for the BZnS production from process streams of a zinc refinery plant. Neutralizing behavior of BZnS was evaluated in iron precipitation as jarosite, in order to establish the feasibility of replacing the calcine and decrease the loss of zinc and other metals values during the iron removing step of the hydrometallurgical circuit of the zinc refinery under study.

Jan 1, 2014

By A. Vilinska

Microorganisms have a tremendous influence on their environment through the transfer of energy, charge, and materials across a complex biotic mineral-solution interface. Recent developments in biotechnology have not only aided hydrometallurgical leaching operations but also shown great promise in mineral beneficiation processes. The adhesion of bacteria on minerals alters the surface properties relevant to flotation and flocculation of minerals. The biomodification of mineral surfaces occurs through the attachment of microbial cells, oxidation reactions and adsorption or chemical reaction with the metabolite products. Several types of heterotrophic and chemolithotrophic bacteria have been successfully applied in flotation and flocculation processes for the last two decades. Al-though the potential of microorganisms in minerals beneficiation has been realised by several re-searchers from their laboratory investigations, the studies were mostly confined to pure mineral systems and there is hardly any sincere effort to apply the methodologies on ores. This paper presents a brief summary of the literature in bioflotation and bioflocculation, and attempts to outline new dimensions of research for a practicable application of this technology in mineral industry.

Jan 1, 2014

By Olli Haavisto, Heikki Häkkänen, Tommi Kauppinen, Navid Khajehzadeh

Raman analysis is a well-established method for finding the abundant minerals in an ore sample. In this study, Raman spectroscopy is tested as a method for rapid and contactless on-line mineral analysis. Rapidness might enable on-site analysis of rock drillcore, which in turn would lead to more cost-efficient solutions in mineral exploration. This paper discusses the use of Raman analysis to identify minerals and to measure their concentration. The sample set under study consists of rock drillcore collected from Agnico-Eagle Kittilä Mine, Finland. Selected parts of the sample set are measured by Raman spectroscopy and the minerals are identified using reference spectra from a public source. Moreover, the direct measurement of concentration of different minerals with the help of Non-negative least squares (NNLS) optimisation algorithm is considered. The optimisation algorithm was constructed to form a linear combination of reference spectra which best represent the measured spectrum, or an average of measured spectra, from an ore sample. The results show that NNLS can identify abundant minerals in a given sample. Also through this method of analysis the results of a traditional point-count method can be expanded: It was observed that, due to grain size, multiple minerals consistently appear in the spectra measured over an area, which means that point-count method is not a proper way to interpret the spectra. This can be seen as a new result, as formerly the discussion has attended to other methods.

Jan 1, 2014

By Meredith Scaggs, Emily Sarver, Lucas Rojas Mendoza

"Early on Jan. 9, 2014, approximately 37,800 L (10,000 gal) of crude 4-methylcyclohexanemethanol (MCHM) leaked from a storage tank sitting on the bank of the Elk River near Charleston, WV (WVDEP, 2014; CSB, 2014). MCHM is a chemical commonly used in preparation of fine coal and is considered nonhazardous in terms of transportation, storage regulations and also toxicity (CDC, 2014a). Freedom Industries Inc., a producer and vendor of specialty chemical products, had acquired the storage facility from Etowah River Terminal, LLC just a few weeks prior in December 2013 (WVDEP, 2014; Freedom, 2005). The direct cause of the spill was ultimately determined to be two small holes in the base of the 76-year-old tank, which were created due to corrosion damage (Bauerlein and McWhirter, 2014).The spill site was located a little more than 1.6 km (1 mile) upstream from the intake of a municipal water treatment facility operated by West Virginia American Water (WVAW), which serves a population of 300,000 across nine counties in central West Virginia (CDC, 2014a). In a matter of hours, the leaked MCHM made its way through the treatment facility and into the water of nearby homes and businesses, where its strong smell was noticed almost immediately. On the evening of the spill, WVAW concluded that its conventional treatment processes, which include carbon filters to remove a variety of contaminants from water, were not capable of fully removing the MCHM and a "Do Not Use" order was issued for all customers (WVAW, 2014a).With little information readily available regarding the potential human health effects of MCHM, the U.S. Centers for Disease Control and Prevention (CDC) quickly issued an advisory ruling that set a maximum screening level of 1 ppm for safe drinking water (CDC, 2014a). Based on this recommendation, the "Do Not Use" order remained in effect for a total of eight days, until Jan. 17, when the WVAW distribution water was confirmed to have MCHM concentrations below the approved level (WVAW, 2014a). However, due to the pungent odor of the chemical, its presence was still recognizable in the WVAW facility and in consumers’ tap water after the order was lifted (Manuel, 2014). Recent studies have shown that the chemical can be detected in water at sub-ppb concentrations, a fact that undoubtedly added to growing public concern (Rosen et al., 2014; Gallagher et al., 2014). In response to numerous complaints and demands, WVAW continued flushing the treatment facility and pipes until Feb. 25 when MCHM levels were measured below 2 ppb (WVAW, 2014b), and eventually replaced the affected filter media (WVAW, 2014c)."

Jan 1, 2014

By Ghislain Bournival, Seher Ata, Graeme J. Jameson

A common method to prevent bubbles from coalescing in a flotation cell is by the addition of surfactants, called frothers. The gas dispersion properties in a column were tested for solutions of 1-pentanol, tri(propylene glycol) methyl ether, and poly(propylene glycol) in the presence of sodium chloride. The dependency of surfactant on the gas holdup can be divided into regions. It seemed that for a sufficiently low concentration of surfactant, even a stronger surfactant could show a transition in gas holdup from constant/decreasing to increasing with concentration. This region, however, was not marked by a decrease in the average bubble size. In addition, PPG gave higher gas holdup values while averaging larger bubbles. On the other hand, sodium chloride mostly affected the gas holdup when the concentration was high enough to prevent bubble coalescence. Another parameter affecting the gas holdup was the superficial gas velocity. A linear dependency was found between the two under a bubbly flow regime. The current study showed that both surfactants and salt could slightly affect the influence of the superficial gas velocity on the gas holdup.

Jan 1, 2014

By T. Shumba

The solvent extraction section of an old Uranium Plant in the Vaal River region produced a sub-stance called Crud (Chalk River Unidentified Deposit) that formed within the aqueous/organic interface of the settler of the solvent extraction circuit. The crud was deposited together with gold tailings to the tailings dam many years ago. Previous research done on the crud confirmed that ex-posed crud leaches Mn and Ni at concentrations that are well above their acceptable risk limits as well as Zn that leaches at concentrations that are slightly lower than its acceptable risk limit. Soil washing and bioremediation technologies were employed to treat the contaminated soil. Various laboratory test work and the pilot scale studies were conducted in parallel with each other and the results of the laboratory studies were used to determine critical parameters. Four lixiviants, i.e. sulphuric acid, acetic acid, oxalic acid and ethylene diamine acetic acid were tested at three concentration levels i.e. 0.001M, 0.0001M and 0.00001M, respectively. Column tests showed that the leaching of the heavy metals increases as the soil porosity increases. Silica sand was added to increase porosity of the contaminated soil. Highest Mn removal was achieved mainly by sulphuric and oxalic acid at 0.001M at all soil levels. EDTA was significantly efficient in the removal of Ni and Zn. The recovery of heavy metals, particularly Mn, decreased as the depth of sampling in-creased. Heterogeneous bacteria and filamentous organism plate counts were conducted to evaluate the growth of the bacteria and filamentous organisms in the soil. Results showed that more organism growth took place in the bioremediated soil with a fertilizer added to it. The leaching of metals from the soil that was bioremediated in the pilot study was generally higher than the extraction of the metals from the soil that was leached with no bioremediation carried out. The results from this study suggest that the leaching of heavy metals from the contaminated soil is to a large extent dependant on the pH of the leaching solution. By increasing the soil?s porosity and bioremediating the soil, higher extractions of metals were achieved.

Jan 1, 2014

By Silvia Serranti, Giuseppe Bonifazi, Roberta Palmieri

The possibility to develop an efficient recovery and reuse of concrete materials from Demolition Waste (DW) represents one of the main targets applied to end-of-life constructions dismantling/recycling. The need to recycle end-of life concrete materials is strongly increasing in these last years for several reasons: i) the decrease of steady supplies of good quality natural aggregates, ii) the need to secure ample supplies of concrete aggregates to the construction industry and, finally, iii) the environmental constraints limiting the DW wastes disposal. The fulfilment of these goals produces several benefits, that is: i) a reduction of new resources consumption, ii) a strong reduction of the costs linked to transport and energy production, iii) the possibility to utilize materials, otherwise lost (e.g. land filled), iv) land preservation and, finally, v) the reduction of the environmental impact of new exploitation activities. A lot of efforts have been addressed to develop, set-up and apply innovative technologies to maximize DW conversion into useful secondary raw materials. The possibility to utilize efficient, reliable and low cost analytical tools to perform detection/control actions: i) to assess concrete characteristics, before demolition, and ii) to detect the presence of contaminants in coarse aggregates (e.g. bricks, gypsum, steel, glass, plastics, wood, etc.) represent the key issues to fulfil in order to develop innovative process/control actions/procedures inside the DW sector. In this paper a new technology, based on HyperSpectral Imaging (HSI) sensors is investigated to develop suitable and low cost strategies finalised to define and implement innovative smart detection engines for sorting and/or DW flow stream quality control, addressed to perform recovered materials and/or products certification. The proposed sensing architecture is fast, accurate, affordable and it can strongly contribute to bring down the economic threshold above which recycling is cost efficient.

Jan 1, 2014

By T. Hadley, E. Catovic

"Northern Minerals Limited’s (ASX: NTU) flagship project is the Browns Range Rare Earth Project (the Project) located in Western Australia, consisting of a number of deposits with high value, heavy rare earth elements, in particular yttrium, terbium, and dysprosium. The deposits are dominated by xenotime mineralisation, which occurs within hydrothermal silicified and hematitic breccias. The Company delivered an initial JORC compliant resource estimate for the Project at the end of 2012 of 10,500 t of contained total rare earth oxides (TREO), which was increased to 28,084t of contained TREO in October 2013 and further enlarged to 47,997 t of contained TREO in February 2014. Concurrent with the growth of the Project resource base, significant progress has been made in developing the metallurgical process for the beneficiation and extraction of rare earth elements (REE’s) from the xenotime mineralisation. Development of the beneficiation circuit evaluated several process options and selected whole-ore flotation and magnetic separation, followed by flotation (hybrid circuit) as the two preferred flowsheets to pilot, following encouraging results on the bench of 83% and 86% recovery to a 20% TREO mineral concentrate respectively. Several downstream hydrometallurgical extraction flowsheets were evaluated. However, the following two preferred process flowsheets were ultimately selected for further detailed investigation during the prefeasibility study: 1. Sulphation bake, water leach, purification, oxalate precipitation, and/or calcination to produce a mixed RE oxide; 2. Sulphation bake, water leach, phosphate precipitation, caustic conversion, HCl leach, and oxalate precipitation to produce a mixed RE oxalate. Excellent heavy rare earth oxide (HREO) extractions (~ 90%) from beneficiation concentrates were achieved on the bench for both circuits, however flowsheet 1 was ultimately selected as the preferred flowsheet to pilot due to lower capital and operating cost. A mixed rare earth oxalate (42% TREO) or oxide (92% TREO) can be produced with low levels of Th and U of 3 ppm and 6 ppm respectively."

Jan 1, 2014

By V. Avdochin

The main reason of flotation process fluctuations is mixing ores of various properties from various sections of a deposit. Other, also important reasons are changes in parameters of facilities of technological cycle, as well as properties of reagents applied. According to estimates, instability and non-optimized parameters of flotation owe 3% to 6% of valuable component losses. Without ore averaging systems flotation process is characterized by considerable fluctuations of all input, output and intermediate parameters. Stab One more way is optimizing the process, providing for determination and maintaining optimal parameters of the process. In these conditions application of various mathematic models does not allow controlling the process by the way of action on input parameters of the process with further precise reaching required values of output parameters. More effective is to be application of flotation models for solution of questions of choosing and optimizing of automatic control systems. The work presented examples of application mathematic model of flotation process for estimation of effectiveness and choice of parameters of automatic control system that reduces considerably a stage of preliminary studies in elaboration, designing and modernizing automatic control systems.

Jan 1, 2014

By Xiao Jian Li, Dai Xiong Chen, Jian Wen Yang

In one kind of lead and zinc bearing polymetallic ore containing secondary copper, the characteristic of low sulfur, high zinc, and particularly the existing of secondary copper minerals can lead to lead concentrate with high content of zinc because the dissociation of Cu2+ in the grinding process may have an activation influence on sphalerite. Considering its process mineralogy analysis, a new process of seperation of lead and zinc has been put forward. The experiments focused on the analysis of the advantages and disadvantages of the inhibition effect of traditional adjustment reagent + zinc sulfate on activated sphalerite compared with new organic inhibitor, polysaccharide xanthate. According to the numerical calculation and test results, a reagent system of polysaccharide xanthates is developed, which has a good inhibition effect on Cu2+ activated zinc minerals, achieving high-efficiency separation of lead and zinc. A new reagent system and flotation process was developed under optimal conditions. Under the condition of the run-of-mine ore containing 2.37% Pb and 12.48% Zn, lead of 67.69% grade and lead concentrate with the recovery rate of 86.06%, zinc of 60.32% grade and zinc concentrate with the recovery rate of 96.15% were achieved.

Jan 1, 2014

By Kwan Ho Kim

In this study, free fall tests are conducted with the objective of understanding the breakage properties of waste concrete for the guide of the direction of the better comminution process. Waste concrete of 75mm×53mm is tested at various drop heights with or without heat pretreatment. Test results indicate that a block of waste concrete does not break by free fall, but eventually breaks by repeated free falls. The number of free falls required for complete separation of large aggregates from the cement mortar considerably reduced when the samples were heated at 400?. Therefore, a great energy saving can be obtained when heating the waste concrete prior to crushing. The energy saving was found to be dependent on the height of free fall but in all cases, was still large enough to offset the additional energy required for heating. Also, it was found that the heat pre-treatment gives an additional advantage in that it produced cleaner recycled aggregates. This may result from easier detachment of cement mortar from the aggregates due to weakening of bonding forces by heating. By analyzing the size distribution of the crushed product, a free-fall breakage model is developed using the particle breakage ratio and the breakage pattern. The developed model can be used to predict and to analyze waste concrete processing circuit.

Jan 1, 2014

By Chris Harris, Kamal Adham

The use of HCl acid is gaining momentum among hydrometallurgical processes. However, the issue of environmentally efficient and economically viable ways to regenerate HCl acid (from various metal chloride intermediate products) remains a technology and operational challenge. The authors provide a state-of-technology review based on Hatch’s years of testing, design and commissioning experience with high-temperature units (fluid bed and spray roasters), plus the recent efforts in the area of low-temperature HCl regeneration.

Jan 1, 2014

By Paulo Castillo, Cesar Gomez, Jaime Alvarez

Operations using flotation to produce mineral concentrates require testing of frothers to characterize their ability to preserve bubble formation size and to build a stable froth. Many techniques have been proposed to measure parameters associated with these two roles. These techniques focus, in general, on only one of these roles and are based on special equipment operated at conditions quite different from those existing in industrial cells and columns. Both roles have been simultaneously characterized in a laboratory flotation column, but the requirements associated with the installation and operation of one of these units, are a serious limitation for its use on-site. A technique based on the use of a laboratory mechanical cell, a common piece of equipment in operations, will have wider application. Establishing the ability of a frother to control coalescence by preserving bubble formation size is done through bubble size measurements as a function of frother concentration. Froth build-up and stabilization is associated with the amount of water carried by bubbles into the froth layer, which has been demonstrated to correlate with the gas holdup in the collection zone. Procedures devised for determining the critical coalescence concentration (CCC) from measurements of bubble size as a function of frother concentration, and the gas holdup by collection of water displaced from the cell by the presence of bubbles at different frother concentrations, were tested. Three analytical-grade frothers were utilized: a straight-chain (1-heptanol) and a branched (MIBC) alcohol and a polyglycol (PPG425). The results obtained at a standard set of conditions, demonstrated consistent differences between these frothers, and the ranking from least to most effective for reducing bubble size or decreasing water drainage followed the same sequences found when more complex frother characterization techniques are used.

Jan 1, 2014