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By Gavin Erickson, Lucas R. Moore, Clint Stoddard, Garret Bryant

As global mineral feed grades decline, phosphate beneficiation faces mounting challenges. Chief among these being achieving high recoveries of industry quality concentrates from ores of decreasing quality. Apatite, a critical mineral for meeting global fertilizer demand, remains the primary source of phosphorus and is typically recovered through beneficiation by multi-stage flotation. However, traditional saponified fatty acid collectors lack the selectivity needed to beneficiate these lower quality ores, which are containing a higher concentration of more complex gangue minerals. Enhancing collector performance is essential to the industry moving forward. This study introduces a novel alkyl polyglucoside based surfactant designed as an additive for conventional fatty acid systems. Its incorporation significantly improves the grade recovery in direct apatite flotation, even at low concentrations. Flotation results as well as surfactant properties will be discussed.

Feb 22, 2026

By M. S. Safarzadeh

Cu-As feedstocks are among the most problematic copper sources that have been avoided over the past years. The high arsenic content of such ores/concentrates combined with their refractory nature have directed the metallurgical industry towards developing efficient technologies for the treatment of high-arsenic copper ores/concentrates. As the most important member of Cu-As-S mineral system, enargite (Cu3AsS4) is frequently encountered in some of the important copper deposits. Several hydrometallurgical and pyrometallurgical processes have been examined for the treatment of enargite concentrates, but currently, no commercial operation exists. In an effort to develop an original processing option, an acid bake-leach process has been identified and applied to an enargite concentrate containing ~67% enargite, ~27% pyrite (FeS2), ~3% chalcopyrite (CuFeS2), ~6% sphalerite (ZnS) and <1% galena (PbS). Sulfuric acid baking of this concentrate resulted in the transformation of the concentrate to S8, As2O3, HFe(SO4)2?4H2O, PbSO4 and Cu0.47Fe0.53SO4?H2O, all of which (except elemental sulfur and PbSO4) dissolved during the water leaching step. More than 87% Cu and 64% As were leached when the concentrate was baked at 200°C over 7 h with a sulfuric acid to concentrate weight ratio of 1.6. Less than 1% As was lost to the gas phase. Upon water leaching, copper and arsenic were released to the solution at a concentration ratio of about 3:1. While enargite is very reactive during the sulfuric acid baking reaction, other minerals present in the concentrate such as pyrite, galena, and sphalerite may compete to consume sulfuric acid and be converted into their corresponding sulfates at different levels. The purpose of this paper is to evaluate phase transformations during the acid bake-leach process for the treatment of an enargite concentrate, and to study the effect of sulfuric acid dosage on the extraction of Cu, Fe, and As. In this regard, the concentrate, baked concentrate, and the leach residues are characterized and a conceptual process flowsheet is described for the acid bake-leach process for the treatment of enargite concentrates.

Feb 23, 2014

By J. A. Organiscak

Enclosed cab filtration systems are typically used on mobile mining equipment to reduce miners? exposure to airborne dusts and diesel particulates generated during mining operations. Various filter configurations can be used within the heating, ventilation, and air conditioning (HVAC) systems of cabs to remove the airborne contaminants. The air cleaning performance of cab filtration systems is highly dependent on the efficiency of the air filters, the number of filters used, and their placement within the HVAC system. This paper shows how to mathematically model cab filtration systems and illustrates a methodology for developing other cab filtration system design models. Node diagrams of several filtration system circuits are illustrated with their mathematical models at steady state airflow and concentration conditions. Laboratory and field data are presented to demonstrate the validity and utility of modeling enclosed cab air cleaning performance. The paper concludes that incorporating multiple filters throughout the HVAC system improves the air cleaning performance and robustness of the cab filtration system design.

Feb 23, 2014

By Calvert D. Iles

Open-pit mines in the US and throughout the world are typically characterized by increasing operating costs and decreasing ore grades. Thus, companies must continue to improve their use of human and technological resources to remain competitive in the marketplace. Duval Corp. has historically been very sensitive to mining costs, in part because of relatively low grade copper-molybdenum ore bodies. These concerns have resulted in three haulage system generations at the 218 kt/d (240,000 stpd) Sierrita-Esperanza open-pit mine south of Tucson, AZ. Each generation has exceeded the performance of the one replaced. The latest system of portable crushers and conveyors reduces hauling costs by combining both hardware and technique. Savings are achieved not only bysubstituting conveyors for haul trucks, but also by permitting the crusher-convey or system to closely follow mining as the pit deepens and/or mining areas change location. The Duval system is capable of easy and inexpensive relocation in varying site configurations in relatively short time periods. Its implementation in active mining areas results in minimum disruption to both the mine operation and mine design. This haulage concept allows the mining engineer maximum freedom to design an open pit for profit rather than for equipment. Maximum savings with a portable system are achieved by minimizing truck haulage costs. At Sierrita, for example, the yearly estimated operating cost savings for each thousand feet of +10% truck ramp replaced by conveyors is about $1 million per portable crusher. A savings of $30 million could be achieved fora three-portable system overa 10 year period simply by reducing the average truck Iiftto the crusher by 30 m (100 ft), There is also the added capital expense of buying trucks to cover the additional 30 m (100 ft) of lift. Relocation costs are an important consideration in a portable system. Direct costs can become a significant operating expense if frequent relocations are necessary to take full advantage of potential haulage cost savings. A site preparation cost of $375,000, for example, would add an additional operating cost of 2.8¢/t(2.5¢/st) for a system handling 13.6 Mt/a (15 million stpy), assuming one move a year, In addition to the direct cost of site preparation, such as installation of retaining walls, apron feeder slots, and equipment pads, there is the cost of site renovation after abandonment. Indirect relocation costs, while less tangible and more dependent on specific mine design and scheduling, can be of significance. A slowdown in the mining rate or a less efficient mining plan can result from a site not being immediately available for mining after abandonment. Conversely, mining in narrow areas can be adversely affected if two or three month lead times are required for site preparation.

Jan 4, 1983

By T. H. Combs

Increased productivity in the U.S. underground coal industry has taxed pre-existing conveyor belt haulage systems. The usual remedies are costly and can disrupt production. A reduction in the belt feeder discharge rate on mobile haulage sections results in more uniform loading and reduces the spillage vulnerability. An investigation is made to determine the effect, if any, on shuttle car discharge time arising from lower feeder discharge rates. A five-section, underground mine is visualized, and belt spillage is introduced. The sectional feeder discharge rate is progressively lowered until spillage is precluded. At each level, the simulated spillage is measured and compared to the loss in face production. Methods of predicting the loss in face production from lower feeder discharge rates are discussed.

Jan 1, 1993

By Jr. Smith

Borates have been mined in the desert areas of California and Nevada for more than 100 years. To about 1890, playa surface mining provided the chief sources of boron minerals. Underground mining of colemanite and later of borax and kernite was predominate until about twenty years ago. Open pit mining of the large deposits of borax and kernite near Boron, California has been most significant for the past twenty years. Mining of colemanite in the Ryan, California area, near Death Valley, began in 1907. Following the discovery of the large deposits in the Boron area (about 1957), mining in the Death Valley area became nearly nonexistent. Only small tonnages were mined for special uses. Little mining was done in the Boraxo area near Ryan. The first claim was made in about 1915 In 1960 the area became the property of the Kern County Land Company, which was acquired by Tenneco Oil Company in 1967. In 1976 the various borate properties and claims in this region were acquired by American Borate Corporation. The open pit mine is now approximately 400 feet (121.9 m) deep, 3000 feet (914.4 m) long and 1000 feet (304.8 m) wide. The borates in the Boraxo pit consist primarily of three minerals. These are about 50% coiemanite (C2B6O11&apos; 5H2O), about 40% probertite (NaCaB5O9.5H2O), and 10% ulexite (NaCaBcO9.8H2O). The colemanite, along with boric acid and high-grade coiemanite ore from Turkey provide the only sodium-free borates for production of textile grade fiberglas. When heated to its decomposition temperature, colemanite decrepitates to a fine powder. This provides the basis for the concentration process. The gangue minerals in this deposit are primarily calcite and clays, including bentonite. The ore body has a very low arsenic content.which is a desirable feature. Test work had been done with samples prior to the results discussed herein. This paper will discuss results of test work which were the basis for erection of a plant, and the subsequent plant operations.

Jan 1, 1978

By A. L. Coello Velázquez

The subject of this paper is particle population balance models (PBM) that describe mineral impact crushing behavior; it is mainly concerned with the selection and fragmentation distribution function due to their importance in this context. The data obtained by Datta (1999) by applying impact pendulum testing to single limestone particles, used by Austin (2002, 2004a and 2004b) to obtain the principal parity of fragmentation functions, were processed in order to compare them with the results of other authors, such as Nikolov (2002 and 2004) and Vogel and Peukert (2003 and 2005) so as to increase knowledge of impact crushing. From this data it has been possible to obtain the performance models of the principal parameters of fragmentation function, thereby reducing the number of experiments necessary to model the impact crushing process. The authors also propose a simplification of the selection function model posited by Austin (2002).

Jan 1, 2011

By Stephen C. Moore

The Grossschloppen vein-uranium deposit, Bavaria, West Germany, was examined utilizing underground workings during 1980-82 by Esso Erz GMbH, an affiliate of Exxon Minerals Company (EMC). Geologic evaluation entailed dense drilling of a portion of the deposit from workings constructed specifically for the program. Discovered in 1977, the deposit was initially explored by surface diamond drillholes which allowed definition of a 30-60 m wide vein system discontinuously mineralized along a 1000 m strike length and to at least a 450 m depth. The underground program was conceived as a cost effective procedure to answer questions on vein correlation, grade continuity and variability. A 1200 m decline allowed access for detailed sampling of approximately 10% of the known area of mineralization. Fanned drillholes, logged by gaga probe, were spaced to provide intersections of veins at 10 to 20 m intervals. Six cross cuts also penetrate the pitchblende and uranophane mineralization which occurs in 0.1 to 2.5 as thick quartz veins. Detailed cross-sections and level plans were constructed for resource estimates of the intensively studied portion of the vein system. The program resulted in the discovery of local, high grade areas and an average grade in the evaluated area nearly double that expected from surface drilling.

Jan 1, 1983

By F. Stanley, A. Noble, G. Luttrell

"The supply chain for coal-fired power stations involve a multi-stage network of mining units, preparation plants, blending facilities and transportation systems. Attempts to optimize the supply chain have historically been difficult due to the lack of communication/coordination between the various groups involved in coal production, transportation and utilization. In light of this issue, a new approach for globally optimizing the coal supply chain called Micro-Price Optimization has been developed to simplify the optimization problem and to provide coal producers with fundamental insight needed to improve the profitability of their operations. This fundamental concept assigns unit values to each particles (or groups of particles) passing through production units. Optimization occurs whenever the maximum tonnage of positive value particles are recovered and passed to market, while the minimum tonnage of negative value particles are recovered. Elements considered by the concept include factors such as target boiler cost/efficiency, waste disposal costs, coal quality parameters, emission penalties, transportation charges, or other quantifiable impact factors. This article reviews the basis for the micro-price concept and provides a detailed industrial case study involving the determination of optimum coal qualities that need to be supplied by mine operators to feed a coal-fired power station. INTRODUCTION The performance of coal preparation plants have long been known to play an important role in determining the overall profitability of mining operations. This significance is due to the fact that the misplacement of just 1 ton/hr of clean coal to reject resulting from poor plant performance can represent nearly $300,000 per year in lost revenues for a mine producing a steam market coal (i.e., 1 ton/hr x $50/ton x 6,000 hr/yr = $300,000/yr). This loss can be even more pronounced, occasionally approaching $1 million per year for each 1 ton/hr of misplaced clean coal, for operations producing high-quality coking coal products sold into the premium metallurgical market (i.e., 1 ton/hr x $150/ton x 6,000 hr/yr = $900,000/yr). Detailed economic studies indicate that improvements in plant yield resulting from increases in organic efficiency have one of the largest overall impacts on mine revenue when compared to other cost centers within the mining operation. One of the first studies to show this important financial impact was reported by Norton-Hambleton Consultants (Norton, 1979). Their study indicated that an unfavorable change in plant efficiency was second only to coal transportation in terms of its impact on profitability, while an unfavorable change in the cost of underground mining was a distance third. This longstanding realization has continued to provide a strong financial incentive for coal producers to optimize the separation efficiency of their coal processing and blending operations."

Jan 1, 2015

By S. S. Klima, H. Jiang, T. W. Beck, Y. Zheng

Researchers at the National Institute for Occupational Safety and Health (NIOSH) performed a series of lab tests to evaluate the respirable dust removal capacity of an industrial air-cleaning fan. Limestone and coal dust were tested separately in NIOSH’s full-scale drill table simulator at the Pittsburgh Mining Research Division (PMRD). Gravimetric samplers with Dorr-Oliver Cyclones and 37-mm filters were used at two upstream and four downstream locations inside and outside of the drill shroud chamber. There were six tests performed for both the limestone and coal dust experiments. In the limestone tests, an average respirable dust concentration of 98.86 mg/m3 was achieved upstream of the air-cleaning fan. The filter results show that the averaged respirable limestone dust reductions were 7.84%, 8.81%, 10.94%, and 18.02% at the four sampling locations downstream of the fan. In the coal tests, upstream samplers achieved an average of 129.03 mg/m3 of respirable coal dust. The averaged dust reductions were 9.54%, 9.83%, 18.54%, and 19.21% at the four downstream sampling points. The results indicate limited cost benefits of using this technology because of the relatively low dust reductions determined from this laboratory study.

Feb 1, 2023

By Göksel Hızlı, Selim Ertürk, Ayşegül Bilen, Raşit Sezer, Cüneyt Arslan

The carbothermic reduction of celestite is the first step in producing many strontium products. The way materials move in the rotary kiln has an essential effect on the carbothermic reduction efficiency as well as the temperature. In this study, the reduction of celestite ore and excess carbon blend in a laboratory-scale rotary kiln was investigated. In the experiments carried out at three different temperatures, the rotational speed and slope of the furnace tube were altered, and their effects on the reaction efficiency were examined. The leachability of the reduced powders and the content of the unburned coke indicated the optimal parameters for the reaction.When the speed was increased to 10 rpm, the powders weremoremobile in the stack and could react more easily with the furnace atmosphere. According to the results, celestite can be reduced by carbon at temperatures of 1000–1200 °C, at rates of between 5% and 75%. The maximumreaction yield (75%) was obtained with a slope of 2° and a rotational speed of 6 rpm at 1100 °C.

May 7, 2020

By G. A. Kordosky

There are a number of reasons why the solvent extraction of molybdenum deserves attention: 1. The solvent extraction chemistry of molybdenum is interesting and complex, 2. The price of molybdenum is predicted to average about US$ 20.00 / pound in 2010 and, as China, India and other countries develop, the demand for specialty steels will increase putting long term demands on molybdenum supply, 3. Uranium ores often contain significant concentrations of molybdenum[1] and typically yellow cake will have a moly specification which when exceeded brings penalties, and 4. The valuable metal rhenium is a byproduct of molybdenum recovery circuits.

Jan 1, 2010

By D. Akers

Many of the trace elements found in coal are associated with mineral matter, making it possible to remove them by physical coal cleaning. As part of work funded by the Electric Power Research Institute, both conventional and advanced coal cleaning processes were found to provide large reductions in the concentration of many trace elements that, if released into the atmosphere, are considered to be potentially toxic or environmentally harmful. Advanced physical cleaning technologies appear to provide greater reductions than conventional technologies. Chemical cleaning processes may also remove many trace elements, possibly including organically-bound elements such as beryllium. Care must be taken in the disposal of coal cleaning plant refuse because oxidation and leaching of this material can create highly acidic leachate and many trace elements are mobile in an acid environment. Laboratory leaching procedures are potentially useful in determining the degree of risk of water contamination by trace elements should an acid environment form.

Jan 1, 1992

By V. Anthony Cammarota

MINERALS INFORMATION PROGRAM Mineral data collection by the Federal Government actually began in 1882 with an appropriation by Congress to the U.S. Geological Survey (USGS). Although the Bureau of Mines was instituted in 1910, it was not until 1924 that the collection, interpretation, and dissemination of worldwide information on production, consumption, and availability of minerals became the responsibility of the Bureau. The objective of the Bureau&apos;s minerals information program is to maintain and provide reliable, timely, and comprehensive data for analysis of national minerals problems. This program is implemented by a staff of specialists who cover about 100 mineral commodities and the mineral industries of 168 countries. Data are also provided on the minerals industry on the State and county level. The specialists analyze information to identify trends and problems, forecast future U.S. and world supply and demand for the nonfuel minerals, and relate trends and developments to their impact on the domestic minerals industry. Data Sources and Publications The primary sources of data concerning the domestic minerals industry are the companies that produce, use, and trade in these minerals. Approximately 60,000 survey forms are sent to industry, on a monthly, quarterly, semiannual, or annual basis, to obtain the data. Domestic trade data are provided by the Bureau of the Census, U.S. Department of Commerce. Information on mineral developments abroad is developed by Bureau specialists from mineral reports supplied by U.S. embassies worldwide, from primary source documents, from a review of the technical mining literature, and from onsite mine and plant visits in foreign countries. The information is disseminated through a number of Bureau publications: "Mineral Industry Surveys" provide aggregated data on a monthly. quarterly, or semiannual basis to give timely information on the most important mineral commodities. "Mineral Commodity Summaries," published each January, provides preliminary annual data on supply and demand and discusses significant events of the previous year. The final data are published later in the "Minerals Yearbook," which is the definitive historical record for mineral statistics. "Mineral Facts and Problems," an encyclopedic work issued every 5 years, covers industry structure, technology, supply-demand analysis. economic factors, reserves, and forecasts of U.S. and world demand for individual commodities. "Mineral Perspectives" and "Mineral Issues" cover important international mineral developments and significant issues of current U.S. policy as they relate to minerals. Discussions and analyses of mineral trends and developments also appear in other Bureau publications, such as "Minerals and Materials" and "Information Circulars." These publications provide the basis for analysis and policy determinations by the Bureau and by virtually every Federal agency concerned with minerals, defense issues, the national economy, and foreign relations. The data are also used by industry in planning capital investments in mines and processing plants, by financial analysts, by U.S. delegations in their work with international commodity groups, and by a host of other minerals related organizations. Data Bases The data bases used by the specialists for preparing publications or in response to a continuous stream of inquiries include both those that contain individual commodity data from respondents, and those that are summary data bases on production, trade, capacity, employment and a number of other minerals-related items, not all of which are derived from data reported to the Bureau of Mines. The data bases maintained on the mainframes are not accessible by non- Bureau users. A 10-year data base of supply- demand data, published each year as an update of tables that appear for each commodity in Mineral Facts and Problems, is available on a floppy

Jan 1, 1987

By L. G. Hagenbuch

Several factors need to come together in creating an integrate mining equipment dispatching system. At the hub of these factors ace the central dispatching formulas. This paper details the development of these central dispatching formulas and explores the combining of these formulas with other elements to create an integrated dispatching decision. WHY DISPATCHING? Truck dispatching implies and in reality should equate to mine equipment efficiency. Good truck dispatching will yield good mine equipment efficiency while poor truck dispatching will yield the alternative. Truck dispatching can either be automated through a computerized, process or it can be manual. Every mine with haul trucks has a truck dispatching system whether it is recognized or not. Even a system wherein the hauler operators determine where they are going for their next load is a truck dispatching system.

Jan 1, 1987

By T. J. Lutz, L. Yan, J. R. Srednicki, J. A. Yonkey, G. T. Homce

"Federal regulations require the installation of refuge alternatives (RAs) in underground coal mines. Of the in-use RAs, over 95% are mobile RAs with the remainder being built-in-place (BIP) RAs. Heat/humidity buildup has been one of the major concerns with mobile RAs. For BIP RAs, however, there is a lack of in-mine heat/humidity test data to determine the extent of heat and humidity buildup. To quantify heat/humidity buildup in BIP RAs, the National Institute for Occupational Safety and Health (NIOSH) performed a series of heat/humidity tests on a 60-person BIP RA with and without a borehole air supply. At various times during the year, tests were performed with cooled, heated, or unconditioned borehole air to examine how various outdoor temperatures may affect the thermal conditions inside a BIP RA. The results show that the air supplied to a BIP RA may require heating and cooling, depending on the outside air temperatures and the temperature of the mine. For example, during tests with an external ambient temperature above 70°F and a humidity that reached 90 %RH, providing 55°F dew point air was able to keep the internal apparent temperature below the mandated 95°F. Results for each test case are presented. INTRODUCTION The Mine Safety and Health Administration (MSHA) has required the installation of refuge alternatives (RAs) in underground coal mines since 2008 [1]. MSHA requires that RAs provide an environment with breathable air for entrapped miners for a 96-hour period. Heat buildup inside an occupied RA is a serious concern. Without a means to dissipate the heat and humidity generated by the occupants and the carbon dioxide scrubbing system, the temperature and humidity inside RAs could lead to severe discomfort or heat stress depending on the mine ambient temperature before and during occupation of the RA. In its 2006 report, the West Virginia Mine Safety Technology Task Force recommended an apparent temperature limit of 95°F for RAs [2]. In 30 CFR 7.504, MSHA specifies a maximum apparent temperature of 95°F inside an occupied RA [3]. The apparent temperature is calculated using both air temperature and relative humidity [4]. To determine if their RAs meet the apparent temperature limit, RA manufacturers have been performing 96-hour-long heat and humidity tests in laboratories. During these tests, a heat input of 117 W (400 BTU/hr) per person is used to represent the metabolic heat of a single miner [2]. The heat generated by the RA’s carbon dioxide system is also accounted for in testing. To account for this heat, 50 W (170 BTU/hr) of heat per miner is used for a lithium hydroxide scrubbing system, or 30 W (100 BTU/hr) of heat per miner is used for a soda lime scrubbing system [5]. In these tests, air velocities around the RA are minimized to represent the worst-case scenario of an interruption in mine ventilation that might occur in a mine disaster."

Jan 1, 2017

By E. A. Schmidt

The Thompson Creek molybdenum deposit is located in the Bayhorse mining district about 20 air miles southwest from Challis, Idaho. Cyprus Mines Corporation began exploration on the property in 1968, and at present is in the pre-production stripping phase. Molybdenum mineralization is contained in a late Cretaceous (88 m.y.), composite, biotite granodiorite-quartz monzonite intrusive complex. The complex intruded carbonaceous argillites, causing local silicification and hornfelsing of the sedimentary rocks. The main portion of the orebody is unconformably overlain by up to 1000 ft of Challis volcanic rocks (49 m.y.). Surface mineralization and related rock alteration can be recognized over a 2500- x 8000-ft area extending northwesterly from the discovery outcrop. Molybdenite occurs in a network of subparallel quartz-biotite-muscovite-orthoclase veins and veinlets within the intrusive rocks. The zone of +0.020/0 Mo mineralization outlines a steeply dipping tabular configuration in the main orebody and gradually changes into a hood-shaped configuration along strike to the northwest. The overall grade [ ] of the deposit is controlled by the abundance of the quartz- molybdenite veins and veinlets in the intrusive rock. Very little disseminated mineralization is present, and no economic mineralization occurs in the argillaceous sedimentary rocks. Muscovite, biotite, and orthoclase/microcline define three alteration zones that conform with the overall zone of mineralization. The upper alteration zone contains dominantly muscovite and sericite associated with quartz veins. The central zone contains coarse biotite and locally orthoclase and microcline. Molybdenite is most abundant within this zone. The lower zone contains thin envelopes of orthoclase/microcline around quartz veins. Based on about 313,000 ft of drilling and 8592 ft of underground development work, computer-derived ore reserve calculations indicate 200 million tons averaging 0.1 1% Mo at a 0.050/0 Mo cutoff grade with a waste to ore stripping ratio of about 3:l.

Jan 1, 2013

By Y. J. Zhang

This paper presents the results of a recent study on the development of an in-situ testing method for determining the coal strength in mine pillars. The strength testing is performed in the horizontal holes drilled into the coal rib using the penetrometer. It is a hydraulically powered device that uses an indenter to press the surface of the borehole until the load reaches the failure point of coal. The pressure and the penetration of the loading pin are recorded by the data acquisition unit. The results collected from several coal mines indicate that this testing method is ideally suited for the realistic coal strength measurements. The new testing system not only improves the accuracy of pillar strength determination, but it is more cost efficient than the conventional method.

Jan 1, 1995

By S. Corrent, F. A. V. Guimarães, M. G. Barbosa

"INTRODUCTION Moisture can be a villain, so new technologies have been explored to make more viable the production of high moisture iron ores. The current work presents the attempt of the utilization of a superabsorbent polymer (SAP) to aid in the screening process and in the ore handling process, such as stockpiles reclaiming and vessels/trains discharge in sub-zero temperature conditions. The results have shown that the polymer can be used in certain cases to improve productivity and increase safety in the process of handling the material (by increasing the TML). However, for size separation no advantages were found upon the use of the polymers. WATER ADSORPTION MECHANISMS The use of water in mineral processing is constant as its utilization brings an increase in the efficiency of separation. Although we have better results in the processing with water, materials with a high content of “natural” moisture can be very difficult to be treated by the conventional methods of separation. Nowadays many studies have been conducted in order to understand the effect of adsorption of water in the particles of complex minerals. Those studies have being divided in many different lines of research such as contact angle of a drop of water and the surface of the mineral to determine hydrophobicity, the particle size distribution and the porosity of particles. Mainly two forms of adsorption of water by the particles are possible: one the water is retained inside porosity of the particles. Laboratory tests developed in China have showed that capillary adsorption is faster in coarser particles that achieve the saturation degree earlier than finer particles (Xuewei Lv et al., 2011). The so called non-porous model considers the effect of water in the bulk sample of iron ores, in a physical connection when all the water works as a binder between particles as shown in the figure 1.If we take into account the compressibility of the system and compaction due to the weight of the bed over the particles, the thickness of the water film between particles is the same but the volume inside different particle size systems is much higher than in a system with particles of same size."

Jan 1, 2018

By J. Kou

In this paper the activation behavior of quartz using Ca(OH)2 as an activator in quartz reverse flotation with anionic collector was evaluated and their adsorption behavior was investigated using a variety of techniques. The adsorption of the collector KS-I on the surface of quartz with and without Ca2+ was primarily characterized using Quartz Crystal Microbalance with Dissipation technique (QCM-D), which is a high sensitivity in-situ surface characterization technique. The flotation performance was evaluated using a laboratory mechanical flotation cell at different process parameters such as pH, collector dosage, and Ca(OH)2 dosage. The anionic collector evaluated was a commercial fatty acid KS-I. The QCM-D data showed that the collector adsorbed on quartz more readily with Ca2+ as activator. The mass and structural property of the collector layer adsorbed on quartz surface at 2.16×10-3 mol/L of Ca2+, 0.3 g/L of collector and pH 12.0 have been studied using the technique of QCM-D. The chemisorption of the collector KS-I on the surface of quartz in presence of Ca2+ were also demonstrated by means of zeta potential, QCM-D and FTIR analysis.

Feb 23, 2014