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By Earle Faig

Earle Faig Along with other transportation modes, the barge industry will be greatly affected by trends in domestic coal production. Traditionally, coal has been one of the major commodities moved by barge. Now, because of events in the international energy market, coal is finally getting the recognition it deserves as a major component of the country's energy program. Perhaps even more significantly, a series of events has caused other countries to turn to the United States as a source of coal. Although the outlook for coal demand is optimistic, it will be greatly influenced by the ability of the transportation sector to handle the additional traffic. Because of its long experience in moving large quantities of coal, the barging industry is in an excellent position to capitalize on coal's increased popularity. A brief description of the barging industry should facilitate the discussion of coal as it relates to that industry. Barge companies operate on a river system that is over 40 Mm (25,000 miles) long. It includes the East and West Coasts and the Mississippi River System comprised by the Allegheny, Monongahela, Kanawha, Ohio, Illinois, Missouri, Tennessee, Cumberland, Arkansas, Warrior-Tombigbee, and Mobile Rivers, and some smaller tributaries. The Gulf Intracoastal Waterway stretching along the Gulf Coast from Brownsville, TX, to Apalachicola, FL, also is considered part of the inland waterway system. Approximately 1,800 companies operate on the inland river system and have a combined fleet of about 4,400 towboats and 28,000 barges. The fleet of towboats represents 4.8 GW (6.4 million hp) of power. The towboats comprising this fleet vary in size from a small harbor boat to a large line haul boat with 7.5 MW (10,000 hp) of power. The choice of size and power of the boat depends on a number of factors, including the size of the river and operational constraints, such as lock size, river-current rate, and water level. The choice also depends on the tow size. A single tow on a river capable of locking through 15 barges at a time handles up to almost 20 kt (22,000 st), whereas a tow on the lower Mississippi, which has no locks, can accommodate up to 41 kt (45,000 st) of cargo. Because the quality of coal is not typically damaged by exposure to the elements, it is usually moved in open hopper barges, although covered barges are used occasionally. The most frequently used size is the jumbo barge that measures 59 m (195 ft) long by 11 m (35 ft) wide by 4 m (12 ft) deep and can handle up to 1.4 kt (1,500 st) of coal. Advantages of Barge Transportation Barging offers several inherent advantages in transportation of bulk commodities like coal. First, barges can carry large quantities of product. A single jumbo hopper barge can handle 1.4 kt (1,500 st) of cargo while it takes 15 91-t (100-st) capacity rail cars or 57 trucks hauling 24 t (26 st) each to move an equivalent amount of cargo. Thus, barges can move more tonnage with less equipment than competing forms of transportation. Second, barging offers the most fuel efficient means of transportation. Less energy is required to push a load over water than to pull a similar load over land. The amount of pollution attributable to barge traffic is minimal because barges consume less fuel. Third, barging is an inexpensive form of transportation. The inland waterway industry transports about 12% of the nation's freight for about 2% of the total freight bill. This can be attributed to competition between the large number of companies on the river system and competition with other transportation modes. Fourth, barging is an environmentally safe method of transportation. Inland river routes expose fewer urban areas to hazardous substances than rail or truck. And barge spills occur less frequently than rail or truck spills. The industry does pose some disadvantages. The waterway system is constrained by the natural river network, so barges cannot travel on the most direct straight-line route. This means that barging is usually an incomplete form of transportation requiring interface with truck or rail. The industry's market is limited to those geographical areas that are located on or near the rivers. In addition, it is a time-consuming transportation mode, making it impractical for many types of commodities.

Jan 10, 1982

By K. P. Stricker, H. Keddeinis, K. Grebe

Recent investigations by Mannesmann Research have shown that disintegration of sinter with widely varying quality levels is subject to a much more complex set of influences than was previously assumed. It was confirmed that disintegration at temperatures between 300° and 600°C (570° and 1,110°F) is triggered by the degradation of hematite. The specific tendency of hematite to disintegrate is, however, not constant: sinters containing the same amount of hematite can show widely differing disintegration tendencies, depending on structural homogeneity, porosity, and gangue quantity. Sinters with heterogeneous structures transmit stress to the hematite phase and this favors disintegration. Another factor is the brittleness of the glassy silicate phase, which can be influenced even by small modifications of minor gangue constituents.

Jan 2, 1984

By Paul F. Ziemkiewicz, Aaron Noble, Christopher R. Vass

Many modern industries rely on rare earth elements (REEs) to produce products that are essential to both civil and defense applications. In a prior study (Vass et al., 2019), the authors showed that REE grades in acid mine drainage (AMD) and associated byproduct precipitates from AMD treatment (AMDp) warrant evaluation as a feedstock for REE production. The current work extends that effort through a broad survey of 141 AMD treatment sites in Northern and Central Appalachia. In this study, 185 raw AMD and 623 AMDp field samples were obtained and analyzed to assess the REE and major metal concentrations. Results show that an average of 282 μg/L and 724 g/tonne of REEs occur in AMD and AMDp respectively. Additionally, both basins contained similar distributions of REEs, and these distributions tended to favor heavy and critical REEs when compared with traditional REE ore deposits. Geospatial analysis identified a total resource of 340 tonnes stored at the 141 sites sampled in this study. While this analysis did not quantify the basin-wide REE inventory, it does indicate the impact that processing cut-off grades will have on the overall AMDp resource base.

By Paul F. Ziemkiewicz, Aaron Noble, Christopher R. Vass

Many modern industries rely on rare earth elements (REEs) to produce products that are essential to both civil and defense applications. In a prior study (Vass et al., 2019), the authors showed that REE grades in acid mine drainage (AMD) and associated byproduct precipitates from AMD treatment (AMDp) warrant evaluation as a feedstock for REE production. The current work extends that effort through a broad survey of 141 AMD treatment sites in Northern and Central Appalachia. In this study, 185 raw AMD and 623 AMDp field samples were obtained and analyzed to assess the REE and major metal concentrations. Results show that an average of 282 μg/L and 724 g/tonne of REEs occur in AMD and AMDp respectively. Additionally, both basins contained similar distributions of REEs, and these distributions tended to favor heavy and critical REEs when compared with traditional REE ore deposits. Geospatial analysis identified a total resource of 340 tonnes stored at the 141 sites sampled in this study. While this analysis did not quantify the basin-wide REE inventory, it does indicate the impact that processing cut-off grades will have on the overall AMDp resource base.

By QINGXIANG CAI, Lin Li, PENG LIU, IZHAR MITHAL JISKANI, XIANG LU, Wei Zhou, YONGLI ZHOU

Green mining is the latest technological advancement to reduce mining’s environmental impact with minimal energy and resource consumption. Green mining — aimed at protecting nature and providing socio-economic benefits — is a multifaceted network of its connotations and key indicators. China has not yet defined its connotation and formed an effective evaluation system for surface mining. We defined its connotation and developed an evaluation index system based on the theory of green grades. As the indicators are selected based on extensive research, they express the advantages and disadvantages of various aspects of a mine. The index is composed of three attributes (safety, efficiency and environment), nine criteria and 35 indicators. The indicators were quantified according to experts’ opinions using the fuzzy comprehensive evaluation method. The results of a case study show that the environment is the most critical aspect, followed by efficiency and safety. This study can provide technical support for the development of green mining.

By Magnus Ericsson

The unexpectedly quick recovery in world crude steel production in the second half of 2009 was due almost entirely to increased production in China that began in late 2008. Previous peaks in monthly production in China were matched by April 2009. The rest of the world had still not reached pre-crisis production rates by May 2010. Chinese production drives growth, but there has been some growth in most other larger crude steel producing countries as well, compared to production in 2009. If the production rate of the first four months of 2010 continues, the total output of crude steel in 2010 will be somewhere around 1,410 Mt (1.5 billion st), the same as in the record year of 2007.

Jan 1, 2010

By Ricardo Oliveira Gallart de Menezes, Claudio Gerheim Porto, Reiner Neumann

The Jiboia heavy mineral sands deposit is a new discovery associated with the São Francisco River delta on the northern coast of Sergipe state. The identified resources are part of the much larger mineralized trend. Mineralization is hosted in paleodunes deposited on Holocene marine terraces (Fig. 1). The dunes are up to 30 m above sea level, and mineralization occur from 6 m above sea level upward. The main ore minerals constitute pseudorutile, ilmenite, zircon, rutile and monazite. This work presents a thorough characterization of the mineralogy and granulometric distribution of the Jiboia orebody.

Apr 1, 2024

By A. E. Halim, J. F. Brune

The 2006 Sago, Darby, and Aracoma mine disasters in the United States (US) forced the US government to implement the 2006 MINER Act and additional regulations that require all US underground coal mines to install and maintain refuge chambers to manage entrapment emergencies, in particular, fires and explosions. However, there is a debate on whether barricading in refuge chambers is a good strategy to survive such emergencies. Australian coal mines are not required to use refuge chambers and, instead, have adopted a strategy that focuses on instructing and training miners to self-escape to the surface. This paper analyzes merits and problems of using refuge chambers and self-escape to the surface to manage emergencies in fires or explosions in an underground coal mine. The authors found that the use of refuge chambers may not be the best strategy during extensive fires or when multiple explosions happen. In these situations, mine rescuers are unlikely able to extract miners who are sheltered in chambers and conversely, self-escape may save more lives than sheltering. Chances for successful self-escape are further improved by regular, externally assessed training such as Level 1 Emergency Exercises required in the Australian State of Queensland. These exercises put pressure on mine operators to ensure and maintain the effectiveness of their emergency management system.

By Ashutosh Kumar Bharati, Rajesh Rai, B. K. Shrivastva, Arunava Ray

Opencast mining method is one of the most productive mining methods available at present, which is generally associated with the removal and handling of a huge amount of overburden material. Hence it imposes a serious challenge of dump slope stability and that too, mainly in the case of internal dumps. The study is primarily focused on the stability of dragline dumps and the subsequent development of a rating system to classify the stability of dragline dump profiles. Initially, numerical simulation is executed through RS2 (Version 9.0) software, which is based on the finite element method. Thereafter, simulation results are used to perform the sensitivity analysis of various geometrical and strength parameters of the dump slope, and the two-factor interaction method is also incorporated into the analysis, this method included the dependency of closest parameters while calculating the sensitivity index, and thereafter, it is converted into the rating of each parameter. The strength parameter like the angle of friction and the geometrical parameter like slope angle of the bench between the coal-rib roof and dragline sitting level are assigned the highest rating value. Based on the overall rating of the dragline dump, the dump slopes are classified into various classes, viz., very safe, safe, vulnerable, unstable, and highly unstable. This classification proved to be handy in the quick estimation of the stability of the dragline dump and also gives an idea of designing optimum and safe dragline dump profiles. The developed classification chart has been validated by the previous research works and has found similar results.

Feb 15, 2021

By Lee W. Saperstein

In surface mining for coal, common practice for the disposal of preparation plant refuse is to bury it. As with surface refuse piles, these buried wastes can ignite and can also lead to ground and surface water pollution. Steps to ameliorate these problems have been devised over the years. C and K Coal Company, of Clarion, Pa., the largest Pennsylvania surface mining company, has incorporated all of these steps and added of few, of their own in their latest disposal practice. In addition to layering and compacting, C and K practices selective placement and dilution to minimize longterm problems.

Jan 1, 1977

By George A. Savanick

The objective of this paper is to review advances in the art of borehole (slurry) mining made by the Bureau of Mines. The introduction gives historical and general background information on borehole mining. The borehole mining concept is defined and justified in terms of economics, health and safety, the environment, and resource conservation. This is followed by a description of the design of a prototype borehole mining tool (BMT) developed by the Bureau of Mines. Included are design drawings and performance specifications. The next section describes the application of the BMT in the extraction of metallurgical coal from steeply pitching seams near Wilkeson, Wash., during 1975-76. The field test showed that the BMT produced coal at the rate of 8 tons per hour (tph) (7,272 kg/hr) from a depth of 88 feet (26.8 m) and was effective in producing coal as far as 15 feet (4.6 m) from the center of the borehole. The data are used as a basis for an economic analysis of borehole coal mining and for the suggestions for the design of a second-generation borehole coal mining tool. The following section describes Bureau efforts in applying borehole mining to the extraction of uraniferous sandstone at Rocky Mountain Energy Corp.'s Nine-Mile Lake site, Natrona County, Wyo. BMT design changes appropriate to uranium mining are described along with production, reliability, and reclamation data taken during 1977-73. The field test revealed that the BMT produced 900 tons (81.8x105 g) of uraniferous sand at an average race of 8 tph (7,272 kg/hr) from a depth of 75 (22.8 m) to 90 (27.4 m) feet and created a cavity 25 feet (7.6 m) in radius. These data are used as the basis for an economic analysis of borehole mining of shallow uraniferous sandstones. Reclamation data included will be the results of backfilling experiments conducted at Nine-Mile Lake during 1978. The most significant of these data were that backfill was emplaced at the rate of 16 tph (14.5x103 kg/hr) and that 90 percent of the material extracted from a cavity can be backfilled.

Jan 1, 1979

By Robin J. Hickson

The Grasberg copper-gold deposit was discovered in the spring of 1988, one year before the planned closure of Freeport Indonesia's original Ertsberg openpit copper mine. In spite of Grasberg's remote location, 600 m (1968 ft) above the Ertsberg, atop a hitherto inaccessible mountain, Freeport-McMoRan brought its latest open-pit mine into production in the last week of 1989, less than two years after discovery. Freeport Indonesia's (FI) copper-gold mining operations are located in Irian Jaya, the easternmost province of Indonesia on the western side of the island of New Guinea. Fl's six ore deposits are all located within a 10- x 10-km' (3.9- x 3.9-sq mile) Contract of Work area. They are all between the elevations of 2900 and 4300 m (9515 and 14,100 ft) above sea level, some 96 km (60 miles) from the island's southern coast. A 118-km (74-mile) access route connects FT's port site of Amamapare on the Arafura Sea to the project area. The first section is an 18-km (11-mile) barge waterway. The final 100-km (63mile) is a two-lane gravel highway. The highway terminates 9 km (5.5 miles) beyond the FI townsite at the project's central mill, some 2850 m (9250 ft) above sea level. The mining areas are separated from the mill by a 780-m (2560-ft) sheer cliff face. The world's longest free span tramway system, with a total length of more than 1.6 km (1 mile), is the only means of access for men and materials between the mill and the surface mines. Weight restrictions for the tramway for equipment considered for the project are 15.4 t (17 st). The minimum clear width dimension of two tunnels along the portsite access road is 5.6 m (18.4 ft).

Jan 1, 1991

By C. Feng, W. Song, B. Moudgil, P. Zhang, W. Xiao

Separation of dolomite from phosphate is the most challenging problem in phosphate mineral processing. Over 50% of the future phosphate reserves in Florida contains too much dolomite to process using the current industry practice. The FIPR Institute has collaborated with worldwide experts in the field to address this issue. As a result, the industry is now offered with three feasible options. Optional 1 involves crushing and grinding of high-dolomite phosphate pebbles followed by dolomite flotation at slightly acidic pH using a new collector that does not require phosphoric acid as a phosphate depressant, achieving a final concentrate analyzing less than 0.9% MgO at about 87% P2O5 recovery. Option 2 offers three methods for reducing MgO content in the concentrate from the Crago process, including adding a dolomite depressant in the rougher flotation step, dolomite flotation of the cleaner concentrate, and scrubbing the cleaner concentrate in quartz sand. These methods could reduce MgO content in the final concentrate by 20-40%. Option 3 is a gravity separation technique using an innovative separation jig, and may well be the ultimate solution to the problem. INTRODUCTION Magnitude of the Dolomite Problem With the depletion of the higher grade, easy-to-process Bone Valley deposits, the central Florida phosphate industry has moved into the lower grade, more contaminated ore bodies from the Southern Extension. The phosphate deposits in the Southern Extension may be divided into two zones: an upper zone and a lower zone. The upper zone is readily processable using the current technology, but the lower zone is highly contaminated by dolomite. Geological and mineralogical statistics (Hassan and Bogan, 1994) show (Table 1) that more than 50% of the phosphate resource would be wasted if the lower zone is bypassed in mining, and about 13% of the resource would be wasted if the dolomitic pebbles in the lower zone were discarded.

Jan 1, 2019

By J. Sanko

When faced with the task of designing a process control system the control engineer must consider the following: 1. The type of process to be controlled and the manner in which the process must be controlled (the algorithm). 2. The type of equipment to be used to implement the control system. 3. A means of describing the control system for use in the following areas: a. Project engineering. b. Procurement of the control system equipment. c. Plant startup. d. Operator training and reference.

Jan 1, 1981

By S. M. Bulatovic

The western industrial world has to rely more and more on complex polymetallic sulphide ores as sources for base metals. These ores are composed of fine grained sulphide minerals such as chalcopyrite, galena, sphalerite, pyrite, pyrrhotite and marcasite. The liberation sizes of the individual minerals can range between 30 um and 5 um. Therefore, applying conventional techniques to recover these finely disseminated minerals usually results in unsatisfactory metallurgical performances with high losses of the valuable mineral to the slime , fraction of the tailing. New concepts for treating these polymetallic complex ores are discussed in this paper. Beneficiation techniques utilizing new reagents and a new approach to pulp preparation are described. Some of these techniques were applied to ores from existing concentrators as well as to new ores. The results of these studies are discussed in the following sections.

Jan 1, 1990

By V. T. McLemore

"Production of industrial minerals remains important to the rural economy of New Mexico. In 2014, some 240 mines were registered in New Mexico, including 25 industrial mineral operations and 189 aggregate operations. New Mexico leads domestic production of potash, perlite, zeolite, and travertine. Other production includes aggregate, humate, pumice, gypsum, salt, common and fire clay, scoria, limestone, fly ash, cement, magnetite, silica, and decorative stone. New Mexico has potential for additional production of industrial minerals. One company is exploring for garnet. Cretaceous black sandstones in the San Juan Basin have drawn interest for titanium, rare earth elements (REE), and zircon. Other REE deposits are being explored. REE-Th-U veins are found in the Gallinas, Capitan, and Cornudas Mountains and Laughlin Peak-Chico Hills. Recent exploration has occurred for beryllium in the San Mateo Mountains, Iron Mountain, and Victorio districts. Companies also are examining High-Ca limestone and High-Mg dolomite for potential development. Aggregate continues to be important in urban areas and along highways. INTRODUCTION Industrial minerals and rocks are literally the building blocks of our way of life and they are an exceptionally diverse and vital group of raw materials that underpin almost all aspects of human activity, infrastructure, and standard of living. Industrial minerals and rocks are used in the manufacture of many products, from ceramics to plastics and refractories to paper. Although industrial minerals permeate every aspect of daily life, their presence and their role are typically invisible. A widely used definition of industrial minerals and rocks is “any rock, mineral, or other naturally occurring substance of economic value, exclusive of metal ores, mineral fuels, and gemstones: one of the non-metallics” (Bates, 1975). This definition includes the important construction materials sector as well as specialized industrial minerals, but complex interactions between consumer industries produce a number of apparent anomalies to this definition. Some metals are included as industrial minerals because their use is industrial rather than as a metal. Sulfur is now predominantly extracted as a by-product of cleaning natural gas, one of the world's major energy fuels. Production of industrial minerals has been and remains important to the rural economy of New Mexico. Industrial minerals constitute nearly 40% of the more than $2.8 billion generated by mineral production in New Mexico in 2013 (Table 1, see APPENDIX). In 2015, some 240 mines were registered in New Mexico. This total includes 25 industrial mineral operations and 189 aggregate operations. New Mexico leads domestic production in potash, perlite, zeolite, and travertine. Other industrial minerals production from New Mexico includes aggregate, humate, pumice, gypsum, salt, common and fire clay, scoria, limestone, fly ash, cement, magnetite, silica, and decorative stone. Additional production statistics are in Harben et al. (2008). Major industrial mineral districts are shown in Figure 1."

Jan 1, 2016

By P. C. Thakur

The productivity in coal mines, measured in terns of the output per manshift depends largely on the efficiency and speed of men and materials transport between working faces and the surface. The mechanization of coal winning and material handling processes has led to a great rise in the mine productivity (1). Early applications of power in U. S. coal mines were mainly electrical. The excellent traction available with the DC motor and the ease of the distribution of the DC power have made trolley wire installations for haulage very popular. In shallow mines with very limited emissions of methane it did not constitute a major hazard but as mine depths increased and corresponding emissions of methane also increased fire and methane ignition hazards have become very serious. Conveyors have proved economic where intense mechanization of coal faces generates a large output of coal from a single face, but the fire and respirable dust hazard associated with them are no less serious. Recognizing these shortcomings, the Federal Coal Mine Health and Safety Act of 1969 laid down numerous provisions for the safe use of trolley-wire haulage and conveyors (2) which generally improve safety but in some cases complicate mining operations and have decreased productivity significantly since 1969. In course of time as coal mines become deeper and hence gassier and as the emphasis on safety increases it would be inconceivable to use trolley-wire haulage under ground as already witnessed in several other countries with deep coal mines. With rising capital investments and cost of the protection against fire and respirable dust, the use of conveyors may also have to be limited to special areas, e.g. main entries. Indeed, there are only two alternatives available, namely; (1) Degasify the coal seams prior to mining and use conventional electrical power, or (2) Develop alternate sources of power which would be safer and yet efficient and cheap.

Jan 1, 1975

By Jon A. Hummer, MICHAEL R. SHAHAN, Aleksandar D. Bugarski, Shawn Vanderslice

A study was conducted in an undergroundminewith the objective to identify, characterize, and source apportion airborne aerosols at the setup face and recovery room during longwall move operations. The focus was on contributions of diesel- and battery-powered heavy-duty vehicles used to transfer equipment between the depleted and new longwall panels and diesel-powered light-duty vehicles used to transport personnel and materials to various locations within the mine. Aerosols at the setup face were found to be distributed among diesel combustion-generated submicrometer and mechanically generated coarse aerosols. According to the data, the submicrometer aerosols downstream of the setup face were sourced to diesel exhaust emitted by vehicles operated inside and outside of the panel. Depending on the intensity of the activities on the panel, the outby sources contributed between 12.5 and 99.6% to the average elemental carbon mass flow at the setup face and recovery room. Extensively used light-duty vehicles contributedmeasurably to the elemental carbon concentrations at the setup face. The number concentrations of aerosols downstream of the setup face were associated with aerosols generated by combustion in diesel engines operated in the shield haulage loop and/or outside of the longwall panels. Entrainment of road dust by diesel or battery-powered load-haul-dump vehicles operated near the measurement site appears to be the primary source of mass concentrations of aerosols. The findings of this study should help the underground mining industry in its efforts to reduce exposures of miners to diesel and coarse aerosols.

Apr 14, 2020

By Eugie Kabwe

The increase in depth of mines due to the depletion of surface deposits leads to unsafe tunnel construction and overall ore extraction. This is due to tunnel instability associated with the surrounding rock mass’s ability to exhibit creep that occurs over time. However, the explicit description of this mechanism using conventional constitutive models has proven to be difficult and inadequate. Hence, this paper presents an integrated viscoelastic viscoplastic visco-damage model with the Duvaut-Lions function. The presented model is calibrated by experimental data to determine the viscoelastic viscoplastic and visco-damage parameters. It is further implemented in a finite volume numerical code and verified on an experimental scale by numerical modeling of a cylindrical specimen. It describes the 3-phase creep mechanism perfectly as compared to the inbuilt conventional integer-order derivative model. Results from the conducted verification show that it can successfully be employed to describe the long-term behavior associated with the creep mechanism.

May 16, 2021

By Abdelaziz Baçaoui, Imane Aarab, Mohammed Derqaoui, Abdelrani Yaacoubi, Khalid El Amari, Abdelmoughit Abidi, Abderahman Etahiri

Numerous researchers have addressed the complexity of the direct flotation separation of apatite from low-grade phosphate ore. The majority of these studies were limited to the micro-flotation scale. In fact, there is no warranty that a reagent scheme that showed a direct flotation of apatite at a micro-flotation scale on pure minerals would automatically replicate the same expected results on the natural ore in the mechanical flotation cell and so was the case for the phosphate ore studied. The overall trend was concentrating apatite in the non-float product. This study aspired to thoroughly assess the flotation performance of this never-exploited low-grade sedimentary phosphate using design of experiments (DOE). Unveiling new insights on such a strategy twist, various parameters and operating conditions, namely, desliming, type of collector and depressant, reagents dosages, conditioning times, flotation time, and pH, were addressed by multiple-factor screening using asymmetrical fractional factorial design followed by statistical interpretations. The collectors tested were the sodium oleate and a fatty acid mixture (FAM). The depressants tested were sodium alginate (NaAL), corn starch, carboxymethylcellulose (CMC), and sodium silicate. The results of the multivariable analysis revealed that desliming, pH, collector dosage, and flotation time significantly influenced the flotation process. Desliming was beneficial for the yield, P2O5 recovery, and SiO2 removal; however, there was still a compromise between grade and recovery. A strongly alkaline pH value of 12 stood out from the whole range. P2O5, CO2, and SiO2 grades of the products and flotation recoveries were improved, except for P2O5 recovery, which was negatively affected. A collector dosage between 2000 and 3000 g/t increased the P2O5 grade and reduced CO2 grade and recovery, enhancing the apatite/carbonates separation. A flotation time of 15 min was significant for P2O5 grade and CO2 recovery, nevertheless, at the expense of yield and P2O5 recovery. The products having initial concentrates of 28.08% P2O5 with a recovery of 88.96% and 29.41% P2O5 with a recovery of 62.71% were obtained using 25 g/t of NaAL and 2000 g/t of the collector FAM and sodium oleate, respectively, at pH 12.

Jun 5, 2022