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Development and Use of Certain Flotation Reagents

Description: From Forward: "When the experiments described in this bulletin were begun many of the reagents were available only in trial quantities. Some of them are now available in commercial quantities and are of different compositions from those that were available for experimental work. It was not possible to determine the exact chemical composition of some of the reagents."
Date: 1944
Creator: Dean, R. S. & Ambrose, P. M.
Partner: UNT Libraries Government Documents Department

A Kinetic Model for Conventional Flotation of Coal

Description: The U.S. Bureau of Mines has developed a computer model to 'describe a flotation process. Coal data from conventional flotation has been converted to a simple, two-parameter kinetic model developed by Reuter and van Deventer (j,2 3. Each set of coal data was represented by two constants, a and a, and an average flotation rate. The success of the model was demonstrated when the calculated and experimental recoveries showed good correlation. The two-parameter model allows complex data to be defined much more efficiently than traditional knowledge-based models.
Date: 1995
Creator: Susko, Frank J. & Stanley, Don A.
Partner: UNT Libraries Government Documents Department

Engineering Development of Advanced Physical Fine Coal Cleaing for Premium Fuel Applications

Description: The ash in six common bituminous coals, Taggart, Winifrede, Elkhorn No. 3, Indiana VII, Sunnyside and Hiawatha, could be liberated by fine grinding to allow preparation of clean coal meeting premium fuel specifications (< 1- 2 lb/ MBtu ash and <0.6 lb/ MBtu sulfur) by laboratory and bench- scale column flotation or selective agglomeration. Over 2,100 tons of coal were cleaned in the PDU at feed rates between 2,500 and 6,000 lb/ h by Microcel� column flotation and by selective agglomeration using recycled heptane as the bridging liquid. Parametric testing of each process and 72- hr productions runs were completed on each of the three test coals. The following results were achieved after optimization of the operating parameters: The primary objective was to develop the design base for commercial fine coal cleaning facilities for producing ultra- clean coals which can be converted into coal-water slurry premium fuel. The coal cleaning technologies to be developed were advanced column flotation and selective agglomeration, and the goal was to produce fuel meeting the following specifications -- Less than 2 pounds of ash per million Btu (860 grams per gigajoule) and
Date: September 26, 1997
Creator: Smit, Frank J.; Schields, Gene L.; Jha, Mehesh C. & Moro, Nick
Partner: UNT Libraries Government Documents Department

PROGRESS RELATING TO CIVILIAN APPLICATIONS DURING NOVEMBER 1958

Description: The effect of irradiation on the thermal conductivity and electrical resistivity of U and U0/sub 2/ is being investigated. The creep properties of 15% cold-worked Zircaloy-2 are being investigated in the 290 to 400 deg C temperature range for times exceeding 10,000 hr. The density distribution of crushed graphite is being investigated by the sink-float method. Centrifugal- casting techniques for the production of Al-35 wt.% U casting in the form of hollow cylinders are being investigated. A study of the processes involved in the solidification of U castings in graphite molds is being made. Work continued on electrolytic oxide and electroless oxide coatings on Croloy-2 1/4. Experimental work was continued to determine the effect of additive oxides on the oxidation characteristics and phase stability of U0/sub 2/. The fueled-moderator study has continued with the determination of additional hydrogen-absorption isotherms for the Zr-25 wt.% alloy and high-temperature x-ray diffraction patterns of hydrides of the 1 and 50 wt.% alloys. The irradiation of type 347 stainless steel at ETR process-water temperature. about 120 deg F and at 600 deg F, and subsequent determination of irradiation damage are being done in support of the KAPL-33 loop to be installed at the ETR. AIloys of U and Nb are being considered as possible high-temperature reactor fuels. Thorium-uranium base alloys are the subject of an investigation aimed at improving irradiation stability and corrosion resistance by ternary alloying and control of processing techniques Cermet fuel materials consisting of from 60 to 90 vol.% U0/sub 2/, UN, or UC dispersed in stainless steel are being investigated. Several types of 1 1/ 2-inch-diameter fueled graphite spheres containing 10 wt.% of fully enriched U0/ sub 2/ are being evaluated before and after irradiation in the BRR. Some localized attack has been observed after prolonged exposure of Ti steam tubes ...
Date: December 1, 1958
Creator: Dayton, R.W. & Tipton, C.R. Jr.
Partner: UNT Libraries Government Documents Department

POC-Scale Testing of an Advanced Fine Coal Dewatering Equipment/Technique

Description: Froth flotation technique is an effective and efficient process for recovering of ultra-fine (minus 74 mm) clean coal. Economical dewatering of an ultra-fine clean coal product to a 20% level moisture will be an important step in successful implementation of the advanced cleaning processes. This project is a step in the Department of Energy's program to show that ultra-clean coal could be effectively dewatered to 20% or lower moisture using either conventional or advanced dewatering techniques. The cost-sharing contract effort is for 45 months beginning September 30, 1994. This report discusses technical progress made during the quarter from January 1 � March 31, 1998.
Date: August 28, 1998
Creator: Karekh, B. K.; Tao, D. & Groppo, J. G.
Partner: UNT Libraries Government Documents Department

An Advanced Control System For Fine Coal Flotation

Description: A model-based flotation control scheme is being implemented to achieve optimal performance in the handling and treatment of fine coal. The control scheme monitors flotation performance through on-line analysis of ash content. Then, based on the economic and metallurgical performance of the circuit, variables such as collector dosage, frother dosage, and pulp level are adjusted using model-based control algorithms to compensate for feed variations and other process disturbances. Recent developments in sensor technology are being applied for on-line determination of slurry ash content. During the ninth quarter of this project, Task 3 (Model Building and Computer Simulation) and Task 4 (Sensor Testing) were nearly completed, and Task 6 (Equipment Procurement and Installation) was initiated. Previously, data collected from the plant sampling campaign (Task 2) were used to construct a population balance model to describe the steady-state and dynamic behavior of the flotation circuit. The details of this model were presented in the Eighth Quarterly Technical Progress Report. During the past quarter, a flotation circuit simulator was designed and used to evaluate control strategies. As a result of this work, a model-based control strategy has been conceived which will allow manipulated variables to be adjusted in response to disturbances to achieve a target incremental ash value in the last cell of the bank. This will, in effect, maximize yield at an acceptable product quality. During this same period, a video-based ash analyzer was installed on the flotation tailings stream at the Moss No. 3 preparation plant. A preliminary calibration curve was established, and data are continuing to be collected in order to improve the calibration of the analyzer.
Date: August 25, 1998
Creator: Luttrell, G. H. & Adel, G. T.
Partner: UNT Libraries Government Documents Department

An Advanced Control System for Fine Coal Floatation

Description: A model-based flotation control scheme is being implemented to achieve optimal performance in the handling and treatment of fine coal. The control scheme monitors flotation performance through on-line analysis of ash content. Then, based on the economic and metallurgical performance of the circuit, variables such as collector dosage, frother dosage, and pulp level are adjusted using model-based control algorithms to compensate for feed variations and other process disturbances. Recent developments in sensor technology are being applied for on-line determination of slurry ash content. During the eighth quarter of this project, the analysis of data collected during Task 2 (Sampling and Data Analysis) was completed, and significant progress was made on Task 3 (Model Building and Computer Simulation). Previously, a plant sampling campaign had been conducted at Pittston�s Moss No. 3 preparation plant to provide data for the development of a mathematical process model and a model-based control system. During this campaign, a one-half factorial design experiment, blocked into low and high feed rates, was conducted to investigate the effects of collector, frother, and pulp level on model parameters. In addition, samples were collected during the transient period following each change in the manipulated variables to provide data for confirmation of the dynamic process simulator. A residence time distribution (RTD) test was also conducted to estimate the mean residence time. This is a critical piece of information since no feed flowrate measurement is available, and the mean residence time can be used to estimate the feed flowrate. Feed samples were taken at timed intervals and floated in a laboratory flotation cell to investigate the magnitude of feed property disturbances and their duration.
Date: June 1, 1998
Creator: Luttrell, G. H. & Adel, G. T.
Partner: UNT Libraries Government Documents Department

Surfactant Spray: A Novel Technology to Improve Flotation Deinking Performance: Final Report

Description: Based on the fundamental understanding of ink removal and fiber loss mechanism in flotation deinking process, we developed this innovative technology using surfactant spray to improve the ink removal efficiency, reduce the water and fiber loss, reduce the chemical consumption and carry over in the flotation deinking. The innovative flotation deinking process uses a spray to deliver the frothing agent during flotation deinking to control several key process variables. The spray can control the foam stability and structure and modify the fluid dynamics to reduce the fibers entrapped in the froth layer. The froth formed at the top part of the flotation column will act as a physical filter to prevent the penetration of frothing agent into the pulp suspension to eliminate fiber contamination and unfavorable deinking surface chemistry modification due to surfactant adsorption on the fiber surface. Because of the filter effect, frothing agents will be better utilized. Under the sponsorships of the US Dept. of Energy (DOE) and the member companies of the Institute of Paper Science and Technology, we studied the chem-mechanical mechanism of surfactant spray for flotation deinking using different furnishes, chemicals, and flotation devices in the past four years. In the final year of the project, we successfully conducted mill trials at Abitibi-Consolidated, Inc., Snowflake paper recycling operation of 100% mixture of ONP/OMG. Results from laboratory, pilot-plant and mill trials indicated that surfactant spray technology can significantly reduce fiber loss in flotation deinking. It can be concluded that paper industry can profit greatly when this technology is commercialized in flotation deinking mills.
Date: January 31, 2004
Creator: Deng, Yulin & Zhu, Junyong
Partner: UNT Libraries Government Documents Department

Removal of Wax and Stickies from OCC by Flotation

Description: Laboratory research indicates that wax is amenable to removal by froth flotation provided it is free or detached from the fiber. The only effective means, at this time, of maximizing detachment of wax is through the use of low consistency pulping at temperatures above the melting point of wax. Wax removal from WCC through washing, flotation, or a combination of both was approximately 90% in these laboratory studies, indicating that not all of the wax is detached from fibers. These results were summarized in Annual Report 1, December 1, 1997 to November 30, 1998. Pilot trials were conducted in which the authors simulated a conventional OCC repulping process with and without flotation. Additional aggressive washing and water clarification were also examined during the study. The inclusion of flotation in the OCC stock preparation system significantly improved the removal of wax spots and extractable material from the furnish. Based on this study, the authors predict that a compact flotation system with 2 lb surfactant/ton of fiber would improve the OCC pulp quality with regard to wax spots by 60% and would not negatively affect strength properties. Flotation losses would be in the 2-5% range. Two mill trials were conducted during the last quarter of the project. One trial was carried out at Green Bay Packaging, Green Bay, WI, and a second trial was conducted at Menasha Corporation, Otsego, MI. A 250-liter Voith Sulzer Ecocell was used to evaluate the removal of wax and stickies from the OCC processing systems at these two mills. The inclusion of flotation in the OCC stock preparation system significantly improved the removal of wax spots from the furnish. The data indicate that flotation was more effective in removing wax and stickies than reverse cleaners. The mill trials have demonstrated that flotation can be substituted for or ...
Date: January 31, 2000
Creator: Doshi, M. R. & Dyer, J.
Partner: UNT Libraries Government Documents Department

Micro-agglomerate flotation for deep cleaning of coal. Quarterly progress report, July 1, 1995--September 30, 1995

Description: The development of practical technologies for the deep cleaning of coal has been seriously hampered by the problems of carrying out efficient coal/mineral separations at the very fine sizes (often finer than 10 mm) needed to achieve adequate liberation of the mineral matter from the coal matrix. It is generally recognized that surface-based separation processes such as froth flotation or selective agglomeration offer considerable potential for such applications but there remain many problems in obtaining the required selectivity with acceptable recovery of combustible matter. In froth flotation, selectivity is substantially reduced at fine sizes due, primarily, to overloading of the froth phase which leads to excessive carryover of water and entrained mineral matter. Oil agglomeration, on the other hand, can provide good selectivity at low levels of oil addition but the agglomerates tend to be too fragile for separation by the screening methods normally used. The addition of larger amounts of oil can yield large, strong agglomerates which are easily separated but the selectivity is reduced and reagent costs can become excessive.
Date: July 1, 1995
Creator: Chander, S. & Hogg, R.
Partner: UNT Libraries Government Documents Department

Micro-agglomerate flotation for deep cleaning of coal. Quarterly progress report, October 1--December 30, 1995

Description: Goals are to demonstrate the technical and economic feasibility of a micro-agglomerate flotation process (combination of oil-agglomeration and froth flotation) and to establish the essential criteria for reagent selection and system design and operation. The research program was organized into the following tasks: interfacial studies, emulsification, agglomerate growth and structure, and agglomerate flotation. Work on the first two tasks has been completed.
Date: April 1, 1996
Creator: Chandler, S. & Hogg, R.
Partner: UNT Libraries Government Documents Department

Micro-agglomerate flotation for deep cleaning of coal. Quarterly progress report, October 1, 1994--December 31, 1994

Description: The development of practical technologies for the deep cleaning of coal has been seriously hampered by the problems of carrying out efficient coal/mineral separations at the very fine sizes (often finer than 10 mm) needed to achieve adequate liberation of the mineral matter from the coal matrix. It is generally recognized that surface-based separation processes such as froth flotation or selective agglomeration offer considerable potential for such applications but there remain many problems in obtaining the required selectivity with acceptable recovery of combustible matter. In froth flotation, selectivity is substantially reduced at fine sizes due, primarily, to overloading of the froth phase which leads to excessive carryover of water and entrained mineral matter. Oil agglomeration, on the other hand, can provide good selectivity at low levels of oil addition but the agglomerates tend to be too fragile for separation by the screening methods normally used. The addition of larger amounts of oil can yield large, strong agglomerates which are easily separated but the selectivity is reduced and reagent costs can become excessive. We are investigating the use of a hybrid process - micro-agglomerate flotation - which is a combination of oil-agglomeration and froth flotation. The basic concept is to use small quantities of oil to promote the formation of dense micro-agglomerates with minimal entrapment of water and mineral particles, and to use froth flotation to extract these micro-agglomerates from the water/dispersed-mineral phase. Since the floating units are agglomerates (about 30-50 mm in size) rather than individual coal particles (1-10 mm) the problems of froth overload and water/mineral carryover should be significantly alleviated. Micro-agglomerate flotation has considerable potential for the practical deep cleaning of coal on a commercial scale.
Date: January 1, 1995
Creator: Chander, S. & Hogg, R.
Partner: UNT Libraries Government Documents Department

An Advanced Control System for Fine Coal Flotation. Sixth quarter, technical progress report, July 1-September 30, 1997

Description: Over the past thirty years, process control has spread from the chemical industry into the fields of mineral and coal processing. Today, process control computers, combined with improved instrumentation, are capable of effective control in many modem flotation circuits. Unfortunately, the classical methods used in most control strategies have severe limitations when used in froth flotation. For example, the nonlinear nature of the flotation process can cause single-input, single-output lines to battle each other in attempts to achieve a given objective. Other problems experienced in classical control schemes include noisy signals from sensors and the inability to measure certain process variables. For example, factors related to ore type or water chemistry, such as liberation, froth stability, and floatability, cannot be measured by conventional means. The purpose of this project is to demonstrate an advanced control system for fine coal flotation. The demonstration is being carried out at an existing coal preparation plant by a team consisting of Virginia Polytechnic Institute and State University (VPI&SU) as the prime contractor and J.A. Herbst and Associates as a subcontractor. The objectives of this work are: (1) to identify through sampling, analysis, and simulation those variables which can be manipulated to maintain grades, recoveries, and throughput rates at levels set by management; (2) to develop and implement a model-based computer control strategy that continuously adjusts those variables to maximize revenue subject to various metallurgical, economic, and environmental constraints; and (3) to employ a video-based optical analyzer for on-line analysis of ash content in fine coal slurries.
Date: October 27, 1997
Creator: Adel, G. T. & Luttrell, G. H.
Partner: UNT Libraries Government Documents Department

POC-scale testing of an advanced fine coal dewatering equipment/technique

Description: Froth flotation technique is an effective and efficient process for recovering of ultra-fine (minus 74 pm) clean coal. Economical dewatering of an ultra-fine clean-coal product to a 20% level moisture will be an important step in successful implementation of the advanced cleaning processes. This project is a step in the Department of Energy`s program to show that ultra-clean coal could be effectively dewatered to 20% or lower moisture using either conventional or advanced dewatering techniques. The cost-sharing contract effort is for 36 months beginning September 30, 1994. This report discusses technical progress made during the quarter from July 1 - September 30, 1997.
Date: September 1, 1998
Partner: UNT Libraries Government Documents Department

AN ADVANCED CONTROL SYSTEM FOR FINE COAL FLOTATION

Description: A model-based flotation control scheme is being implemented to achieve optimal performance in the handling and treatment of fine coal. The control scheme monitors flotation performance through on-line analysis of tailings ash content. Then, based on an on-line estimate of incremental ash, the pulp level is adjusted using a model-based control algorithm to compensate for feed variations and other process disturbances. Recent developments in sensor technology are being applied for on-line determination of slurry ash content. During the tenth quarter of this project, Task 6 (Equipment Procurement and Installation) was completed through the efforts of J.A. Herbst and Associates, Virginia Tech, Pittston Coal Company, and FGR Automation. As a result of this work, a model-based control system is now in place which can predict incremental ash based on tailings ash content and general plant data, and adjust pulp level accordingly to maintain a target incremental ash. Testing of this control system is expected to be carried out during the next quarter, and the results of this testing will be reported in the Eleventh Quarterly report. In addition, calibration of the video-based ash analyzer was continued and an extensive set of calibration data were obtained showing that the plant is running remarkably well under manual control. This may be a result of increased attention being paid to froth flotation as a result of this project.
Date: October 25, 1998
Partner: UNT Libraries Government Documents Department

Removal of wax and stickies from OCC by flotation. Progress report No. 2, April 1--June 30, 1998

Description: During the second quarter of the study the authors examined the conditions necessary for repulping a mixture of wax-coated boards that would be conducive to the flotation of detached wax. Also important for the economic viability of a waxed-board repulping process is adequate defibering of the recovered paper. Several methods for the dewaxing of pulped waxed-boards were investigated. The authors have continued to survey the literature to determine what other efforts are being made to ameliorate the impact of waxed boards during the recycling of OCC.
Date: August 1, 1998
Creator: Doshi, M.R.; Dyer, J. & Heise, O.
Partner: UNT Libraries Government Documents Department

Removal of wax and stickies from OCC by flotation. Progress report No. 3, July 1--September 30, 1998

Description: In this quarter we completed low consistency laboratory pulping trials. Pulping results were analyzed in terms of defibering index or yield and the concentration of free wax. The objective of these trials is to identify pulping conditions that will give higher yield and higher concentration of free wax. The yields from low consistency pulping trials ranged from 90 to 99% based on 6-cut laboratory screen rejects. In general, high temperatures (140-150{degree}F) and high pH (9.5-10) conditions resulted in higher yield and the generation of free wax. Factors such as rotor speed and the gap (between the rotor and grate) were not significant in affecting defibering. Generally, the turbidities of filtrates from wax-contaminated pulps increased with increase in temperature and/or pH. The filtrate turbidity indicated the relative concentration of finely dispersed wax that could be removed from pulp dewatered on a 30 {micro}m filter paper. Preliminary experiments were conducted to study flotation conditions necessary for effective removal of wax from pulp. Factors which are important for effective flotation include flotation time, volume of air, surfactant concentration and type, and low temperature. Future plans include additional flotation trials to better optimize conditions. Other contaminant types include pressure sensitive adhesives and hot melts will also be examined. This will be followed by pilot plant and mill trials.
Date: November 1, 1998
Creator: Doshi, M.R.; Dyer, J.; Heise, O. & Cao, B.
Partner: UNT Libraries Government Documents Department

Engineering development of advanced physical fine coal cleaning technologies: Froth flotation. Quarterly technical progress report No. 25, October 1, 1994--December 31, 1994

Description: A study conducted by Pittsburgh Energy Technology Center of sulfur emissions from about 1300 United States coal-fired utility boilers indicated that half of the emissions were the result of burning coals having greater than 1.2 pounds of SO{sub 2} per million BTU. This was mainly attributed to the high pyritic sulfur content of the boiler fuel. A significant reduction in SO{sub 2} emissions could be accomplished by removing the pyrite from the coals by advanced physical fine coal cleaning. An engineering development project was prepared to build upon the basic research effort conducted under a solicitation for research into Fine Coal Surface Control. The engineering development project is intended to use general plant design knowledge and conceptualize a plant to utilize advanced froth flotation technology to process coal and produce a product having maximum practical pyritic sulfur reduction consistent with maximum practical BTU recovery. This progress report provides a summary of the technical work undertaken during this period, highlighting the major results. A brief description of the work done prior to this quarter is provided in this report under the task headings.
Date: December 31, 1994
Partner: UNT Libraries Government Documents Department

Surface Properties of Photo-Oxidized Bituminous Coals: Final report

Description: Natural weathering has a detrimental effect on the hydrophobic nature of coal, which in turn can influence clean-coal recovery during flotation. Few techniques are available that can establish the quality of coal surfaces and that have a short analysis time to provide input for process control. Luminescence emissions which can be quantified with an optical microscope and photometer system, are measurably influenced by degree of weathering as well as by mild storage deterioration. In addition, it has been shown that when vitrinite is irradiated with a relatively high intensity flux of violet- or ultraviolet- light in the presence of air, photo-oxidation of the surface occurs. The combination of measuring the change in luminescence emission intensity with degree of surface oxidation provided the impetus for the current investigation. The principal aim of this research was to determine whether clear correlations could be established among surface oxygen functionality, hydrophobicity induced by photo-oxidation, and measurements of luminescence intensity and alteration. If successful, the project would result in quantitative luminescence techniques based on optical microscopy that would provide a measure of the changes in surface properties as a function of oxidation and relate them to coal cleanability. Two analytical techniques were designed to achieve these goals. Polished surfaces of vitrain bands or a narrow size fraction of powdered vitrain concentrates were photo-oxidized using violet or ultraviolet light fluxes and then changes in surface properties and chemistry were measured using a variety of near-surface analytical techniques. Results from this investigation demonstrate that quantitative luminescence intensity measurements can be performed on fracture surfaces of bituminous rank coals (vitrains) and that the data obtained do reveal significant variations depending upon the level of surface oxidation. Photo-oxidation induced by violet or ultraviolet light fluxes does result in a progressive and significant increase in the amount of near-surface oxygen ...
Date: September 1, 1998
Partner: UNT Libraries Government Documents Department

Oxidation of coal and coal pyrite mechanisms and influence on surface characteristics. Quarterly technical progress report, December 1, 1993--May 31, 1994

Description: The objective of this research is to develop a mechanistic understanding of the oxidation of coal and coal pyrite, and to correlate the intrinsic physical and chemical properties of these minerals, along with changes resulting from oxidation, with those surface properties that influence the behavior in physical cleaning processes. The results will provide fundamental insight into oxidation, in term of the bulk and surface chemistry, the microstructure, and the semiconductor properties of the pyrite. During the fourteenth and fifteenth quarters, flotation tests were done on Upper Freeport coal from the Troutville No. 2 Mine, Clearfield County, Pennsylvania and on coal samples from the Pennsylvania State Coal Bank. The influence of electrode potential on the surface properties of coal pyrite was tested using contact angle measurements on polarized Pittsburgh coal pyrite electrode.
Date: January 1, 1996
Creator: Doyle, F.M.
Partner: UNT Libraries Government Documents Department

Preliminary evaluation of resinite recovery from Illinois coal. Technical report, December 1, 1994--February 28, 1995

Description: Resinite is a naturally occurring substance found in coal and derived from original plant resins. It is ubiquitous in North American coals. It makes up one to four percent by volume of most Illinois coals. It has been commercially exploited in the western USA for use in adhesives, varnishes and thermal setting inks. The overall objective of this project is to compare the properties of the resinite contained in Illinois Basin coals to resinite being commercially exploited in the western United States, and to recover the resinite from Illinois coals by microbubble column floatation techniques. This project is relevant to priority 1.4A identified in ICCI/RFP93-1. The significance of this study is that it has the potential to show the way to recover a valuable chemical, resinite, from coal using only physical processing techniques. The value of the resinite at $1.00/kg or $0.50/lb makes it about fifty times more valuable than steam coal. The removal of resinite from coal does not decrease the value of the remaining coal in any way. The unique aspects are that: (1) it is the first examination of the resinite recovery potential of Illinois coal, (2) it integrates the latest characterization techniques such as density gradient centrifugation, microspectrofluorometry, and gas chromatography-mass spectrometry, and (3) it uses microbubble column flotation to determine the resinite recovery potential. During this quarter samples were obtained, information from both the databases of both the Illinois State Geological Survey (ISGS) and the Pennsylvania State University (PSU) was obtained and evaluated, and IBCSP samples from the Herrin No. 6, the Springfield No. 5 and the Colchester No. 2 seams were analyzed petrographically and the resinites in these samples were characterized by fluorescence spectral analysis.
Date: December 31, 1995
Creator: Crelling, J.C.
Partner: UNT Libraries Government Documents Department

The hydrophobic character of nonsulfide mineral surfaces as influenced by double-bond reactions of adsorbed unsaturated collector species. Progress report, 15 December 1992--14 December 1995

Description: Goal is to provide a basis for improved flotation separation efficiency in nonsulfide minerals by establishing the collector (surfactant) adsorption reactions and developing appropriate surface chemistry control strategies. In-situ measurements of surfactant adsorption were made for selected nonsulfide mineral systems using FT-IR/IRS with reactive internal reflection elements. The IRS adsorption density equation was developed to measure the surfactant adsorption, and its validity was confirmed using transferred Langmuir-Blodgett films. Order and organization of adsorbed surfactants were established from linear dichroism spectroscopy. Hydrophobicity and stability of adsorbed surfactants at mineral surfaces can now be explained. The surface charge/collector colloid adsorption mechanism was used to explain the anomalous behavior of KCl and flotation of double salts (schoenite, kainite, borax, etc.) from saturated brines. Adsorbing surfactnat colloids at salt surfaces in brines were studied by photon correlation spectroscopy and atomic force microscopy. Studies are being initiated of the interparticle forces in soluble salt flotation and of interfacial water near hydrophilic and hydrophobic surfaces.
Date: June 1, 1995
Creator: Miller, J.D.
Partner: UNT Libraries Government Documents Department

Engineering development of advanced physical fine coal cleaning technologies: Froth flotation. Quarterly technical progress report No. 26, January 1, 1995--March 31, 1995

Description: A study conducted by Pittsburgh Energy Technology Center of sulfur emissions from about 1,300 United States coal-fired utility boilers indicated that half of the emissions were the result of burning coals having greater than 1.2 pounds of SO{sub 2} per million BTU. This was mainly attributed to the high pyritic sulfur content of the boiler fuel. A significant reduction in SO{sub 2} emissions could be accomplished by removing the pyrite from the coals by advanced physical fine coal cleaning. An engineering development project was prepared to build upon the basic research effort conducted under a solicitation for research into Fine Coal Surface Control. The engineering development project is intended to use general plant design knowledge and conceptualize a plant to utilize advanced froth flotation technology to process coal and produce a product having maximum practical pyritic sulfur reduction consistent with maximum practical BTU recovery. The overall project scope of the engineering development project is to conceptually develop a commercial flowsheet to maximize pyritic sulfur reduction at practical energy recovery values. This is being accomplished by utilizing the basic research data on the surface properties of coal, mineral matter and pyrite obtained from the Coal Surface Control for Advanced Fine Coal Flotation Project, to develop this conceptual flowsheet. This progress report provides a summary of the technical work undertaken during this period, highlighting the major results. A brief description of the work done prior to this quarter is provided in this report under the task headings.
Date: July 1, 1995
Partner: UNT Libraries Government Documents Department

Controlling incipient oxidation of pyrite for improved rejection. Eighth quarterly technical progress report, July 1, 1994--September 30, 1994

Description: The major objectives of this work are (1) to determine the Eh-pH conditions under which pyrite is stable, (2) to determine the mechanism of the initial stages of pyrite oxidation and (3) to determine if the semi-conducting properties of pyrite effects its oxidation behavior. It is known that moderate oxidation of pyrite produces a hydrophobic surface product. This hydrophobic product makes it extremely difficult to depress pyrite in coal flotation circuits. The eventual objective of this work is to prevent pyrite oxidation in order to better depress pyrite in coal flotation circuits. In this work clean, unoxidized pyrite surfaces are being produced by fracturing pyrite electrodes in an electrochemical cell. It has been shown that pyrite assumes a unique potential referred to as the ``stable potential`` at the instance it is fractured and that this potential is several hundred millivolts more negative than the steady state mixed potential of pyrite. It has also been shown that by holding the potential of pyrite at its stable potential during fracture, pyrite undergoes neither oxidation nor reduction. It has also been found that fresh pyrite surfaces created by fracture in an electrochemical begin to oxidize at potentials that are about 200 mV more negative than the potentials reported in the literature for pyrite oxidation. This is attributed to the fact that most work on pyrite has employed polished electrodes that have pre-existing oxidation products on the surface. The existence of a pH dependent stable potential for freshly fractured pyrite electrodes was based on studies conducted mainly on pyrite from Peru.
Date: December 31, 1994
Creator: Yoon, R.H. & Richardson, P.E.
Partner: UNT Libraries Government Documents Department