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By John M. Hill

Automation technology has many facets, some well tested and proven, some yet to be put to the acid test of economic reality. In this paper, we will limit our purview to the former. Consider, if you will, an automated handling system combining high-speed conveyors and automatic devices on-line which not only provide signals for routing and sorting, but also format those signals for the production of manufacturing, inventory, shipping and billing paperwork. This is not futuristic, but practical and a realistic accomplishment. Therefore, the following discussions will address today's challenges not with tomorrow's solutions, but rather, with an established technology which is playing an increasingly prominent role in materials handling systems. Until recently, relatively modest importance has been attached to the timeliness of information feedback from the production or assembly line, warehouse or distribution center. Thus, initial applications of automatic identification equipment focused almost exclusively upon the control of materials flow - that is, routing, sorting, etc. However, these systems have performed successfully and quietly established an enviable track record as reliable materials control tools.

Jan 1, 1973

By H. Reed

The precious metal mining industry in Nevada handles and generates a certain amount of hazardous materials and waste on a regular basis. These products range from processing material additives to wastes from laboratory testing, heap leaching, and hydrocarbon treatment and disposal. The volume of materials and wastes is dependent upon the amount of ore processed. Handling, treatment and disposal is dependent on the type of material handled and the waste generated. Owing to the health and safety concerns and due to the existing regulations that control handling and disposal of hazardous materials and wastes, the mining industry is obligated to comply with all applicable requirements for proper handling of these products. Plus, in an effort to minimize any impacts from this effort, the industry is continually looking for alternative methods to accomplish these requirements and to also minimize costs. This paper will discuss the general, and in some cases the specific conditions, by which the industry is coping with the issue and efforts to minimize any impacts from handling, treatment and disposal for hazardous materials and wastes. The subject of compliance with the Toxic Release Inventory (TRI) requirements and bio-treatment of wastes and other technologies will be discussed.

Jan 1, 2001

By S. D. Hill, G. E. McClelland

To maximize productivity and improve minerals processing technology, the U. S. Department of the Interior, Bureau of Mines, is investigating a particle agglomeration technique as a means of increasing the percolation rate of leaching solutions through heaps of clayey or finely crushed, low- grade, gold-silver ores. Bench-scale and pilot-scale experiments conducted on different ores indicated that the percolation rate of cyanide leaching solution was enhanced markedly by mixing the ore with a binder, such as lime or portland cement, moistening the mixture, then mechanically agglomerating and aging the feed prior to heap building and leaching. In addition, the rate of silver and gold extraction markedly increased without sacrificing total recovery of values. The use of concentrated cyanide solution instead of water during the agglomeration procedure substantially decreased the leaching time required to obtain maximum recovery. Results from bench-scale and pilot-scale experiments using the particle agglomeration technique are discussed.

Jan 1, 1981

By Claude W. Sill

In the usual volumetric determination of uranium, the solution containing uranium is reduced in a Jones reductor, yielding a mixture of trivalent and tetravalent uranium; the trivalent uranium is oxidized to the tetravalent state by bubbling a stream of air through the solution. The resulting solution of. Tetravalent uranium is titrated with a standard oxidant, generally sulfatoceric acid, dichromate, or permanganate; It seemed likely that the, same general procedure could be used in determining semimicro quantities of uranium if the conditions affecting the variables involved were understood more clearly than at present. In the method described below, the use of ferric sulfate to oxidize tetravalent uranium allows the titration to be made at room temperature in an essentially colorless solution with sulfatoceric acid. The latter oxidant its turn permits the use of the very stable indicator, ferroin, with its sharp color.., change and exactly reproducible blanks. Solutions of uranyl sulfate were prepared by diluting a stock solution that had been standardized gravimetrically according to the method of Lundell and Knowles (8).3/ Solutions of sulfatoceric acid were prepared according to the directions of G. F. Smith (12) and were standardized against arsenic trioxide in the presence of osmic acid according to the directions of Gleu. The cerium solutions were stored in 18-liter carboys fitted with siphon arrangements so that the bottles did not need to be opened and protected from light in a dark cupboard. Under these conditions, even the 0.01 N solution changed by less than 1 part per thousand over a period of about 6 months.

Jan 1, 1952

Techniques and results achieved during the excavation of the Melbourne Underground Rail Loop (HURL) are summarised and discussed in the context of the various restraints present in a typical urban construction project. Mechanical methods (as distinct from those utilising blasting)accounted for the bulk of the excavation. Ground support was critical in this particular geological excavation setting, but is not discussed in detail except insofar as it constitutes a restraint to excavation progress.

Jan 1, 1978

By D. W. Scott, D. G. Minnes

Introduction Ontario's diverse industrial mineral resource base includes structural minerals such as sand and gravel, crushed stone, building stone, clay, shale, limestone, and dolostone. These resources are used to produce aggregates, brick, metallurgical stone, fillers, cement, lime, and other construction materials. The majority of the operations are in deposits of Palezoic and Quaternary age in southern Ontario, close to the major markets. Province-wide, there were more than 140 Mt (154 million st) of aggregates produced in 1985. About 115 Mt (128 million st) of that was produced in southern Ontario with the rest being largely from Crown land in northern Ontario. Structural industrial minerals account for more than 80% of the value of total industrial mineral production. The remaining 20% is accounted for by the nonstructural minerals, such as salt, which is produced in the southwestern part of the province. A host of other nonstructural industrial minerals are known. Production, though, is currently restricted to calcite, gypsum, quartz, talc, nepheline syenite, and byproduct metallurgical sulfur products (Fig. 1). Major production is close to the large markets of urbanized southern Ontario and the northeastern and northcentral US. With an abundant variety of industrial mineral resources and the large population within 650 km (400 miles) of most deposits, the market offers great potential. Ontario's nine million people accounted for about 35% of Canada's entire $476.3 billion gross domestic product in 1985. This equates to about one-third of the nation's buying power being within a 200-km (125-mile) radius of Toronto. This major concentration of industrial and economic activity has resulted in a well-developed industrial minerals industry that fulfills most of the structural industrial minerals demand in Ontario. Nonstructural industrial minerals are similarly well placed to compete in this high demand area. Although Ontario manufacturers still import some of these materials, Ontario products are achieving significant market share. And, they serve the needs of neighboring provinces and states. Present production and trends Ontario has traditionally produced significant amounts of industrial minerals. This produc¬tion had a value of $956 million in 1984 (Table 1). Structural materials production in 1985 and 1986 approached or exceeded levels not seen since the early 1970s. Many new products have been developed using these raw materials. The industry is becoming concentrated in the hands of several large companies, mainly four large cement com-

Jan 12, 1987

By Frederick H. Williams

THE object of this paper is to bring to the attention of those members of the Institute who are interested in the subject, a method for the estimation of manganese, which has been frequently used in the laboratory of the Vulcan Steel Works during the last eight months, and which is deemed worthy of more general use. It is simply an adaptation of well-known processes, for the purpose of determining this element in pig iron and steel. In general, the method consists in precipitating the manganese as binoxide, dissolving in dilute sulphuric acid in the presence of an excess of a standardized solution of oxalic acid, and titrating the remainder of the oxalic acid left unoxidized with permanganate of potash. For this method, therefore,. two standardized solutions are needed, viz., a permanganate solution and an oxalic acid solution. The permanganate solution is made so that 1 c.c. is equivalent to 1 mgr. of iron. By using so weak a solution and keeping the bulk of the solution to be titrated down to 75 c.c. or a little less, the accuracy of the process is greatly increased, since the final reaction is almost if not quite as sharp as if a stronger solution were used. The oxalic acid' may be of almost any strength, but if made so that 1 c.c. requires 3 c.c. of the permanganate to oxidize it, it will auswer well. The process is then, as follows : from 1 to 2 grams of pig iron or steel are dissolved in 40 to 50 c.c. of concentrated nitric acid with the aid of heat. As soon as solution is effected, in the case of steel, add gradually and cautiously, the solution being kept boiling, sufficient pulverized chlorate of potash to precipitate the manganese as binoxide. Two grams will be a great abundance. In the me of pig iron, first remove the carbon and silica by filtering the solution through asbestos and washing with concentrated nitric acid. Filter the strong acid solution in which the binoxide has been precipitated, through asbestos with the aid. of the filter pump. When it has entirely passed through wash well with water. Blow the contents: of the funnel into the beaker in which the precipitation was made and rinse the funnel with a little water.

Jan 1, 1882

By Woodcock J. T

During the dissolution of gold in fully aerated cyanide solutions the CN ion is the active agent, and consequently the usual method of evaluating the dissolving power of such solutions is to determine the CN- concentration analytically. The presence in the solutions of copper and/or zinc which themselves form complex cyanides, may result in erroneous conclusions as to the free cyanide ion concentration determined by titration.In this paper the theory of titration of such solutions has been developed, and potentiometric methods have been used to follow the behaviour of complex cyanides of copper and zinc. The results for cuprocyanides show Cu (CN)s to be the most important copper complex, and in addition they explain the reported low rates of solution of gold in copperbearing solutions which when titrated in the usual way, appear to have adequate free cyanide. An explanation of the misleading value of the titration is given, and suggestions for recognition of the condition are offered. Preliminary results for zinc-bearing solutions show that there is no satisfactory end-point for the titration of CN- in excess of that in the complex Zn (CN) 4=, which dissociates to CN and Zn(CN)g-.

Jan 1, 1950

By P. Somasundaran

Three major types of solution chemical equilibria involving flotagents (Le. flotation reagents such as collectors, frothers and modifiers), minerals and solution play a crucial role in determining the behavior of complex flotation systems. Minerals of phosphates (apatite and francolite), tungsten (wolframite and scheelite) and associated carbonates (calcite and dolomite) are sparingly soluble in aqueous solution and form dissolved mineral species in bulk solution. Such dissolved species interact with mineral solids, often resulting in surface conversion of the minerals. In addition, they can interact with various flotagents and lead to surface or bulk precipitation and loss of selectivity in the flotation. Relevant solution equilibria of such sparingly soluble minerals and their interactions with oleic acid and structurally modified reagents were determined in this study using a multi-pronged experimental approach. Methods to manipulate and control the solution chemical equilibria and thus achieve selectivity in flotation systems are discussed.

Jan 1, 1990

By Shimi Tzobery, Jay Davenport, Raymond Henn, Sam Bandimere

Over the past several decades, the use of cement-based grouts using ultra fine cement as a replacement for portland cement has begun to gain acceptance as an alternative to chemical solution grouts used in permeation grouting. The amount of information currently available on grouts made with ultrafine cement is limited. The authors used a previously developed field testing program to perform additional tests to evaluate the permeation performance of portland and ultrafine cement-based grouts. For the first time, the 2003 testing program included an attempt to determine the 28 day compressive strength of the sand permeated by the grout.

Jan 1, 2005

By Frederick H. Williams

The object of this paper is to bring to the attention of those members of the Institute who are interested in the subject, a method for the estimation of manganese, which has been frequently used in the labratory of the Vulcan Steel Works during he last eight months, and which is deemed worthy of more general use. It is simply an adaptation of well-known processes, for the purpose of determining this element in pig iron and steel. In general, the method consists in precipitating the manganese as binoxide dissolving in dilute sulphuric acid in the presence of an excess of a standardized solution of oxalic acid, and titrating the remainder of the oxalic acid left unoxidized with permanganate of potash. For this method, therefore, two standardized solutions are needed, viz., a permanganate solution and an oxalic acid solution. The permanganate solution is made so that 1 C.C. is equivalent to 1 mgr. of iron. By using so weak a solution and keeping tile bulk of the solution to be titrated down to 75 C.C. or a little leas, the accuracy of the process is greatly increased, since the final reaction is almost if not quite as sharp as if a stronger solution were used. The oxalic acid may be of almost any strength, but if made so that 1 c.c. requires 3 O.C. of the permanganate to oxidize it, it will auswer well. The process is then, as follows: from 1 to 2 grams of. pig iron or steel ate dissolved in 40 to 50 C.C. of concentrated nitric acid with the aid of heat. As soon as solution is erected, in the awe of steel, add gradually and cautiously, the solution being kept boiling, sufficient pulverized chlorate of potash to precipitate the manganese as binoxide. Two grams will be a great abundance. In the case of pig iron, first remove the carbon and silica by filtering the solution through asbestos and washing with concentrated nitric acid. Filter the strong acid solution in which the binoxide has been precipitated, through asbestos with the aid of the filter pump. When it has entirely passed through wash well with water. Blow the contents of the funnel into the beaker in which the precipitation was made and rinse the funnel with a little water.

Jan 1, 1882

By L. Xiao, P. Somasundaran

Three major types of solution chemical equilibria-involving minerals, solution, and flotation reagents such as collectors, frothers and modifiers-play a crucial role in determining the behavior of complex flotation systems. Minerals of phosphates (apatite and francolite), tungsten (wolframite and scheelite) and associated carbonates (calcite and dolomite) are sparingly soluble in aqueous solution and form dissolved mineral species in bulk solution. Such dissolved species interact with mineral solids, often resulting in surface conversion of the minerals. In addition, they can interact with various floation reagents and lead to surface or bulk precipitation and loss of selectivity in the flotation. Relevant solution equilibria of such sparingly soluble minerals and their interactions with oleic acid and structurally modified reagents were determined in this study using a multi-pronged experimental approach. Methods to manipulate and control the solution chemical equilibria and thus achieve selectivity in flotation systems are discussed.

Jan 1, 1992

In 1991, US mine production of barite decreased 3.4%. Barite consumption, sold or used by grinding plants, decreased by 11.7%. Imports also decreased by 15.4% over 1990. World mine production increased I%, according to the US Bureau of Mines. The value of domestically produced barite, f.o.b. mine, increased 3.3% according to the Bureau. The declared value c.i.f. US port of all imported crude barite during 1991 increased from $40.61/t ($36.84/st) in 1990 to $42.35/t ($38.42/st), the Bureau stated. Nevada was the leading producer of barite with 78% of the total, followed by Georgia and Missouri. It is estimated that 75% of the domestically mined barite was used as a weighting agent in drilling fluids. The remaining 25% was used in barium chemicals, glass or as a filler. Most of the production from Missouri, Georgia and Tennessee was used in the non-oilfield sector. Of the total barite used by grinding plants and chemical manufacturers, it is estimated that 93% was used in drilling fluids. The remaining 7% was in the non-oilfield sector, including barium chemicals and fillers in paper, plastics and glass. Tonnage consumed in the drilling fluids market decreased due to the lower average rig count during 1990. The average number of rotary rigs operating was 860. That was 14.9% less than the 1990 average of 1010 in the US. Crude barite imports were 138 kt (152,000 st) less than 1990 or 15.4%. Imports accounted for 70% of the (ap¬parent) barite consumed in the US. During 1991, China continued to be the leading exporter of crude barite ore to the US with 85.1 %. India followed with 14.8%. About 97.5% of the imported barite ore was used in the oilfield sector. Ground barite imports decreased from 56.7 to 46.2 kt (62,500 to 51,000 st) 1991. Mexico was a major exporter to the US, accounting for 75.3% of the total ground barite imports. Canada shipped 23.7%, while other countries accounted for less than 1 %, primarily for the nonoilfield market. During 1991, the number of grinding plants supplying the drilling fluids market along the Gulf Coast was reduced from 12 to 10. Baroid Drilling Fluids completed its mining program at the Rossi Mine near Dunphy, NV.

Jan 1, 1992

By M. R. Tavakoli Mohammadi

Novel solvent extraction technologies in recent decades have made attempts to show the problems in applying this method for dilute solutions and find appropriate solutions to overcome them. Improving the equipments performance used in this method for dilute solutions, cause development of usable resources and reduction of operational costs. Furthermore, appropriate conditions provide for using dilute solutions produced in various industries as a new source of valuable elements. Thus, this proposal can be a very good solution for treatment of these solutions and reduce the environmental impacts associated with them. The purpose of this study is to introduce a new method of Column Floto Extraction (CFE), which has been invented in this regard. In this method, using spargers similar to Jameson cell downcomer in floatation process, the organic phase bubble dispersion has been used instead of its drop dispersion in aqueous phase for the two-phase mixture operation. This operation mode has caused a higher extraction percentage of solute in high aqueous to organic ratios due to enhancement of contact area. In this study, in addition to explaining the advantages and features of this method, we have dealt with its design and performance mode.

Sep 1, 2012

By Harry E. Brownlow

The United States Bureau of Mines contracted Norecol to prepare a report identifying the regulatory processes associated with metal mine development in British Columbia using the Snip Mine as a case study. The intent of this study is to assist industry and regulatory agencies in developing understanding as to differences in objectives, perspectives and operating methods. The case study will be incorporated into a larger report summarizing the comparative advantages and disadvantages of metal mine permitting in British Columbia and Alaska. The purpose of the report is to identify the development schedule and permitting process at Snip which will assist the U.S. Bureau of Mines in suggesting improvements in environmental review and permitting processes for mine developments. The report provides an abstract of the environmental assessment review processes in Canada and the Mine Development Review Process in British Columbia and provides an understanding of the linkages between policy, legislation, and environmental review.

Jan 1, 1992

By Philip Henry

THERE is a difference of opinion among engineers on the subject of depreciation in general, and still more on its application to any given case. The committee which was appointed by the American Society of Civil Engineers to make a report on Valuation of Public Utilities, states "There is no subject connected with valuation about which there are more diverse views than those relating to depreciation;" and in the discussion which took place upon the presentation of the preliminary report of this committee in January, 1914, that part of the report dealing with depreciation called forth more discussion than any other. From this discussion it was evident that the word " depreciation" was not always used in the same sense, so it is quite important that some definition be adopted. As this paper relates to the proper method of treating depreciation by corporations or individuals operating oil properties, both of which must make a return of annual net income to the government in connection with the income tax, it will be in order to adopt the definition of the Internal Revenue Bureau. Under date of Mar. 29, 1910, the Commissioner of Internal Revenue of the Treasury Department stated "Deduction on account of depreciation of property must be based on lifetime of property, its cost, value and use." Again, on Form 1035, "Return of Annual Net Income" for miscellaneous corporations (Section 2, Act of Congress approved Oct. 3, 1913), a deduction from gross income is allowed for "Total amount of depreciation for the year." This item is defined more particularly as follows: "The amount claimed under Item No. 5 (b) for depreciation should be such an amount as measures the loss which the corporation actually sustains during the year in the value of buildings, machinery, and such other property as is subject to depreciation on account of wear and tear, exhaustion, or obsolescence. The amount taken credit for on this account in order to be allowable should be so entered on the books as to constitute a liability against the assets of the corporation. The amount claimed under this item should not cover losses in the value of stocks and bonds. Decrease in the book value of securities owned, so far as such decrease represents a decline in the actual value of such securities, should be deducted under item 5 (a) of the return.

Jan 1, 1915

By Philip W. Henry

There is a difference of opinion among engineers on the subject of depreciation in general, and still more on its application to any given case The committee which was appointed by the American Society of Civil Engineers to make a report on Valuation of Public Utilities, states "There is no subject connected with valuation about which there are more diverse views than those relating to depreciation;" and in the discussion which took place upon the presentation of the preliminary report of this committee in January, 1914, that part of the report dealing with depreciation called forth more discussion than any other. From this discussion it was evident that the word "depreciation" was not always used in the same sense, so it is quite important that some definition be adopted. As this paper relates to the proper method of treating depreciation by corporations or individuals operating oil properties, both of which must make a return of annual net income to the government in connection with the income tax, it will be in order to adopt the definition of the Internal Revenue Bureau. Under date of Mar. 29, 1910, the Commissioner of Internal Revenue of the Treasury Department stated "Deduction on account of depreciation of property must be based on lifetime of property, its cost, value and use." Again, on Form 1035, "Return of Annual Net Income" for miscellaneous corporations (Section 2, Act of Congress approved Oct. 3, 1913), a deduction from gross income is allowed for "Total amount of depreciation for the year." This item is defined more particularly as follows: "The amount claimed under Item No. 5 (b) for depreciation should be such an amount as measures the loss which the corporation actually sustains during the year in the value of buildings, machinery, and such other property as is subject to depreciation on account of wear and tear, exhaustion, or obsolescence. The amount taken credit for on this account in order to be allowable should be so entered on the books as to constitute a liability against the assets of the corporation. The amount claimed under this item should not cover losses in the value of stocks and bonds. Decrease in the book value of securities owned, so far as such decrease represents a decline in the actual value of such securities, should be deducted under item 5 (a) of the return. "Where depreciation of physical property is made good by renewals, replacements,

Jan 1, 1915

By A. Chakravarti, C. C. Harris

First-order kinetics adequately describe the recovery of a single floatable species. The conditions under which cell behazior can be simulated by a single-phase model are discussed; deviations from the multiphase model are accountable. The rate coefficient depends upon operating conditions besides particle size and mineralogy and the physicochemical properties of the pulp constituents. The model for a real flotation system combines the first -order, single-phase model with a distribution of noninteracting species. Methods for determining the distributions are discussed. Applications of the procedure to flotation studies are outlined. The mathematical description of flotation as a rate process can be traced to Garcia1 who reported cases in which the fraction of solid remaining in a cell in semi-batch operation, F (for Notation used throughout, see Table l), decays exponentially with experimental time T. F = e-k>r. (1 The differential equation leading to Eq. 1 is dF ----= -k,F (2) dT which is recognized as the algebraic analog of the chemical kinetics first-order reaction equation.' This has led to suggested mechanisms for flotation and mathematical relationships other than first order: with very little foundation other than analogy. The flotation rate coefficient kl can be accounted for as the product of several probabilities concerning bub-ble-particle attachment and detachment, aggregate entry from pulp into froth and return from froth to pulp, and removal from froth as concentrate. These factors clearly contribute to the magnitude of the overall flotation rate, and there are others also, but describing flotation merely as the overall probability of consecutive gross events hardly appears a significant advance in understanding. More recently, it has been described in terms of a stochastic process, which promises to provide a more satisfactory approach? The present paper will be more concerned with a phenomeno-logical description of the flotation process than with an account of the internal mechanics of the process. This is not a statement of priorities, or a judgement of the relative importance of these options but rather an assessment of what is presently possible. Previous investigators'" have developed methods for interpreting semi-batch flotation data in terms of species distribution. These methods have been used in an attempt to explain flotation behavior in response to changes in operating conditions." Inspection of examples given in the literature" reveals discrepancies between theory and experiment, and data obtained in the Colum-

Jan 1, 1971

By Steve Davidow, Ashely E. Evans, Peter M. Kandaris

"Annually thousands of deep foundations are constructed across North America supporting high voltage transmission line structures. However, a recent state of the practice survey by the Deep Foundation Institutes’ Electric Power Systems Foundation Working Group discovered that the electric power utility industry lacks consistent foundation design guidelines. The survey identified a wide variability in design assumptions, a minimal understanding of risk based analysis, and a need to standardize design methodologies. This paper summarizes the state of practice in electric system foundation design and proposes a framework for risk-based foundation design by accounting for uncertainty from both loads and resistances. Loads derived from electric system codes do not necessarily provide a compatible level of reliability for the design of foundations, as they are a mixture of probabilistic and deterministic values. Load uncertainty is derived from variability in weather conditions, structural models and material properties, typically accounted for by code derived overload factors. Resistance uncertainty arises from variability in natural soil properties, resistance models, subsurface construction techniques, material sampling methods, and limited observations. A consistent methodology is offered relating nominal resistance capacity (strength) to structure loads and service state criteria. Discussion also includes the need for risk-based assessments to account for non-structure load influences (fluvial loads, scour ground loss, liquefaction, etc.).INTRODUCTIONNearly 40 years ago the Electric Power Research Institute (EPRI) embarked on a major research effort to optimize reliability and economics of transmission line foundation design. Strategies focused on improvements in design models, site characterization, exploration strategies and testing to reduce uncertainty and variance in analysis. Transmission line engineers realized that safety and reliability advancements in design based on probabilistic approaches, with a focus on the unique nature of transmission line, could better control risk and cost.Some transmission line professionals took full advantage of these advancements, particularly where research led to improved software and models. Yet, even after two decades of extensive research, by 1995 the industry still had made little progress in changing design habits. The majority of designers were still characterizing sites via deterministic methods, using loads that may or may not relate to a consistent probability of occurrence, and applying a traditional global factor of safety approach (Phoon, et al. 1995). The following two decades have seen even greater developments in software and reliability-based analysis methods, but old habits seem to die hard as recent surveys show less than half of design professional quantitatively assess risk in their design process."

Jan 1, 2017

By M. Sokoto, H. Hata, K. Nishina, K. Haiki

Fluoride ions in zinc electrolyte cause corrosion to aluminum cathode plates at zinc electrowinning process, so we have developed an iron compound as a fluoride ion adsorbent used in zinc sulfate solution. The iron compound is synthesized from FeC13 solution with a small amount of sulfate ion by neutralizing reaction with Na2CO3 solution. The fluoride ions adsorbed on the surface of the iron compound are desorbed in alkaline solution and the iron compound can be reuse as a fluoride ion adsorbent. Moreover, if adsorption capacity of the iron compound decreases, it can be dissolved in HCl solution and re-synthesized.

Jan 1, 2008