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By Don Muraoka

Soda ash, anhydrous sodium carbonate, is produced from underground trona deposits occurring in the Green River Sasin of Southwestern Wyoming. Stauffer Chemical Company of Wyoming, a jointly owned subsidiary of Stauffer Chemical Company and Rocky Mountain Energy Company mines the trona and processes it into high-purity soda ash. Stauffer Wyoming has been in operation since 1962 with a current production capacity of approximately 2.2 million tonnes (2 million short tons) per year of soda ash. The Refinery has five parallel operating trains utilizing the monohydrate process which is a series of chemical processing unit operations described below. Screening and Crushing the Trona The mined trona is brought to the surface in two counterbalancing ore skips. The ore is initially screened with Refinery feed, less than peagravel size material, entering the process while the oversize is conveyed to an outdoor stockpile.

Jan 1, 1984

By Juan Ares, Enrique Fernández, Alejandro Sanz, Francisco González

"INTRODUCTION Crossrail is a subsidiary company of Transport for London created for the construction of a new transverse train line 118 km long between Maidenhead and Heathrow in the West, and Shenfield and Abbey Wood in the East, including 21 km underground below London. Crossrail C305 Eastern Running Tunnels project is the biggest contract within Crossrail Project and involved boring 11.8 km of twin tunnels through London’s city center. Crossrail C305 Project interfaced with different contracts along its alignment and therefore logistics and solutions had to be developed to minimize disruptions or interferences with other contractors and the neighborhood. The paper describes this innovative approach. C305 CONTRACT APPROACH C305 contract was split into three drives, to be excavated by four EPB TBMs 7.1m diameter, as shown in Figure 1. •,Drive Y: 8.2km long between Limmo Peninsula and Farringdon Station in the city center •,Drive Z: 2.7km long between Pudding Mill Lane and Stepney Green Junction •,Drive G: 0.9km long between Limmo Peninsula and Victoria Dock Portal in the East. Crossrail C305 Project scope of works included the excavation of TBM tunnels and shafts at Limmo Peninsula and Stepney Green (including 17m span turnout caverns), along with the requirement to traverse station and shaft structures of other Crossrail contracts. Limmo Peninsula Site was a strategic element as it was the only access point on the tunnel alignment with sufficient available area at the surface for tunnelling logistics and also connected to the Lea River, tributary of the River Thames which facilitated marine operations for segment supply and muck removal. These were the reasons for operating Drive Y & Drive G TBMs from that location. Drive Z TBMs were originally planned to be launched from Stepney Green to Pudding Mill Lane, supplying the TBMs during Drive Z excavation from Limmo Peninsula site through the excavated section of Drive Y between Limmo and Stepney Green. During the early stages of the project, a value engineering proposal with a new tunneling strategy was agreed wherein the Pudding Mill Lane contractor would provide space for TBM assembly and operation in their portal, allowing for reversing Drive Z excavation and launching the two TBMs from Pudding Mill Lane. This optimization reduced some of the shaft requirements at Stepney Green which were contingent upon critical enabling works and provided program certainty and cost savings for the full Crossrail Project. It allowed for the reuse of both the Drive Z TBMs for Drive G excavation from Limmo to Victoria Dock Portal thereby saving on the procurement of two TBMs, in addition to easier logistics for both Drives Y&Z, therefore de-risking the TBM excavation process and the C305 Project program completion."

Jan 1, 2016

By Angelus S. C. Owili-Eger

The investigation into the hydrologic and hydrogeochemical influence of longwall coal mining in the Appalachian coal basin was under- taken in response to the need to technically address problems of damaged or impaired well yields, and quality deterioration. Prior to this study, issues regarding reduced aquifer yields and degraded water quality had to be handled in a very qualitative manner. Such an approach would, in the long run, claim a heavy toll on the mining industry. The primary objective of this undertaking, therefore, was to provide sufficient and reliable information base for the determination of the local and possibly the regional effects of longwall mining on well yields, and the hydraulic and hydrogeochemical parameters of the immediate surface and subsurface water systems. Specifically, the program was designed to supply definitive data to answer the following series of questions: 1. Does longwall mining affect the quantity and quality of water in local wells above and adjacent to longwall panels and barrier pillars? 2. If the water quality is affected as soon as mining takes place, does it heal? or if it is not affected immediately, does it change over a longer period of time? 3. How do the aquifer water transmitting characteristics respond to induced physical ad hydrologic variations? 4. What is the extent of the various changes in quantity and quality of the water resources? 5. Should and can standard hydrologic evaluation techniques be used to determine the hydraulic properties of highly fractured zones located within a larger and less permeable aquifer?

Jan 1, 1983

By M. Kehnemuyi

The U.S. Department of Energy is charged, by federal law, with the responsibility for developing and implementing programs for long- term storage and terminal disposal of high- level radioactive wastes from both commercial and defense nuclear operations. Approximately 288,000 cubic meters of defense high-level wastes are currently in storage at the government's Hanford Reservation in the State of Washington, the Savannah River Plant in South Carolina, and the Idaho Chemical Processing Plant in Idaho (U.S. Department of Energy, 1980a). High-level wastes from commercial nuclear power production are stored in water pools or basins at various power plant sites. At the end of 1980, approximately 7.460 metric tons of uranium, contained within 28,300 fuel assemblies was in storage at various reactor basins. Although the present inventory of defense wastes are many times larger in volume and in total level of radioactivity than the commercial wastes, in the future, the latter will constitute a substantial quantity of wastes that will have to be disposed of. The present electric generating capactiy of nuclear power plants in the United States is 56.5 Gigawatts-electric (GWe). The amount of spent fuel that would be discharged and accumulated by the year 2000 from these operating reactors would be 38,000 metric tons. With a projected growth of the nuclear industry to 180 GWe in the year 2000, the amount of spent fuel accumulated at the turn of the century could reach 89,000 metric tons of uranium or approximately 318,000 assemblies. In any case, whether one postulates a no growth pattern or one where nuclear power provides its share in the country's electric generating capacity in the next two decades, a means for safe and environmentally accept- able disposal of high-level nuclear wastes must be found. Storage of commercial wastes in water basins, either at reactor (AR) sites or at away from reactor (AFR) sites, and storage of reprocessed defense wastes in surface or near surface tanks is a temporary solution and is not an alternative for permanent disposal.

Jan 1, 1981

By J. W. Meckenstock

Evidence of the fact that the beneficiation of sand and gravel is now going on is readily observed by visiting various and and gravel plants almost throughout the U.S.A. of necessity this beneficiation process is concentrated more in certain areas than in others, and it is steadily increasing. Therefore, it can be said that beneficiation is now one of the processes inn the manufacturing of sand and gravel, It started some ten to twelve, years ago when the need for beneficiation made itself known, and when the manufacturers of sand and gravel producing machinery began to make equipment available to the industry.

Jan 1, 1958

By John E. Edkins

Metal sulfides, chiefly pyrite and mFnor sphalerlte zssociated with che Herrin (No. 6) coal member of the Pennsylvania Carbondale Formation, have been concentrated in a coal refuse deposit in southern Illinois. Oxidation of pyrite has produced highly acid waters with high concentrations of iron, zinc (up to 200 parts per million) and toxic trace elements that have leached downward to a water system perched on glacial drift. Chemical, petrographic, low-temperature ashing and x-ray diffraction were performed on cores. The data show that economic recovery of zinc and other trace metals is unlikely at this site. Energy (coal) recovery at the Superior Washer site is possible if resultant environmental problems are considered in the planning.

Jan 1, 1981

By Gabino Preciado, Louis Sandbak

Corrosion has long been identified as a potential risk to the long-term ground support stability due to degradation of internal ground support elements such as rock bolts but also to surface support from mesh, straps, bolt plates, and ancillary support of utilities such as hangers. The emphasis is to understand the corrosion mechanisms on the primary ground support elements and any supplemental steel or arch sets. The water and chemical processes from oxidation(rust), stress corrosion cracking, and even the electrical charge created during these reactions contribute to the corrosion of the steel support elements. The main goals are to mitigate the effects of corrosion and to be able to predict those areas of high water or high sulphide for potential rehab maps. It is also essential to identify and classify the visible corrosion as part of damage mapping and provide bolt testing to those areas of suspected internal damage from corrosion. This is important to get an estimate of the support longevity or expected life before rehab to minimize the overall cost of the operation.

Feb 1, 2024

By W. G. Lawrence

The rapid development of science and technology in Russia has been the result of well laid plans since 1918. At that time the Institute of Silicates was established is Moscow and later the establishment of similar more specialized institutes for the study of cement, glass, refractories, construction ceramics, electrical ceramics, building materials and asbestos provided the necessary research facilities for studies related to all types of ceramic inorganic materials. The' Institute of Ceramics and the Institute of Silicate Chemistry, Academy of Sciences, USSR, were founded in Leningrad. The work now going on in these various research' institutes covers every branch of silicate science and ceramics The impetus behind such establishment of special¬ized laboratories is no doubt due to the 5-year plans and the necessity of improving the scientific knowledge regarding the materials being used and the products being manufactured.

Jan 1, 1960

By T. Luterbach, V. T. McLemore

"Trace element analysis of placer gold can be used as a valuable exploration tool in order to determine the original deposit source and locating lode gold deposits. Placer gold collected from multiple districts in New Mexico and Alaska, coupled with a broad database of previously analyzed placer gold samples indicate correlations between chemical signatures (especially gold, silver, and copper) and type of deposits (i.e., Au-rich copper porphyry deposits, Au porphyry deposits, and epithermal deposits). By completing a chemical analysis and determining the particle morphology of placer gold collected from these districts using an electron microprobe, patterns in the chemical signatures from each location can be used to examine chemical variability (1) within the individual placer gold particles, (2) within the same district and (3) among different districts. INTRODUCTION Although there are numerous past studies on the chemical composition of placer gold by Newberry et al. (1997), Melchiorre (2001, 2009), Townley et al. (2003), and McLemore et al. (2014), the gold analyzed tends to be collected from one or few specific districts. Rarely do those studies compare compositional results to additional districts, or elaborate on the correlation between the elemental composition of the placer gold and the original deposit source for the respective districts. This research analyzes the composition of placer gold from multiple districts and within the same district. There are a number of elements, which can, in various quantities, be present in placer gold particles. Native gold can be in complete solid solution with native silver and contain additional elements including Cu, As, Pb, Fe, and S. The chemical signature of the gold is determined by the thermodynamic conditions of precipitation and transport as well as the total metal content of the system. As Townley et al. (2003) explains, “These thermodynamic conditions and metal budget differ from one type of hydrothermal deposit to another, and hence different deposit types will each have a characteristic gold compositional signature.” Identifying this signature can be a highly valuable tool in exploring for gold, as it can not only be used to determine the original source deposit of the placer gold, but provide valuable insight as to the erosion level of the present deposit."

Jan 1, 2016

By D. M. S. Bhatia

The intimate association of iron formation and massive sulfide deposits has been documented by many investigators (McAllister, 1960; Hutchinson, 1972). In a classic example of such an association four distinct facies (oxide, carbonate, silicate, and sulfide) were identified in an Algoma type iron formation occurring in Paleozoic rocks, but exhibiting physical features (banding) and chemical composition (SiO2 + A1203 + Fe2O3) typical of Precambrian iron formations. The geochemical variation of the iron formation was studied by analyzing 62 samples for Si, Al, Fe, P, S, and CO2. Following a model proposed by James (1954), the geochemical and mineralogical variation of the iron formation can be used as an excellent tool for the exploration of massive sulfide deposits.

Jan 1, 1981

By L. J. Lindsay

Kaiser Resources Ltd. operates a coal mining complex in Southeastern British Columbia. A large surface mine, a conventional underground mine, and an innovative hydraulic underground mine are presently in operation. The products of these mines are fed to the Elkview plant. This coal has to be prepared to 9. 5% ash and 6'o total moisture for export from the port of Roberts Bank near Vancouver, British Columbia to Japan at a rate of 4. 5 Mltpy. The moisture requirement for the coal product was recently increased to 8. 0% total moisture. The entire operation has been described in various publications (1), (2), (3). Details of the venture will not be repeated in this paper. In this paper we hope to describe the modifications made to the original coal preparation plant in order to satisfy market requirements for quality and quantity of coal.

Jan 1, 1974

By H. Boyd

Fluid energy grinding, or jet pulverization, refers to the process of entraining solid particles in high velocity gaseous or vaporous streams and reducing their size by impact and attrition against other particles or some sort of target. Since all desired size reduction is not achieved in one pass through the zone where energy is applied, some form of classification is necessary to return oversize particles to the grinding zone for further size reduction. Applications Fluid energy mills have normally been used to produce products where the particle size is basically finer than 325 mesh. Products having particle size distributions with a maximum size of 4 or 5 µm, and with a high percentage finer than I µm, can be produced using fluid energy mills. More recently, some fluid energy grinding units have been applied economically to produce ground products with 1 or 2% coarser than 200 mesh. It is also possible to consider usage of a jet-pulverizing zone, without the usual integrated air classi¬fier, operated either in open circuit or in conjunction with a screen. Feed sizes to be delivered to the fluid energy mill depend on the material involved, the type of jet pulverizer used, the finished product size requirement, and the upstream process. In some units feed sizes up to l in. or larger can be accepted, but practical economics usually require the starting material to be -4 mesh or smaller and some pulverizers are typically fed at 20 mesh top size. It is not unusual to find feed materials at essentially -325 mesh when extremely fine products are needed, since capacities are improved with finer feeds. Conventionally the fluid energy grinding process has been used for relatively soft and nonabrasive materials. This includes very low¬melting-point and temperature-sensitive materials or coatings, since there is no measurable temperature rise during fluid energy milling. More recently, however, jet pulverizers are being used on highly abra¬sive materials such as silica, feldspar, glass, zircon, calcined alumina, coke, boron carbide, and similar materials. Since the primary energy application is by impact of particles against themselves, there is a low rate of wear resulting in a small amount of product contamination and in low maintenance costs. Usually the fluid energy pulverizer produces a more narrow particle size distribution than other mills provide, and this is useful where such a requirement exists. It is possible, within limits, to adjust classifi¬cation and other functions of the overall fluid energy system to vary the particle size distribution curve and thereby approach the broader distribution obtained from other grinding methods. By controlling the temperature, composition, and humidity of the fluid used, it is possible to incorporate other functions with the size-reduction process. These include drying or adding moisture, coating, mixing and blend¬ing, and even oxidation or reduction and other chemical reactions or their inhibition. The finished product is discharged in the fluid stream and is conveyed pneumatically to the desired point, where a suitable dust collector must be provided. Operation and Mechanical Features One of the earliest fluid energy mills is the Micronizer now manu¬factured by the Sturtevant Mill Co. Similar units are also manufac¬tured by Jet Pulverizer Co. and others. As shown in Fig. 81, the micronizer consists of a shallow circular grinding chamber with noz¬zles arranged at the outer periphery to discharge tangentially inward. Fluid (usually compressed air or superheated steam) is provided to the nozzles from a manifold at pressures normally in the range of 100-150 psig and at temperatures up to 800°F or higher, depending on the raw material, required results, and economic factors. The com¬pressible fluid expands to high velocity through the nozzles and gener¬ates a spiral flow pattern in the grinding chamber, and discharges

Jan 1, 1985

By J. D. Patsey, G. T. Lineberry

Introduction A computer program was developed for analyzing drum-type hoists before modifying an existing system or designing a new one. Its use permits the preliminary evaluation of a system before seeking technical assistance from mine hoist designers and manufacturers. The user-friendly program accepts a variety of data and analyzes hoisting systems for any balance state. The program can be used to calculate skip capacity to yield a desired production rate, solve for drum face width, select a permissible wire rope, estimate total horsepower of the hoist plant, and estimate annual power cost. Whether required for a large mining complex or for a relatively small operation, a hoisting system must be carefully designed to ensure the efficient, reliable, and safe flow of material. Because shaft sinking and hoist installation can total between 2.5% and 3% of the cost of opening a deep mine, proper hoist selection is critical. Today's mining engineer has at his disposal the most powerful design and analytical aid ever, the micro- computer. There is, unfortunately, limited software for the study of hoisting systems, unlike that for other materials handling equipment (Manula and Albert, 1980; Prelaz et al., 1964; Bucklen, 1969; Thompson, 1985). HOIST reduces a time-consuming set of calculations to a concise package of interrelated subprograms. A literature review revealed no common-user pro- grams to analyze hoisting systems, although at least four major hoist designers/manufacturers/installers have their own in-house programs. To provide a tool with which the mining engineer could preliminarily analyze a materials hoisting system or could check the calculations of a hoist contractor, a computer program was developed. HOIST was written in BASIC for the IBM-PC for ease of program adaptation and to en- courage field use on compatible systems. Details of program development are omitted, since the basic principles of hoisting analyses are relatively straightforward, simple, and readily accepted (Har- mon, 1973; Nordberg, n.d.; Adler, 1957). Program features, intended usage, and benefits of the com- puterized solution are emphasized over theory development and mathematical rigor. Background The mine hoist system that is selected and installed at a mine is the "lifeline" of that mine, with installations lasting 20 years or more. Thorough study is warranted to ensure that productivity demands are met at a minimum cost per ton. The increased cost of a large, powerful, high-speed hoist must be offset by increased production to justify its selection. To optimize this tradeoff, an extensive hoisting analysis should be performed. The analyses to properly size the skip (or cage ) , the drum, and the hoist drive are conducive to computerization, permitting rapid evaluation of changeable operating and design parameters, such as velocity, acceleration, state of balance, and productivity demand. The program is particularly useful in conducting sensitivity trials, such as investigation into the effect of change of productivity on skip capacity and on horsepower of the hoist drive. HOIST is currently limited to the study of drum-type hoists with cylindrical drum(s). However, only minor changes to the program would permit analysis of friction hoists and conical drum configurations. Model development and testing The program is based on accepted equations and physical relationships. Examples of manual calculations formed the basis for decision points and program branching. Data is input in the order that it would be needed if the problems were solved manually. The choices are arranged likewise. HOIST was developed in sections, with manual solutions performed to check program logic. The testing became more rigorous as sections were completed. Output from one section becomes input for following sections, as appropriate. The simplified flow diagram of HOIST is given in Fig. 1.

Jan 1, 1988

By Peter L. Dunn

With the advent of new high-strength magnetic materials, rare-earth magnetic separators have become more common place for processing heavy mineral sands. In many instances, rare-earth magnets have replaced conventional separators such as electromagnetic cross-belt and induced-roll type machines. This paper will present the results from a detailed test program developed to evaluate the performance of rare-earth drum and roll separators for processing heavy mineral sands. The effect of machine design parameters, such as magnetic element configuration and separator diameter, will be reviewed in light of these test results. The impact of basic operating parameters (i.e. feed rate and roll speed) on separation efficiency will also be presented.

Jan 1, 1999

By M. Ramachandran, R. G. Reddy

"A direct route for the reduction of magnesium oxide to magnesium using thermal plasma processing, with methane as the reducing gas, has been systematically evaluated. A feasibility study of the reduction reaction has been performed on the MgO-CH4 system at different methane concentrations and temperatures. The effects of changes in the key process parameters, such as the oxide-to-methane ratio and plasma power, on the yield of magnesium have been systematically evaluated. A maximum yield of about 61 mol% Mg was obtained using power of 20.0 kW and a molar ratio of MgO:CH4=1:1. Phase, morphological, elemental and binding energy analyses were performed on the product powders to understand the reduction reaction. Surface oxidation was observed in smaller magnesium particles in all the experiments, while the in-situ sintering of magnesium rods was observed at a molar ratio of MgO:CH4=1:1.5. Magnesium carbide (Mg2C3) was observed in the product, and its mechanism of formation is proposed using phase equilibrium data and a predominance diagram.IntroductionMagnesium has an excellent combination of low density and high strength. These properties have increased worldwide demand for and use of magnesium. Two major processes are used in the commercial synthesis of magnesium metal. The first method is electrolytic reduction and the second is thermal reduction using Pidgeon process. These processes can be classified as traditional techniques, but there are numerous emerging technologies that aim at reducing the production cost of Mg, its environmental impact and energy consumption. Thermal plasma processing is one emerging technique that has great potential in all the abovementioned key areas of magnesium production.Traditional reduction techniques. Two major reduction techniques, namely electrolytic and thermal reduction, have been used in the commercial production of magnesium. Electrolytic reduction is typically carried out in electrolytic cells from magnesium chloride (obtained from seawater or well and lake brines) (Tripp, 2009). The following simplified reaction shows the reduction of magnesium chloride to liquid magnesium and chlorine gas:"

Jan 1, 2015

By S. K. Mishra

The history of the Australian coal industry is almost as old as the history of Australia after new settlement. The first cargo of coal was exported from Newcastle to India in 1799. Although coal has been mined in Australia for almost two centuries, there are indications that the first coal was processed in 1877 in the New-castle area, nearly a half-century after the first coal processing in Europe. Processing on any significant scale began only in 1944 at the Newcastle Steel Works. In Queensland, however, coal processing did not begin until the second quarter of this century. The well-known dramatic growth of mining and processing of Australian coal since the mid-sixties has primarily been due to the expansion of the export market in Japan and other Asian and European countries. Black coal occurs in most of the major sedimentary basins in Australia. The better known deposits of commercial importance are in Sydney, Bowen, Oakland and Gailiee Basins (Figure 1). Apart from Collie Basin in Western Australia, other coal deposits of the Arckinga Basin in South Australia, the Bonaparte Basin in Northern Territory and Tasmania Basin, Tasmania, are basically unexploited. Sydney Basin of New South Wales and Bowen Basin of Queensland remain the major producers of black coal in Australia.

Jan 1, 1985

By James E. Lonergan

Linear goal programming is a multi-objective optimization technique where the constraints of a linear programming formulation of a problem are considered as additional objectives. The optimal solution is the one that comes closest to satisfying all the objectives. An interactive computer program was written to utilize this technique in solving the feed blending problem faced by power plants de- pendent on multiple sources of coal supply. This program determines the amount of coal from each supplier to utilize in the blend. Examples of the use of the program in both long and short term coal procurement planning scenarios are given.

Jan 1, 1984

By Paul Kents

The Canadian Javelin Limited Cerro Colorado copper-porphyry deposit in Panama, possibly the largest known copper-porphyry, contains between 1350 and 450 meter elevations, drill proven and probable ore in excess of 3.0 billion tons averaging 0.65% of copper equivalent. The deposit is located in the Central Cordillera Range, straddling the Continental Divide at 1500 meter elevation. Local topography is very steep. Accessibility is difficult, all logistics made by helicopter, and only recently a 52 km. road from the Pan-American highway was completed into the area. The deposit was discovered in 1969, and since then 75 shallow exploratory holes and 98 deep holes, the deepest 1340 meters, totalling 45,000 meters have been drilled. Deep holes were drilled at the corners of a regular rectangular 150 meter grid.

Jan 1, 1975

By Ronald G. Schmidt

AND SOME RIN UP HILL AND DOWN DALE, KNAPPING THE CHUCKY STANES TO PIECES WI' HAMMERS, LIKE SAE MANY ROAD MAKERS RUN DAFT. THEY SAY IT IS TO SEE HOW THE WARLD WAS MADE. Sir Walter Scott St. Ronan's Well - 1824 In the minds of many, geologic exploration has advanced little since the early nineteenth century. In truth, despite the development and refinement of new and potentially valuable technological tools, the approach or philosophy of the explorationist has received meager attention in professional literature. In many areas, the explorationist relies upon experience, subjective judgement and general intangible inspiration, often traveling together under the misleading pseudonym of "art," in achieving both an exploration plan and in making the myriad day to day decisions necessary to the execution of that plan. Without a solid, objective basis for decisions, exploration under this concept is little more than guesswork largely by intuition, and it is small wonder that many exploration programs flounder in a sea of over-expenditure inefficiency or fail to fulfill their expected goals within the funding which has been provided. From a rational management point of view, such a state of affairs is frustrating and inconsistent with the application of the same scientific principles which are presumed to be the basis for the exploration methods which are used. This somewhat presumptuous point of view cannot be extended as a general condemnation of the many exploration programs which are both technically and economically successful. On the other hand, the

Jan 1, 1968

By M. H. H. Mahmoud, T. A. El-Barbary, E. A. Abdel Aal, I. A. Ibrahim, A. K. Ismail

Fertilizer-grade phosphoric acid with a P2O5 concentration of 50% should contain less than 1.5% Fe2O3, otherwise, the P2O5 water solubility of the fertilizers prepared from high-iron acids will be low. High-iron Egyptian phosphate concentrates fromAbu-Tartur and Sebaiya- West were leached with sulfuric acid and recycled phosphoric acid to produce 50%-P2O5 phosphoric acids containing 4.0% and 2.7% Fe2O3, respectively. The high iron contents were reduced to the industrially accepted limit of 1.5% Fe2O3 by precipitation with potassium sulfate. The factors affecting the effi¬ciency of the precipitation process, e.g., temperature, time and K2O/Fe2O3 ratio, were systematically studied, and the optimum conditions were achieved. The clarification of the prepared phosphoric acid from iron-containing sludges was also investigated by varying the time and temperature. The utilization of the separated sludges as fertilizer and recovery of P205 by pulping in water were also evaluated.

Jan 1, 2000