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By Weihua Song, Hongwei Zhang, Feng Zhu, Sheng Li, Guoshui Tang

"Rock burst is one of the most serious dynamic disasters in coal mining. Rock burst prevention involves two difficult tasks: systematically evaluating the occurrence conditions and effectively forecast for rock burst. This paper systematically studies the effects of natural geological dynamic conditions and mining engineering on and forecast for rock burst. It establishes the evaluation method and index system of rock burst geological dynamic conditions and proposes a method of forecasting rock bursts by monitoring fault activity with anchor cables. Natural geological dynamic conditions are a necessary condition while mining engineering is a sufficient condition for the occurrence of rock bursts. Rock bursts in mine must have suitable geological dynamic conditions, and mining engineering activity is merely an inducing factor. There is a good correlation between anchor cable stress variation and fault activity, when the anchor cable dynamometer indicates that the fault is active. It can forecast a rock burst a few days in advance. This technique has been successfully applied to Panel 83003 of a coal mine in China, which improved the safety production level of the mine and found a new way of rock burst evaluation and prediction.INTRODUCTIONRock burst is one of the most serious dynamic disasters in coal mining. With the increase of mining depth, rock burst disaster is becoming more and more serious. Systematically evaluation and effective forecasting of the occurrence of rock burst in the coal mines are important and difficult work in the control of rock bursts. Chinese researchers have performed numerous researches on rock bursts, Qi et al., established the rock burst model of frictional sliding instability, explained the occurrence mechanism of rock bursts by stick-slip phenomenon in frictional sliding, gave full consideration to the influence of primary rock stress and mining-induced stress on rock burst occurrence, and proposed the stress controlling theory of rock burst. Pan et al., [3] put forward the criterion of perturbation response, explained and analyzed the problem of rock burst in circular openings, put forward the ratio of coal-rock elastic modulus and reduced modulus is the significant parameters for the determination of stabilization; systematically summarized the rock burst distribution, type, mechanism and control in China. They classified rock bursts into three types: coal compression, roof fracture and fault movement. By applying energy transfer principle and conservation of energy, combined with the analysis of the weakening of rock fabric damage, Zhou and Jiang put forward the theory and equation for the occurrence of coal-rock mass impact effect. They analyzed and discussed the formation mechanism of rock burst by combining impact effect theory and energy equation. Wang et al., recognized that the mechanism of rock burst which induced by fault, fold and phase transition is the superposition of tectonic stress and mining stress and that the axes of syncline and anticline and their flanks are the location where rock bursts mostly occur. To prevent stress superposition is the efficient way to control the structural rock burst [7]. Jiang et al., summarized the research achievement of rock burst mechanism and controlling techniques and existing problems in recent years in China, and pointed out the direction to improve the level of prevention of controlling rock bursts in coal mines."

Jan 1, 2015

By N. Pajunen

The basic objectives of current EU waste policy are to prevent waste and promote re-use, recycling and recovery to reduce negative environmental impact (2008/98/EC). In this paper, we focus on drivers and barriers for sustainable development by decreasing amount of waste and increasing material efficiency. Main target is to understand what are the most efficient drivers for environmental friendly decision making for reasonable consumption and use of raw materials. Environmental control instruments usually mean those actions the regulatory authority uses to control and limit environmentally harmful behavior of companies. A major change in the environmental control system took place in the 1980s with the focus moving from specific environmental issues to the environment as a whole. The environmental control system i.e. the legal (administrative), economic and informative instruments focuses on prevention. Before and still, the legislation is one of the main drivers in improving material efficiency. In this paper, we focus on drivers and barriers for effective industrial material use, and mainly on drivers. The objective of this study is to analyze how the drivers are working and are there any possibilities to influence on those. Our aim is also to introduce few examples of the existing supply chains and the drivers for better environmental performance and material efficiency. These examples are also compared with ideal reference scenarios. Our main research question in this article is: ?Are the financial issues the most important driver for environmental friendly strategic decisions?? In addition, retell the story from another perspective: ?The most important barrier for environmental friendly innovations seem to be the investment cost, the high risk involved in committing capital to unproven technology.? Other drivers, like the corporate social responsibility, stakeholder pressure, and general public pressure, will also affect the final decision. This article is based on research projects and literature. Keywords: drivers, decision-making, environmental management, saving primary raw material, material efficiency, sustainable production, critical raw materials

Sep 1, 2012

By A. Rousselet, H. Gilbert-Tremblay, A. Berton

"Robex Resources interrupted production at the Nampala Mine in September 2014 following throughput and gold recovery results which were below expectations during the first months of operation. After a thorough plant audit, an important brainstorming took place in order to identify an economical path to resume production. It was clearly identified that a significant investment was necessary at the concentrator prior to restarting the plant, namely the addition of a ball mill and a new elution system.The mineral processing simulation software USIM PAC was used in order to simulate the grinding circuit in design. The simulations’ outputs allowed the ball mill characteristics and the surrounding classification devices to be designed with more accuracy. Many ball mills available from second hand retailers were therefore studied in the simulated circuit. The chosen ball mill, which was in perfect condition, had the advantage of being available for rapid delivery on site.The paper first describes the ball mill sizing method in comparison with the conventional Allis Chalmers method. It then describes the phase 2 concentrator start-up (that took place in 2016) with the commissioning of the ball mill, the classification circuit, the gravity concentration, the four (4) new carbon-in-leach (CIL) tanks, and the Zadra elution system (The phase 1 start-up took place in 2014). It finally provides production data compared to expected simulation data, as commercial production was reached in January 2017.IntroductionDesigning a new concentrator or new equipment within an existing concentrator requires significant efforts to identify possible bottlenecks and their causes (i.e. limiting equipment or sectors) and accurate sizing of major equipment can have a tremendous impact on the economy of the whole project. In the presented case study, the ball mill was the critical equipment and oversizing it could have brought the Capex to a level where the project would not have gone through. Inversely, undersizing the mill could have resulted in lower production and therefore no economic viability for the project once it is in operation.During engineering studies, equipment sizing often relies on a static mass balance and one-by-one sizing of all pieces of equipment. The sizing is then left to the equipment manufacturer or in the case of mills, evaluated with empirical models mostly relying on the Bond equations (Allis Chalmers method) [Rowland and Kjos, 1978]. This methodology shows the disadvantage of not considering interaction between equipment in a mineral processing circuit, especially when recirculation occurs. Also, it has the disadvantage of not using the more advanced grinding models that include the use of the whole particle size distribution as well as phenomenological components by only using limited parameters in the ore particle size distribution (i.e. the P80). This can be explained by the lack of data that sometimes needs to be gathered in order to tune the more advanced models but also by the conservative mindset in mineral concentration engineering which does not always favor the use of process simulation. In many aspects of process engineering, Soutex has demonstrated its affinity to using simulation in order to size equipment with more accuracy, consider process variability, simulate complex systems, and study supply chain management (Berton et al., 2015)."

Jan 1, 2018

By J Rowland

"This paper was primarily put together in order to demonstrate what are believed to be acceptablestandards, in relation to ventilation surveys and the subsequent model assembly process. Thiswas brought about by the fact that in many parts of the world it is regarded as acceptable to carryout ventilation surveys and then build and supply the client with a æstick fi gureÆ type ventilationmodel. Such stick models have arguably litt le use and a very short life span in the real world and isalmost impossible for site staff to maintain. Thankfully most underground coal mines in Australia strive to maintain a true replica model of their ventilation circuits and to keep them in a relatively good state. Given that these mines own and maintain the models, it is often seen as necessary to update or rebuild them. The level of survey detail required to do so is totally dependent on the end use of the data and the criticality of the accuracy of the data set, to the ongoing safety and viability of the business. Mine technical personnel should think clearly about the use and importance of the ventilation survey and subsequent report outputs required that will help them bett er understand their mines and bett er prepare them to manage their ventilation circuits, on an ongoing basis. This paper provides some guidance for Australian ventilation engineers so they may plan and execute this work æin houseÆ, should they rightly choose to do so. To this end, methods of data collection and circuit analysis required for surveys of a high order of accuracy are detailed. Also, some of the issues which are important when formulating a strategy to carry out the appropriate ventilation survey for the required purpose are summarised. As well, the major details that should be furnished within any survey and some survey/report outputs and/or omissions, which are clearly not acceptable, are highlighted."

Jun 1, 2012

By Gabriel S. Esterhuizen

The design of support for underground excavations is a complex process in which the interaction between supports and the rock mass must be evaluated. The strength reduction method (SRM) is useful because it provides a stability factor of the supported excavation that can easily be compared between support alternatives. The method is based on numerical model analysis where the stability factor is determined by reducing the rock mass strength until collapse is indicated in the model. This paper presents the results of validation studies that were conducted using the FLAC3D stress analysis software to compare SRMcalculated stability factors to the empirically based Coal Mine Roof Rating (CMRR) and the Analysis of Roof Bolt Systems (ARBS). The objective was to determine whether the SRM, with its basis in mechanics, would predict similar outcomes as the fundamentally different ARBS and CMRR methods with their basis in empirical observations. A total of 450 different scenarios were evaluated in which the geology, horizontal stress, depth of cover, entry width, support spacing, and support length were varied. The results showed that the SRM-calculated stability factors were able to satisfactorily capture both the ?weak bed? and ?strong bed? adjustments in the CMRR. The SRM results were found to be well correlated to the ARBS stability factors for the 450 cases considered. Further analysis showed that the SRM accurately captures the effect of bolt length, depth of cover, and entry width on the overall stability of an entry.

Jan 1, 2013

By S. P. Winkelmann

The expansion in gold production in the Carlin 'Trend over the last few years has been one of staggering proportion. To increase gold production while minimizing capital requirements and providing for the safe and efficient mining and processing of ores has required a tremendous effort by the Mine Engineering group at Newmont Gold. This paper discusses the organizational changes implemented to effectively deal with a full range of engineering problems and how the Newmont Gold Mine Engineering group dealt with these problems. Specially developed computer software and their applications will be explained. Improvements in the techniques used in converting geologic resources into reserves, and in scheduling the mining of multiple pits to feed multiple processing facilities, as well as ore control procedures are presented. Current mine engineering practices are discussed.

Jan 1, 1990

By Michael W. Driller, Wen Yan (Grace) Chen, Steven J. Friesen

"Remediation for Perris Dam has been proposed in response to deficiencies identified in a seismic stability study prepared by the California Department of Water Resources (DWR) in 2005. Lenses of potentially liquefiable soil have been identified within the dam foundation which may lose strength during a seismic event. The remediation was designed primarily to limit deformation of the dam. Nineteen construction methods were compared and evaluated for the remediation. The final decision was to use cement deep soil mixing (CDSM) to strengthen the foundation and to construct a downstream berm to stabilize the dam. The entire CDSM treatment will cover over 4,000 linear feet of the downstream toe of the dam. Over 300,000 cubic yards of CDSM will be used to strengthen the foundation. The construction of the project started in Fall 2014 and is anticipated to take approximately 3 years. This paper describes the design aspects of using CDSM to treat the foundation, including laboratory testing, investigation of overstressing/cracking, extent of treatment, effect of CDSM on pore pressures under the dam, and the results of a full-scale CDSM test section.INTRODUCTIONPerris Dam is a zoned earthfill dam with a length of 2.2 miles, a maximum height of 128 feet, and a capacity of 131,450 acre-ft of water. The dam is located in Riverside County, California at the terminus of the East Branch of the State Water Project. The embankment was constructed between 1971 and 1973 over an alluvial deposit between the Bernasconi Hills to the South and Russell Mountains to the North. A rock outcrop divides the dam into left and right reaches when viewed from the reservoir looking downstream. The embankment soil was obtained from a borrow source at the North end of the reservoir. The dam has a sloping sandy clay core (Zone 1) with a 10-foot deep cutoff trench and a silty sand shell (Zone 2) with a downstream chimney and blanket drain (Zone 3 and Zone 4) as shown in Figure 1."

Jan 1, 2015

By Dan Yang

Pile foundation designs are performed routinely based on geotechnical information available at the time of design, often with due consideration of large uncertainties inherent to soils and site conditions. These uncertainties frequently are the causes of piles being installed not the same as those designed, especially by factors beyond quality assurance and quality control. With a variety of both satisfactory and unsatisfactory pile test results from these nonconforming piles, the design engineers are required to examine the foundation performance as a whole against the project design requirements before signing off on them or calling for potentially costly remediation. Over the years, as-built analysis has been a consistent way of dealing with pile non-conformity and damage in our practice, avoiding many construction delays and it is an integral part of our pile foundation design. In this paper, the key elements of an as-built analysis along with several major bridge projects are presented.

Jan 1, 2010

By B Darlington, L Sandberg, O Vallati

The D47 and D39 Mechanical Dynamic Extra bolts (D47 MDX and D39 MDX) have been developed in response to the ever-increasing demand from the mining industry for rock bolts with high dynamic capacity. To prove such capacity, Sandvik has performed numerous in situ dynamic testing with the unique Dynamic Test Rig (DTR) (Darlington, Rataj and Roach, 2019; Roach, Rataj and Darlington, 2019). To complement the collection of testing data, Sandvik, in collaboration with the Swedish Research Institute for Mining, Metallurgy and Materials (Swerim) have performed additional experiments in laboratory condition using Swerim’s new drop test rig. This rig utilises a momentum transfer method to apply a dynamic load to the bolt. The sample falls together with the mass until the support beam impacts stationary dampers and the momentum energy is transferred to the bolt. Part of the charged energy is released by the dumpers while the remaining portion is absorbed by plastic deformation and/or displacement of the ground support element. The D47 and D39 MDX bolts have been tested at Swerim’s test facility with different levels of input energy. Six tests were performed at the specification energy of 36 kJ and six tests were carried out with the maximum allowable energy from the facility, ie 44 kJ. The bolts confirmed their dynamic performance absorbing the input energy without failure. The D47 MDX bolt absorbed up to 33 kJ with 150 mm displacement while the D39 MDX bolt absorbed up to 35 kJ with 162 mm displacement. This work will present an overview of the drop test rig at Swerim’s facility and a collection of results of the test performed on the D47 and D39 MDX bolts. The test method and results will be analysed and compared to the tests carried out with the in situ DTR.

Nov 29, 2022

By D J. Kilkenny, D A. O’Toole, P B. Hills, K L. Seah

An investigation was undertaken to critically analyse the use of fibre reinforced shotcrete (FRS) for a variety of applications in large diameter shafts. Those applications included the use of FRS with or without the addition of subsequent rock bolting in the temporary support cycle prior to the installation of a permanent lining, most likely cast in situ concrete or as the final lining medium.Numerous authors have considered the early re-entry and strength characteristics of FRS in recent years. The current study has investigated the practical application of the recommendations of many leading authors in an endeavour to establish practical and acceptable risk-assessed procedures for the use of FRS for rapid, safe, efficient and cost-effective shaft sinking.Shaft sinking is regarded as a specialist and potentially higher risk activity due to the confined work environment, exposure to ground conditions and a high degree of manual handling associated with getting materials to the sinking face. The use of robotically applied FRS as a primary lining in shaft sinking has significant safety advantages in reducing manual handing associated with mesh safety support and bolting, as well as reducing direct exposure to ground conditions.The study involved both field testing and a literature review. The study established an initial set of criteria for the use of FRS in the development of large diameter shafts and demonstrated a number of scenarios where the technique of robotically applied FRS provided significant safety and cycle time advantages. The opportunity for a fully sprayed single pass lining was also investigated as part of the project.CITATION:Hills, P B, O’Toole, D A, Kilkenny, D J and Seah, K L, 2014. Exploring the use of fibre reinforced shotcrete in large diameter shafts, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 295–306 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By H. F. Beardmore

PETROLEUM consumption during 1946 broke all previous records and further increases are expected during 1947. U. S. consumption amounted to an average of 5,280,000 bbl a day, of which 4,745,000 bbl was domestic crude oil, with the rest from natural gasoline production and crude oil imports. World consumption during the past year, excluding Russia, is estimated at 7,200,000 bbl daily. Forecasts for 1947 indicate a U. S. consumption of 5,425,000 bbl daily of petroleum products. This is expected to be made up of 4,655,000 bbl of domestic crude oil production, 340,000 bbl of natural gasoline production, 400,000 bbl of crude oil imports, and the rest from stocks. Petroleum's principal use is still as a fuel. The field remains highly competitive, but petroleum has been continuously progressing. Less than fifty years ago, oil supplied only one twentieth as much of the nation's total energy as coal, but today it supplies over half as much.

Jan 1, 1947

By T. Nghipulile, G. Dzinomwa, J. Kurasha, M. Amwaama, B. Mapani, K. Maweja, T. E. Moongo

The effect of mineralogy on the grindability was investigated using three copper ores – two sulphides and one oxide. The dominant copper minerals were identified by optical microscopy and mineral chemistry derived from SEM-EDS analysis. The sample designated sulphide 1 was borniterich, sulphide 2 ore was mainly chalcopyrite, and the oxide ore was predominantly malachite and minor azurite. The gangue minerals were identified using semi-qualitative XRD analysis. Sulphide 1 contained more than 80% (w/w) of quartz compared to about 70% in the other two ores. The Bond work indices were 13.8, 21.6, and 17.3 kWh/t for sulphide 1, sulphide 2, and oxide ore respectively. This suggested that the chalcopyrite-rich ore is the hardest, while the malachite-rich ore has intermediate hardness, and the bornite-rich ore is the softest. The brittleness indices of the ores were calculated using the chemical composition of the gangue, and a good correlation between brittleness indices and Bond work indices was observed, which highlights the importance of the gangue composition in determining the fracture behaviour of the ores. There is scope for further investigation into the relationship between ore mineralogy and comminution behaviour using other breakage characterization techniques.

Mar 30, 2023

By Michel L. Bilodeau, Brian W. Mackenzie, Dallas W. Davis

"The paper formulates an evaluation procedure for examining the effects of location on the economics of developing mineral deposits. This methodology is applied to assess locational aspects of Nova Scotia's competitive position f or mine development relative to other Canadian regions and provinces. The appraisal concerns two representative mine development opportunities, a medium-size open-pit tungsten deposit, and a small underground gold deposit. The influence of regional economic conditions is initially assessed. Then, the consequences of taxation are isolated. Finally, the combined impact of regional and taxation conditions is examined. SettingThe economic potential of mining may be assessed in a number of ways. One approach, increasingly used for both corporate planning and government policy purposes, is to evaluate the competitive position of an actual or potential mineral producer in the international marketplace relative to other suppliers.Such examinations of competitive position vary from cost league comparisons of breakeven costs for operating mines, through the assessment of medium-term costs associated with developing new mine capacity, to long-term evaluations of the economics of mineral supply from the start of exploration. The complexity of the analysis increase s with the scope and timeframe of interest. Many factors are involved. One component of competitive position is the quality of the mineral resources available. Other key factors include existing technology, wage and salary rates, labour productivity, the cost of capital, infra structure requirements, distances from sources of materials supply an d to mineral markets, management attributes, organizational efficiency, government mineral policies (particularly taxation), and inflation and exchange rates. The paper fits within this competitive position framework.The variable economic conditions which exist within Canada have a direct bearing on the viability of mine development and, thereby, on mineral exploration potential. The paper examines locational aspects of Nova Scotia 's competitive position."

Jan 1, 1986

By E. P. Carman

1. CARMAN, EVERETT P., OPPERMAN, MARTHA, NISHIYANA, SALLY, AND RACOOSIN, LEE. Bibliography of Bureau of Mines Investigations of Coal and Its Products, 1945 to 1950. B. 528, 1954, 60 pp. 40 cents. 2. ROSE, HAROLD J. Industry-Sponsored Coal Research in the United States. Chap. in Proceedings: Fifth International Conference of Directors of Mine Safety Research. B. 489, 1950, pp. 9-12. $1.25. Minerals Yearbook 3. STRINER, HERBERT E., CARMAN, E. P., AND GOODING, RICHARD M. Review of the Mineral-Fuel Industries in 1952. Minerals Yearbook 1952, Fuels, vol. 2 (pub. 1954), pp. 1-28.

Jan 1, 1958

Rotary kiln incinerators are widely used in the incineration of various types of hazardous wastes. However, the complex transport processes within the incinerator are not well understood. Due to large variations in waste types and difficulties in feed characterization, the incineration process meets great challenges in a smooth operation, and expects uncertainties in the process chemistry and emission control. In order to get better understanding of the incineration process, process simulation was made on the kiln behavior by using Computational Fluid-dynamics (CFD) to characterize gas flow, temperature distribution and waste combustion in the incinerator. Temperature measurement was conducted in an operating incinerator to validate the CFD model. This paper addresses the environmental issues related to the hazardous incineration process, and reports the recent simulation results on gas flow and mixing, combustion heat transfer, and potentials to reduce emissions.

Jan 1, 2002

By J. B. Littlefield

The term "konimeter" is used generally to designate a type of dust-sampling instrument that collects the dust from a small volume of air by impingement on a glass plate prepared aced with an adhesive film. The konimeter was first developed by Sir R. N. Kotze about 20 years ago and was followed a few years later by the circular-type konimeter, by which a number of samples may be collected on a glass disk. The present discussion will be confined to the circular type, as it is used most. Various techniques have been developed for using the konimeter, and many materials, such as petrolatum, mineral oil, and glycerine jelly, have been used in preparing the adhesive film. In South Africa, Australia, and Canada, where the konimeter has been employed most widely, dust samples are treated by ignition and washing before being counted. In Canada the dust samples are collected on a disk of special heat-resistant glass prepared with a film of mineral oil; the disk is then heated to a dull cherry-red in a muffle-furnace to remove the film and organic matter, cooled, and washed with a few drops of 50-percent hydrochloric acid followed by distilled water and alcohol, and then heated again to remove residue left by evaporation of the alcohol. After this treatment, the dust samples are counted under a magnification of 150 diameters with dark field illumination.

Jan 1, 1938

By A. G. Waters, N. J. Bristow

A comparative study was made of an untreated and a heated haematite ore and a sinter produced from a feed consisting of 100% ore, to study the influence on reduction behaviour of sinter bonding phases such as SFCA (silico-ferrite of calcium and alumina). Under low-temperature reduction conditions the order of increasing reducibility followed that of increasing porosity and surface area but under similar conditions at 900 degrees C the sinter exhibited higher reducibility than the ores even though the total porosity and chemical reducibility of the individual phases were lower. This behaviour can be explained in terms of the higher total porosity of the natural ore at low temperatures and the higher level of fine pores in the sinter at high temperatures due to the presence of SFCA, which acts to support the fine (c.0.1 micrometre) pores created by the reduction process. This leads to the conclusion that the main role of SFCA in sinter during high-temperature reduction is to maintain a high level of fine porosity. Some implications of this work for granule design and sintering practice are discussed

Apr 1, 1991

By J. D. Davis

THIS report gives results of an investigation of the carbonizing properties of the following eastern Kentucky coals: Elkhorn No. I bed, No. 28 mine, Wayland, Floyd County; Elkhorn No. 2 bed, Turner No. 5 mine, Drift, Flood County; Leatherwood (Haddix No. 5) bed, Leatherwood mine, Leatherwood. Perry County; and Harlan bed, Path Fork mine, Path Fork, Harlan County. The carbonizing properties were determined by Bureau of Mines-American Gas Association (BM-AGA) tests at 800° and 900° C. and by expansion tests in the sole-heated oven. Plastic properties were determined by tests in the Gieseler and Davis plastometers. The coals were tested singly and as blends with 20- and 30-percent low-volatile Pocahontas No. 3 coal. The dry, mineral-matter-free, fixed-carbon content of the carbonizing samples ranged from 56.7 percent for Elkhorn No. 2 to 59.7 percent for Leatherwood, and the heating values on the moist, mineral-matter-free basis ranged from 14,420 B. t. u. per pound for Elkhorn No. 2 to 14,720 for Harlan. The percentage of ash ranged from 2.9 to 6.1. The fluidity of three coals, measurer. In the Gieseler plastometer, ranged from 230 to 670 dial divisions; the fluidity of Elkhorn No. 2 could not be determined by this method. Blending lowered the fluidity of each coal; the fluidity of the blends containing 20 and 30 percent Pocahontas No. 3 ranged from 16 to 53 and from 8 to 17 dial divisions, respectively. Agglutinating values determined on silicon carbide-coal mixtures in the ratio 15:1 ranged from 3.8 to 6.3.

Jan 1, 1952

By R. August Heindl

A process for recovering manganese from open-hearth steel-plant slags was investigated. The proposed method of accomplishing this is indicated by the flow diagram in figure 1. Mixtures of open-hearth, steel-plant flush slags and limestone, so proportioned as to have molar [CaO -3P205] ratios of approximately 2, were fired at approximately 2,400° F. in an oxidizing atmosphere and then cooled slowly. This treatment produced a clinker consisting principally of two solid phases comprised of (1) various combinations of the oxides of manganese, iron, aluminum, and magnesium, probably in spinel complexes, and (2) a dicalcium silicate phase, which contains the phosphorus. Reduction of these clinkers with hydrogen or with gaseous mixtures containing CO, CH4, and other hydrocarbons at about 1,300° F. formed manganous oxide as well as varying amounts of ferrous oxide and iron. Carbon monoxide and mixtures of hydrogen and carbon monoxide effectively reduced the clinkers but also gave higher proportions of soluble iron when the manganese was extracted from the reduced clinkers by leaching at about 80° F. with ammonium carbonate solutions containing 26 to 28 percent ammonia and 15 to 26 percent carbon dioxide. It is believed that the manganese is in solution as an ammonia-manganese complex. Concentrations of about 90 grams of manganese per liter were obtained by batch countercurrent procedures. By distilling 50 percent of the ammonia, the ammonia-manganese complex was decomposed, and approximately 90 percent of the manganese was precipitated as the carbonate with the simultaneous precipitation of 15 to 30 percent of the iron, the larger amounts of iron precipitating in the continuous tests. The manganese-iron ratio in the product could be increased either by recycling more manganese from the distillation to the extraction or by aerating the liquor to purge it of iron before, rather than after, the distillation step. Calcination of the pelletized manganese carbonate in an oxidizing stmosphere at 2,000° F. or above gave a final product, Mn304, resistant to crushing and apparently possessing the other physical properties essential in a ferromanganese blast-furnace feed.

Jan 1, 1955

By Guowen Dong, Qiyong Li, Qiang Li, Tiejun Chen, Zhihong Wu, Junying Wan

In order to search for a more economical and effective roasting additive for extracting vanadium from stone coal and solve the question of the disposal of PVC waste, PVC waste was proposed as a novel roasting additive to enhance extraction of vanadium from stone coal and realize the comprehensive utilization of resources. By adding this roasting additive, the leaching rate of vanadium reached 94.5% under the conditions that the PVC waste addition was 10 wt%, the roasting temperature was 800 °C, the roasting time was 1 h, the sulfuric acid concentration was 15 vol%, the liquid-to-solid ratio was 1.5 cm3 /g, the leaching temperature was 95 °C, and leaching time was 4 h, which increased by 8.4% compared with that of blank roasting. The thermodynamics calculation showed that the decomposition reaction of mica was performed easier with the participation of HCl produced by pyrolysis of PVC. Meanwhile, The SEM-EDS and aperture test analyses demonstrated that more cracks and voids appeared in the roasted sample by roasting with PVC waste, which could facilitate the release and extraction of vanadium. Additionally, the TG-DSC analyses indicated that PVC could provide large amounts of heat for the roasting process to promote the decarbonization and roasting efficiency of stone coal because of its high calorific value.