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By Yuzo Hiroshige, Kiyotaka Tahara, Hiroki Hatayama, Masaharu Motoshita, Tomohiko Akahori

Large amount of rare earth metals is stored in the used electric products. Hitachi has started to develop the environment-friendly process for rare earth metals recovery from used magnets. We report here the environmental impact of our process, in comparison with the conventional recycle process utilizing solvent extraction. As an evaluation method, Life-cycle Impact assessment Method based on Endpoint modeling ver.2 (LIME2) developed by the National Institute of Advanced Industrial Science and Technology (AIST) in Japan is applied. It was found that the environmental impact of the new process was more than that of the conventional process. For further reduction of its environmental impact, minimization of energy consumption to operate the equipment was most effective. Decreasing the amount of magnesium, used as an extractant, and the improvement of the extraction rate of rare earth metals were also considered as specific options for reducing energy consumption in the plant development.

Jan 1, 2014

By Larry B. Fiske

Elimination of dust and processing of fines for both thermal and metallurgical coals is addressed. The efficiency of treatment with lignosulfonates compares favorably to oil in thermal coal. Effect of treatment with various lignosulfonates upon cokability of metallurgical coal was determined by Free Swelling Index, Gieseler Plasticity and Arnu Dilatation.

Jan 1, 1992

By I. C. Knight

The current levels of copper smelter by-product acid production are reviewed on a regional basis, together with the possible changes in the future. There will be increasing pressure for all smelters to achieve a sulphur capture level of at least 95% by the end of the decade.

Jan 1, 1996

By G. Roderick Eggert

Material criticality reflects the degree to which a raw material is both necessary and subject to supply-chain risks. This study compares the criticality of selected raw materials from the differing perspectives of the manufacturing sectors of China, the European Union, Japan and the United States.

By Katsukiyo Marukawa, Mashamichi Sano, Shigeta Hara

"Various subject of studies are discussed to develop ·innovative refining processes in the 21st century for cost reduction, production of high quality steel and environmental conservation. The future refining reactor should have abilities of highly efficient mixing and separation of different phases. It is stressed ·that applications of electromagnetic and ultrasound energies, and control of flow fields rate required to create the highly efficient mixing I separation reactor.IntroductionIn recent years, it seems that the research and development in the field of steelmaking has shifted its emphasis to the solidification I ingot-making process in which continuous casting plays the leading role. From a long-range point of view, however, the need for continual development of the refining process will probably increase but is very unlikely to decrease. In order to meet such demands, it is required that problems and issues of the present process should be clearly grasped and that there must be rapid progress in process elements, such as highly efficient mixing and separation of different phases.Applications of electromagnetic and ultrasound energies and flow field control will become important options for resolving the above-mentioned problems. By efficiently and skillfully incorporating these new technologies into high-efficiency mixing/separation reactors, the innovative refining process will be established in the early 21st century."

Jan 1, 2000

By A. V. Tarasov

The lack of technology for processing of sub-grade ore concentrates and intermediate products for extraction of Zn, Pb, Cu and precious metals at the metallurgical stage was a constraint for an increase in the production of these metals. The technology developed in the Gintsvetmet Institute is based on an improved electrothermal smelting process for treating calcined charge, ensuring thereby a reduction in power requirement and improving the environmental performance of the process. Electric smelting of sub-grade polymetallic concentrates produces lead bullion, to which the bulk of gold and silver reports, as well as well segregated matte and slag concentrating the bulk of zinc. Lead bullion and matte are commercial-grade products; zinc is recovered from high-grade (15% Zn) slag by slag fuming process. Reduced loss of precious metals in slag ensured by the given technology is attributed to the fact that the slag contacts with matte with low contents of gold, silver and lead, rather than with lead bullion. Limited amounts of off-gas typical of electrothermal processes ensure cost-effective operation of dust recovery devices and a reduction in emissions of harmful pollutants into the ambient air.

Jan 1, 2002

By Ronald C. Askin

Dredging is a common method of remediating ponds containing contaminated wastes. However, dewatering of the dredged solids is usually not well integrated with the dredging phase. As a result, overall project efficiency can be poor. Specifically, since dredges deliver material in a widely varying slurry form and since dewatering presses require the delivered material to be uniform, union of the two systems often results in inconsistent operation of the overall process. In an effort to enhance overall dredging and dewatering process production rates as well as minimize the return of suspended solids in the decant water, a new process was developed to provide a consistent dredged sludge for delivery to the press. This paper discusses modifications made to a conventional dredging and dewatering process to improve production rates and dewatering capabilities. These modifications are applicable to any project where efficient solids dewatering is required and where returning decant water must be visually free of suspended solids.

Jan 1, 1996

By A. Siegmund, Gerhard Martin

The recycling of metal containing scrap is a common practice in the industry and has a long tradition. . In rec~nt years, this philosophy has been transferred to organic materials, in particular to thermoplastic polymers. BSB . Recycling GmbH, a company with a long experience in the treatment and recovery of lead from battery scrap,· had recognized this exploitation at an early stage and challenged it by a consequent continuation of the idea to recycle materials other than metals without degradation and maintaining the quality. These efforts resulted in an economic and environmentally acceptable solution producing high quality polypropylene compounds at BSB beside lead and lead alloys from battery scrap. The raw material fair the production of polypropylene compounds is shredded plastics from the separated casings of spent lead-acid batteries. The production of polypropylene with specific physical and mechanical properties is carried out by the accurate dosing of organic as well as inorganic additives. The result of the procedure is a novel product group "Seculene PP", a registered trademark of BSB Recycling GrnbH.

Jan 1, 2000

By B. Willit, J. Martin

"Continued emphasis on water and energy conservation with less operator attention has created a need for more sophisticated cooling tower controls. A joint Betz/ASARCO project has produced a computerized water parameter controller and automated pumpless feed unit. Interfacing the unit via radio modem to the operator control room computer allows real time system status monitoring. Incorporating SPC principles to monitor and regulate all pertinent parameters yielded enhanced water control. This paper described the system design and present the results of a six month trial.BackgroundReducing operating costs and better manpower utilization are two of the largest concerns confronting maintenance managers today. At the ASARCO plant in Amarillo, a trial has been initiated to prove that it is possible to accomplish both of these objectives by using automated cooling tower control. The system is being adapted from a unit that was designed for continuously operating cooling towers in refineries and power plants by Betz Equipment Systems Division, a subsidiary of Betz Laboratories, Inc. The System l3000™ is designed to continually monitor conditions in the cooling system and to provide adjustments to the chemical balance for corrosion and deposition control. At Asarco, the unit was installed on the Rodline cooling system which operates on an intermittent basis.The primary justification for this project is to reduce costs of the five cooling systems in the plant. Current procedures require an operator to make visual checks every two hours on the five cooling towers as well as run lab tests on the water to insure proper treatment levels. This manpower can be better utilized by controlling the towers and collecting all the data available at one central location, in this case, the boiler house."

Jan 1, 1989

By Yuuki Hagio, Hiroyuki Tobo, Michihiro Kuwayama, Yasutaka Ta

"Reduction of CO2 emission is necessary to remedy global warming, however, promising approaches of CO2 separation require a large amount of energy. Molten slag, which is generated as by-product of steel production, has high temperature, but its energy has not been harnessed. To recover the thermal energy from the slag and to apply to separation of CO2 are economical and environmental conscious ways. We propose a new heat recovery system, in which, molten slag is solidified continuously on water-cooled roll and the solidified slag plates are charged into counter-current heat recovery equipment. In laboratory scale experiments, heat recovery ratio of more than 30% was acchived by controlling the thickness of slag.IntroductionThe steel industry in Japan has been working on the projects of ""Environmentally Harmonized Steelmaking Process Technology Development (COURSE50)"". COURSE50 aims at developing technologies to reduce CO2 emissions by approximately 30%. One of the main technologies is to capture and recover CO2 from blast furnace gas using chemical absorbents to regenerate CO2-laden chemical absorbents by separating CO2 from the absorbents. As one of the solutions, JFE Steel Corporation has been developing sensible heat recovery process from steelmaking slag. It is effective to recover and use unutilized high temperature waste heat within a steel plant as the thermal energy required."

Jan 1, 2012

By E. L. Frueh

AMAX Base Metals Research & Development, Inc. has developed a process for treating copper-nickel mattes to produce copper cathodes and a pure nickel sulfate solution. In this process, the input matte is preleached in a copper sulfate electrolyte bleed solution so as to dissolve nickel from the matte and cement copper from solution. The preleach leaves a substantially pure nickel sulfate solution. The residue from the preleach is roasted to less than about one percent sulfur. A portion of the calcine is leached with sulfuric acid to make a copper sulfate solution for input to the tank house. The residue from this leach and the remaining calcine are smelted to form a bimetallic (copper/nickel.) anode. The anodes are electrolytically refined and copper is preferentially deposited on the cathode while the nickel reports to the electrolyte, A bleed stream is taken from the electrolyte and used in the preleaching of the input matte. This process produces high purity metal streams while consuming less energy and smaller amounts of reagents as compared with other matte processes.

Jan 1, 1983

By Jack Thibodeau

During the past six years, most states have promulgated water quality regulations which contain numerical aquatic life standards for heavy metals. In addition, the Environmental Protection Agency (EPA) promulgated national water quality standards in 1992 which also include numerical aquatic life criteria for heavy metals. Numerous wastewater discharge permits have been issued by the states and EPA to industrial facilities which include low microgram per liter heavy metal limitations. In many instances, the limitations are below detection limits or treatability limits using state-of-the-art analytical methods or treatment technologies. This paper will discuss options for conducting studies, including the use of water-effect ratios, metal partitioning coefficients, and recalculation procedures to develop site-specific metals criteria and higher permit limitations. The installation of expensive metal treatment systems to remove trace metals may be avoided if higher permit limits are indicated by the site-specific studies.

Jan 1, 1996

By Akira Nishikawa

During the twentieth century, the copper smelting industry achieved dramatic expansion corresponding to the vast growth of global economy. This was largely due to innovations in pyro-metallurgical processes, such as autogenous smelting and continuous smelting and converting technologies. However, as copper production capacity increased, its impact on the environment also could not be ignored, and thus with increasing global environmental awareness, many smelting operations either had to renew or rebuild their facilities. In addition to these changes, in places like Japan and Europe, with scarce primary resources, the treatment and recovery of metals from a variety of items such as car shredder dust, used electrical appliances and electronic devices, on top of scraps traditionally treated, is having a profound effect on the reduction of waste and the preservation of primary resources. Thus compared to the days when copper smelting focused on the environmental control in order to break with "Smoke Stack Industry", copper smelting today is making an important contribution to the sustainable development of human society.

Jan 1, 2003

Iron(II), sulphur dioxide and sugars such as lactose are potential reducing agents for manganese dioxide to produce manganese(II) for subsequent hydrometallurgical treatment. The leaching of limonitic laterite and manganiferrous ores with sulphur dioxide produces iron(II) which in turn can catalyse the leaching of manganese dioxide in acid media. This paper presents a critical analysis of the kinetics of reductive dissolution of synthetic manganese dioxide and manganese ore to compare and contrast the effect of sulphur dioxide and iron(II) in acid media containing sulphate or perchlorate anions. Both one-electron and two-electron mechanisms are considered in the case of sulphur dioxide. The current knowledge on chemical speciation is used to construct an Eh-pH diagram to show the effect of complexation of Mn(II), Fe(II) and Fe(III) with sulphate. Heterogeneous and electrochemical reaction kinetic models are combined to propose reaction mechanisms which rationalize the dissolution kinetics.

Jan 1, 2003

By L. Trincado

Mantoverde is a heap leach-SX-EW plant that was commissioned in December 1995 at a production rate of 42,130 ton of copper per year and 5.4 million ton of ore per year. Copper production has steadily been increased to 57,290 ton in 2002. Forecast copper production for 2003 is 60,000 ton for an ore treatment rate of 8.5 million ton. Several improvements in the heap leach process have been implemented. The main process improvements are related to the optimization of heap height, particle size, irrigation rate and leach cycle, in addition to a better heap drainage design and a solution management system. A first dump leach operation was started in 1999 at a production rate of 1,922 ton of copper. A second dump leach operation was started in early 2002 at a production rate of 2,805 ton of copper. Dump leach production will be increased over time to as much as 24,000 ton of copper. The main heap leach process improvements, as compared to the original plant design, as well as the main dump leach operating parameters are discussed in this paper.

Jan 1, 2003

By A. V. Tarasov

The natural resources of lead and zinc are primarily constituted by polymetallic and lead-zinc ores. Beneficiation of these types of ores to produce standard nonmetallic concentrates inevitably results in an increase in the loss of base and precious metals with tailings. An improvement in the grades of lead and zinc concentrates can be achieved by re-cleaner flotation, but it results in production of intermediate products (middlings) to which substantial amounts of lead, zinc, copper and precious metals report. Without an appropriate technology for treating such intermediate products, the recoveries of valuable constituents from lead-zinc ores would remain unsatisfactory. A process has been developed in the Gintsvetmet Institute for processing of polymetallic intermediate products produced at the ore beneficiation plants. This process is based on electrothermic smelting to produce lead bullion containing precious metals, commercial-grade copper-lead matte and high-zinc slags (up to 15-20% Zn) from which zinc can be extracted by slag-fuming or Waelz process. Tests have indicated that the recovery of lead from intermediate products into lead bullion and matte is about 83-85% and 13-14% respectively (the total recovery is 97-98%), while copper recovery into the matte and zinc recovery into the slag is 90-92% and 95-96% respectively. Precious metals (about 96-97%) report into the lead bullion.

Jan 1, 2006

By James E. McNulty

Today's energy era is the beginning of a transition from the Petroleum Age to a future age of renewable fuel resources. Fuels for the transition era will come from unconventional sources and conversion technology. Affecting the practicability of transition technologies are attitudes of the public, capital requirements and availability, patterns of fuels utilization, producibility of fuels and the actions of governments. Primary energy sources to replace deficiencies of oil and gas and provide growth in the period of transition will be coal, oil shale, nuclear energy and peat.

Jan 1, 1981

By George H. Edwards

Most cullets consumed in large-volume glass manufacturing processes receive little processing beyond crushing. But lead-glass cullets for specialty glasses such as industrial lighting refractors or cathode-ray tubes are combined with metals and various coatings that prohibit their direct recycling into the glass-melting processes that created them. In many cases, the contained lead renders these cullets hazardous. At present, virtually all industrial processes to separate one cullet from another depend on hand sorting, and thus are necessarily costly per unit weight. Lead-glass cullets of differing lead content are of interest because they offer the possibility of separating one glass composition from another by high-speed, automated processes at low cost. A potential process for comminution, cleaning, and separation of lead-glass cullets would involve primary and secondary crushing, magnetic and other metals separation, attrition scrubbing in water, separation of glass types by gravity techniques, drying if necessary, sampling, and preparation for transport to the point of use. Process water would be filtered to remove finely divided coating materials and glass, and reused. If carried out on a scale similar to a specialty industrial mineral processing plant, the cost per unit weight of such processing should be substantially less than the raw material value of the cullet in specialty glass production. The added value of avoiding waste disposal costs makes this process economically attractive.

Jan 1, 1994

By S. J. Hogan, T. William

"By the year 2000, the steel industry, not only in the United States but in the rest of the world, will undergo significant changes. On the other hand, there will be a number of areas in which change will be minimal.The current capacity of the industry worldwide is approximately 800-810 million metric tons. This may grow to some extent, as Third World countries install capacity. However, much of it will be neutralized as the industrialized countries shrink their current capacities.There will be several breakthroughs in terms of technology, some of which deal with the production of iron outside of the blast furnace. However, these processes will not be far enough advanced by that time to replace the blast furnace, rather they will supplement it.In terms of steelmaking and the subsequent rolling process, there should be a number of basic improvements. The strip mills will roll sheets with a very slight variance in gauge, which will give the customers a better product for automatic stamping machines. Ordinary carbon steel, in a number of instances, will be replaced by high-strength, low-alloy steel, which will reduce the tonnage necessary for present-day applications, such as construction.The corporate organization will be significantly changed as joint ventures and mergers will reduce the number of companies, as well as facilities in operation. This will enable the industry to reduce its capital investment and improve operating costs, so that it will be able more effectively to compete with other materials, such as plastics, cement, aluminum, etc."

Jan 1, 1988

By Patrick R. Atkins

Energy issues will have increasing impacts on decision making in all facets of society over the next few decades. Industrial users of energy and producers of products that affect energy use must be fully aware of the implications of their processes and products on the energy situation. This paper describes a model that has been developed for the aluminum industry that allows scenarios to be evaluated to gain improved understanding of possible implications for our businesses. A brief overview of the model is provided.

Jan 1, 2006