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By Ludwig Hermann

"Phosphorus is required by every cell of living organisms and essential for plant growth. It is a non-renewable resource that must be mined from natural deposits, going gradually into depletion. Abundant secondary resources are available in sewage sludge and meat and bone meal, with the highest exploitable P concentrations in ashes that remain from their widely used combustion with energy recovery. ASH DEC has successfully removed heavy metals and transformed sewage sludge ash into a marketable P fertilizer by application of a thermo-chemical treatment process. Pilot scale investigations in which ash was treated proved that generally heavy metal limits required by fertilizer legislation can be attained. To achieve a high P availability for crops – an essential fertilizer quality feature – was a more challenging R&D task. Our presentation demonstrates the scientific approach and R&D results that lead from assessment of market requirements to licensed products.IntroductionPhosphorus (P) is required by every cell of living organisms. It is one of the major elements for plant nutrition and therefore essential for crop production. P supply in plant nutrition depends entirely on external inputs into soils [1]. This is achieved by P-fertilizers deriving from rock phosphate deposits that are gradually going into depletion. Serious prognoses anticipate that rock phosphate will be the first low running resource in the world [2]. In the EU, last year 2.530 kt of phosphorus (P2O5 in fertilizers) was consumed and only 313 kt (P2O5 in rock phosphate) was mined. Since 2007, rock phosphate prices have increased by 500% because of a tight supply situation [3].For these reasons, P recycling is becoming an increasingly important issue. Suitable secondary raw materials with regard to their high P-content and abundance are sewage sludge and meat and bone meal. In the EU 989 kt P2O5 are accumulated annually in theses materials, of which 632 kt P2O5 are permanently lost to landfills and other forms of disposal. The main reasons for their limited recycling are concerns on heavy metal contents and organic pollutants that may incite health hazards. As an additional shortcoming, the availability of P from these materials to plants is poor and storage and transportation are problematic issues [4, 5]."

Jan 1, 2008

By Nural Kuyucak

Acid mine drainage (AMD) occurs at operating and abandoned mine sites as a result of oxidation of sulphide minerals, and is characterized by low pH and heavy metal contamination (e.g. Fe, Zn, Cu, Cd, Al, Mn). It usually requires treatment before release in order to meet regulatory requirements. Chemical methods, such as lime neutralization and sulphide precipitation, are commonly used to treat AMD. However, the conventional processes require high capital and operating costs, and constant attention for many years into the future. In addition, the amount of sludge produced by conventional lime treatment processes poses an increasingly significant disposal problems at decommissioned mining operations. There is, therefore, an urgent need to develop passive, cost-effective processes for mitigating AMD and seepages originating from tailings and waste rock areas. Noranda Technology Centre (NTC) has been evaluating various methods being developed by other institutions, and exploring new ideas, to achieve passive in situ processes for treating AMD. These methods include anoxic limestone (ALS), lime-organic mixture (LOM), biosorbents (BIOS) and biotrench (BT). Current investigations at NTC involve preliminary bench-scale testing. Based on the outcome of the bench tests, a field test will be performed at a selected site. Details of the bench tests are discussed in the paper. Key Words: Acid mine drainage, treatment, metals removal, passive treatment, anoxic lime, limestone, biological treatment, sulphate reducing bacteria, biosorption, biosorbent

Jan 1, 1993

By Kenji Sasaki

Tamano Smelter started its operation in January, 1972 adopting FSFE ( Flash Smelting Furnace with Furnace Electrodes ) type smelting furnace at a production capacity of 101,00Ot/y of anode copper and 285,00Ot/y of sulfuric acid. Since then, it had experienced several production expansion program, it had twice as production capacity as start. 196,000t/y of anode copper and 436.000t/y of sulfuric acid. This time, we have completed the plan for increasing production capacity up to 226,000t/y of anode copper and 510,000t/y of sulfuric acid, by the oxygen enriched operation. We carried out several improvements and modifications, changing of cooling system ill FSFE, enlargement of converter and anode furnace, and some progresses in sulfuric acid plant and environmental facilities.

Jan 1, 1993

By Christopher R. Casias

A basic methodology is presented (employing both standard and theoretical assessment, analysis. and data interpretation techniques) for classifying waste containing trace levels of radionuclldes. Despite increased regulatory requirements for handling. transporting. and disposing of such waste: (I) no formal characterization methodology has yet been Implemented. and (2) no limits have been set to define the point at which a waste material is considered to be low-level and below which it Is "below regulatory concern" (BRC) or can be considered to contain no more than a diminimus level of radioactivity (i.e . is nonradioactive). 'I1le concept of diminimus limits specific to waste streams and waste forms is introduced. and a mechanism fur evaluating waste In relation to BRC and diminimus limits is outlined. This methodology can be used to perform a complete and adequate characterization of waste for classification according to its level of radioactivity.

Jan 1, 1992

By S. Suzuki, Y. Maeda, N. Wakamatsu

"A new pyrometallugical technology, named KLS process, has been developed by Dowa Mining at its Kosaka Smelter to smelt various kinds of lead raw materials.The process consists of clearly separated two reaction steps, smelting and reduction. For this purpose, respective stationary furnaces are installed which are connected by a slag launder.Dry raw materials, together with pulverized coal and oxygen-enriched air, are injected through a lance pipe into the molten slag in the first furnace. It is kept under a high oxygen potential to remove sulfur completely. Resultant PbO rich slag overflows to the second furnace where pulverized coal and insufficient air are also injected through a lance pipe to reduce PbO to lead bullion and to compensate for thermal deficit. The entire operation is carried out continuously. The process development started back in 1981. In late 1986, a pilot plant with a capacity of 3.5t/H was constructed.Already nearly 20,000 tons of raw materials, mostly lead sulfate mixtures have been smelted successfully.IntroductionFor a long time, main raw materials for lead smelting at Kosaka smelter have been such secondary incombustibles as lead sulfate and lead-barium sulfate. The former is leach residue of the copper smelter flue dust and the latter originates from Iijima zinc refinery. While the most of lead concentrates produced locally has been smelted by an ISF of Hachinohe smelter in which Dowa Mining has a share.The surplus lead concentrates were processed at Kosaka by a hydrometallurgical method to convert PbS to PbSO 4 as pretreatment, and followed by simultaneous smelting together with the above secondary materials (1). Approximate output has been 1,5000 /M of lead bullion and slightly more than 2,000t/M of refined lead by adding lead bullion returned back from Hachinohe smelter (2)."

Jan 1, 1988

By Michel Boisvert

Noranda Metallurgy is presently completing construction of the new Noranda Converter (NCV) at its Home Smelter in Rouyn-Noranda. This capital investment of CDN$56M is the continuation of the Emissions and SO2 Reduction Program that was initiated in the late 1980s with the acid plant for Reactor off-gas treatment. The Patented Noranda Converter was developed and pilot tested at the Home Smelter in the early 1990s. The project will replace the Peirce-Smith Converters and enable sulphur fixation to be 'increased from 70% to over 90% by 2002 with an accompanying reduction of dust emissions to the atmosphere. The construction site is an extension of the present Noranda Reactor area. A number of existing facilities including the acid plant and process air supply were used to minimize the capital cost of the project. This paper provides a brief history of the Noranda converting process, the Home Smelter Emissions and SO2 Reduction Program, ,project implementation and construction, a description of the different facilities, and preparation of human resources for start-up.

Jan 1, 1998

By John A. Vallomy

"The CONSTEEL Process introduces a new concept in electric steelmaking by continuously feeding-preheating-melting and refining ferrous scrap or direct reduced iron. The process uses the furnace off-gas and fuel to preheat the scrap in a specially designed preheater. Thermal incineration of the flue gas reduces the carbon monoxide level to the more stringent requirements. Hot water or steam production from heat of flue gas is optional. The tap-to-tap time is set to match the cycle of the caster. The steel is treated via ladle metallurgy. The environment inside and outside of the steelplant is improved by decreasing levels of noise and hazardous emissions. Energy consumption decreases and disturbance to the electric network is eliminated. A CONSTEEL prototype was tested at Nucor Steel, Darlington, SC. A greenfield project is in the completion stage at the Florida Steel plant of Charlotte, NC, USA. The Process PhilosophyThe philosophy of the CONSTEEL Process is not solely to enhance efficiency; this was just a natural result of the change from a batch to a continuous practice. The primary objective in development was four-fold:1) 100% process control2) Rational use of available energy3) Improved environment inside and outside the plant4) Stability of energy input from the power systemIt was to make electric steelmaking more a science than an art and amenable to modern automation.The Basic Concept of CONSTEELThe concept of the process is shown in figure and includes basically a continuous feeding system, a preheater and a melting - refining furnace. A pre-established amount of heat is introduced into the scrap while traveling through the preheater using the sensible and chemical heat contained in the furnace off-gas and additional fuel. Melting-refining is carried out in the electric furnace. Slag formers, slag foaming additions and oxygen are injected to refine the melted steel continuously, to minimize the refractory erosion, to shield the arc, thus optimizing the transfer to the metal bath of the heat generated in the arc, to keep the bath homogeneous in composition and temperature and to produce carbon monoxide (CO) which is fuel for the preheater."

Jan 1, 1988

By B. Farouk, Y. G. Kim, D. Apelian

"Continuous strip casting has received considerable attention in recent years due to its economic advantages with increased energy savings and the elimination of intermediate processing steps. A promising concept in strip casting is the twin-belt (Hazelett) process which incorporates two cooled continuously moving thin metal belts wrapped around pulleys which tension and drive the belts at a predetermined speed. Molten metal is introduced at the entry end of the caster through a tundish and feeding nozzle into the mold. The twin-belt process has been successfully used with non-ferrous metals such as aluminum, copper and brass, and is a prime candidate for strip casting of ferrous materials. A numerical model has been developed which predicts the interface locations, the temperature fields in the solid and liquid regions of the cast and the velocity fields of the liquid metal at the entrance region of the twin-belt caster. The process variables considered are the velocity and cooling conditions of the belt and the nozzle shape. A body fitted coordinate system is used to track the front locations and to solve .the Navier-Stokes equations in the liquid region. Results obtained can help design efficient casters for thin strip steel castings. The development of the numerical model is presented, and sample results are discussed. I. IntroductionContinuous strip casting of steel has attracted world-wide concerns in recent years due to its economic advantages with increased energy savings and the elimination of intermediate processing steps. New methods of thin strip casting of steel are developing. One of the promising concepts is the Hazelett process, which is being used in nonferrous applications. The process incorporates two continuously moving, intensely cooled, thin metal belts. Metal blocks linked together are sandwiched between the moving belts and form moving side mold walls.In this work, the freezing front position, the temperature field and the liquid region flow field will be analyzed for the strip casting of metal using the twin belt caster (the Hazelett process). Up to now almost all theoretical analyses undertaken of the continuous casting of metal [1-3] have used a heat conduction equation, assuming slug flow in the liquid region. The effect of convection in the liquid pool during continuous casting were first investigated by Szekely and Stanek [4]. They considered potential flow between the feed metal orifice and the liquidus front, and slug flow in the mushy and solid regions of a vertical static continuous casting process for steel. Viscous effects and natural convection affects were not included Kroeger and Ostrach [5] studied the effect of natural convection flow in the liquid pool during solidification for a pure metal."

Jan 1, 1986

By Yoshihiko Maeda

It is said that the 21 st century will be an era of the remedy of the global environment. In order to reserve natural resources for the future and to avoid the dispersion of heavy metals after usage and to avoid pollution problems, it is extremely important to recycle heavy metals as much as possible by reasonable recovery procedures. The nonferrous metal industry is expected to play a important role in the recycling of heavy metals that are originally their products. From the depressed metal price experienced in Japan in 1980th due to the sudden change in current exchange rate between US dollar and Japanese yen, one of major nonferrous metal company, Dowa Mining, has diversified its business area not only to the so-called down stream, but also to the environmental business including metal recycling, industrial waste treatment and soil remediation by utilizing technologies and facilities once used or still used for mining and smelting of copper, zinc, lead and precious metals. In this paper some of these applications will be presented.

Jan 1, 2003

By Sun Ying, Zhang Jing, Li Qiuju

A new process of enrichment Cu in molten copper slag under electric field is presented in this article. The experiments were carried out in the laboratory on a kilogram scale. The mobility of copper slag was improved by the technique of carbon reduction. The effects of temperature, electric field strength and intermittent feeding speed were investigated on Cu migration. The results showed that the best experimental conditions were the temperature at 1523K, electric field strength was 1.5V•cm-1 and feeding rates was 15 g•(10min)-1. The copper content of the slag decreased below 0.6wt%. The process was compared to the traditional electric furnace process of slag cleaning, there was reduced the energy consumption and heat loss, and also harmful gas emissions such as SO2 and CO2, accompanied by improved the efficiency of slag cleaning.

Jan 1, 2016

By Kurt Westerlund

Cooling of hot sticky gases with solids in a circulating fluidized bed called FLUXFLOW is described. Fluxflow is used for gas streams from metallurgical reactors, e.g., Isasmelt copper in Australia and TBRC for lead in Sweden. The features and potential of this technology in metallurgy and waste treatment ie described. The FluxfLow la a new, cost efficient high availability solution to treat hot sticky gases that has made new gas handling and heat recovery flow sheets available to the process industry.

Jan 1, 1994

By Hideo Nakae, Hideki Yamaura, Toshiaki Kimura

"In 1968 J. N. Reding et al. suggested processes for fabricating composites. According to their patent, decompression atmosphere, which occurs during the reaction between magnesium and oxygen and/or nitrogen in the closed system, causes the spontaneous infiltration of melt into narrow spaces such as ceramic preforms. However, they did not report the proof of this phenomenon or the industrial manufacturing method. Therefore, this research measured the pressure change among SiC particles surrounding molten aluminum. As a result, the pressure reduction during the Mg reaction was identified. Moreover, the existence of Mg3N2, which improves the wettability between Al alloy melt and SiC particles on the interface, was observed on the surface of particles. Applying these two phenomena, a new process for the manufacturing of cast discontinuously reinforced aluminum composites (DRA) was developed. This new method is expected to produce DRA without additional pressure.IntroductionWith the increasing demands for light-weight materials in the automotive and aerospace industry in recent years, ceramic particulate reinforced aluminum matrix composites called DRA (Discontinuously Reinforced Aluminum Composite) have been receiving significant attention because of its lightness, superior abrasion resistance, high heat conductivity and low thermal expansion [1-3]. Consequently, DRA was considered for electronic parts such as heat-sinks or a base for power semiconductors, and began to be applied for automotive parts including brake drums, discs, cylinder liners, pistons and so on [4- 6]. However, high machining cost is one of the significant barriers to widespread use ofDRA. One solution to this problem is the adoption of cast DRA that can be produce to near-net shape, reducing machining cost."

Jan 1, 2000

By Fumio Hashiuchi, Yushiro Hirai, Masatoshi Maeda, Toshihiro Nagata

"Increase in the copper smelting capacity at Saganoseki Smelter & Refinery was attained through various improvements in the PSconverters and the flash furnace. Two of the major innovations in the converting process were: a new operational technology which avoids increase in the copper content in the converter slag even when higher copper grade matte (65%) are treated in the slag making stage and a technology which shortens the operational interruption time which is caused by coolant charging. The latter was realized by introducing a new automated coolant charging system with which it was made possible to charge the coolant without stopping the blowing into the converter. These improvements brought about a remarkable increase in · the production capacity per converter and an annual production of 450,000 tons of copper without adding new furnaces was made possible. In addition, good results have been obtained of the tests with modified tuyeres to further increase the production.IntroductionIn a bid to renovate its Saganoseki Smelter & Refinery and to establish a leading production unit in terms of global competitiveness, Nippon Mining & Metals undertook major restructuring efforts since 1994. One of its themes was the shift from· a two-flash furnaces operation to a single-flash furnace operation. The shift was successfully completed in 1996 while maintaining the production at the same level (330,000 tons per annum of copper). Then, the productivity was enhanced to 450,000 mtpy without adding new furnaces through technological and operational improvements. It is now planned to increase the smelting capacity further to 470,000 mtpy this year.Some technological and operational improvements in the matte converting process and the new plan resulted from the tests with modified tuyeres are presented in this paper."

Jan 1, 2000

By Steve Naruk

Microscopic point-count analyses, although time-consuming, provide detailed mineralogical information which is not obtainable by any other means. Such information can be invaluable for evaluating mill circuit behavior. In comparing two months of operation of a Cu-Pb-Zn sulfide flotation circuit, chemical analyses show that higher copper recoveries and concentrate grades were obtained from lower grade ore, but they provide no explanation of how the improvements were obtained. Quantitative micro-scopic analyses, on the other hand, show the following: 1. There was no change in the identity of the Cu-bearing minerals. 2. Increased copper recovery was achieved primarily by increased recovery of chalcopyrite middling particles. 3. The increased recovery of chalcopyrite middling particles also increased the amount of gangue entrained as locked particles. 4. Increased rejection of free gangue particles, particularly those finer than 25 microns in size, resulted in a net decrease in gangue content.

Jan 1, 1981

By Robert G. Telewiak

During the past few years, the international nickel industry has taken some important steps to respond to conditions of global production overcapacity, relatively flat demand and low prices. These include the implementation of major cost reduction programs by most producers, closure of some high cost operations and the establishment of the Nickel Development Institute. Consumption in the western world increased by about 7 per cent in 1987 compared to 1986, supplies were less than demand, inventories were low, and late in the year prices increased dramatically. By year-end 1987, most producers were operating at, or close to, their effective capacities. Nickel demand is expected to increase to the year 2000 at an annual rate of about 1.7 per cent, led by increasing usage in the stainless steel sector. If this rate of growth is realized, then there will be need for the effective capacity of the nickel industry to be increased. Producers in Canada have put considerable effort in the past few years into reducing costs - with impressive results. Mining costs, in particular, have been reduced dramatically. While production is still less than the peak years of the yearly 1970's, it has increased substantially from levels of the early 1980's. Over the next few years, production is expected to increase slowly. A key determinant of the level of production in the 1990's could be the effect that regulations on sulphur dioxide emissions have on limiting production.

Jan 1, 1988

By Ma Ying

The continuous directional solidification technique of five kinds of special ZA alloys with eutectic, peritectic and eutectoid transfonnation under the condition of continuous casting by heated mold was studied. The mechanism of surface defects appearing in ZA alloy line was discussed and the structure of some defects were analyzed by SEM. The results show that only when the fitting of various technique factors, pressure head, outlet temperature, pulling speed and cooling condition are reasonable under a certain range, can the ZA alloy smooth line be continuously pulled out. Unreasonable techniques will result in hot tear, rough surface, mush outlet, leaking and other defects. The shape and location of solid-liquid zone have an important influence on the formation of the above defects. When the solid-liquid zone is located in the mould outlet or inner mould, the surface of solidification will protrude into the inner mould. If the remaining liquid cannot counteract the solidification contraction, a rough surface will appear. If the solidification surface further into the mould, the ingot in the mould will have a great friction force when pulling and will form a hot tear. When the solid-liquid zone is moved out of mould, the solidification surface will turn into a plane, which easily results in leaking. A vibration or unstable operation will cause an ingot winding during pulling.

Jan 1, 2003

By Lv Guozhi, Niu Liping, Liu Yan, Zhao Qiuyue, He Jicheng, Zhang Ting’an, Dou Zhihe

"This paper proposed a new method of Mg and Cl2 circulating for titanium sponge production by direct pyrolysis and thermal reduction process. Effects of pyrolysis temperature, pyrolysis time and partial pressure of oxygen on pyrolysis efficiency were researched, and the crystallite structural transformation of MgO productions at different pyrolysis temperature and time were analyzed by XRD. The experimental results indicates that the pyrolysis temperature and time effects the pyrolysis efficiency obviously, and the reasonable pyrolysis conditions by using MgCl2 in molten state are as follows: the pyrolysis temperature is 1100?, pyrolysis time is 60min and the partial pressure of oxygen is 100%, the pyrolysis efficiency get above 95% at this conditions. The dynamic analysis of molten magnesium chloride pyrolysis reaction shows that, as a chemical reaction process control, the response of the apparent activation energy Ea=70.4 kJ/mol.IntroductionTitanium is a young metal, it is applied in industrial until the Second World War. It is 160 years from the discovery of titanium to the industrial production of ductility titanium by magnesium reduction method in the United States in 1948. As a new kind of metal, titanium and titanium material are better than the traditional metal materials in mechanical properties, heat resistance and thermal conductivity. Titanium is a kind of landmark structure and function material, which is called “space metal”, “Marine metal”, “Intelligent metal” [1-3]. Although the study of new methods of titanium melting get more at present, Kroll method and Hunter method are really applied to industrial production methods for titanium smelting, and Hunter method is already discontinued because of costs at present. The core technology in Kroll method of sponge titanium production process can be ome down to two circulation, namely the cycle of magnesium and chlorine in preparation-process of titanium sponge. In the traditional Kroll method, the cycle is realized through magnesium chloride which is produced by the electrolytic magnesium reduction process in hot molten state. But because investment of equipment for electrolysis method is too high, this method has not been used by most titanium sponge production enterprise in China. At present most titanium sponge production enterprise in China produce titanium sponge by the outsourcing of titanium tetrachloride, but the main disadvantage of this method is that the by-product of magnesium chloride is difficult to deal with."

Jan 1, 2012

By E. M. Weenink

One of the new direct smelting technologies for the production of lead from sulfide concentrates that has reached the commercial stage is the Outokumpu lead flash/electric furnace ?smelting process. Using data from pilot plant test work, energy and mass balances for a commercial plant were initially calculated by hand. To optimize process conditions, a large number of such balances had to be generated and a computer program using Lotus 123 was developed which provided an excellent opportunity for computer simulation. Operating parameters can be calculated by iteration using input values for feed composition, feed rate, smelting temperature, and lead content of the slag'" The output is presented by means of various views of the appropriate process steps, or in 68 different graphs.

Jan 1, 1990

By Nobuhiro Shinihara, Makio Naito, Keizo Uematsu, Tadashi Horta, Hiroya Abe, Masataro Okumiya

"A significant variation of strength was noted in silicon nitride ceramics made through the powder compaction processing with minor processing changes. The relevance of the fracture strength to the microstructure was examined in these ceramics. In the examination of microstructure, the ceramics were made into thinned specimens, and their internal structures were observed with an optical microscope in the transmission mode. This technique can distinguish a difference in microstructure associated with the minor processing changes. The strength of all ceramics examined in this experiment was qualitatively correlated with the -pore size distribution in the specimens. Clearly, the elimination of these detrimental defects will enhance the reliability of ceramics.IntroductionIn ceramics made through powder processing, a variation of properties is often encountered [l ,2]. This brings a major problem on producing reliable and cost-effective ceramics. The variation is often ascribed to the changes in the characteristics of defects. However, there is no clear evidence f\)r this explanation due to the lack of an adequate tool for identifying the defects determining the properties. Details of the origin of the variation have still been poorly understood.A new technique is very promising for clarifying the origin of the variation [3,4]. This has very high potential in detecting minor differences in structure for .engineering ceramics. With this technique, ceramics are made transparent with its thinning down to about 50 µ m and their internal structures are observed with various types of optical microscopes in the transmission mode. The characteristics of the defects determined through this approach were found to be directly related to the strength of the ceramics [4-6].The objective of this study is to clarify the ongm of fracture strength of silicon nitride ceramics. This material is representative of high performance ceramics, and the origin is of great practical interest. For this study, silicon nitride ceramics with minor changes in processing condition were prepared. Specific feature focused in this study is the difference of large pore structure determined with the new technique and its relevance to the strength of the silicon nitride ceramics."

Jan 1, 2000

By Jin-tao Gao

In order to recover Ti resource from titanium bearing blast furnace slag, a new technology to separate perovskite phase from CaO-TiO2-SiO2-Al2O3-MgO system by supergravity is researched. In the condition of gravity coefficient of 750g, treatment temperature of 1305°C and time of 20min, the significant layers appear in samples which are obtained by means of centrifugal treatment. Along the direction of the supergravity, the volume fraction of perovskite phase increases gradually, and the equivalent diameters of perovskite phase crystals increases with the area approaching to the bottom of the sample. It is indicated that TiO2 is enriched in the bottom of sample as concentrate with a recovery ratio of 74.05% by supergravity treatment.

Jan 1, 2014