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By J. V. Happ

The investigation reported in this paper was prompted by the belief that vacuum processing of copper mattes could provide significant advancement to present-day copper smelting and converting technology. Specifically, vacuum distillation of copper mattes in a unit such as the R.H. vessel used in vacuum degassing of steel, can lead to improvements in: converter flue-gas-cleaning system, purity of acid (or liquid SO2), aisle hygiene, purity of electrorefined copper and smelter flexibility. In the study conducted, removal of Volatile impurities (arsenic, antimony, bismuth, lead and zinc) from liquid mattes, by vacuum distillation in a laboratory-scale equipment was performed. The conditions investigated covered a temperature range of 1123-1223K, absolute pressure of 6.5-0.5kPa (50 - 3 mm Hg) and with bleed gas consisting either of pure oxygen or argon. Six matte samples (four U.S. and two foreign) were tested. Under the "best" conditions arsenic and antimony were reduced to << 0.01% in the product matte. The removal of bismuth, lead and zinc was variable and appeared to be influenced by the matte composition of the sample. As might be expected, the rates of distillation of the various species were increased at higher temperatures and lower absolute pressures. The influence of a small flow rate of gas (02 or Ar) over the melt did not have a signifi¬cant influence on the extent of impurity removal. The magnetite content of the matte was reduced by up to 30% during vacuum treatment and was favored by a low partial pressure of oxygen over the melt. Substantial amounts of sulfur were also evaporated and an, overall increase in copper grade of the matte was realized. The paper concludes with an evaluation of industrial aspects of the process as applied to conventional smelters.

Jan 1, 1983

By Guy Deschênes

In spite of the wide use of lead compounds to enhance cyanidation of free milling sulphide-bearing gold ores, an industrial control method was only implemented four years ago. This study presents the results of the investigation that led to the development of the on-line control technology. Two free milling sulphide-bearing gold ores and high purity minerals were used to develop and test the concept. The first ore contains 2.8 g/t Au, 6.2% pyrrhotite, 2.1% pyrite 0.6 % arsenopyrite, 0.1% chalcopyrite and 0.1% organic carbon. The second ore contains 10.4 g/t Au, 3.2% pyrite, 0.8% pyrrhotite and 0.38% chalcopyrite. The first ore showed a much higher oxidation rate in the pre-leach than the second one and consumed seven times more cyanide. A relation between the formation of thiosulphate and thiocyanate and the additions of lead nitrate were quantified. The ?reducing power?, a titration with permanganate, predominantly determines the concentration of thiosulphate and thiocyanate in cyanide solution. The relation between the reducing power and the addition of lead nitrate at various concentrations of pyrrhotite and chalcopyrite in the ores was established, providing a monitor/control strategy for lead nitrate addition.

Jan 1, 2006

By Terence Makanyire, Animesh Jha

The dissolution and chemical properties of vanadium, zirconium, and niobium in rutile lattice are analyzed by comparing the octahedral site preference energies, with respect to Ti4+ ion in the solvent phase. The oxides are often present in rutile lattice and interfere in achieving the quality of pigment grade TiO2 due to favourable Gibbs energy for dissolution in the solvent rutile matrix. Binary mixtures of V2O5 { TiO2; Nb2O5 { TiO2 and ZrO2 { TiO2 with compositions of 80, 85, 90, 95 and 97 wt% TiO2 were made, pelletized and sintered at 1100 °C for 24 hours. The solidsolution mixtures were then cooled and leached in 2M NaOH for 3 hours at 60 °C. Phase and lattice parameter characterizations, and microstructural and compositional analyses were then carried out using X-ray diraction and SEM/EDX, respectively. The leachates were analysed by Atomic Absorption Spectroscopy (AAS), using which the solute dissolution model for oxides were investigated.

Jan 1, 2014

By Yoichi Takeda

Copper solubility in Si02-CaO-FeOx slag equilibrated with copper matte in 10% S02 atmosphere at 1573K was estimated. Essential parameters are activity coefficients of copper oxide and sulfide, oxygen and sulfur potentials and activity of copper in the slag-matte system. A large number of experiments provide proper parameters to calculate copper solubility in slag. A classical thermodynamic model postulating CUOO.5 and CuSo.; molecules assists in estimating copper solubility in slag. Additions of Si02 and CaO reduce copper solubility almost in any condition. Copper loss, that is function copper solubility and slag volume, in the silica saturated Si02-FeOx binary slag is minimally equilibrated with less than 66% copper matte while copper loss in the 50% FeOx-SiOrCaO ternary slag saturated with 2CaOSi02 is minimally equilibrated with over 66% copper matte. This slag composition has potential for continuous copper converting, direct copper production or high-grade matte production.

Jan 1, 2003

By M. Cavallini, G. Cannavale, P. P. Milella, A. Pescetelli, C. Lupi

Ni-Cd sealed and vented cells have been widely used in the last few years. The environmental hazard related to the heavy metals contained in Ni-Cd batteries is well known. Therefore, a number of scientific studies and commercial processes have been implemented in order to recycle them. Since spent batteries are a heterogeneous and complex material, any kind of recovery process needs some preliminary treatments. The proposed process described in this paper has been tested in laboratory and further developed in a pilot plant. It consists of a combination of mechanical and hydrometallurgical treatment steps, and is able to treat all type of Ni-Cd batteries. In particular, the mechanical treatments have to be done separately on vented and sealed cells, while the hydrometallurgical step is performed on a mixture of the two products obtained from mechanical steps. A fully automated dismantling line would allow the separate recovery of the plastic or metallic casing, terminals, KOH electrolyte, and electrodes to be further processed· for Ni and Cd recovery. The electrodes coming from dismantling line and sealed batteries are submitted separately to an original crushing and elutriation treatment to separate metallic and active paste in the first case and metallic, plastic and active paste in the second case. The hydrometallurgical treatment is carried out on active paste bearing product to produce Ni, Cd, and Fe comn1ercial salts through acidic leaching followed by a multi-step solvent extraction operation to obtain pure solutions.

Jan 1, 2000

By Gustavo Díaz, Miguel A. García, Carlos Frías

"Under the auspices of the Commission of the European Union, a consortium composed of six European organi~ations has conducted a project to scale up the PLACID electrowinning cell to industrial size within the Placid process development. This paper is concerning the results and achievement of the industrial cell prototype after more than 1,000 hours operating time and about 10,000 Kg electrolytic lead production. In general, results have been very satisfactory, demonstrating the ability ofthe PLACID electrowinning cell to produce top quality electrolytic lead (> 99.99 %) with high current efficiency and low energy consumption.IntroductionThis paper is concerning the development of an industrial size PLACID electrowinning cell within the PLACID process development. This project began on January 1993 and was finished on April 1996.Lead metal production and manufacturing industries produce large amounts of dusts and also lead bearing slags. Spent lead-acid battery recycling also produces lead oxides from the battery pastes rather similar to those mentioned above. Those lead secondary materials are hazardous and difficult to handle by usual procedures.Existing processes to treat-lead oxides may inflict considerable damage on the environment, incur high operating costs and have limitations to produce top quality lead.The main aim of this project has been to develop a novel hydrometallurgical process able to deal with different lead bearing materials, mainly lead oxide secondaries: lead-acid battery pastes, lead fumes, furnace slags, oxide residues, etc., producing ""four nines"" pure lead in an efficient manner with a benign influence on the environment; it is called the PLACID process."

Jan 1, 1997

By G. G. Krishna Murthy

Interactions of wustite and hematite pellets with Fe-C melts were investigated experimentally by examining the effect of pellet size and bath temperature on the reduction rates of the pellets. Experiments were carried out in the temperature range 1473-1923 K. A flash X-ray equipment was used to obtain images of the melt surface during its reaction with an oxide pellet. The reduction rates were calculated using experimentally estimated time for complete reaction of a pellet, tR. The value of tR was determined employing gas mass flow rate, or pressure rise in the sealed furnace, versus time traces. The value of tR was the same for both wustite and hematite pellets of equal weight at or above 1723 K and it decreased with increasing melt temperature. But the reduction rate was substantially lower at temperatures below 1651 K, the melting point of wustite. The rates were defined as the rate of moles of oxygen removed from the pellet per unit area of bath free surface and it was found that the bath surface area affects the reduction rates. It was established that the overall reaction followed nth-order rate kinetics with the values of n falling between 0.3 and 0.4 for temperatures above the melting point of wustite. The apparent activation energy determined using the apparent rate constants obtained from the experimental data was 76.2 + 27.7 kJ/mol-O.

Jan 1, 1992

By W. S. Hui, M. G. Silva-Valenzuela, H. Wiebeck, F. R. Valenzuela-Diaz, B. B. Michel

Biodegradable polymer microcapsules have been used as a control sustained release system with many applications. Studies reveal that the incorporation of nanoparticles improves matrix properties, even more so if the clay is modified. The objective of this work was to compare microcapsules of poly (succinate-co-butylenelactate) (PBSL) reinforced with Brazilian clay, composed of smectites and kaolinite, in its natural (MMT/K) and modified (O-MMT/K) forms. Nanocomposites and microcapsules were synthesized by emulsification-diffusion of solvent and solvent diffusion methods. Its characterization was then performed by scanning electron microscopy (SEM), stereo microscopy and wide-angle X-ray diffraction (XRD). The results reported corroborate that PBSL/OMMT-K form an intercalated montmorillonite and kaolinite nanostructure, capable of generating uniform spherical microcapsules with diameter values smaller than that of PBSL/MMT-K, reaching 5–10 lm. DRX indicates that there was a real change in the clay structure. The incorporation of modified clay showed an improvement in surface quality and the strength of microcapsules, making it possible to produce smaller sizes.

Mar 1, 2018

By H. Soto, J. Jara, F. Nava

A method has been developed to recover cyanide and copper from solutions containing copper complexes and thiocyanate. Copper is precipitated as copper thiocyanate or as copper cyanide depending on pH and the concentrations of thiocyanate and cyanide in the effluent. The copper precipitate assays over 50% copper and presents good dewatering characteristics. After settling it can be separated from the effluent by filtration. The solution containing the bulk of the cyanide is then oxidized with ozone to transform the remaining thiocyanate into cyanide. This results in a regenerated solution rich in free cyanide that can be recycled to the cyanidation process. Careful control of the pH of the solution is required. First, pH of the effluent is lowered to optimize the precipitation and oxidation stages, then the pH is restored to an alkaline value to regenerate the cyanide solution. Recoveries of over 96% copper and cyanide were obtained in laboratory tests using industrial solutions. With this procedure, cyanocidic gold/copper ores could be treated economically by heap leaching, since the cyanide consumed by the copper impurities could be regenerated at very low cost (most of the cost of cyanide regeneration would be compensated by the copper credits). In order to achieve this, a bleed of the barren solution could be treated by the proposed method, and then recycled to the leaching step. The volume of solution to be treated should be large enough to keep a cyanide/copper molar ratio higher than 3:1. This would assure that copper does not cause undue interferences in the leaching or the carbon adsorption stages. If the thiocyanate content is low, the oxidation stage can be avoided, and the solution can be recycled to the leaching stage directly after the solid-liquid separation stage.

Jan 1, 1997

By Robert W. Bartlett

Hazardous metal contaminants in liquid and solid wastes and from ground spills are important environmental problems in many metallurgical production operations. Acid rock drainage, from mines and huge quantities of permeable mine waste, is probably the most ubiquitous example. Fixing mine waste contaminants in situ has been practiced, using sulfate reducing bacteria (SRB) and organic reagents as electron donors to create anaerobic conditions and precipitate metal sulfides. Aqueous solutions of sugar and alcohol have been percolated into mine wastes with good results. However, maintaining anaerobic conditions permanently is unlikely, as these solutions are eventually washed out of solid waste and contaminated ground by inflow of either groundwater or meteoric water, allowing re-oxidation from entering air. Emulsions of inexpensive, non-aqueous organic microdroplets dispersed in water provide earth wettablility equal to aqueous solutions and easy percolation into both the ground and mine waste. Subsequent breakdown of the O/W emulsion provides permanent retention of the organic phase, attached to earth particles, that secures lasting anaerobic conditions, precipitates metals as sulfides and prevents re-oxidation of these sulfides. This process and its optimization are described, including experiments with sand-filled columns representing a vertical section through solid waste. Results of organic and metal retention in solid waste are provided from analyses of acid mine water drainage before and after waste treatment.

Jan 1, 2006

By C. M. Acuña

At the Chuquicamata Division of Codelco-Chile high arsenic concentrates are produced, which at the smelter are processed via the Outokumpu Flash Furnace and Teniente Converters to obtain copper mattes. In the case of the Teniente Converters the production of matte grade near white metal composition is a common practice since the eighties and provided in the pyrometallurgical route no appropiate measures are taken, penalties have to be paid because of arsenic content in the anodes. During smelting huge volume of slag is produced and elimination of arsenic by slagging at this step is not economically attractive. Although during fire refining is possible to eliminate arsenic by use of mixtures of calcium and sodium carbonates this alternative is expensive, takes long process time and decreases the lifetime of the refractory lining. In spite of these facts a reasonably way to control arsenic in metal, and therefore in the anode, is taking, action in the converting step. The effects of oxygen and arsenic content in metal, arsenic in white metal and basicity index of the slag upon the distribution coefficient of arsenic between metal and slag were investigated at pilot and industrial levels. The best results are obtained for metals around 7,000 ppm oxygen and 0.3 basicity index slag, which results in a 5.7 distribution coefficient for a 5,800 - 7,100 ppm arsenic content in white metal, 18%-24% CaO slag at 1473 - 1523K. Furthermore, no significant/visible refractory wear has been realized.

Jan 1, 1999

By I. Moscoso, R. Padilla, M. C. Ruiz

Antimony and arsenic are impurities in copper concentrates found normally as stibnite (Sb2S3), tetrahedrite (Cu12Sb4S13) and enargite (Cu3AsS4). When copper concentrates contain appreciable amounts of As and Sb, they must be removed before smelting to avoid environmental pollution. Oxidizing volatilization roasting at 500–700 °C has been used to eliminate these impurities. However, only a fraction of Sb volatilizes in those conditions; thus, a more effective process to eliminate antimony from concentrates is needed. In this study, the chloridizing roasting of Sb2S3 using CaCl2–O2 was investigated to remove the antimony from concentrates. XRD analysis of calcines indicated that the overall reaction could be written as: Sb2S3 þ3CaCl2 þ6O2 ¼ 2SbCl3 þ3CaSO4 Temperature and oxygen partial pressure have a significant effect on the rate of reaction. An estimated conversion of about 90% was obtained at 750 °C, 5.4% oxygen in 20 min. High oxygen concentrations arrest the advance of the reaction forming various antimony oxides including Sb6O13, Ca5Sb5O17 and Sb2O4.

Mar 1, 2017

By Himaki Nakano, Kenji Hara, Toshiaki Tsuru, Shunsuke Kawano, Takeshi Ohgai, Hisaaki Fukushima, Shigeo Kobayashi, Tetsuya Akiyama

"Electrodeposition of Fe-Ni and Zn-Ni alloys from aqueous solutions is one of the well-known examples of anomalous codeposition in which less noble metal deposits preferentially. In this paper, the electrodeposition behavior of these alloy systems was compared between the methanol and aqueous baths. In Fe-Ni system, the significant suppression of the deposition rate of more noble Ni was observed over a wide range of electrolysis conditions in both methanol and aqueous baths. However, the electrodeposition of Zn-Ni alloys showed the typical feature of normal type codeposition in the methanol baths, which was completely different from that in aqueous sulfate baths. The difference in the electrodeposition mechanism between Fe-Ni and Zn-Ni alloys was discussed on the basis of the alloy deposition behavior in the baths in which the activity of water was varied:INTRODUCTION'It has been well known that Fe-Ni alloys show an excellent soft magnetic property. Therefore, thin films of this alloy have been used to fabricate the'-various magnetic devices. For the production of Fe-Ni thin films, dry processes such as sputtering, PVD and CVD are 'employed frequently and the resulting films showed a preferable property as a magnetic material. Electrolyses as a production technique of thin films, on the other hand, has the advantage over other processes in its cheaper production cost due to the simplicity of the production unit The Zn-iron-group metal alloys such as Zn-Ni and Zn-Fe electrodeposited on a steel sheet ale known to exhibit excellent corrosion resistance and therefore the electrodeposition of these, alloys has been applied to the production of surface treated steel sheets mainly for automotive body panels.According to Brenner (1), the electrodeposition behavior of Fe-Ni and Zn-Ni alloys was' classified into the' 'anomalous type. In this type of codeposition, less noble metal, i.e. Fe for Fe-Ni and Zn for Zn-Ni system, deposits preferentially and the change in -the alloy composition- with the variation of electrolysis conditions was unpredictable because of their obscure deposition mechanism. Since most properties of the alloys mainly depend on their composition, the composition of the deposited' alloys must be controlled strictly. Therefore, it is neces5al)' to clarify the mechanism of anomalous codepasition in Fe-Ni and Zn-Ni systems: Several mechanisms have been proposed so fur, and among them the hydroxide .suppression mechanism (2), (3) has been regarded most plauslble depend on their composition, the composition of the deposited' alloys must be controlled strictly. Therefore, it is necessary to clarify the mechanism of anomalous codeposition in Fe-Ni and Zn-Ni systems: Several mechanisms have been proposed so far, and among them the hydroxide suppression mechanism (2), (3) has been regarded most plausible. According to this mechanism, it can be predicted that the codeposition behavior depends greatly on the characteristic of water solvent in this study, using methanol as a solvent, the electrodeposition behavior of the anomalous codeposition was investigated to discuss the validity of the hydroxide suppression mechanism."

Jan 1, 2000

By Zhigang Liang

Effects of the configuration parameters of submerged entry nozzle on the flow field in slab mold were investigated through a water modeling. The experimental results showed, when the original submerged entry nozzle was applied, there was an appreciable level fluctuation in the mold with obviously naked surface and entrapment of mold flux at higher casting speed. By increasing the outlet area of submerged entry nozzle, without any change of other configuration parameters and submergence depth, a proper fluid field with active surface and good covering of mold flux can be obtained, which is proper to meet the requirement for increasing the casting speed and improving the slab quality simultaneously.

Jan 1, 2009

By Naixiang Feng, Shaohu Tao, Zhihui Wang, Yuezhong Di

"A novel vacuum aluminothermic reduction lithium process was developed in present work which used lithium carbonate, alumina and calcium oxide as raw material. The process mainly contained three steps. The first step is that LiA102 clinker is prepared in ambient environment, then metal lithium is vacuum extracted from LiAl02 clinker with aluminum power as reducing agent, and the last step is that alumina is leached from the reduction residue with a mixture of sodium hydroxide and sodium carbonate. The results show that the lithium reduction ratio can be over 95% under the conditions of reduction temperature 1423K, reduction time 3h, and aluminum excess 20%. The main components of reduction residue are CaO· Al203 and 12Ca0·7Alz03. The alumina leaching rate of calcium aluminate in residue is over 80%. High-whiteness aluminum hydroxide can be obtained by carbonation precipitation of the reduction slag leaching solution.IntroductionWith a density about half of water, lithium is with the lowest density of all solids, mere 0.5 g/cm3 at 20 °C [l]. Lithium is widely used in aerospace, aviation, nuclear-generated power and electric battery industry. Nowadays, over 90 % of the world's primary lithium is produced by molten salt electrolysis [2-4]. But the development of molten salt electrolysis will be effected by some factors: cost, environment, and so on. Vacuum thermal reduction may be used extensively in future because of its low-energy consumption, high-purity and short-cycle."

Jan 1, 2013

By Motang Tang, Chaobo Tang, Shenghai Yang, Lulu Guo, Yun Li, Yongming Chen, Jing He

A new innovative process for one-step and cleaner extraction of lead from spent lead-acid battery by reductive sulfur-fixing smelting was presented. This paper summarized and discussed several potential sulfur-fixing agents and molten salts which can be used in this new technique. Thermodynamic analysis involving reaction mechanism, ΔGT and predominance-area diagrams of different smelting systems were performed, respectively. The results proved the technical feasibility and high-efficiency of this process. Copper oxide ash (CuO), zinc oxide ash (ZnO) and iron oxide bearing residues (FexOy) can be used as sulfur-fixing agent to extract lead through exchange reactions. Sulfur-fixed efficiency of CuO, ZnO and FeO decrease slightly in turn. Sulfur contained in PbSO4 is fixed in form of Cu2S, ZnS and FeS respectively which avoids SO2 emission. The addition of molten salt can significantly decrease temperature of reductive sulfur-fixing reactions. Molten salt can be regenerated and recycled in smelting system after filtering solid residues.

Mar 1, 2017

By Zhenyang Wang, Yiran LIU, Xiangdong Xing, Jianliang Zhang, Zhengjian Liu

Basic characteristics of marine placer were systematically studied by chemical analyze, scanning electron microscope and X-ray diffraction in this paper. It could be found that the marine placer mainly consists of titanomagnetite and titanohematite. A series of experiments were performed to investigate reduction-magnetic separation for Fe and Ti from the marine placer. Effects of reduction temperature, reduction time, carbon ratio, magnetic density, and grinding fineness on the reduction-magnetic separation process were investigated. And the optimal process parameters were obtained as follows: the reduction temperature 1300, the reduction time 30 min, the carbon ratio 1.1, the magnetic density 50mT, and the grinding fineness of 0.074μm 86.34%. Under such conditions, the metallization rate, iron grade of magnetic substance and iron recovery reached to 94.23%, 97.19% and 90.28% respectively, and the titanium grade in non-magnetic substance and recovery of was 57.94% and 87.22% respectively. The effective separation of iron and titanium could be achieved in reduction-magnetic separation process.

Jan 1, 2015

By Shiju Zhang, Yongnian Dai, Songli Liu, Kuisong Zhu, Wenhui Ma, Li Cao

There is an abundance of vanadium-titanium magnetite in Panzhihua, China, which contains more than 8.73 x 10^8 tons of TiO2 accounting for 90.6% of the national reserves. To fully utilize Panzhihua titanium resources, many processes were proposed. The present status and future development of technologies for comprehensive utilization of vanadium-titanium magnetite including blast furnace, electric smelting, and ilmenite upgrading processes are reviewed.

Mar 1, 2017

By C. A. Natalie

Prediction of average residence times for different particle size intervals during sulfide roasting was investigated. Calculations were done to predict average residence times using a model which employs empirical correlations for elutriation constants. Experimental average residence times were determined using a continuous., six inch diameter,. fluid bed roaster and compared with calculated residence time values. Comparison of calculated and experimental data showed that geometry effects may have .been significant when attempting to apply elutriation data to this roaster.

Jan 1, 1985

By Olga K. Karakasi, Angeliki Moutsatsou, Ioanna Kavallari

"The present study focuses on the amelioration of the behaviour of high calcium fly ash (HCFA), investigating its application in a new environmental field: oil spill clean up. High calcium fly ash is a by-product of electric power plants, produced annually in large quantities, whose greater amount is landfilled. Some of its properties, such as its chemical and mineralogical composition, its fine particle size, its porosity, floating ability and hydrophobic character make it an attractive material for this purpose. Researches showed that when added to an oil spill, it forms a semi-solid phase, which allows the quite total removal of the oil, but it is not stably retained on the surface. In order to ameliorate its floating ability, the decrease in its specific gravity by mixing with a lighter material is investigated. In the present study the mixing with two materials, already used in oil spill clean up, sawdust and a polymer, has been examined. Addition of 15-25% w/w sawdust to HCFA results in a material with better performance than HCFA or sawdust alone: it has a satisfactory floating ability and allows total removal of oil. Addition of the polymer, however, has resulted in no significant amelioration of the oil sorption behaviour of HCFA, probably because no affinity between HCFA and polymer has been achieved.IntroductionCoal fly ash is a by-product of coal combustion in electric power plants, produced worldwide in huge quantities, approximately 500 million tones annually. High calcium fly ash (HCFA) is classified to class C presenting a (Al2O3 + SiO2 + Fe2O3) > 50%. The production of lignite fly ash in Greece comes up to 13 million tones annually, of which only 12% is used in construction applications, the other being landfilled [5, 6].Besides its limited application worldwide as a construction material, research is focusing on the development of new environmental applications, such as waste stabilisation and solidification, soil and water environmental improvement [9, 12]. For the application of fly ash in further environmental fields several chemical modifications have been applied, in order to improve its properties. Extensive research has been focused on the conversion of both coal and lignite fly ash to zeolite and its further application in environmental field, such as the uptake of inorganic (heavy metals and ammonium [8, 11]) or even organic compounds (methylene blue [15]) from waste water streams, or the use as molecular sieves, to adsorb water molecules, SO2 and NH3 from gas streams, due to the high cation exchange capacity and porosity of the produced zeolithic material. Furthermore, lignite fly ash has been combined with sodium silicate solution, prepared by treatment of rice husk ash, and tetrapropylammonium bromide, to synthesise hydrophobic zeolite ZSM-5 [4]."

Jan 1, 2008