L’augmentation des fréquences de commutation des alimentations induit de nouvelles problématiques pour les composants. Que ces composants soient actifs ou passifs, il est nécessaire de contrôler les pertes afin que les rendements restent acceptables. La thèse se propose d’étudier et de fabriquer une nouvelle structure de transformateur destiné à s’insérer dans une alimentation à découpage. Ces transformateurs sont produits à l’aide du procédé PECS/SPS, qui est une technologie de frittage. Cette technologie permet de fritter des ferrites tout autour des enroulements primaires et secondaires. Il en résulte que les composants sont monolithiques.Une première partie présente l’état de l’art, ainsi que le magnétisme dans la matière. Il s’ensuit un chapitre dédié à la fabrication des matériaux magnétiques utilisés durant la thèse : les ferrites.Une deuxième partie concerne les ferrites fabriqués par le procédé PECS/SPS. Il est question dans un premier temps d’étudier l’anisotropie magnétocristalline de ces matériaux, et il est possible de la diminuer en jouant sur la composition chimique. Dans un second temps, d’autres grandeurs telles que la perméabilité ou la polarisation sont mesurées, toujours en fonction de la composition chimique. Les principaux résultats montrent que le frittage par le procédé PECS/SPS est plus réducteur que le frittage classique, ce qui dégrade certaines propriétés comme la résistivité des ferrites. Un dernier chapitre est dédié à la réalisation des transformateurs monolithiques. Un protocole détaillé de la fabrication est alors présenté.Une troisième partie illustre le fonctionnement des transformateurs réalisés. Les mesures usuelles permettent d’identifier les inductances propres, mutuelles et de fuite. Les valeurs de ces inductances montrent qu’il est plus judicieux d’utiliser les composants fabriqués non pas en tant que transformateur, mais en tant que coupleur. Enfin un convertisseur basé sur une structure de type VRM est réalisé. La fréquence de découpage est de 2 MHz, le rendement est supérieur à 90 %, et la densité de puissance est de 15 kW/litre. / The increase in switching frequency of power supply induces new problems for the components. These components are active or passive, it is necessary to control the losses so that efficiency remains acceptable. The thesis deals with the study and production of a new transformer structure intended to be part of a switching power supply. These transformers are produced using PECS/SPS method, which is a sintering technology. This technology can be sintered ferrite around the primary and secondary windings. It follows that the components are monolithic.A first part presents the state of the art, and magnetism in the matter. It follows a chapter dedicated to the manufacture of magnetic materials used in the thesis : the ferrites.A second part concerns the ferrites produced by the PECS / SPS process. Firstly, the magnetocrystalline anisotropy of these materials is studied, and it is possible to decrease it by varying the chemical composition. In a second stage, other variables such as the permeability or the polarization are measured, always depending on the chemical composition. The main results show that the sintering by PECS / SPS method is more reducing than conventional sintering, which degrades certain properties such as the resistivity of the ferrites. The last chapter is dedicated to the realization of monolithic processors. A detailed manufacturing protocol is presented.A third part shows the operation of the realized transformers. The usual measurements allow identifying self, mutual and leakage inductances. The values of these inductances show that it is better to use components made not as a transformer, but as a coupler. Finally a converter based on a VRM structure is realized. The switching frequency is 2 MHz, the efficiency is greater than 90%, and the power density is 15 kW / liter.

The development of radio frequency integrated circuits (RFICs), especially the dream of integrating analog, digital and radio frequency (RF) components on the same chip that is commonly known as System-on-a-Chip (SoC), is crucial to mobile communications of the future. Such SoC approach offers enhanced performance, greater reliability, and substantially less power consumption of integrated circuits while reducing overall physical size and thus manufacturing cost. However, the progress has been stalled by the lack of miniaturized inductor elements. Rise of unwanted parasitic effects limits down-scaling of the inductor structures and leaves the use of magnetic coating as a viable and attractive option to enhance the inductance and thus inductance density. It is also essential to shift from perm alloy and other amorphous alloys to ferrites and hex ferrites as the core material because of their very high electrical resistivity so as to keep losses in check, a criterion that cannot be compromised on in GHz frequency applications. This is viable, however, only if the integration of the magnetic core (film), particularly a ferrite film, is fully compatible with the CMOS fabrication process. Various approaches have been taken to meet this requirement, including investigations of employing layers of ferrite materials to envelop the inductor loop. However, the deposition of thin films of ferrites, whether by PVD or CVD, usually calls for the deposited ferrite layer to be annealed at an elevated temperature to crystallize the layer so that its magnetic characteristics are appropriate for the optimum performance of the circuit element. Such annealing is incompatible with CMOS process flow required for aggressive device geometries, as the inductor element is added after the active semiconductor circuit is processed, and any exposure of the processed circuit to elevated temperatures risks disturbing precise doping profiles employed and the integrity of the inter-layer dielectrics. What is called for is a low-temperature process for the deposition of a ferrite layer on top of the patterned inductor element – a layer of thickness such that most of the fringe field is encapsulated – while ensuring that the layer comprises crystallites of uniform size that leads to uniform magnetic behaviour. Recognizing the difficulty of meeting the various stringent requirements, it has recently been remarked that such a goal is a formidable challenge. In an attempt to address this challenge, in this work, we have adopted a counter-intuitive approach - the deposition of the desired ferrite composition on a processed die (that contains the inductor structures along with active semiconductor circuits) by immersing it into a chemical (reactant) solution, followed by a brief irradiation of microwave frequency. However, to identify the desired ferrite composition and the appropriate recipe to deposit them, a systematic effort had to be made first, to understand the inter-relationship between synthesis process, structure of resulting material, and its physical and chemical properties. Therefore, at the beginning, a general introduction in which key concepts related to the magnetic-core inductors, the microwave-irradiation-assisted synthesis of nanostructures, the ‗state of the art‘ in the field of integration of appropriate magnetic material to the RFICs, are all outlined. As a proof of concept, microwave-irradiation-assisted solution-based deposition of zinc ferrite thin films on the technologically important Si (100) substrate is demonstrated. The highlight of the process is the use of only non-toxic metal organic precursors and aqua-alcoholic solvents for the synthesis, which is complete in 10 minutes @< 100 °C, without any poisonous by-products. Effects of various process parameters such as solute concentrations, surfactant types, and their concentrations are investigated. A wide range of deposition rates (10 - 2000 nm/min) has been achieved by tweaking the process parameters. The simultaneous formation of zinc ferrite nanocrystallites (ZFNC) along with deposition of thin film is the hallmark of this synthesis technique. Unlike its bulk counterpart, both film and powder are found upon investigation to be rich in magnetic behavior– owing to plausible cationic distribution in the crystal lattice, induced by the inherently quick and far-from-equilibrium nature of the process. The accurate estimation of magnetic characteristics in film is, however, found to be difficult due to the high substrate-to-film mass ratio. The simultaneously prepared ZFNC is examined to arrive at the optimized process recipe that imparts the desired magnetic properties to the zinc ferrite system. The crystallographic cationic distribution in zinc ferrite powder is, however, difficult to study due to the nanoscale dimension of the as prepared material. To enable crystal growth, slow and rapid annealing in air at two different temperatures are employed. The effects of these annealing schemes on various attributes (magnetic properties in particular) are studied. Rapid annealing turns out to be an interesting pathway to promote rapid grain-growth without disturbing the crystallographic site occupancies. The presence of inversion, i.e., the amount of Fe3+ in the ‗A‘-sites in the spinel structure that ideally is zero in normal spinel structure of zinc ferrite, is evident in all annealed ZFNC, as determined by Riveted analysis. Such partially inverted ZFNC exhibits soft magnetic behavior with high saturation magnetization, which can easily be ―tuned‖ by choosing appropriate annealing conditions. However, a few unique strategic modifications to the same microwave-irradiation-assisted solution-based synthesis technique are tried for the formation of nanocrystalline powder with desired sizes and properties without the necessity of anneal. The approach eventually appears to pave a way for the formation of oriented structures of zinc ferrite. The effects of anneal, nevertheless, are studied with the help of neutron powder diffractometry and magnetic measurements. The magnetic ordering at various temperatures is analyzed and connected to the magnetic measurements. The study shows that long-range magnetic ordering, present even at room temperate, originates from the distribution of cations in the partially inverted spinel structures, induced by the rapid and kinetically driven microwave synthesis. Keeping the mild nature (<200 °C) of the processing in mind, a large degree of inversion (~0.5) is a surprise and results in a very high saturation magnetization, as much as 30 emu/g at room temperature (paramagnetic in bulk), in the ZFNC system. Based on the knowledge of process-structure-property interrelationship, a recipe for the deposition of ferrite thin films by the microwave-assisted deposition technique is optimized. Successful deposition of smooth and uniform zinc ferrite thin films on various substrates is, then, demonstrated. The mystery behind the strong adherence of the film to the substrate - an unexpected outcome of a low-temperature process - is probed by XPS and the formation of silicates at the interface is identified as the probable reason. The uniformity and consistency of film composition is also examined in this chapter. Another salient feature of the process is its capability to coat any complex geometry conformally, allowing the possibility of depositing the material in a way to ―wrap around‖ the three-dimensional inductor structures of RF-CMOS. Integration of nanostructure zinc ferrite thin films onto on-chip spiral inductor structures has been demonstrated successfully. The magnetic-core inductors so obtained exhibit the highest inductance density (700 nH/mm2) and the highest Q factor (~20), reported to date, operate at 5 GHz and above, by far the highest reported to date. An increase in inductance density of as much as 20% was achieved with the use of just 1 µm thick film of zinc ferrite covering only the ―top‖ of the spiral structure, i.e., up to 20% of chip real estate can potentially be freed to provide additional functionality. The microwave-assisted solution-based deposition process described in this thesis is meant for ‗post-CMOS‘ processing, wherein the film deposited on some specific electronic components can add desired functionality to or improve the performance of a component (circuit) underneath. However, the effect of such ‗post-CMOS‘ processing on the active MOS devices, interconnects, and even inter-layer-dielectrics fabricated prior to the deposition has to be mild enough to leave the performance of delicate MOS characteristics intact. Such CMOS-compatibility of the present deposition process has been tested with a satisfactorily positive result.

This thesis describes the convenient routes and the preparation conditions (temperature, oxygen partial presssure) which lead to the formation of single phase materials within the quaternary system Cu-Ni-Fe-O. The investigated compositions are the solid solutions CuxNi1-xFe2O4, the ferrites occurring in the phase triangle Cu0.5Ni0.5Fe2O4 -Cu0.9Fe2.1O4 - Cu0.5Fe2.5O4 and some copper-nickel oxide solid solutions. Three synthesis routes have been used, namely (i) the preparation and the thermal decomposition of freeze-dried carboxylate precursors, (ii) the preparation and the oxidation of intermetallic phases and (iii) the preparation and the heat treatment in air of mixed oxide/metallic powders. The thermal decomposition of freeze-dried Cu-Ni-Fe formate has been found as a suitable method for preparing single spinel phases within the Cu-Ni-Fe-O system. In comparison with the conventional solid state reaction, the required temperature is much lower. Concerning the solid solution CuxNi1-xFe2O4 , a single phase spinel is formed at 1000¢XC for x &amp;lt; 0.7; for CuO is identified as second phase. In this latter range the formation of a pure phase required an increase of the iron content in the mixture. The other single spinel phases in the phase triangle Cu0.5Ni0.5Fe2O4 - Cu0.9Fe2.1O4 - Cu0.5Fe2.5O4 have been synthesized under special synthesis p(O2)/T-conditions. For copper ferrites Cu1-xFe2+xO4 with x ?­ 0.1, 0.2, 0.33, 0.4 and 0.5, the change in the conductivity with the temperature is irreversible. The deviation from the linearity of the conductivity ?ã as a function of the temperature occurs due to the thermal history of these samples. The saturation magnetic moment (nB) at 5K, of some synthesized CuxNi1-xFe2O4 compounds has been determined. It has been found that nB increases with the nickel content in the ferrite sample.

Im Rahmen dieser Arbeit wurde der Einfluss von Defekten auf die Eigenschaften von Ferrit-Dünnfilmen untersucht. Die Dünnfilme wurden mit Hilfe von gepulster Laserabscheidung bei verschiedenen Züchtungsparametern hergestellt. Durch Variation der Substrattemperatur und des Sauerstoffpartialdrucks wurden Dünnfilme verschiedener kristalliner Qualität gezüchtet. Diese wurden hinsichtlich ihrer chemischen Komposition mit Hilfe von energie-dispersiver Röntgenspektroskopie und Röntgenphotoelektronenspektroskopie untersucht. Durch Korrelation der Ergebnisse mit Messungen zum zirkularen magnetischen Röntgendichroismus, konnte eine partielle Inversion der Spinellstruktur nachgewiesen werden. Der Grad der Inversion ist höher für geringe Abscheidetemperaturen. Für diese defektreichen Dünnfilme zeigen Röntgenbeugungsuntersuchungen eine geringere kristalline Ordnung der Dünnfilme. Die strukturellen Defekte haben einen maßgeblichen Einfluss auf die elektrischen und magnetischen Eigenschaften der Ferrit-Dünnfilme. So zeigen die Ferrit-Dünnfilme für geringe Züchtungstemperaturen eine erhöhte elektrische Leitfähigkeit, während Dünnfilme, die bei hohen Substrattemperaturen gezüchtet wurden, isolierend sind. Die Temperaturabhängigkeit der elektrischen Leitfähigkeit kann auf thermisch aktivierte Hopping-Leitung oder die Leitung zwischen Clustern, die in einer Matrix eingebettet sind, zurückgeführt werden. Die magnetischen Eigenschaften von Zinkferrit-Dünnfilmen werden maßgeblich durch Defekte in der Spinellstruktur bestimmt, da es nominell in der normalen Spinellstruktur kristallisiert und daher antiferromagnetisch ist. Die partielle Inversion der Eisen- und Zinkionen führt zu Ferrimagnetismus in den Zinkferrit-Dünnfilmen, der mit Hilfe von SQUID-Messungen in dieser Arbeit eingehend untersucht wurde. Durch Korrelation der Ergebnisse der verschiedenen Untersuchungsmethoden konnten Rückschlüsse auf die dominierenden Defekte in den Ferrit-Dünnfilmen geschlossen werden. So sind zum einen Defekte auf atomarer Skala, wie Antisite-Defekte und divalenten Fe-Ionen für die erhöhte elektrische Leitfähigkeit und die größere Magnetisierung der defektreichen Dünnfilme verantwortlich. Zum anderen können ausgedehnte Defekte, im Speziellen Cluster, die in einer amorphen Matrix eingebettet sind, nicht ausgeschlossen werden.

The doping of BiFeO3 with lanthanide elements like Ho, with a radius smaller than Bi, is ideal to improve the ferroelectric and magnetic properties of BiFeO3, which in principle can cause structural distortions of the lattice that improve the electrical and magnetic properties. In this work, we report on the temperature dependence of the structural and magnetic properties of Ho substituted BiFeO3 (BHFO) samples, which have been investigated by X-ray diffraction (XRD) and Mössbauer spectroscopic techniques. The XRD and Mössbauer measurements were done at room temperature on the as-synthesized BHFO samples and after annealing the samples in Argon up to 1073 K. The resultant XRD patterns have shown that BHFO is of rhombohedral R3m space group, with a majority Bi25FeO90 phase and a minority Bi2Fe4O9 phase. These two phases are attributed to the local stoichometry fluctuations in BiFeO3 (BFO). A new phase was evident in the XRD spectra after annealing the sample between 673 – 873 K; this has been assigned to the octahedral B-site of Fe3O4. The Mössbauer spectra were characterized by broadened features and the magnetic hyperfine splitting patterns were indicative of magnetic ordering mostly probably screwed or slightly antiferromagnetic ordering. The spectra were fitted with two symmetric sextets (S1 & S2) which were present in all annealed samples, a symmetric sextet (S3) which was observable at annealing temperatures greater than 673 K, a Lorentzian doublet (D) and a single line (SL) which were present in all spectra. The extracted hyperfine parameters of sextet S1 are consistent with those of rhombohedral BiFeO3 and are characteristic of magnetically ordered Fe3+. At TA > 673 K, a third sextet S3 was assigned to the high symmetry cubic spinel phase. The paramagnetic doublet D was attributed to the Bi25FeO40 phase and the singlet line SL to the Bi2Fe4O9 phase which has been observed previously in the studies of BiFeO3 and other BiFeO3 doped systems. The isomer shift and quadrupole splitting values of the paramagnetic doublet D corresponds to an oxidation state of Fe3+, while the isomer shift of S1 remained fairly constant up to TA = 623 K then decreased gradually after the appearance of S3 indicating an increase of the s-electron density at the Fe nucleus. The quadrupole splitting of S2 showed no systematic change with annealing temperature, however at TA > 623 K this parameter changed dramatically to a negative value with a slightly larger magnetic field. The distribution of the isomer shift and the difference in the quadrupole splitting values and signs are due the variation in the angles between the principal axis of the electric field gradient (EFG) and the spin direction. The hyperfine fields of S1 and S2 remained fairly constant for all measured samples, however at TA > 623 K the hyperfine field of S3 showed a slight increase which could be due to Ho being substituted at the Fe site in BiFeO3. In addition, in-situ Mössbauer measurements at temperatures in the range 300 – 748 K were made on the BHFO samples. The room temperature spectrum showed similar features as observed on the annealing series of measurements. The hyperfine magnetic fields of the two sextet components (S1 and S2) decreased with increasing temperature and finally collapsed at T > 588 K. The hyperfine fields of both the S1 and S2 components decreased systematically with temperature to a field distribution just below the Néel temperature. From our measurements, we estimated the Néel temperature for BHFO to be in the range 598 – 617 K. The isomer shift for all spectral components showed a linear decrease with increasing temperature which closely followed the usual second order Doppler shift variation with temperature. The S1 and S2 spectral components present at room temperature disappeared just before the Néel temperature resulting in the area fraction of the paramagnetic doublet D dominating the spectrum. From the site populations, an average Debye temperature (θD) was estimated to be 240 ± 81 K for BHFO which is lower than the value of 340 ± 50 K cited for BiFeO3.

Orientador: Miguel Jafelicci Junior / Banca: Inês Joekes / Banca: Adley F. Rubira / Banca: Élson Longo / Banca: Carlos de Oliveira Paiva Santos / Resumo: A substituição parcial de íons Fe3+ por pares de íons (Co2+-Ti4+ ou Co2+-Sn4+) na ferrita de bário hexagonal (BaFe12O19) leva a uma substancial diminuição no campo coercitivo (Hc) com uma pequena mudança na magnetização de saturação (Ms), permitindo seu uso em gravação magnética e magneto-óptica de alta densidade. Os diferentes métodos de preparação de ferritas de bário resultam em produtos com propriedades distintas. Neste trabalho, preparou-se BaFe12-2xCoxTixO19 e BaFe12-2xCoxSnxO19 (0,25 £ x £ 1) por coprecipitação, utilizando cloretos dos metais precursores e solução de KOH/K2CO3 como precipitante. Após a secagem, o produto obtido foi calcinado a 950oC por 3h, lavado e seco. Os difratogramas de raios X indicaram a formação da ferrita de bário. As micrografias eletrônicas de varredura mostraram que os pós obtidos apresentam-se na forma de plaquetas hexagonais de 1 a 2mm. As curvas de magnetização das ferritas de bário dopadas mostraram que o campo coercitivo e a remanência diminuem em função do aumento da razão de substituição x. A curva de magnetização da amostra dopada com Co-Ti, com x = 1 é característica de uma ferrita mole, com Hc = 13,5 kA.m-1 (0,17 kOe), Ms = 46,1 emu.g-1 e Mr = 11,0 emu.g-1. Para a amostra dopada com Co-Sn a diminuição de Mr não é significante. Estes resultados mostraram que as propriedades magnéticas das ferritas de bário dopadas obtidas por coprecipitação foram melhoradas, em relação aos dados da literatura para ferrita de bário pura ou dopada. / Abstract: The partial substitution of Fe3+ ions with pairs of ions (Co2+-Ti4+ or Co2+-Sn4+) in hexagonal barium ferrite (BaFe12O19) leads to a substantial reduction on coercivity (Hc) with only a low change in saturation magnetization (Ms), allowing its use in high density magnetic and magneto-optical recording. Different preparative methods result in barium ferrites with distinguished properties. In this work, BaFe12-2xCoxTixO19 and BaFe12-2xCoxSnxO19 (0.25 £ x £ 1) were prepared by the coprecipitation method using chloride salt precursors and KOH/K2CO3 solution. After drying, the powder was calcinated at 950oC by 3 h, washed and dried. The X ray diffraction patterns indicated the barium ferrite phase formation. The scanning electron micrographs showed that the particles are hexagonal platelike with diameter size ranging from 1 to 2 mm. The magnetization curves of substituted barium ferrites showed that the values of Hc and Mr decrease with the increase of the substitution ratio x. The magnetization curve profile for Co-Ti substituted sample with x =1 is characteristic of a soft ferrite with Hc = 13.5kA.m-1 (0.17 kOe), Ms = 46.1 emu.g-1 and Mr = 11.0 emu.g-1. These results indicated that the magnetic properties of substituted barium ferrites obtained by coprecipitation were improved when compared with the literature data for pure and substituted barium ferrite. / Doutor

Stainless steels are high-alloyed, usually with multiple components and often also dual matrix phases, as for duplex stainless steels. This make predictions and calculations of alloying effects on equilibria and transformations complicated. Computational thermodynamics has emerged as an indispensable tool for calculations within these complex systems with predictions of equilibria and precipitation of phases. This thesis offers examples illustrating how computational methods can be applied both to thermodynamics, kinetics and coarsening of stainless steels in order to predict microstructure and, to some extent, also properties. The performance of a current state-of-the-art commercial thermodynamic database was also explored and strengths and weaknesses highlighted. / <p>QC 20130429</p>

Surface Biological Modification and Cellular Interactions of Magnetic Spinel Nanoparticles Eva Liang-Huang Heintz 191 Pages Directed by Dr. Z. John Zhang The interest in magnetic nanoparticles is multi-dimensional. Fundamentally, it is important to be able to control their magnetic properties and to correlate to specific applications. In biology, magnetic nanoparticles offer promising potential as magnetic carriers or chaperones for magnetic localization and manipulation of therapeutic reagents. The synthesis of superparamagnetic CoFe2-xSmxO4 nanoparticles and the tunability of their magnetic properties by size and composition variations are discussed. An increase in size of CoSm0.19Fe1.81O4 nanoparticles produced an increase in blocking temperature and saturation magnetization, but a non-linear coercitivity response was observed with change in size. By varying the composition, the saturation magnetization of CoFe2-xSmxO4 decreased dramatically while the coercitivity increased when compared to native cobalt spinel ferrite (CoFe2O4) nanoparticles. These results demonstrate how the magnetic properties of cobalt spinel ferrite nanoparticles can be tailored to specific applications. Surface modifications of cobalt spinel ferrite nanoparticles facilitated the conjugation of oligonucleotides. Using a transfection reagent, CoFe2O4 ??igonucleotide conjugates were delivered into mammalian cells. Post transfection, synchronized movement of cells in response to an external magnetic field was observed. This demonstrated the possibility of magnetic manipulation and localization of therapeutic reagents coupled to CoFe2O4 magnetic nanoparticles. Results from this thesis demonstrate the potential role of magnetic spinel nanoparticles in cell biology and will facilitate the progress towards in vivo testing.

Biological and physical chemistry treatment methods always are used to remove COD of organic wastewater contains PCB. The effect is not obvious when the compositions of pollutant are too refractory or complicated. The primary treatment method of wastewater containing copper is chemical coagulation/sedimentation and its disadvantage is producing a large of sludge. The objective of this study, using two combinative method of UV/H2O2-Ferrite Process and Fenton-Ferrite Process, is to remove organic compounds and heavy metal in real wastewater. Not only supernatant liquid could meet the standard of discharge wastewater but also produce general(non-hazardous) industrial wastes of heavy metal. The primary operation condition of Fenton and UV/H2O2 process, was ferrous ion and hydrogen peroxide concentration, pH, reaction time, and chemical dosing, searching best operation condition to combine with Ferrite Process. Operation of Fenton and UV/H2O2 process under acid condition (pH=2) and neutral condition (pH=8) showed the best operation condition of Fenton and UV/H2O2. The removal decreased when the dose of hydrogen peroxide was added too more or too less. As Fenton and UV/H2O2 process test finished, Ferrite Process is next used for treatment of heavy metal wastewater; Ferrite Process conducted as three stages and the operation conditions were controlled with temperature, pH and the ratio of Fe/M mole. The results showed that the best removal of treatment of copper containing wastewater by Ferrite Process achieved when the ratio of Fe/M mole was at 10. Treatment of PCB industrial real wastewater by Fenton-Ferrite Process and UV/H2O2-Ferrite Process which combined with Fenton, UV/H2O2 and Ferrite Process. The supernatant liquid containing organic compounds and heavy metal both could meet the standards of discharge wastewater and the sludge was judged with general(non-hazardous) wastes. The characteristic of the sludge were the diameter lattice less 100 nm and with magnetism and to develop recovery and utilization in a further work.

ABSTRACT This study was aimed to investigate the operational conditions for stabilizing and recycling copper sludge in electronic industry by serially using acid leaching, cementation and ferrite methods. The physical/chemical characteristics of copper sludge were examined, and TCLP (Toxic Characteristics Leaching Process) tests were conducted. Results show that the copper sludge from electronic industry is weakly alkaline and consists of 6-15.8% Cu and 50-75% moisture. The TCLP tests show that copper in the sludge exceeds the regulation standard. Acid leaching tests indicate that the optimal combination of control factor levels yielding more than 99% of copper extraction is: 2.0 N in sulfuric concentration (A3), pH = 1.5 (B3), 90 minutes in treatment time (C3), and 50 oC in treatment temperature (D3). Moreover, the sediment of treated sludge fulfills the standards of the TCLP, and is thus a general industrial waste. Cementation tests indicate that the optimal combination of control factor levels yielding 96.87% of copper recovery and 92% of copper purity is: addition mole ratio of iron element Fe/Cu = 2.0 (A2), pH = 1.0 (B1), agitation speed = 200 rpm (C1), and 50 oC in treatment temperature (D3). Ferrite tests indicate that the optimal combination of control factor levels yielding more than 99% of copper removal is: addition mole ratio of ferrous sulfuric acid Fe2+/Cu = 10.0 (A3), pH = 9.5 (B2), air supply rate = 3.0 L/min (C3), and 80 oC in treatment temperature (D3). The cost analyses indicate that the expenses would be NT $7.45 for the acid leaching-cementation-ferrite process, less expensive than NT $ 8.0 for the solidification process given the same copper sludge. Thus, the proposed method in this study is competitive and feasible. Keywords: Copper sludge, Acid Leaching, Cementation, Ferrite Process, Recycling