Rückgewinnung von Indium aus Flüssigkristallbildschirmen

Ziel der Arbeit ist es ein industriell umsetzbares Verfahren aufzuzeigen um Indium aus Flüssigkristallbildschirmen (LCDs) zurückzugewinnen. Indium ist ein Element, das derzeit im Wesentlichen in elektronischen Komponenten verwendet wird. Es wird von verschiedenen Staaten und internationalen Zusammenschlüssen als kritisches Element angesehen. Hierbei ist insbesondere die zunehmende Verwendung, als auch die begrenzte Primärgewinnung von Bedeutung. Indium wird zum überwiegenden Teil als Indium-Zinn-Oxid als durchsichtiger Leiter in LCDs verwendet. Somit steht hier ein bedeutendes Potential für eine Rückgewinnung nach der Nutzungsphase zur Verfügung. Das Indium befindet sich als eine dünne Schicht auf der bildgebenden Einheit des LCDs (Panel) und ist somit auf einem bestimmten Bauteil gut lokalisierbar. Bezogen auf das Panel beträgt die IndiumKonzentration ca. 170 mg/kg. Um eine industriell umsetzbare Rückgewinnung zu ermöglichen müssen die entwickelten Prozesse nach Möglichkeit robust und mit gängigen Aggregaten und Hilfsmitteln umsetzbar sein und das Indium von der sehr geringen Ausgangskonzentration in en Konzentrat im Prozentbereich überführen. Dies wird durch eine Kombination aus mechanischer und hydrometallurgischer Aufbereitung dargestellt. In der mechanischen Aufbereitungsstufe werden die Panels mittels eines Shredders selektiv zerkleinert und anschließend gesiebt. Hierdurch wird zum einen das Indium für die nachfolgenden hydrometallurgischen Prozesse zugänglich, zum Zweiten kann durch die selektive Zerkleinerung und anschließende Siebung eine erste Aufkonzentration auf 200 mg/kg erfolgen. Das so entstandenen Vorkonzentrat wird anschließend gelaugt, um das Indium von dem Panel in eine Lösung zu überführen. Hierbei konnte jeweils ein Lauge-Regime mit Schwefelsäure und eines mit Salzsäure als zielführend identifiziert werden. Bei den nachfolgenden Versuchen zum Erhalt von höheren Konzentrationen wurden verschiedene Möglichkeiten untersucht. Als zielführendes zeigte sich die mehrmalige Verwendung der gleichen Lösung in hintereinander folgenden Laugungen mit jeweils neuem Vorkonzentrat. Auch die Nutzung von Ionentauscher-Harzen zeigten positive Resultate, jedoch ist hier auf Grund der geringen Beladung der Laugelösung bei einer Umsetzung mit deutlichem Mehraufwand zu rechnen. Durch eine gezielte Fällung kann ein Indium-Konzentrat von 15 Prozent erzeugt werden, was eine Anreicherung um den Faktor 900 bedeutet. Ausgehend aus den Ergebnissen der Laboruntersuchungen wurde ein Gesamt-Prozess entwickelt, der die Einzelschritte verknüpft. Basierend hierauf wurde eine Anlage konzeptioniert, die rein theoretisch die anfallende Menge an Alt-LCD-Panels in Deutschland zur Indium-Rückgewinnung behandeln könnte.The aim of this work is to demonstrate an industrially feasible process to recover indium from liquid crystal displays (LCDs). Indium is an element that is currently mainly used in electronic components. It is considered a critical element by various countries and international associations. Of particular concern is its increasing use, as well as its limited primary production. Indium is predominantly used as indium tin oxide as a transparent conductor in LCDs. Thus, there is a significant potential for recovery after the use phase. The indium is located as a thin layer on the imaging unit of the LCD (panel) and can thus be easily localized on a specific component. In relation to the panel, the indium concentration is about 170 mg/kg. In order to enable industrially feasible recovery, the processes developed must, if possible, be robust and implementable with common aggregates and auxiliaries and must convert the indium from the very low initial concentration into an concentrate in the percentage range. This is performed by a combination of mechanical and hydrometallurgical processing. In the mechanical processing stage, the panels are selectively crushed by a shredder and then screened. On the one hand, this makes the indium accessible for the subsequent hydrometallurgical processes, and on the other hand, the selective comminution and subsequent screening can be used to achieve an initial concentration of 200 mg/kg. The resulting pre-concentrate is then leached to transfer the indium from the panel into a solution. In each case, a leaching regime with sulfuric acid and one with hydrochloric acid were identified as effective. In the subsequent experiments to obtain higher concentrations, various possibilities were investigated. The use of the same solution several times in successive leaching operations, each time with a new preconcentrate, proved to be the most effective. The use of ion exchanger resins also showed positive results, but due to the low loading of the leaching solution, a considerable additional effort has to be expected. By selective precipitation, an indium concentrate of 15 percent can be produced, which means an enrichment by a factor of 900. Based on the results of the laboratory tests, an overall process was developed that links the individual steps. Based on this, a plant was designed that could theoretically treat the accumulating quantity of old LCD panels in Germany for indium recover

Adaptation of Black-Box Software Components

The globalization of the software market leads to crucial problems for software companies. More competition between software companies arises and leads to the force on companies to develop ever newer software products in ever shortened time interval. Therefor the time to market for software systems is shortened and obviously the product life cycle is shortened too[...]The approach introduced here presents the novel technique together with a supportive environment that enables developers to cope with the adaptability of black-box software components. A supported environment will be designed that checks the compatibility of black-box software components with the assistance of their specifications.Comment: 16 pages, exposed on 2nd "European Conference on Computer Science & Applications" - XA2008, Timisoara, Romani

Crystal engineering of ibuprofen using starch derivatives in crystallization medium to produce promising ibuprofen with improved pharmaceutical performance

Ibuprofen exhibits poor flow, poor compaction and dissolution behaviour, and it is prone to capping after ejection from the die. Therefore, the aim of the present research was to engineer ibuprofen crystals in the presence of two disintegrants (starch and sodium starch glycolate) in order to improve its flow, compactibility and dissolution behaviour simultaneously. To this end ibuprofen and different concentrations of disintegrant (0.25 to 10% w/w in case of starch and 0.25 to 7% w/w in case of sodium starch glycolate) were dissolved in ethanol and water respectively. The ibuprofen solution was then added to the aqueous solutions containing the different concentrations of disintegrant. Ibuprofen precipitated within 10 min and the crystals were separated and dried for further studies. The obtained crystals were characterized in terms of flow, density, tablet hardness, dissolution behaviour and solid state. The results showed most of engineered ibuprofen to have better flow with a high compactibility. The results also showed that an increase in the concentration of starch in the crystallization medium resulted in a reduction in the hardness of ibuprofen tablets, but this was not the case for ibuprofen samples engineered in the presence of sodium starch glycolate. It is interesting to note that although engineered ibuprofen showed superior dissolution as compared to untreated ibuprofen, the highest concentration of starch (10%) or sodium starch glycolate (7%) slowed down the release remarkably due to an increase in the viscosity of the dissolution medium around drug particles. Solid state analysis (FT-IR, XRPD and DSC) ruled out the presence of different polymorphic forms and also any interaction between these disintegrants and ibuprofen. In conclusion, the engineering of ibuprofen in the presence of disintegrant showed how properties such as flow, compaction and dissolution behaviour can be simultaneously manipulated to suit a desired application

Agglomeration of celecoxib by quasi emulsion solvent diffusion method: effect of stabilizer

Purpose: The quasi-emulsion solvent diffusion (QESD) has evolved into an effective technique to manufacture agglomerates of API crystals. Although, the proposed technique showed benefits, such as cost effectiveness, that is considerably sensitive to the choice of a stabilizer, which agonizes from a absence of systemic understanding in this field. In the present study, the combination of different solvents and stabilizers were compared to investigate any connections between the solvents and stabilizers. Methods: Agglomerates of celecoxib were prepared by QESD method using four different stabilizers (Tween 80, HPMC, PVP and SLS) and three different solvents (methyl acetate, ethyl acetate and isopropyl acetate). The solid state of obtained particles was investigated by differential scanning calorimetry (DSC) and Fourier transform infrared (FT-IR) spectroscopy. The agglomerated were also evaluated in term of production yield, distribution of particles and dissolution behavior. Results: The results showed that the effectiveness of stabilizer in terms of particle size and particle size distribution is specific to each solvent candidate. A stabilizer with a lower HLB value is preferred which actually increased its effectiveness with the solvent candidates with higher lipophilicity. HPMC appeared to be the most versatile stabilizer because it showed a better stabilizing effect compared to other stabilizers in all solvents used. Conclusion: This study demonstrated that the efficiency of stabilizers in forming the celecoxib agglomerates by QESD was influenced by the HLB of the stabilizer and lipophilicity of the solvents

Specific Cellular Immune Response and Cytokine Patterns in Patients Coinfected with Hepatitis C Virus and Schistosoma mansoni

Patients coinfected with hepatitis C virus (HCV) and Schistosoma mansoni show high incidence of viral persistence and accelerated fibrosis. To determine whether immunological mechanisms are responsible for this alteration in the natural history of HCV, the HCV-specific peripheral CD4+ T cell responses and cytokines were analyzed in patients with chronic hepatitis C monoinfection, S. mansoni monoinfection, or HCV and S. mansoni coinfection. An HCV-specific CD4+ proliferative response to at least 1 HCV antigen was detected in 73.3% of patients infected with HCV, compared with 8.6% of patients coinfected with HCV and S. mansoni. Stimulation with HCV antigens produced a type 1 cytokine profile in patients infected with HCV alone, compared with a type 2 predominance in patients coinfected with HCV and S. mansoni. In contrast, there was no difference in response to schistosomal antigens in patients infected with S. mansoni alone, compared with those coinfected with HCV and S. mansoni. These findings suggest that the inability to generate an HCV-specific CD4+/Th1 T cell response plays a role in the persistence and severity of HCV infection in patients with S. mansoni coinfectio

Cerebrospinal Fluid Pressure Dynamics as a Bedside Test in Traumatic Spinal Cord Injury to Assess Surgical Spinal Cord Decompression: Safety, Feasibility, and Proof-of-Concept

BACKGROUND: Sufficient and timely spinal cord decompression is a critical surgical objective for neurological recovery in spinal cord injury (SCI). Residual cord compression may be associated with disturbed cerebrospinal fluid pressure (CSFP) dynamics. OBJECTIVES: This study aims to assess whether intrathecal CSFP dynamics in SCI following surgical decompression are feasible and safe, and to explore the diagnostic utility. METHODS: Prospective cohort study. Bedside lumbar CSFP dynamics and cervical MRI were obtained following surgical decompression in N = 9 with mostly cervical acute-subacute SCI and N = 2 patients with non-traumatic SCI. CSFP measurements included mean CSFP, cardiac-driven CSFP peak-to-valley amplitudes (CSFPp), Valsalva maneuver, and Queckenstedt's test (firm pressure on jugular veins, QT). From QT, proxies for cerebrospinal fluid pulsatility curve were calculated (ie, relative pulse pressure coefficient; RPPC-Q). CSFP metrics were compared to spine-healthy patients. computer tomography (CT)-myelography was done in 3/8 simultaneous to CSFP measurements. RESULTS: Mean age was 45 ± 9 years (range 17-67; 3F), SCI was complete (AIS A, N = 5) or incomplete (AIS B-D, N = 6). No adverse events related to CSFP assessments. CSFP rise during QT was induced in all patients [range 9.6-26.6 mmHg]. However, CSFPp was reduced in 3/11 (0.1-0.3 mmHg), and in 3/11 RPPC-Q was abnormal (0.01-0.05). Valsalva response was reduced in 8/11 (2.6-23.4 mmHg). CSFP dynamics corresponded to CT-myelography. CONCLUSIONS: Comprehensive bedside lumbar CSFP dynamics in SCI following decompression are safe, feasible, and can reveal distinct patterns of residual spinal cord compression. Longitudinal studies are required to define critical thresholds of impaired CSFP dynamics that may impact neurological recovery and requiring surgical revisions