This study provides a global substance flow analysis for gallium (Ga), germanium (Ge), and indium (In) for 2011, quantifying the amount of metal lost during extraction, beneficiation/smelting/refining, manufacturing of intermediate products, and the amount embodied in end-use products. Thus far, studies illustrating their cradle to end-use life cycle on a global scale are either missing or outdated, and thus opportunities to increase their supply remain unknown and/or not quantified. The results illustrate the losses and inefficiencies stages, thereby identifying potential additional supply by process improvement, recovery, and recycling. Results show that there are significant opportunities to meet future demand of Ga and Ge by concentrating recovery efforts in the extraction and beneficiation/smelting/refining stages. Further, 1.4% Ga, 0.7% Ge, and 54% In of the theoretical available amount in the attractor ores are extracted to meet the primary refined demand in 2011. Of the 9,065 tonnes (t) of Ga embodied in the Bayer liquor (from aluminum production), only 263 t are refined. This is owing to low capacities of Ga refining, combined with a refining efficiency of 60%. Ge presents a similar case for the same reasons, in which only 43 t of Ge of the 7,636 t of Ge available from zinc leach residue are refined. Meeting future In demand, on the other hand, will require greater efforts in increasing end-of-life recycling. Process efficiencies for Ga (46%), Ge (56%), and In (78%) demonstrate further potential. We quantify the flows into use by distinguishing among dissipative and nondissipative end uses, as well as the recyclable fraction for each metal for 2011

Global substance flow analysis of gallium, germanium, and indium: Quantification of extraction, uses, and dissipative losses within their anthropogenic cycles

With the recent development of less costly uncooled detector technology, expensive optics are among the remaining significant cost drivers. As a potential solution to this problem, the fabrication of IR lenses using chalcogenide glass has been studied in recent years. We report on the fabrication of a molded chalcogenide-glass lens for car night vision and on the evaluation of the lens. The moldability of chalcogenide glass was characterized through transcription properties of the mold's surface. In addition, both IR transmittance and x-ray diffraction patterns of the molded chalcogenide-glass lens were evaluated to verify the compositional and structural stability of the glass material under the given molding conditions.

Fabrication of molded chalcogenide-glass lens for thermal imaging applications.

Ga–Sb–S Chalcogenide Glasses for Mid‐Infrared Applications

Optical technologies in the midwave and long wave infrared spectrum (MWIR, LWIR) are important systems for high resolution thermal imaging in near, or complete darkness. While IR thermal imaging ha...

100th Anniversary of Macromolecular Science Viewpoint: High Refractive Index Polymers from Elemental Sulfur for Infrared Thermal Imaging and Optics

The composition dependence of density ( d ), refractive index ( n ) and optical bandgap ( E g ) of Ge-As-S chalcogenide glasses is investigated. It is shown that d correlates linearly with sulfur content but relatively poorly with the mean coordination number (MCN). It is also shown that n does not correlate directly with d , and instead a semi-empirical relation based on the molar refractivity ( R ) of Ge, As and S is derived, permitting to predict n from d with E g of Ge-As-S glasses with good accuracy. It is shown that the value of E g is dominated by the S content. These findings make it convenient to tailor the physical and optical properties of glasses in Ge-As-S system.

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Composition dependence of physical and optical properties in Ge-As-S chalcogenide glasses

We examine the effect of temperature on the molding of chalcogenide glass for infrared (IR) lens fabrication and evaluate a molded chalcogenide glass lens. Both the adhesion of the chalcogenide glass to the mold's surface and lens breakage depended on the initial heating temperature and on the molding temperatures in the glass molding process. In addition, the molded chalcogenide glass lens was evaluated based on transcription characteristics of the mold's surface, IR transmittance, and x-ray diffraction patterns. From the analysis results, we verified that the chalcogenide glass lens for IR imaging application could be fabricated by well-controlled temperature conditions.

Du Hwan Cha

Papers

Fabrication of molded chalcogenide-glass lens for thermal imaging applications.

Effect of temperature on the molding of chalcogenide glass lenses for infrared imaging applications.

Optical Design and Analysis for Automotive Thermal Cameras Using the Chalcogenide-glass Lens