A literature review of titanium metallurgical processes

The mechanical properties of bulk metallic glasses (BMGs) and their composites have been under intense investigation for many years, owing to their unique combination of high strength and elastic limit. However, because of their highly localized deformation mechanism, BMGs are typically considered to be brittle materials and are not suitable for structural applications. Recently, highly-toughened BMG composites have been created in a Zr–Ti-based system with mechanical properties comparable with high-performance crystalline alloys. In this work, we present a series of low-density, Ti-based BMG composites with combinations of high strength, tensile ductility, and excellent fracture toughness.

https://www.pnas.org/content/pnas/105/51/20136.full.pdf

Development of tough, low-density titanium-based bulk metallic glass matrix composites with tensile ductility

System for removal of targeted pollutants, such as oxides of sulfur, oxides of nitrogen, mercury compounds and ash, from combustion and other industrial process gases and processes utilizing the system. Oxides of manganese are utilized as the primary sorbent in the system for removal or capture of pollutants. The oxides of manganese are introduced from feeders into reaction zones of the system where they are contacted with a gas from which pollutants are to be removed. With respect to pollutant removal, the sorbent may interact with a pollutant as a catalyst, reactant, adsorbent or absorbent. Removal may occur in single-stage, dual-stage, or multi-stage systems with a variety of different configurations and reaction zones, e.g., bag house, cyclones, fluidized beds, and the like. Process parameters, particularly system differential pressure, are controlled by electronic controls to maintain minimal system differential pressure, and to monitor and adjust pollutant removal efficiencies. Reacted sorbent may be removed from the reaction action zones for recycling or recycled or regenerated with useful and marketable by-products being recovered during regeneration.

System and process for removal of pollutants from a gas stream

Titanium ores are very plentiful in the earth crust but the demand for titanium metal is restricted by its high cost in spite of its excellent mechanical properties, corrosion and oxidation resistance and low density. Titanium was first produced by the Hunter process but this has been superseded, except for special applications, by the Kroll process which entails carbochlorination of rutile and ilmenite to obtain titanium tetrachloride followed by metallothermic reduction with magnesium. In the past ten years, ∼20 novel processes have been investigated as possible low cost routes for titanium, based upon electrolytic processes, both anodic and cathodic, and variations of the Hunter and Kroll processes. The anodic processes use a conducting anode consisting of Ti–O–C and the titanium is essentially electrorefined, in a molten salt, from the anode. The cathodic routes rely on either the electrodeposition of calcium or the electro-deoxidation of the oxide. The variations on the Hunter and Kroll proce...

Novel methods for the production of titanium

Microstructure and mechanical behavior of a Ti–24Nb–4Zr–8Sn alloy processed by warm swaging and warm rolling

A method and an apparatus for sorting mined material, such as mined ore, are disclosed. The apparatus comprises a chamber for exposing fragments of a material to be sorted to electromagnetic radiation, with the chamber comprising an inner wall for fragments to move downwardly and outwardly over from an upper inlet of the chamber to a lower outlet of the chamber. The apparatus also comprises a detection system for assessing one or more than one characteristic of the fragments. The apparatus also comprises a sorting means for separating the fragments into multiple streams in response to the assessment of the detection system.

Sorting mined material

Light metals have great potential for application in the automotive and aerospace industries because of their excellent physical properties. The usage of aluminium, titanium and magnesium is limited by relatively high costs of production, associated energy costs and large ecological footprint. In the case of aluminium, significant improvement to the Hall–Heroult process is still achievable through advances in cell design, materials and process control. Alternative production processes, including carbothermic reduction and low temperature routes are also possible. Magnesium and titanium production are currently dominated by batch metallothermic processes and new process routes are required to develop these industries. Research at CSIRO, through the Light Metals Flagship, is currently focused on step change improvements in the production of light metals, aiming at lowering energy usage, increasing productivity and reducing the overall environmental impact. In the present paper, the overall status of...

https://researchbank.swinburne.edu.au/file/791946f5-12da-4faa-8ef3-792aff941bfc/1/PDF (Accepted manuscript).pdf

Challenges in light metals production

A dehydrided Ti powder of very high oxygen content was successfully consolidated using back pressure equal channel angular processing into a fully dense bulk ultrafine-grained Ti showing apparent compressive ductility as well as high true yield and ultimate strengths of 1350 and 1780MPa, respectively. Interstitial solid solution strengthening contributed to the majority of the increase in strength with additional contribution from ultrafine grains. Significantly, the material also exhibited much improved ductility for such a high interstitial content, thanks probably to the nonequilibrium grain boundaries and bimodal grain structure introduced during severe plastic deformation.

Ultrafine-grained titanium of high interstitial contents with a good combination of strength and ductility

A method and an apparatus for sorting mined material is based on using a range of options for sensing multiple properties of a mined material on a fragment by fragment basis and then analysing the multiple types of data and making decisions about the classification of each fragment and then sorting the fragment based on the analysis. The multiple sensing options include the response of the fragments to electromagnetic radiation. Other sensing options may include sensors that look at the response of fragments of a mined material to an acoustic wave or a magnetic field or optical sensors that evaluate texture or other surface characteristics of fragments.

Sorting mined material on the basis of two or more properties of the material

A gas scrubbing process is disclosed whereby particulate material is contacted with a high velocity exhaust gas stream to reduce the resistance to mass transfer attributable to the diffusion boundary layer and provide higher mass transfer rates. The process is particularly suited to the scrubbing of gaseous fluorides from aluminium smelter pot exhaust gas with alumina. Addi-tionally, it has been found that the fines fraction with a particle size of preferably less than 45 µm adsorbs or chemisorbs a dispro-portionate amount of contaminant trace metals from the exhaust gas stream. To avoid recycling these trace metals contained in the exhaust gas back to the smelter pot the fines fraction may be elutriated from the coarse fraction.

Grant Ashley Wellwood

Papers

Sorting mined material

Challenges in light metals production

Ultrafine-grained titanium of high interstitial contents with a good combination of strength and ductility

Sorting mined material on the basis of two or more properties of the material

Gas-solid contacting method