Kroll Process f5r6c

Kroll Process The Kroll process is a pyrometallurgical industrial process used to produce metallic titanium. It was invented in 1940 by William J. Kroll in Luxembourg. After moving to the United States, Kroll further developed the method for the production of zirconium. The Kroll process replaced the Hunter process for almost all commercial production. Refined rutile (or ilmenite) from the ore is reduced with petroleum-derived coke in a fluidized bed reactor at 1000 °C. The mixture is then treated with chlorine gas, affording titanium tetrachloride TiCl4 and other volatile chlorides, which are subsequently separated by continuous fractional distillation. In a separate reactor, the TiCl4 is reduced by liquid magnesium or sodium (15–20% excess) at 800–850 °C in a stainless steel retort to ensure complete reduction: 2Mg(l) + TiCl4(g) → 2MgCl2(l) + Ti(s) [T = 800–850 °C] Complications result from partial reduction of the titanium to its lower chlorides TiCl2 and TiCl3. The MgCl2 can be further refined back to magnesium. The resulting porous metallic titanium sponge is purified by leaching or heated vacuum distillation. The sponge is jackhammered out, crushed, and pressed before it is melted in a consumable carbon electrode vacuum arc furnace. The melted ingot is allowed to solidify under vacuum. It is often remelted to remove inclusions and ensure uniformity. These melting steps add to the cost of the product. Titanium is about six times as expensive as stainless steel. The Kroll Process is comprised of 6 steps to produce the titanium we have come to use and benefit from: Step 1: The pure titanium ore is converted into a sponge through conducting an electrical charge through the ore. This is done in a chlorinator. Chlorine gas is then ed through the charge. Step 2: The titanium tetrachloride that is the result of step 1, has the oxygen removed which results in a liquid form of titanium tetrachloride. This crude form of titanium tetrachloride is then purified through fractional distillation. Step 3: After the distilling process, magnesium or sodium is added to the pure titanium tetrachloride to create a metallic titanium sponge and either magnesium or sodium chloride. Step 4: The newly formed metallic sponge is then crushed and pressed. Step 5: The crushed titanium sponge is then melted in an electrode vacuum arc furnace at extremely high temperatures. Step 6: Because each batch, called an ingot, can weigh as much as 12000 pounds, the melted titanium is allowed to harden and solidify in the furnace rather than being poured out. Titanium was once touted as the metal of the future and it has played a big role in numerous advancements in defense, manufacturing, aerospace, medical, transportation and leisure industries. Without the discovery of titanium and the Kroll Process, we would not have some of the comforts and luxuries we often take for granted today.

Hunter Process Pure metallic titanium was first produced in either 1906 or 1910 by M.A. Hunter at Rensselaer Polytechnic Institute (Troy, New York, U.S.) in cooperation with the General Electric Company. These researchers believed titanium had a melting point of 6,000 °C (10,800 °F) and was therefore a candidate for incandescent-lamp filaments, but, when Hunter produced a metal with a melting point closer to 1,800 °C (3,300 °F), the effort was abandoned. Nevertheless, Hunter did indicate that the metal had some ductility, and his method of producing it by reacting titanium tetrachloride (TiCl4) with sodium under vacuum was later commercialized and is now known as the Hunter process. Metal of significant ductility was produced in 1925 by the Dutch scientists A.E. van Arkel and J.H. de Boer, who dissociated titanium tetraiodide on a hot filament in an evacuated glass bulb. The Hunter process was the first industrial process to produce pure ductile metallic titanium. It was invented in 1910 by Matthew A. Hunter, a chemist born in New Zealand, who worked in the US.[1] The process involves reducing titanium tetrachloride (TiCl4) with sodium (Na) in a batch reactor with an inert atmosphere at a temperature of 1,000°C. Dilute hydrochloric acid is then used to leach the salt from the product.

TiCl4 + 4 Na → 4 NaCl + Ti Ilmenite Ilmenite is the primary ore of titanium metal. Small amounts of titanium combined with certain metals will produce durable, high-strength, lightweight alloys. These alloys are used to manufacture a wide variety high-performance parts and tools. Examples include: aircraft parts, artificial ts for humans, and sporting equipment such as bicycle frames. Rutilo

Ti6Al4V General characteristics The high strength, low weight ratio and outstanding corrosion resistance inherent to titanium and its alloys has led to a wide and diversified range of successful applications which demand high levels of reliable performance in surgery and medicine as well as in aerospace, automotive, chemical plant, power generation, oil and gas extraction, sports, and other major industries. In the majority of these and other engineering applications titanium has replaced heavier, less serviceable or less costeffective materials. Deg with titanium taking all factors into has resulted in reliable, economic and more durable systems and components, which in many situations have substantially exceeded performance and service life expectations. Titanium is available in several different grades. Pure titanium is not as strong as the different titanium alloys are. Special characteristics Ti6Al4V is the most widely used titanium alloy. It features good machinability and excellent mechanical properties. The Ti6Al4V alloy offers the best all-round performance for a variety of weight reduction applications in aerospace, automotive and marine equipment. ArcamEBM system Ti6Al4V also has numerous applications in the medical industry. Biocompatibility of Ti6Al4V is excellent, especially when direct with tissue or bone is required. Applications Ti6Al4V is typically used for: – Direct Manufacturing of parts and prototypes for racing and aerospace industry – Biomechanical applications, such as implants and prosthesis – Marine applications – Chemical industry – Gas turbines Powder specification The Arcam Titanium Ti6Al4V (Grade 5) powder has a particle size between 45 and 100 microns. This limit on the minimum particle size ensures safe handling of the powder. Please refer to the Arcam MSDS (Material Safety Data Sheet) for more information about the handling and safety of the Arcam Ti6Al4V alloy.

http://www.arcam.com/wp-content/s/Arcam-Ti6Al4V-Titanium-Alloy.pdf https://geology.com/minerals/ilmenite.shtml https://www.britannica.com/technology/titanium-processing#ref623435 https://titaniumprocessingcenter.com/what-is-the-kroll-process/

Las principales motivaciones para el uso del titanio en aplicaciones aeronáuticas y aeroespaciales son: · Reducción de peso · Resistencia a la corrosión · Estabilidad térmica y química · Conservación de propiedades mecánicas a altas temperaturas Las aleaciones de titanio están presentes tanto en el fuselaje como en el motor de aeronaves. La reducción de peso es en ocasiones la razón principal para elegir las aleaciones de titanio para las aplicaciones del fuselaje, aunque también influye su alta resistencia específica. Frecuentemente resulta rentable que sustituya a los aceros de alta resistencia aunque ésta sea mayor que la del titanio, pues las aleaciones de titanio poseen una densidad mucho menor. Al mismo tiempo merece la pena que sustituya a las aleaciones de aluminio porque aunque su densidad sea inferior a la del titanio, éste se caracteriza por una resistencia específica superior. Las principales aplicaciones del titanio en el fuselaje de las aeronaves son para detener el crecimiento de posibles grietas debidas a la fatiga. Esto se consigue gracias a unos anillos delgados que se colocan a modo de cinturón alrededor del fuselaje de aluminio [1]. El uso del titanio no se limita al fuselaje; también se usa en los conductos hidráulicos del avión alcanzando hasta un 40% de reducción de peso [1]. Además, se utiliza en el sistema de tuberías para el equipamiento de deshielo. Esto responde a requerimientos de temperatura, resistencia a la corrosión y estabilidad térmica. El tren de aterrizaje es otra parte de las aeronaves susceptible de ser fabricada con aleaciones de titanio (Fig. 1.7). Mientras que un tren de aterrizaje de acero necesita ser sustituido a lo largo de la vida útil de la aeronave al menos una vez, si se fabrica de titanio no existe tal necesidad pues su resistencia a la fatiga es mayor. Además, se pueden llegar a ahorrar hasta 270 kilogramos por cada tren de aterrizaje de titanio con respecto a los de acero