Presentation on theme: "Tungsten reserves are found in China, Canada and Russia. Since tungsten has high melting point it cannot be refined from smelting. So once the ore of."— Presentation transcript:
Tungsten reserves are found in China, Canada and Russia. Since tungsten has high melting point it cannot be refined from smelting. So once the ore of the minerals are crushed they are sent through a series of chemical reactions, precipitations, and washings to obtain ammonium paratungstate (APT). Then it is sold or to be further processed to obtain tungsten oxide. The tungsten oxide can then be roasted in a hydrogen atmosphere to create pure tungsten powder to be the starting point for mill products, tools, wire and other various products.
The filament in light bulbs are made from tightly coiled lengths of tungsten wire. Electricity is ran through the coiled tungsten vibrating the electrons which forms light. Tungsten is used because of its high melting temperature. The tungsten filaments are heated to around 2200°C. So to keep it from combusting the sealed bulb is usually filled with argon Argon is used because combustion requires a heated material and oxygen. Argon will not react because it is an inert gas.
corrosion. Tungsten is a good conductor of heat, this property is what allows the tungsten electrode to withstand the arc temperature well above its melting point. But because of the intense heat some erosion of the electrode will occur, transferring tungsten across the arc to the work. Gas Tungsten Arc Welding or TIG (tungsten inert gas welding) process was invented in the late 1930’s early 1940’s. A process that welds exotic metals uses electricity to produce heat. To use this process, an arc of 6000°C is established and carried by a tungsten electrode to the work and is shielded by mixtures of inert gasses to protect from Tungsten electrode
W(s) +C(graphite)=WC(s) ∆H=-40.5KJ Tungsten carbide (WC, W2C) is one of the most known chemical compounds containing tungsten. The solid is a class of inorganic compounds of carbon, used alone or with 6 to 20 percent of other metals to increase hardness of cast iron, useful in the manufacturing of cutting tools such as edges of saws and drills also as penetrating cores of armour-piercing projectiles. A dense metal that doesn’t melt but decomposes with a high melting point of around 2,600°C. because it is made of both Tungsten and carbon, the empathy for the reaction occurs at 1,400°C. So the combustion of the elements are measured by using Hess’s Law 2W(s)+3O(g)=2WO 3 (s); ∆H=-1685.8KJ C(graphite)+O 2 (g)=CO 2 (G); ∆H=-393.5KJ 2WC(s)+5O 2 (g)=2WO 3 (s)+2CO 2 (G); ∆H=-2391.8KJ W(s)+3/2O(g)=WO3(s); ∆H=-842.9KJ C(graphite)+O2(g)=CO2(G); ∆H=-393.5KJ WO3(s)+CO2(G)=WC(s)+5/2O2(g); ∆H=1195.9KJ