The Kingdom Of Bahrain
produced the first ingots
in 1971 which it made
in Alba factory. Alba is one of the largest factories of the world. It imports alumina which is extracted from bauxite and shipped from Australia.
What is aluminum?
Aluminum is a an abundant metallic chemical element which is widely used throughout the world for a wide range of products.
Aluminum compounds were used before, many years ago.Ancient Egyptians and Persians made many tools and medicines from clay that contained aluminum oxide.
However, pure aluminum was not used in the past widely because it was very difficult to extract aluminum from its natural compounds and isolate it as a pure metal.
After that, two scientists came and discovered a new process called a smelting process. This electrolytic process was used to isolate the aluminum compound as a pure metal.
Metallic aluminum has many properties such as being strong,lightweight, non-magnetic and non-toxic. Also it has many applications such as it is used in mechanical parts, airplanes, cars, surgical equipment, food preservation, doors and windows.
What is aluminum?
Aluminum is a an abundant metallic chemical element which is widely used throughout the world for a wide range of products.
Aluminum compounds were used before, many years ago.Ancient Egyptians and Persians made many tools and medicines from clay that contained aluminum oxide.
However, pure aluminum was not used in the past widely because it was very difficult to extract aluminum from its natural compounds and isolate it as a pure metal.
After that, two scientists came and discovered a new process called a smelting process. This electrolytic process was used to isolate the aluminum compound as a pure metal.
Metallic aluminum has many properties such as being strong,lightweight, non-magnetic and non-toxic. Also it has many applications such as it is used in mechanical parts, airplanes, cars, surgical equipment, food preservation, doors and windows.
The Stages of the Bayer Process
Description of the Bayer Process for refining Bauxite:
Bauxite is the source of all things made of aluminum, and it is found in alot of areas of the world.
In the first stage of the Bayer Process, the Bauxite ore is crushed mechanically after digging it from a mine. In the second stage, the crushed ore is mixed with caustic soda (sodium hydroxide) . Also the crushed ore is processed in a grinding mill to produce a slurry (a watery suspension). Following that , the slurry is pumped into a digester (a tank that works like a pressure cooker). Then the slurry is heated to 110 -270 degrees under pressure and this is maintained half an hour to several hours. Also caustic soda may be added to make sure all aluminium compounds are dissolved. After that the hot slurry is passed through a flash tank and is pumped into a clarification tank where impurities settle to the bottom called red mud (residue).Then filters trap any impurities that remain in the solution.Then the filter material is washed to recover alumina and caustic soda. Next, the filter laquid is pumped through a series of many tanks called precipitation tanks. After that, seed crystals of alumina hydrate are added to the precipitation tanks on top where they attach to dissolved alumina in the soluion and precipitate to the bottom of the tank. Then the crystals are transfered to a kiln(calcination). Finally, the crystals are heated to remove water and white alumina crystals remain. Which Alba import this alumina.
The Aluminium Smelting Process
The process consist of
1. Alumina (Aluminium oxide is the family of
inorganic.
compounds with the chemical formula Al2O).
2. Reduction pot ( container / steel vat )
(cathode).
3. High level of electricity (Approximately 13 -16
kilowatt-hours).
4. Electrodes : pre-baked carbon anodes, and the
graphite lining of the pot (Anode).
5. Cryolite (Na3AlF6, sodium hexafluoroaluminate)
6. Aluminium fluoride and calcium fluoride in small
amounts.
7. Crucible (a refractory container used for metal).
The Process at Work ( This process in Alba Factory )
Firstly, the bottom of the reduction pot is lined with graphite, which acts as one electrode (cathode). Then the carbon anodes are attached to rods. Following that, the anode is lowered into the electrolyte solution (cryolite with alumina dissolved in it), which can conduct the electric current. The anode is held 3.8 cm above the surface of the molten aluminium. After that, other compounds (aluminium fluoride and calcium fluoride) are added to improve the performance of the cell. Following that, a direct current is passed through the solution. The released oxygen is attracted to the electrode (anode), and the feed aluminium atoms are attracted to the graphite (cathode), settling to the bottom of the pot. More alumina is added periodically to the cryolite to replace the decomposed compound. A constant electric current is maintained so that the contents remain in a liquid state, and the crust that forms is broken periodically to allow more alumina to be added for the process to continue. After that, the pure molten metal that accumulates at the bottom is siphoned off, this process is called metal tapping. In the last step, the molten aluminium is collected in crucibles that move down the potline, and it is either transferred to a holding furnace or cast (poured) into molds as ingots. Finally the ingots are sent for farther processing at other plants.
