The aluminium smelters consume approximately 3.5 percent of the global power. The aluminium industry usually emits around 45O MT of the carbon dioxide, which is equal to 1% of the total emissions, experienced in the world. The numbers are increasing due rise in the rate of sharing production of aluminium, from electricity derived from fossil fuels. With the increased demand for energy is the world continuously, the increasing cost of power and the greenhouse effect, energy saving is a very critical thing that society needs to focus on and to help on the continued production of aluminium in the coming years. Power is the primary factor that defines the cost of each position because of the volatile LME prices of aluminium. Cost reduction in the smelting of aluminium is the primary field of research currently.
There are several know reasons as to what aluminium smelting into an effective energy process. The high cell resistance experienced because of ohmic electrolyte and the resistance from the gas bubble is among them. Ohmic resistance present in cathodes and the anodes are also present. The distance between anode and cathode (Anode- Cathode Distance, ACD) must be within a given minimum distance to stop the back reaction between aluminium and carbon dioxide. Heal losses is needed to have a frozen side ledge to protect sidewalls and thus the extra heat must be wasted.
Even with the presence of technical challenges, aluminium smelting may be changed to optimum levels through the reduction of specific cells reaction for energy consumption. Heat losses need to be lowered significantly. The cell voltage can be reduced through design changes through several methods:
- The more massive and modified anode stubs and the yoke, larger anodes
- Slotted anodes are needed to improve gas bubble drainage and thus reduce the anode effect
- Proper procedures of anode ridding should be done to minimize the drops of an external voltage
- Casting instead of ramming cathode bus bars to have active contact resistance
- Modifying the sides using SiC and not Carbon
- Good sidelining and ventilation using a steel shell
- Proper compensation of the magnetic field
- Redesigning the conductor and inserting the trade-off between the heat decrease dissipation and the voltage reduction
The leading smelters in the world have anticipated the changes and have signed up to be involved. China as the topmost producer of the Aluminium plays a vital role in the area of Energy Reduction Technologies. The famous China Aluminium International Engineering Corporation Limited (CHALIECO) is making significant contributions to energy reductions.
Energy reduction as a subject itself encompasses several entities. Every entity will have to be costumed accordingly. The work being done is the simulation of pot operations so that there is a beautiful tune to attain the optimum levels. The normal temperature distribution in the cell helps in designing the sides and the bottom of the cell to have an ideal techno-economic index. Horizontal current lowering is being accounted for by redesigning of collector bars and the cathode assembly improving the stability of the pot.
According to the technology, the Aluminum Smelting production process that we are using now has reduced greenhouse gas production. As discussed above the current focus is to reduce the consumption of the specific energy and to remove the anode effects. Furthermore, there is also a high possibility of reducing the production of carbon dioxide through the reduction of net consumption in the carbon anode even if the reduction possibility is around 10%. From here, inert anodes can be developed so that the aluminum industries can use them and this will be a remarkable breakthrough of the technology because the oxygen will be released from the anodes and not the carbon dioxide. Carbothermic production as an alternative in the manufacturing of aluminium will increase the emissions of carbon dioxide if it is not trapped and the stored.