Titanium and its alloys exhibit a wide range of exceptional properties like high corrosion resistance and high strength at low density. This is why they find a lot of applications. Recycling the rare earth metals like titanium has a lot of challenges involved in the process as reported by experts from Metalliage.
Here are a few such challenges faced by the recycling industries when they recycle titanium:
Increase in the Production Costs
Due to titanium’s high affinity for gases like oxygen, nitrogen, and carbon, the metal should be melted before the recycling process is scheduled. All the processes must be carried out in the inert gas atmosphere. Re-melting allows the removal of volatile impurities from the titanium alloy for better usage. In order to guarantee a homogeneous ingot, re-melting has to been done in multiple steps, which in turn increases the production cost of titanium recycling.
High Extent of Machining
Titanium ingots are processed to final components in the final step only. Due to its poor formability, the processing is quite complicated and it happens via forging or rolling. Due to this, the geometrical complexity of final titanium components requires a high extent of machining (especially in aerospace applications).
Extensive Refining Process
High levels of contaminants can be found in the scrap metal, which has been identified for further refining. While refining titanium additional refining efforts are required to remove the additional carbon contamination. This can only be accomplished by applying a higher vapour pressure. Conventional recycling process has a limited refining potential regards to cleaning the metal from impurities.
Only a Small Volume of Titanium Can Be Melted at a Time
To achieve a homogenous metal, a small volume of titanium is molten at a time during the re-melting process. This is a very tedious task
High Affinity to Oxygen
As mentioned earlier, titanium has high affinity for oxygen. Hence, definite measures must be taken to prevent the metal from getting inhibited to oxygen during the re-melting process. Further, additional calcium must be batched with it to thermochemically stabilize titanium. To avoid mass loss, CaAl2 is used instead of Calcium under high atmospheric pressure.
Special Care for Cleaning
To stabilize the molten titanium, calcium is used along with it. But, since calcium is highly reactive, special care needs to be taken while cleaning the furnace. Further, during machining, titanium exhibits a comparatively thick oxide layer, which leads to considerable contamination. So, CaAl2 must be added to deoxidize titanium alloy. Hence, you need to be extra cautious while cleaning.
These are some of the challenges faced while recycling titanium. So, you need to be in a position to afford the costs that are associated with recycling and make a profit out of it until its requirement is prevalent in the society.