The chemical processing industry (CPI) forms an enormous share of the global economy. Manufacturing a wide variety of commodity, intermediate, fine, and specialty chemicals the approximately USD $4 trillion segment (based on pre-pandemic estimates), also produces many chemical building blocks essential to numerous other industrial areas.
Corrosion-resistant refractory metals like tantalum (Ta) are essential to operations in various chemical processing facilities. We will explore what tantalum is used for in CPIs shortly, but first it is worth looking at some typical processing conditions in CPI.
Corrosion in CPI —An Overview
Active pharmaceutical ingredients (APIs), agrochemicals, detergents, pigments, petrochemicals, and myriad other consumer and industrial base chemicals are produced world-wide in gigantic quantities every single year. The intense economic requirements characteristic to the CPI are compounded by inherent processing difficulties.
Most of the CPI utilizes reagents such as hydrochloric, hydrofluoric, nitric, phosphoric, and sulfuric acids. The corrosivity of each increases with concentration, but additional factors such as temperature, vapour phases and pressure can accelerate the chemical attack of container linings and mixing components. In mixing applications, the velocity of impellers also plays a part. Careful materials selection for chemical processing equipment and vessels is vital for ensuring the long-term safety and economic viability of your workflow.
Often, metals that are susceptible to corrosion in the long-term will be chosen for a given service time with maintenance/replacement scheduled well in advance of failure. This is not a sure-fire solution, however.
Tantalum in Chemical Processing
Tantalum sets the benchmark for long-term performance in corrosive environments. It is inert in the presence of most acids (except for hydrofluoric) and its corrosion-resistance is comparable to glass in chemical reaction vessels and pipework. Tantalum is not suitable for use in caustic environments where sodium or potassium hydroxide, for example, are present.
Although tantalum may seem like an expensive choice when compared with maintenance intensive alternatives like graphite, or silicon carbide (SiC), the total cost of ownership over the many years of virtually maintenance-free operation render tantalum the solution of choice for a broad spectrum of CPI applications. Since tantalum CPI equipment can last multiple decades, the initial investment is easily offset by decreased downtime and higher production rates. In addition, using tantalum eliminates particle generation in systems where purity is essential (i.e. pharmaceuticals). In the end, the go to solution for high purity, high performance and reliable operation is either pure tantalum of the tried-and-trusted Ta2.5W alloy.
Tantalum is an excellent candidate for additive manufacturing (AM) using either powder (for complex shapes with thin walls) or wire-based processes (for rapid manufacturing rates). Depending on the complexity of the equipment being printed, various AM processes have demonstrated the cost-effective creation of tantalum parts and components that would otherwise be physically impossible or prohibitively expensive to manufacture using traditional subtractive techniques (e.g., machining, drilling, etc.). Components such as small high efficiency heat exchangers, micro-reactors, pump impellers, acid mixers, and many others can be manufactured using AM techniques in tantalum and tantalum alloys to suit complex applications in various CPI sub-segments.
Tantalum Alloys from H.C. Starck Solutions
At H.C. Starck Solutions, in addition to the standard Ta2.5W alloy, we offer a modified Ta2.5W that was engineered for enhanced corrosion and hydrogen embrittlement resistance. Our Ultra 76+ products are available in a wide range of formats, including unfinished bars and billets, semi-finished coils, rods, and wires, and tubing. This novel tantalum alloy offers the potential for increased productivity due to its superior corrosion and hydrogen embrittlement resistance at higher operating temperatures and acid concentrations.
Contact a member of the team today if you would like to learn more about our range of tantalum products.