Mr. Beliakou

Tantalum (Ta) metal scrap represents a valuable and sustainable raw material in the scrap metal processing industry, particularly for the production of high-purity tantalum oxide (Ta₂O₅) powder. This powder is a premium product commanding high market prices due to its critical applications, such as the manufacture of lithium tantalate (LiTaO₃) single crystals used in piezoelectric devices, optical modulators, and surface acoustic wave filters in electronics and telecommunications.The primary sources of tantalum scrap are spent tantalum anodes from electrolytic capacitors and manufacturing scraps from capacitor production. These forms of scrap are rich in tantalum, a refractory metal known for its corrosion resistance and high melting point, making it ideal for such components but challenging to recycle.The overall process for converting this scrap into high-purity Ta₂O₅ involves several key steps: (1) dissolution of the tantalum scrap in hydrofluoric (HF) acid to form soluble tantalum fluoride complexes; (2) purification via liquid-liquid extraction to remove impurities; (3) precipitation of tantalum hydroxide; (4) filtration and drying; and (5) calcination to yield pure Ta₂O₅ powder. This Ta₂O₅ product meets stringent purity requirements for advanced applications, enabling economic recovery from what would otherwise be waste material.However, the initial dissolution step—digestion in HF acid—poses significant engineering challenges. The reaction is highly exothermic, proceeds rapidly, and generates substantial hydrogen (H₂) gas, leading to foaming and potential overflow from the reactor vessel. These factors make the process dangerous, uncontrollable, and inefficient, with risks of equipment damage, safety hazards from HF exposure and H₂ flammability, and inconsistent product quality. The primary goal of this engineering project is to develop a controlled and effective digestion method for the initial step, optimizing reaction conditions (e.g., temperature, acid concentration, agitation) to ensure safe, scalable, and reproducible processing of tantalum scrap into high-value Ta₂O₅.

Segmentation, separation - to separate Ta-anodes and HF solution, but to make them interact. So, ensure the wetting of Ta-anodes with a small amount of HF solution and replace the solution

The project addresses instability in the dissolution of tantalum (Ta) anodes in hydrofluoric acid (HF), where hydrogen gas generated during the reaction becomes trapped in the solution, forming foam that disrupts the process and creates safety risks.

Using the PRIZ Platform, a Functional Model of the system was developed. The model revealed that the HF solution is both the most functional and the most problematic component, leading to a physical contradiction: HF must interact with Ta anodes to enable dissolution, but must not retain the hydrogen gas produced during the reaction.

Applying the PRIZ principle of Separation in Space, two reactor concepts were proposed: a spray interaction reactor, where HF is pumped to spray onto anodes placed above the solution, and a surface wetting reactor, where anodes are positioned at the top of the solution, allowing natural circulation and easy hydrogen release.

Both designs eliminate foam formation and provide a stable, controllable, and safer dissolution process.

Ta scrap recycling - How  to dissolve Ta-anodes in HF-solution

Solving problems and innovations in chemical processes

Ta scrap recycling

Issues related to manufacturing, fabrication, and assembly and issues associated with an object or system.  Ease of manufacture.

Ease of manufacture

HF dissolves Ta - converts solid to liquid - reduces the volume of the solid scrap and generates H2

Segmentation

Preliminary action

Mechanics substitution

Parameter changes

Component: HF solution

The number of useful (value-adding) functions or operations performed by a system per unit time.  The time per unit function or operation.  Useful output per unit of time.  Cost per unit output, or amount of useful output.  (See 'Speed' –  #14 – which is more focused on issues of dynamics rather than the output of product.)

Productivity

generate H2 gas and prevents the separation

The objective is to dissolve tantalum (Ta) scrap, primarily spent Ta anodes, in high-concentration hydrofluoric (HF) acid using basic equipment: a plastic reactor, a stirrer, and the acid solution. The Ta scrap is placed into the plastic reactor along with the high-concentration HF, initiating the dissolution reaction. This process is highly exothermic, resulting in a rapid temperature increase and the evolution of significant volumes of hydrogen (H₂) gas. Consequently, excessive foaming occurs, causing the foam and solution to overflow from the reactor. This makes the process dangerous, uncontrollable, and prone to safety hazards, including equipment damage and risks from HF exposure and H₂ flammability.Product is Dissolved Ta

Ta scrap recycling - How to dissolve Ta-anodes in HF-solution

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