Description of Platinum-Palladium-Rhodium Recycling and Refining Production Line
Due to the scarcity of platinum group metal (PGM) resources and the imbalance between supply and demand in China, to meet domestic demand, most of my country’s PGM resources, besides imports, are derived from the recycling of PGM-containing waste materials, such as platinum-palladium catalysts in the petrochemical industry and automotive exhaust catalysts. Different raw materials require different processing technologies. Our company designs targeted processes and equipment based on different raw materials to meet production needs. In September 2021, the project “Short-Process Platinum-Palladium-Rhodium Clean Separation and Refining Technology and Equipment,” jointly developed by our company and Northeastern University, was recognized by Academicians He Jilin and Huang Xiaowei and rated as internationally advanced by the China Nonferrous Metals Industry Association.
Features of our Platinum-Palladium-Rhodium Recycling and Refining Production Line: Our platinum-palladium-rhodium recycling and refining production line can be designed according to the owner’s raw materials and operating habits. It can refine and separate materials with a platinum, palladium, and rhodium content of over 5%, achieving a purity of over 99.95% in each finished product.
1. High Recovery Rate of Platinum, Palladium, and Rhodium: During the recovery process of platinum, palladium, and rhodium waste catalysts, some processes oxidize a small amount of palladium, forming palladium oxide, which is poorly soluble in acids and alkalis. Direct dissolution with aqua regia or chlorination results in very low dissolution rates. Furthermore, the stability of rhodium, iridium, and ruthenium, and their extremely poor solubility in aqua regia, also contribute to low recovery rates. We have designed a pretreatment process specifically for this material, which can effectively improve its dissolution rate and thus increase the recovery rate of precious metals.
2. Continuous Production Line Operation: Our platinum, palladium, and rhodium recovery production line has the following advantages:
- Designed glass high-level tanks reduce manual handling and increase production capacity. Traditional PP high-level tanks are difficult to clean, easily become dirty, and have inconvenient liquid level observation, leading to substandard product quality and high production pressure. The designed glass high-level tanks perfectly meet production requirements; the transparent glass material is easy to clean.
- To facilitate the operation of the glass high-level tanks, the traditional suction filtration bottle has been redesigned as a horizontal filter. After filtration by the horizontal filter, a guide pipe is connected to the bottom, directly feeding the liquid into the glass high-level tank. The horizontal filter has a slight 3° tilt angle, facilitating vacuum extraction of small amounts of solution. This makes the production process more continuous and smooth, doubling capacity.
3. Reasonable Exhaust Design: Traditional platinum-palladium-rhodium refining is carried out in a fume hood, with the exhaust ducts always open. This requires a large overall airflow, and excessive air pressure causes precious metals to evaporate with the steam, resulting in a high precious metal loss rate. The complete platinum-palladium-rhodium refining fume hood provides a sealed environment at the reaction vessel opening, and adds a gas-liquid separation and condensation device to the extreme temperature reaction vessel to condense water vapor, allowing the waste gas to directly enter the corresponding treatment pipelines. For example, in the aqua regia dissolution process, the fume hood seals the reaction vessel. After gas-liquid separation, the condensate containing precious metals returns to the reaction vessel, while nitrogen oxide waste gas directly enters the jet tower for treatment, reducing waste gas diffusion and maintaining a good workshop environment. Throughout the refining process, from aqua regia preparation to finished product output, all precious metal filters and storage tanks are made of glass, ensuring transparency and visibility. It is equipped with a spray scrubbing system to reduce the pressure of precious metals in the equipment.
IV. Mature Waste Gas Treatment Technology: Our company has a mature waste gas treatment technology for precious metal refining, equipped with a multi-stage jet-type high-concentration nitrogen oxide waste gas treatment device, including a gas-liquid separator, NO oxidation tank, jet tower, etc. After treatment, the emission concentration of high-concentration nitrogen oxide flue gas (~30000 mg/m3) generated by platinum, palladium and rhodium dissolution is reduced to <100 mg/m3, as low as <20 mg/m3.
