UV-Vis Leaching of Platinum Group Metals from Spent Catalysts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for recovering platinum group metals from spent catalysts involve the use of toxic substances, such as strong acids and volatile organic compounds, leading to environmental hazards and health risks due to the production of toxic gases.
Innovation Solution
A method utilizing a ferric oxalate complex/hydrogen peroxide-chloride salt solution under UV-vis conditions to produce reactive oxygen species, converting platinum group metals into soluble complexes for leaching, thereby avoiding the use of toxic substances and achieving high platinum leaching rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If acid leaching with aqua regia or HCl/oxidizer methods is used to recover platinum group metals, then the recovery efficiency is improved, but toxic gases such as Cl2 are produced causing environmental harm and health risks
Solution Approach 1:
The patent employs H2O2 as a strong oxidant to replace traditional oxidizers like Cl2 and NaClO3 in the leaching process. H2O2 oxidizes the platinum group metals from the spent catalyst under UV-vis irradiation, achieving high recovery efficiency while avoiding the production of toxic chlorine gases. The oxidative environment generated by H2O2 decomposition under UV light enables effective metal dissolution without harmful byproducts.
Solution Approach 2:
The patent substitutes chemical oxidation methods (which produce toxic gases) with a photochemical oxidation system. UV-vis irradiation activates H2O2 to generate hydroxyl radicals and other reactive oxygen species that oxidize the metals. This substitution of mechanical/chemical oxidation with photochemical oxidation eliminates toxic gas generation while maintaining or improving recovery efficiency.
2Productivity
If cyanide leaching is used to recover platinum group metals, then the recovery efficiency is improved, but highly toxic hydrocyanic acid is formed causing respiratory paralysis and death
Solution Approach 1:
The patent uses H2O2 as a temporary, decomposable oxidizing agent that breaks down into water and oxygen after use. This replaces persistent toxic cyanide reagents with a benign, short-lived oxidant that leaves no harmful residues. The H2O2 decomposes completely after facilitating the oxidation and dissolution of platinum group metals, eliminating long-term toxic exposure risks.
Solution Approach 2:
The patent converts the potentially harmful UV-vis radiation into a beneficial activating energy source that generates reactive oxygen species from H2O2. The UV-vis light, which could be considered harmful radiation, is instead utilized to drive the oxidation process and enhance metal dissolution efficiency without requiring toxic cyanide chemicals.
3Productivity
If volatile organic compounds are used as solvents to dissolve platinum group metals, then the dissolution rate is improved, but the toxicity of the organic compounds cannot be ignored
Solution Approach 1:
The patent changes the fundamental parameter of the solvent system from organic compounds to an aqueous-based system containing H2O2 and chloride ions. This parameter change maintains high dissolution rates through photochemical activation while eliminating the inherent toxicity associated with organic solvents. The aqueous environment with UV-activated H2O2 provides both the necessary oxidizing power and solvent properties without organic toxicity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method achieves a platinum leaching rate of over 97% with mild operating conditions, recycling iron, and reducing environmental impact, making it suitable for industrial application.
Implementation Method 1
uses the ferric oxalate complex/hydrogen peroxide-chloride salt solution as a solvent for extracting platinum group metals under the condition of UV-vis to produce reactive oxygen species (ROS)
Implementation Method 2
under the condition of UV-vis
Implementation Method 3
adding 30 wt% aqueous hydrogen peroxide solution
Implementation Method 4
converts the platinum group metals from metallic state to platinum group metal complex
Data Source
AI summary
The present invention belongs to the field of recovery of secondary resources of noble metals, and discloses a method for leaching platinum group metals from spent catalyst by UV-vis, which uses ferric oxalate complex/hydrogen peroxide-chloride salt solution as a solvent for extracting platinum group metals under the condition of UV-vis, converts the platinum group metals from metallic state to platinum group metal complex, and obtains platinum group metal lixivium to realize the leaching of the platinum group metals. The platinum leaching rate of the method of the present invention can reach more than 97%. The present invention has mild reaction conditions, realizes the green recovery of platinum group metals from spent catalyst, avoids the use of strong acids and bases and toxic substances and avoids the production of toxic gases in the leaching process, so as to reduce the environmental hazards of the spent catalyst.