Microwave Sorption Column for Precious Metal Recovery
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Solution Overview
Problem
Current methods for recovering precious metals like Pt, Pd, Rh, and Au from highly diluted aqueous solutions are inefficient, energy-intensive, and costly, with significant losses and environmental concerns due to toxic reagents and complex multi-stage processes.
Innovation Solution
A continuous method using a sorption column filled with activated carbon inside a microwave reactor, where the solution is heated by microwave radiation to 200-240°C, maintaining pressure and monitoring metal content, allowing for high-efficiency recovery of precious metals until the carbon is saturated, with activated carbon being an inexpensive and non-toxic adsorbent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional adsorption methods using activated carbon are used at ambient temperature, then the process is simple and low-cost, but the recovery efficiency is insufficient for highly diluted solutions
Solution Approach 1:
The patent applies parameter changes by heating the aqueous solution to elevated temperatures (50-250°C) using a microwave reactor during the adsorption process. This temperature parameter change significantly enhances the recovery efficiency of precious metals from highly diluted solutions while maintaining the simplicity of using activated carbon as the adsorbent, thus resolving the contradiction between process simplicity and recovery efficiency.
Solution Approach 2:
The patent replaces conventional thermal heating systems with a microwave reactor that uses electromagnetic radiation for heating. This substitution enables more efficient and uniform heating of the solution, improving the adsorption kinetics and recovery efficiency without adding mechanical complexity to the system.
2Productivity
If multi-stage separation processes are used to achieve high purity recovery, then the recovery efficiency improves, but the process complexity and cost increase significantly
Solution Approach 1:
The patent applies universality by using activated carbon as a multi-functional material that simultaneously adsorbs multiple precious metal ions (Pt, Pd, Rh, Au) from highly diluted solutions in a single stage. The microwave heating enhances this universal adsorption capability, allowing high recovery efficiency for all four metals without requiring separate processing stages, thus eliminating the contradiction between recovery efficiency and process complexity.
3Device complexity
If conventional heating methods are used, then the equipment is simple, but the energy consumption is high and heating uniformity is poor
Solution Approach 1:
The patent replaces conventional mechanical heating systems with a microwave reactor that uses electromagnetic radiation (2.45 GHz) for direct volumetric heating of the solution. This substitution dramatically improves energy efficiency and heating uniformity while keeping the equipment relatively simple, as the microwave reactor directly couples energy to the water molecules in the solution without requiring complex heat transfer mechanisms.
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
Achieves recovery efficiencies above 99.9% with low material costs and environmental benefits, enabling continuous operation without interruptions, and utilizing recycled organic materials for activated carbon production.
Implementation Method 1
introducing said aqueous solution to be treated into a bed of activated carbon placed in a sorption column
Implementation Method 2
the solution is heated by microwave radiation to 200-240°C
Data Source
Figure 1~2
Figure 3~4
AI summary
The method of recovering Pt, Pd, Rh, Au from a highly diluted waste aqueous solution containing up to 100 mg/dm3 of the precious metals Pt, Pd, Rh, Au is that the waste aqueous solution at a temperature of 19-40°C, after establishing its pH>1, is introduced continuously at a rate of 0.5 - 50000 ml/min into an activated carbon bed placed in a sorption column, located inside a microwave reactor, and heated by microwave radiation until the solution temperature reaches 200-240°C. The frequency of microwave radiation is 1-3000 GHz, while the power of the microwave reactor is 200-100000 W. At the same time, the pressure inside the column is continuously measured and maintained in the range of 4-50 bar, and the content of precious metals in the output solution remaining after the process is monitored. Advantageously, the process is carried out until the carbon is completely saturated with precious metals. The invention also relates to a system for recovering Pt, Pd, Rh, Au from a highly diluted waste aqueous solution, in which an input tank (1) is connected to a high-pressure pump (2), behind which a heat exchanger (3) is located, which is connected on one side to a sorption column (4), in the form of a tube filled with a solid bed of activated carbon, located inside a microwave reactor (5), and on the other side to a backpressure regulator (6), behind which is located an output tank (7). All components of the system are connected to a central unit (8), in which process parameters are controlled.