Spent Catalyst Fluid Precious Metal Recovery
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Solution Overview
Problem
In hydroformylation processes, the recovery of precious metals from spent catalyst fluids is hindered by the precipitation of rhodium species during storage and shipment, making it difficult to determine the initial metal content and ensuring all material is removed, which is critical for efficient precious metal recovery.
Innovation Solution
Adding a non-hydrolyzable triorganophosphorous compound, such as triphenylphosphine, to the spent catalyst fluid before storage or shipment to prevent the formation of precious metal precipitates, ensuring the metals remain in solution during storage and shipment to a precious metal recovery facility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spent catalyst fluid is discharged to storage or shipping container for precious metal recovery, then the catalyst can be recovered and reused, but rhodium species precipitate from solution making recovery difficult and unreliable
Solution Approach 1:
A soluble Group 8 metal carbonyl compound is introduced as an intermediary substance to react with precipitated rhodium species and form soluble complexes. This intermediary compound acts as a mediator that converts insoluble rhodium precipitates back into soluble form, ensuring complete and reliable precious metal recovery during storage and shipment.
Solution Approach 2:
The chemical state of rhodium species is changed by adding soluble Group 8 metal carbonyl compounds that alter the solubility parameters. The addition changes the chemical composition and coordination environment of rhodium, transforming it from an insoluble precipitated state to a soluble complexed state, thereby maintaining homogeneity throughout storage and shipment.
2Duration of action of moving object
If spent catalyst fluid is stored long term before recovery, then logistics and processing flexibility is improved, but precipitation of precious metals occurs complicating recovery
Solution Approach 1:
The soluble Group 8 metal carbonyl compound is added to the spent catalyst fluid before storage, performing a preliminary protective action. This pre-treatment prevents precipitation from occurring during the storage period, ensuring that when the fluid is eventually processed for recovery, the precious metals remain in soluble form and can be easily recovered without complications.
3Productivity
If spent catalyst fluid is concentrated to recover product aldehyde, then productivity is improved, but precious metal precipitates form during concentration
Solution Approach 1:
The soluble Group 8 metal carbonyl compound serves as a protective intermediary during the concentration process. As the spent catalyst fluid is concentrated to recover aldehyde, this intermediary compound ensures that precious metal species remain in soluble form even at higher concentrations, preventing precipitation and allowing continuous, high-productivity operation without loss of catalyst material.
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
This approach effectively minimizes or eliminates the formation of precipitates, facilitating long-term storage and shipment of spent catalyst fluids and enhancing the precious metal recovery process by maintaining the precious metals in solution, thereby improving the efficiency and reliability of metal recovery.
Implementation Method 1
Adding a non-hydrolyzable triorganophosphorous compound, such as triphenylphosphine, to the spent catalyst fluid before storage or shipment to prevent the formation of precious metal precipitates
Data Source
AI summary
Embodiments of the present invention relate to processes to prepare a spent catalyst fluid from a hydroformylation process for precious metal recovery. In one embodiment, a process comprises (a) removing a spent catalyst fluid from an active hydroformylation reaction system, wherein the spent catalyst fluid comprises the hydroformylation reaction catalyst and is substantially free of non-hydrolyzable triorganophosphorous compounds; and (b) adding a non-hydrolyzable triorganophosphorous compound to the spent catalyst fluid from step (a) prior to storing the fluid or prior to shipping for precious metal recovery.