Ag Slime Palladium Production with Selective HCl Leaching
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Solution Overview
Problem
Existing methods for producing high-purity palladium from silver slime result in high loss of palladium due to excessive purification processes, leading to reduced recovery rates and increased use of subsidiary materials.
Innovation Solution
A method involving a gold separation, neutralization, hydrochloric acid leaching, chloride precipitation, and purification process is employed, with controlled hydrochloric acid dosage and reaction temperature to maintain high palladium leaching rates while minimizing platinum leaching, thereby reducing the number of purification steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple purification processes are performed to achieve high-grade palladium (99.9% purity or more), then the purity of palladium is improved, but the loss of palladium increases and the recovery rate decreases
Solution Approach 1:
The patent changes the chemical parameters of the leaching process by controlling the hydrochloric acid concentration (30-40%) and temperature (50-70°C) to achieve selective leaching. This allows palladium to be leached efficiently while minimizing platinum dissolution, reducing the need for multiple purification steps and thereby decreasing palladium loss
Solution Approach 2:
The patent applies selective leaching where different regions of the slime material undergo different chemical reactions. By controlling the leaching conditions, palladium is preferentially extracted while leaving platinum and other impurities behind, achieving high purity in a single or few steps without significant palladium loss
2Manufacturing precision
If multiple purification processes are performed to achieve high-grade palladium, then the purity of palladium is improved, but the amount of subsidiary materials needed increases
Solution Approach 1:
By optimizing the hydrochloric acid concentration and temperature parameters, the patent achieves selective leaching that produces high-purity palladium with minimal impurities. This reduces the need for additional purification materials and chemicals, decreasing subsidiary materials consumption while maintaining high purity
3Productivity
If hydrochloric acid leaching is performed without controlled dosage, then the leaching rate of palladium is high, but the leaching rate of platinum increases
Solution Approach 1:
The patent precisely controls the hydrochloric acid dosage at 9-11 equivalents relative to palladium content, along with maintaining temperature at 50-70°C. This parameter optimization enables selective leaching where palladium is efficiently extracted while platinum leaching is suppressed, achieving high productivity without significant platinum loss
Solution Approach 2:
The controlled leaching conditions create selective chemical environments that favor palladium dissolution while protecting platinum. By adjusting the acid dosage and temperature, the process achieves differential extraction rates, maintaining high palladium leaching while minimizing platinum loss
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 effectively maintains high palladium leaching rates while reducing platinum leaching, minimizing palladium loss and subsidiary material use, achieving high-purity palladium production with fewer purification iterations.
Implementation Method 1
a hydrochloric acid leaching process of adding hydrochloric acid to the effluent containing the neutralized precipitate to produce a hydrochloric acid leachate containing leached palladium
Implementation Method 2
a neutralization process of adding a neutralizing agent to the separated effluent to produce a neutralized precipitate containing oxidized palladium
Implementation Method 3
a chloride precipitation process of adding a precipitant to the hydrochloric acid leachate to produce a chloride precipitate containing palladium
Data Source
Figure 1
AI summary
One embodiment of the present disclosure disclosed a method for producing palladium from silver slime, comprising a gold separation process of introducing silver slime into an acid solution to produce a separated effluent containing leached palladium; a neutralization process of adding a neutralizing agent to the separated effluent to produce a neutralized precipitate containing oxidized palladium; a hydrochloric acid leaching process of adding hydrochloric acid to the effluent containing the neutralized precipitate to produce a hydrochloric acid leachate containing leached palladium and platinum; a chloride precipitation process of adding a precipitant to the hydrochloric acid leachate to produce a chloride precipitate containing palladium; and a purification process for recovering the palladium from the chloride precipitate.