High-Purity Platinum Powder Production via Acidic Reduction
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Solution Overview
Problem
Existing methods for producing high-purity platinum are inefficient in reducing alkali metal, precious metal, and iron impurities, requiring multiple washing cycles and high water consumption, which deteriorates the quality of the platinum sponge and is not suitable for high-purity applications such as microelectronics and thermocouples.
Innovation Solution
A process involving the reduction of ammonium hexahalogenoplatinate in acidic conditions, using hydrazine as a reducing agent, which separates iron and non-ferrous metals from the platinum sponge, allowing for the production of platinum with a purity of 99.999% and minimal contamination by alkali metals and other impurities without the need for extensive washing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional reduction methods using potassium hexachloroplatinate are used, then platinum can be produced, but the platinum sponge contains excessive potassium content requiring multiple washing stages
Solution Approach 1:
The patent changes the chemical parameters by using ammonium hexachloroplatinate instead of potassium hexachloroplatinate as the starting material, and conducting reduction in acidic conditions (pH 0-4) rather than neutral or basic conditions. This parameter change fundamentally alters the impurity profile, replacing potassium contamination with ammonium that can be easily removed, and prevents iron precipitation, thereby achieving high purity platinum without extensive washing
Solution Approach 2:
The patent introduces ammonium hexachloroplatinate as an intermediary compound that serves as a superior starting material. The ammonium cation acts as a beneficial intermediary because it is more easily removed than potassium, and its use in acidic reduction conditions prevents iron impurity incorporation, thus mediating between the starting material and final high-purity platinum product
2Manufacturing precision
If conventional reduction methods are used, then platinum sponge is produced, but iron content cannot be reduced and iron hydroxide contaminates the sponge
Solution Approach 1:
The patent changes the pH parameter to acidic conditions (pH 0-4) during reduction, which fundamentally alters the behavior of iron ions. In this acidic environment, iron remains soluble as Fe2+ or Fe3+ ions rather than precipitating as iron hydroxide, preventing its incorporation into the platinum sponge structure and enabling production of platinum with iron content below detection limits
Solution Approach 2:
The patent converts the potentially harmful effect of iron presence into a benefit by utilizing the acidic reduction conditions. The acidity that might seem like an additional constraint actually benefits the process by keeping iron in solution and preventing its contamination of the platinum product, thus turning a harmful factor into a useful feature of the process
3Manufacturing precision
If multiple washing stages are used to remove potassium ions, then platinum purity improves, but water consumption increases and production time extends
Solution Approach 1:
The patent performs preliminary action by selecting ammonium hexachloroplatinate as the starting material before the reduction step. This preliminary choice ensures that the resulting platinum sponge contains ammonium instead of potassium, which requires minimal washing. The preliminary action of material selection prevents the need for extensive subsequent washing operations, thereby maintaining high purity while improving productivity
Solution Approach 2:
The patent takes out the problematic potassium ion from the process chain by replacing it with ammonium ion in the starting material. This extraction of the harmful element (potassium) from the process flow eliminates the need for multiple washing stages to remove it, thereby resolving the contradiction between achieving high purity and maintaining production efficiency
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 process achieves high-purity platinum with reduced alkali metal and iron content, minimizing water consumption and improving the quality of the platinum sponge, making it suitable for advanced applications like microelectronics and thermocouples.
Implementation Method 1
the resulting solution is reduced at a temperature T > +30°C and a pH of 0 to 4 using a reducing agent to precipitate it as a platinum sponge
Implementation Method 2
When the reduction is performed in acidic solution or suspension (pH 0-4), iron salts remain in solution or in the aqueous phase and do not contaminate the platinum sponge
Implementation Method 3
The use of nitrogen-containing, sparingly soluble hexahaloplatinate, preferably (NH4)2PtCl6, as a starting compound for the reduction has the additional advantage that the production of the nitrogen-containing hexahaloplatinate includes a further purification step by precipitation
Data Source
AI summary
The invention relates to a process for the industrial-scale production of high-purity platinum and the use of this high-purity platinum. According to the process, a hexahaloplatinate is reduced to platinum under acidic conditions.