Tungsten(VI) Salt Hydrate Purification for Stable Sodium Tungstate Dihydrate
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing processes for preparing tungsten salt hydrates are economically inefficient due to the need for pure acids, leading to contamination and high costs, and result in unstable hydrates that lose water molecules during processing, failing to meet Good Manufacturing Practices (GMP) standards.
Innovation Solution
A process involving solubilization in an alkaline aqueous solution, filtration at specific temperatures, precipitation of tungsten (VI) salt hydrate below 100°C, followed by washing with a water-miscible solvent, and drying under controlled conditions to retain water molecules, reducing impurities and solvent residues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the known cleaning method using acidification and aluminum ion addition is applied, then impurities are removed from the solution, but the process becomes economically inefficient and introduces new contaminants (sulphate or chlorine ions)
Solution Approach 1:
The patent extracts and removes hydrolyzing ions (silicon, phosphorus, arsenic) from the alkaline tungsten solution by adding aluminum ion, which forms a precipitate that binds these impurities. This selective extraction eliminates harmful contaminants while maintaining the integrity of the tungsten salt solution, avoiding the introduction of new contaminants from acidification steps.
Solution Approach 2:
The patent uses aluminum ion as an intermediary substance to remove impurities. The aluminum ion acts as a mediator that forms a precipitate with hydrolyzing ions, allowing them to be separated from the solution without directly acidifying the tungsten salt solution, thus avoiding the economic inefficiencies and contamination issues associated with traditional acidification methods.
2Loss of energy
If vacuum drying is performed at mild temperature (about 50°C), then energy consumption is reduced, but the hydrate loses water molecules (94% of starting Na2WO4·2H2O lost water)
Solution Approach 1:
The patent changes the drying parameters by performing vacuum drying at a controlled temperature below 50°C, which is mild enough to prevent dehydration but sufficient to remove excess water and solvent. This parameter optimization allows energy-efficient drying while maintaining the hydrate structure and water molecule stability in the final product.
Solution Approach 2:
The patent employs vacuum conditions during drying, which creates an inert environment that prevents oxidation and other unwanted reactions. The vacuum atmosphere allows water and solvent to be removed at lower temperatures without decomposing the hydrate structure, thus maintaining product stability while reducing energy consumption.
3Reliability
If the process is optimized for GMP standards, then product quality and stability are improved, but the complexity of the process increases
Solution Approach 1:
The patent segments the purification process into distinct steps: (a) preparation of tungsten salt in alkaline solution, (b) filtration at controlled temperature, (c) precipitation of hydrate below 100°C, (d) filtration at lower temperature, (e) washing with water-miscible solvent, and (f) drying under controlled conditions. This segmentation allows each step to be optimized for GMP compliance while maintaining overall process clarity and manageability.
Solution Approach 2:
The patent performs preliminary filtration at a specific temperature range before precipitation, removing impurities in advance to prevent contamination during subsequent steps. This preliminary action ensures that the final product meets GMP standards by eliminating potential contaminants early in the process, reducing the need for complex additional purification steps.
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 a stable sodium tungstate dihydrate with low water and solvent content, suitable for pharmaceutical, veterinary, and dietary applications, maintaining GMP standards and ensuring product stability.
Implementation Method 1
Preparing a tungsten (VI) salt in an alkaline aqueous solution
Implementation Method 2
Filtering the aqueous solution at a temperature at which the tungsten (VI) salt remains dissolved
Implementation Method 3
Precipitating the tungsten (VI) salt hydrate from the filtrate resulting from step (b) at a temperature below 100° C.
Implementation Method 4
Washing the resulting filter cake with a water-miscible solvent
Implementation Method 5
Drying the washed cake under conditions that allow the removal of the water-miscible solvent
Data Source
AI summary
The present invention provides a process for preparing tungsten (VI) salts hydrates, the process comprising (a) Preparing a tungsten (VI) salt in an alkaline aqueous solution; (b) Filtering the aqueous solution at a temperature at which the tungsten (VI) salt remains dissolved; (c) Precipitating the tungsten (VI) salt hydrate from the filtrate resulting from step (b); (d) Filtering; (e) Washing the resulting filter cake with a water-miscible solvent; and (f) Drying the washed cake under conditions that allow the removal of the water-miscible solvent. The resulting salts show a level of impurities and solvents so low that they are suitable in the fields of pharmacy, veterinary and dietary.