Potassium Chloride Purity via Carnallite Dissolution Control
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Solution Overview
Problem
Current methods for extracting potassium chloride from carnallite are costly and result in impure products with significant sodium chloride contamination, leading to storage issues due to hygroscopicity and environmental concerns from uncontrolled cavern subsidence and large tailings volumes.
Innovation Solution
A process involving the dissolution of carnallite to form a slurry with controlled magnesium chloride concentration, followed by removal of sodium chloride and crystallization of potassium chloride to achieve high purity, with sodium chloride levels below 2% by weight, preventing co-precipitation and enhancing product quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional mining and processing methods are used to extract potassium chloride from carnallite, then potassium chloride can be obtained, but the product contains significant sodium chloride contamination and requires costly multi-step processing
Solution Approach 1:
The patent applies parameter changes by controlling the magnesium chloride concentration within a specific range (12-25% by weight) during the dissolution process. This parameter control prevents co-precipitation of sodium chloride with potassium chloride, thereby achieving high purity potassium chloride through a simplified single-step process rather than multiple conventional processing steps
Solution Approach 2:
The patent extracts only the necessary component (potassium chloride) from the carnallite mixture by maintaining magnesium chloride at controlled concentrations that prevent sodium chloride from being extracted or co-precipitated. This selective extraction eliminates the need for subsequent flotation and purification steps required in conventional methods
2Manufacturing precision
If flotation is used to remove excessive sodium chloride from mined potassium chloride, then sodium chloride content is reduced, but the product still contains occluded impurities and requires additional processing steps
Solution Approach 1:
The patent performs preliminary action by controlling the dissolution conditions and magnesium chloride concentration before crystallization occurs. This preventive measure ensures that sodium chloride does not co-precipitate with potassium chloride in the first place, eliminating the need for subsequent flotation and multiple processing steps that characterize conventional methods
3Duration of action of stationary object
If potassium chloride is stored for lengthy periods, then product availability is maintained, but the hygroscopic product undergoes coagulation and agglomeration into lumps
Solution Approach 1:
The patent applies parameter changes by controlling the magnesium chloride concentration (12-25% by weight) during dissolution, which results in potassium chloride crystals with reduced hygroscopicity. This parameter control modifies the crystal properties to enhance stability during storage, preventing coagulation and agglomeration even over lengthy storage periods
4Ease of manufacture
If solution mining is used to extract potassium chloride, then production cost is reduced, but uncontrolled cavern subsidence and large tailings volumes create environmental concerns
Solution Approach 1:
The patent applies feedback by continuously monitoring and controlling the magnesium chloride concentration within the specified range during the dissolution process. This feedback control ensures optimal conditions are maintained to prevent sodium chloride co-precipitation, achieving both cost-effective production and high purity product that minimizes tailings volume and environmental impact
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 process effectively produces high-grade potassium chloride with reduced sodium chloride contamination, improving product purity and addressing environmental concerns by controlling cavern pressure and minimizing tailings volume.
Implementation Method 1
dissolving the source of carnallite; dissolving the slurry to form a solution
Implementation Method 2
crystallizing potassium chloride from the solution with a sodium chloride of not greater than 2% by weight
Implementation Method 3
crystallization of the crystals followed by separation from the initial mother liquor
Data Source
AI summary
A process for formulating high purity potassium chloride from a carnallite source. The process takes advantage of solubility differences and saturation levels in a multiple salt system generated upon dissolution of carnallite. In the system, the sodium chloride is kept in solution and the magnesium chloride present in the system is controlled to be in a concentration range of between 12% and 25% by weight. This avoids co-precipitation of sodium chloride with the potassium chloride during crystallization and therefore prevents the sodium chloride from contaminating the potassium chloride. The result is high grade potassium chloride.