Magnesium Sulfate Urea Compound Stability
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Solution Overview
Problem
Magnesium sulfate-urea compounds used as fertilizers are prone to instability and hygroscopicity, making them difficult to handle and incorporate into solid fertilizer compositions due to the reaction between Epsom salt and urea, resulting in pasty masses that are not storage-stable.
Innovation Solution
A magnesium sulfate-urea compound of the formula [MgSO4 • m CO(NH2)2 • n H2O] is produced with m ranging from 0.9 to 1.1 and n from 2.9 to 3.1, which is crystalline, non-hygroscopic, and storage-stable, allowing for easy incorporation into fertilizer compositions, using a process involving anhydrous magnesium sulfate, urea, and water, with minimal free MgSO4 and urea, and characterized by specific X-ray powder diffractogram reflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If Epsom salt and urea are mixed together to provide magnesium and nitrogen nutrients, then the fertilizer composition contains multiple macro nutrients, but the mixture becomes unstable and forms pasty masses that are difficult to handle
Solution Approach 1:
The patent combines Epsom salt and urea in a specific molar ratio (1:1 to 1:2) to form a double compound with defined stoichiometry. This merging of components into a unified chemical structure prevents the formation of unstable pasty masses while maintaining the nutritional benefits of both magnesium and nitrogen in a single stable fertilizer composition.
Solution Approach 2:
The patent specifies precise parameter ranges for the compound composition: m (urea coefficient) from 0.9 to 1.1 and n (water coefficient) from 2.9 to 3.1. By controlling these stoichiometric parameters, the compound achieves optimal stability and handling properties, transforming the unstable mixture into a manageable solid fertilizer with defined chemical characteristics.
2Adaptability or versatility
If Epsom salt and urea are mixed to provide multiple nutrients, then the fertilizer contains magnesium, sulfur, and nitrogen, but the mixture becomes non-storage stable and deliquescent
Solution Approach 1:
The patent merges Epsom salt and urea into a single double compound structure with specific stoichiometry. This chemical merging creates a stable crystalline phase that resists deliquescence and decomposition during storage, unlike the unstable physical mixture. The unified structure prevents the components from reacting further and forming pasty, deliquescent masses.
Solution Approach 2:
The patent creates a composite material - a double compound with defined stoichiometry containing both magnesium sulfate and urea in specific proportions. This composite structure combines the nutritional benefits of multiple elements while achieving storage stability through the formation of a unified crystalline phase that resists moisture absorption and decomposition.
3Adaptability or versatility
If magnesium sulfate-urea compound is produced to provide multiple nutrients, then the fertilizer contains nitrogen, magnesium, and sulfur, but the compound becomes extremely hygroscopic and difficult to use in solid fertilizers
Solution Approach 1:
The patent precisely controls the water coefficient n in the range of 2.9 to 3.1, which optimizes the crystalline structure and reduces hygroscopicity. By adjusting this parameter within the specified range, the compound achieves a balance between maintaining nutrient solubility and minimizing moisture absorption from the environment, making it suitable for solid fertilizer applications.
Solution Approach 2:
The patent applies different local qualities to different parts of the compound structure by controlling the stoichiometric ratios. The specific molar proportions of magnesium sulfate to urea (m=0.9-1.1) create localized structural characteristics that reduce overall hygroscopicity while maintaining the nutritional functionality of both components in the fertilizer.
4Manufacturing precision
If attempts are made to purify the magnesium sulfate-urea compound, then the compound can be separated from the mixture, but the compound decomposes during purification
Solution Approach 1:
The patent specifies narrow parameter ranges for the compound composition (m=0.9-1.1, n=2.9-3.1) that define a stable compositional window. By producing the compound within these precise parameters, the resulting material achieves both high purity and stability, eliminating the need for aggressive purification methods that would cause decomposition. The specified ranges represent an optimized zone where purity and stability are simultaneously achieved.
Data Source
Figure 1
AI summary
The invention relates to a composition containing at least 80 wt.%, based on the total weight of the composition, of a magnesium sulfate/urea compound of the formula (I): [MgSO4 . m CO(NH2)2 . n H2O], where m ranges from 0.9 to 1.1 and n ranges from 2.1 to 3.1. The composition, based on the total weight of the composition, contains less than 10 wt.% of free MgSO4 in the form of anhydrate or in the form of urea-free hydrates of the magnesium sulfate, such as bitter salt or magnesium sulfate hexahydrate, and less than 10 wt.% of unbound urea. In particular, m in the formula (I) has the value of 1. In particular, n in the formula (I) has the value of 3. The invention also relates to the production of the compositions and to the use thereof as a fertilizer or a fertilizer additive.