Magnesium Sulphate-Urea Fertilizer Granulate for Deliquescence Control
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Solution Overview
Problem
Existing fertilizer compositions of magnesium sulphate and urea suffer from instability, deliquescence, and poor mechanical properties, especially at high urea content, making them unsuitable for large-scale production and effective soil fertilization.
Innovation Solution
A fertilizer granulate composed of magnesium sulphate and urea, with a portion of the magnesium, urea, and sulphate present in crystalline phases (MgSO4 • 6NH2-C(=O)-NH2 • 0.5 H2O and/or MgSO4* NH2-C(=O)-NH2* H2O), produced through a granulation process with controlled water addition, ensuring stability and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnesium sulphate granulate and urea are mixed in solid form, then nitrogen loss is reduced, but the mixture becomes unstable and forms pasty masses that deliquesce
Solution Approach 1:
The invention changes the physical and chemical parameters of the mixture by controlling moisture content to 0.5-5% and using specific granulate sizes (0.2-2.0 mm for magnesium sulphate, 0.5-3.0 mm for urea). It also changes the chemical state by forming a stable complex compound rather than a simple physical mixture, which prevents deliquescence while maintaining reduced nitrogen loss
Solution Approach 2:
The invention creates a composite fertilizer material combining magnesium sulphate and urea in a specific complex compound structure. This composite approach allows the mixture to maintain stability while providing both magnesium and nitrogen nutrients, resolving the contradiction between stability and nutrient composition
2Reliability
If aqueous concentrates of magnesium sulphate and urea are used, then stability is improved, but the fertilizer becomes less suitable for some applications
Solution Approach 1:
The invention optimizes the moisture content parameter to a narrow range of 0.5-5%, which is sufficient to prevent deliquescence and improve stability but low enough to maintain solid granulate form suitable for various application methods. This parameter control allows the fertilizer to be both stable and versatile
3Reliability
If complex compounds of magnesium sulphate and urea are prepared, then stability is improved, but production becomes energy-intensive requiring calcination at 450°C
Solution Approach 1:
The invention performs preliminary action by using pre-formed granulates of magnesium sulphate and urea with controlled size distributions before mixing. This preliminary preparation allows the formation of stable complex compounds at lower temperatures without requiring energy-intensive calcination at 450°C, thus reducing energy consumption while maintaining stability
4Quantity of substance
If high urea content is used in the granulate, then nitrogen content is improved, but mechanical stability deteriorates and caking occurs
Solution Approach 1:
The invention optimizes multiple parameters simultaneously: urea content (20-40%), moisture content (0.5-5%), and granulate size distributions. These parameter changes allow high nitrogen content to be achieved while maintaining mechanical stability and preventing caking through the formation of a stable complex compound structure
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 granulate maintains mechanical stability, prevents deliquescence, and allows for large-scale production, even at high urea content, with reduced ammonia emissions and uniform application.
Implementation Method 1
at least a portion of the magnesium, the urea and the sulphate is present in the form of the crystalline phase of formula (I) and/or formula (II): MgSO4 • 6NH2-C(=O)-NH2 • 0.5 H2O and MgSO4* 4NH2-C(=O)-NH2* H2O
Implementation Method 2
produced through a granulation process with controlled water addition
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
Disclosed is a spherical fertiliser granulate, which contains magnesium, sulphate and urea, each with respect to the total weight of the granulate, in the following quantities: Urea, calculated as elemental nitrogen, in a quantity of 20.0 to 38.0 wt%, magnesium, calculated as elemental magnesium, in a quantity of 1.5 to 9.5 wt% and sulphate, calculated as elemental sulphur, in a quantity of 2.7 to 12.0 wt%, wherein at least a portion of the magnesium, the urea and the sulphate is present in the form of at least one of the crystalline phases of the formulae MgSO4 * 6 NH 2-C (=O) -NH2 * 0.5 H2O (I) and MgSO4 * 4 NH2-C (=O) -NH2 * H2O (II), wherein 1 to 20 wt%, in particular 3 to 18 wt% and especially 5 to 15 wt% of the magnesium contained in the fertilizer granulate, calculated in each case as elemental magnesium, is present in the form of water-insoluble magnesium salts. Disclosed also is a process for manufacturing the fertiliser granulate as well as the use of the fertiliser granulate as fertiliser or in fertiliser mixtures.