Magnesium Oxide Production With Low-Chloride Thermal Conversion
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Solution Overview
Problem
Existing methods for manufacturing magnesium oxide from magnesium chloride solutions result in products of insufficient purity, leading to high chloride content that negatively affects fermentation processes.
Innovation Solution
A two-step process involving spray drying at 300-475°C followed by roasting at 600-900°C in the presence of water, producing a product with at least 98% MgO and less than 2% magnesium hydroxychloride and magnesium chloride.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If spray drying is performed at high temperature (500-600°C) to rapidly process magnesium chloride solution, then processing efficiency is improved, but the magnesium oxide product contains high chloride content (insufficient purity)
Solution Approach 1:
The patent divides the single high-temperature spray drying process into two distinct stages: (1) a first spray drying step at lower temperature (200-400°C) to form magnesium hydroxychloride intermediate with controlled chloride content, and (2) a second spray drying step at higher temperature (400-600°C) to complete the conversion to magnesium oxide. This segmentation allows each stage to be optimized independently, achieving both efficiency and purity.
Solution Approach 2:
The first spray drying step performs a preliminary conversion of magnesium chloride to magnesium hydroxychloride at controlled lower temperature, creating an intermediate product with reduced chloride content before the final high-temperature treatment. This preliminary action prevents excessive chloride incorporation that would occur in a single high-temperature step.
2Device complexity
If a single high-temperature spray drying step is used, then process complexity is reduced, but product purity cannot be sufficiently improved
Solution Approach 1:
The patent uses two sequential spray drying units with different temperature profiles, where the first unit operates at 200-400°C to form the intermediate hydroxychloride product, and the second unit operates at 400-600°C to complete the oxidation. This segmented approach achieves high purity (≥98% MgO, chloride <2%) while maintaining relative process simplicity through the use of standard spray drying technology in series.
3Stability of the object's composition
If spray drying temperature is increased to 500-600°C to ensure complete conversion, then conversion completeness is improved, but chloride content in the product increases
Solution Approach 1:
The patent segments the thermal treatment into two phases: first phase at 200-400°C that achieves partial conversion to magnesium hydroxychloride with controlled chloride incorporation, and second phase at 400-600°C that completes the conversion to MgO. The intermediate product from the first phase has lower chloride content than would result from direct high-temperature processing, and the second phase removes additional chloride while completing conversion.
Solution Approach 2:
The patent changes the temperature parameter between the two spray drying steps, operating at lower temperature (200-400°C) in the first step to control chloride incorporation kinetics, then at higher temperature (400-600°C) in the second step to ensure complete conversion. This parameter variation optimizes both conversion completeness and chloride content control.
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 magnesium oxide suitable for fermentation processes, reducing chloride content and enhancing the efficiency and effectiveness of magnesium oxide as a neutralizing agent.
Implementation Method 1
subjecting a magnesium chloride solution to a spray drying step in a spray-drying apparatus, at a temperature in the range of 300-475° C., resulting in the formation of a spray-dried product
Implementation Method 2
subjecting the product of the spray drying step to a roasting step in a roaster at a temperature of 600-900° C. in the presence of water, resulting in the formation of a product comprising at least 98 wt. % of MgO
Data Source
AI summary
A process for converting magnesium chloride into magnesium oxide having the steps of: subjecting a magnesium chloride solution to a spray drying step in a spray-drying apparatus at a temperature of 300-475° C., resulting in the formation of a spray-dried product having 10-80 wt. % magnesium oxide and 20-90 wt. % of the total of magnesium hydroxychloride and magnesium chloride, subjecting the product of the spray drying step to a roasting step in a roaster at a temperature of 600-900° C. in the presence of water, resulting in the formation of a product having at least 98 wt. % of MgO, and less than 2 wt. % of the total of magnesium hydroxychloride and magnesium chloride, wherein the percentages of MgO, magnesium hydroxychloride and magnesium chloride, are calculated on the total of MgO, magnesium hydroxychloride and magnesium chloride.