Rare Earth Hydroxycarbonate Conversion with Carboxylate Particle Control
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Solution Overview
Problem
Existing methods struggle to effectively reduce the content of anions such as Cl−, SO42−, and NO3− and achieve a small particle size in rare earth carbonates and hydroxycarbonates, which are precursors for high-purity rare earth oxides and fluorides, due to the presence of impurities and difficulty in controlling particle size.
Innovation Solution
A method involving mixing rare earth carbonate with an aqueous solution of a carboxylate-containing substance, such as C1-C6 monocarboxylic acid or its ammonium salt, followed by heating to promote phase conversion to rare earth hydroxycarbonate, with controlled conditions to achieve small particle size and reduced anion content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional equipment is used to precipitate rare earth carbonate from rare earth solution, then the production process is simple, but the particle size cannot be controlled to achieve 5 μm or less
Solution Approach 1:
The patent changes the chemical parameters of the precipitation process by introducing carboxylate-containing substances and controlling pH, temperature, and mixing conditions. This allows achieving fine particle size (5 μm or less) through optimized chemical parameters rather than complex equipment modifications.
Solution Approach 2:
The patent uses carboxylate-containing substances as intermediary agents that mediate between the rare earth solution and carbonate precipitate. These intermediaries control the nucleation and growth of particles, enabling precise particle size control without requiring complex equipment.
2Manufacturing precision
If rare earth carbonate is precipitated from rare earth solution using conventional methods, then the production process is straightforward, but anions (Cl−, SO42−, NO3−) remain in high content affecting material performance
Solution Approach 1:
The patent introduces carboxylate-containing substances as intermediary agents that selectively interact with anions in the solution. These intermediaries facilitate the removal of harmful anions (Cl−, SO42−, NO3−) through complexation and precipitation reactions, achieving low anion content (50 ppm or less) while maintaining process feasibility.
Solution Approach 2:
The patent optimizes chemical parameters including pH value, temperature, and carboxylate concentration to control the selective precipitation and removal of anions. By carefully adjusting these parameters, the process achieves high purity product with minimal anion content while maintaining reasonable manufacturing complexity.
3Productivity
If the phase conversion rate from rare earth carbonate to rare earth hydroxycarbonate is increased, then the production efficiency improves, but the control of particle size and anion content becomes more difficult
Solution Approach 1:
The patent uses carboxylate-containing substances as intermediary agents that simultaneously promote phase conversion and control particle characteristics. These intermediaries act as both catalysts for phase conversion and templates for particle formation, enabling high conversion rates while maintaining precise control over particle size and anion content.
Solution Approach 2:
The patent implements a feedback control system that monitors and adjusts reaction conditions (pH, temperature, carboxylate concentration) based on the phase conversion progress. This feedback mechanism ensures that particle size and anion content remain within specified ranges while maintaining high phase conversion rates.
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 method significantly increases the phase conversion rate, reduces anion content from over 200 ppm to 50 ppm or less, and achieves a particle diameter of less than 5.5 μm, facilitating the production of high-purity rare earth hydroxycarbonates.
Implementation Method 1
heating the slurry such that reactions proceed to obtain an intermediate product; and converting the intermediate product into crystals of a rare earth hydroxycarbonate, clusters of a rare earth hydroxycarbonate, or a mixture of crystals of a rare earth hydroxycarbonate and clusters of a rare earth hydroxycarbonate
Implementation Method 2
heating the slurry such that reactions proceed
Data Source
AI summary
The present disclosure provides a method of increasing the rate of phase conversion and use of a carboxylate-containing substance. A method of increasing the rate of phase conversion in the course of preparing a rare earth hydroxycarbonate from a rare earth carbonate comprises: mixing a rare earth carbonate with an aqueous solution of a carboxylate-containing substance to obtain a slurry; and heating the slurry such that reactions proceed. The method of the present disclosure can improve the rate of conversion from a rare earth carbonate to a rare earth hydroxycarbonate.