Free-Flowing Calcium Fluoride Production via Low-Temperature Reaction
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Solution Overview
Problem
Existing methods for producing calcium fluoride from diluted aqueous hydrogen fluoride solutions result in fine particles that are difficult to use in manufacturing processes for anhydrous hydrogen fluoride due to their small size and the need for organic precipitation agents, which also increase energy costs and environmental concerns.
Innovation Solution
Milled calcium carbonate particles are reacted with diluted hydrogen fluoride solutions at low temperatures to produce free-flowing calcium fluoride particles without the need for flocculation agents, maintaining particle size and reducing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If calcium fluoride is precipitated from diluted HF solutions using calcium hydroxide, then calcium fluoride is recovered, but the particle size is very small (below 20 μm) and organic flocculants are required
Solution Approach 1:
The patent changes the chemical parameter by using calcium carbonate instead of calcium hydroxide as the reactant, and conducts the reaction at elevated temperatures (50-100°C) to alter the precipitation behavior. This parameter change results in larger particle sizes (20-200 μm) without requiring organic flocculants, while still achieving effective calcium fluoride recovery from diluted HF solutions
2Ease of operation
If organic precipitation agents are added to improve handling properties of calcium fluoride, then particle aggregation is improved, but organic residues remain in the product
Solution Approach 1:
The patent converts the normally harmful fine particle size into a benefit by conducting the reaction at elevated temperatures, which promotes particle growth and aggregation into larger, easier-to-handle particles (20-200 μm). This eliminates the need for organic flocculants and prevents organic residue contamination, while the temperature condition itself becomes the beneficial factor driving particle growth
3Quantity of substance
If calcium carbonate powder with grain size of 3 to 30 μm is used in the two-step process, then calcium fluoride is produced, but fine calcium fluoride particles (3 to 30 μm) are generated which cannot be processed with sulfuric acid
Solution Approach 1:
The patent changes the particle size parameter of the final calcium fluoride product by conducting the reaction at elevated temperatures (50-100°C) and using calcium carbonate as reactant. This produces particles in the 20-200 μm range, which are compatible with existing sulfuric acid processing methods, unlike the fine 3-30 μm particles produced by conventional low-temperature methods
4Productivity
If temperature is increased to ≥ 50 °C to produce calcium fluoride from calcium carbonate, then reaction rate is improved, but energy cost for heating diluted HF increases
Solution Approach 1:
The patent optimizes the temperature parameter within the range of 50-100°C to achieve an balance between reaction rate and energy consumption. This moderate temperature increase provides sufficient reaction kinetics while avoiding the excessive energy costs associated with higher temperatures, making the process economically viable
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 generates calcium fluoride particles with improved handling properties and reduced energy costs, allowing their use in existing manufacturing processes for anhydrous hydrogen fluoride while minimizing environmental impact and avoiding organic residues.
Implementation Method 1
reacting the diluted aqueous solution of hydrogen fluoride with calcium carbonate particles
Data Source
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AI summary
The invention relates to a process for producing free-flowing calcium fluoride particles from a diluted aqueous solution of hydrogen fluoride comprising the step of reacting the diluted aqueous solution of hydrogen fluoride with calcium carbonate particles at a temperature of less than 50 °C. The invention further relates to the use of the free-flowing calcium fluoride particles for the manufacturing of anhydrous hydrogen fluoride.