Titanium Oxide Particle Synthesis via Controlled Hydrolysis
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Solution Overview
Problem
Current methods for producing titanium oxide particles result in aggregation and wide particle size distribution, failing to achieve nano-crystallinity and metastable phases effectively, which are crucial for advanced industrial applications.
Innovation Solution
A method involving maintaining an aqueous titanium salt solution at temperatures below 70°C to reduce acidity, followed by temperature adjustments, pH modification, and dilution to control particle size and distribution, producing particles between 2 nm and 500 nm with a narrow size ratio and high crystallinity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional liquid phase or vapor phase processes are used to produce titanium oxide, then production is achieved, but heavy aggregation and wide particle size distribution occur
Solution Approach 1:
The patent applies preliminary action by conducting a controlled hydrolysis step before precipitation. The titanium salt solution is hydrolyzed at temperatures below 70°C for a specific retention time to form a pre-hydrolyzed solution with controlled acidity reduction, which then serves as the basis for subsequent precipitation. This preliminary hydrolysis step prevents direct rapid precipitation that causes aggregation, thereby achieving narrow particle size distribution while maintaining production efficiency.
2Productivity
If temperature is increased to accelerate production, then productivity improves, but particle aggregation increases and nano-crystallinity is lost
Solution Approach 1:
The patent applies parameter changes by precisely controlling the hydrolysis temperature to be below 70°C (specifically 20-60°C in embodiments) and maintaining this temperature throughout the retention period. This temperature parameter control prevents excessive thermal energy that would cause aggregation, while still allowing the hydrolysis reaction to proceed at a controlled rate. The modified parameters (temperature, retention time, acidity) work together to produce particles with desired morphology and nano-crystallinity.
3Productivity
If rapid precipitation is used to increase production speed, then productivity improves, but particle size distribution widens and aggregation occurs
Solution Approach 1:
The patent applies preliminary action by preparing a pre-hydrolyzed titanium salt solution before precipitation. This pre-hydrolyzed solution has reduced acidity and controlled titanium species distribution, which creates optimal conditions for subsequent precipitation. The preliminary hydrolysis step ensures that when precipitation occurs, the particles form uniformly without rapid aggregation, achieving both high production speed and narrow particle size distribution.
Solution Approach 2:
The patent applies parameter changes by modifying the pH and acidity parameters of the titanium salt solution through controlled hydrolysis before precipitation. The acidity is reduced to a specific range (pH 2-6 in embodiments) which controls the precipitation rate and particle formation. This parameter modification ensures rapid yet controlled precipitation that maintains particle size uniformity while achieving high productivity.
4Loss of time
If high temperature hydrolysis is used to reduce acidity quickly, then process time is reduced, but particle aggregation and grain growth occur
Solution Approach 1:
The patent applies parameter changes by optimizing the temperature parameter to be below 70°C (specifically 20-60°C) rather than using high temperatures. This temperature optimization balances the hydrolysis rate with particle formation control. The retained time is also optimized (1-24 hours in embodiments) to achieve sufficient acidity reduction without causing aggregation. This parameter optimization resolves the contradiction between process time and particle size 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
This method enables the production of titanium oxide particles with desired size, distribution, and morphology, achieving high porosity and crystallinity, suitable for industrial applications such as catalysts and coatings, while being economically viable.
Implementation Method 1
maintaining an aqueous titanium salt solution defined as the starting aqueous solution at a temperature lower than 70° C. for a time sufficient to reduce the acidity of solution due to hydrolysis
Implementation Method 2
The resulting solution defined as the retained solution is then subjected to a modification in temperature and/or dilution and/or addition of a reagent, thus modifying the pH of the solution to form a modified system
Data Source
AI summary
The invention provides a method for the formation of small-size titanium oxide particles, comprising the steps of a) preparing a starting aqueous solution comprising at least one of titanic ions and complexes thereof, at a concentration of at least 0.1% w/w titanium; b) maintaining the solution at a temperature lower than 70° C. for a retention time in which hydrolysis takes place, the extent of the hydrolysis being sufficient to produce O.i mmol protons per mmol of titanium present in solution, wherein the time does not exceed 14 days, to form a system containing a retained solution; and c) adjusting the conditions in the system by at least one of the steps of: i) heating the retained solution to elevate the temperature thereof by at least 1° C.; ii) changing the pH of the retained solution by at least 0.1 units; and iii) diluting the retained solution by at least 20% whereby there are formed particles, wherein the majority of the particles formed are between about 2 nm and about 500 nm in size.