Spray Drying Core-Shell Particle Synthesis
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Solution Overview
Problem
Current methods for producing core-shell particles with Fe3O4 as the core and a silica shell are inefficient, requiring large solvent quantities, long reaction times, and multiple steps such as washing and sintering, making them unsuitable for large-scale production.
Innovation Solution
A spray drying process that forms a (semi-)metal oxyhydr(oxide) shell on magnetic particles in a single step without the need for washing or sintering, allowing for continuous production and easier control of parameters like temperature and pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If wet process is used to prepare core-shell particles, then silica coating can be formed on magnetic particles, but large quantities of solvent are required and the process takes long time (4-24 hours)
Solution Approach 1:
The invention uses spray drying to transform the coating process from a wet chemical reaction (sol-gel) that requires hours of reaction time into a rapid phase transition process where solvent evaporates quickly, forming the silica shell in minutes instead of 4-24 hours
Solution Approach 2:
The invention replaces the chemical mechanism (hydrolysis and condensation reactions requiring catalysts and long reaction times) with a physical drying mechanism where rapid solvent evaporation drives shell formation, eliminating the need for lengthy chemical reactions
2Manufacturing precision
If wet process is used to prepare core-shell particles, then silica coating can be formed, but multiple steps including washing and drying are required
Solution Approach 1:
The invention combines multiple separate steps (coating, drying, and purification) into a single integrated spray drying operation where the shell forms and the product is recovered in one continuous process, eliminating the need for separate washing and drying steps
Solution Approach 2:
The spray drying process performs multiple functions simultaneously: it forms the silica shell, removes solvent, and purifies the product in one operation, making the process universally applicable without requiring additional equipment for each step
3Reliability
If sintering step is used to obtain magnetic glass particles, then particles can be formed, but high energy consumption is required (750°C)
Solution Approach 1:
The invention changes the temperature parameter from high (750°C sintering) to low (ambient or mild heating during spray drying), achieving particle formation through solvent evaporation rather than thermal sintering, thereby dramatically reducing energy consumption
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 process enables the efficient production of large quantities of core-shell particles with a homogeneous and stable silica coating, reducing production time and energy consumption while maintaining the magnetic properties of the core.
Implementation Method 1
injecting the dispersion in a spray dryer whereby a (semi-)metal oxyhydr(oxide) shell is formed on the magnetic particles during spray drying
Implementation Method 2
optionally adding a hydrolysis agent for said one or more precursor(s)
Data Source
AI summary
The invention relates to a process for preparing core-shell particles comprising the steps of (i) providing a dispersion of primary magnetic particles having a mean diameter lower than 200 nm in a solvent; (ii) adding one or more (semi-)metal (oxyhydr)oxide(s) and/or one or more precursor(s) of a (semi-)metal (oxyhydr)oxide to said dispersion; (iii) optionally adding a hydrolysis agent for said one or more precursor(s); (iv) injecting the dispersion in a spray dryer; whereby a (semi-)metal (oxyhydr)oxide shell is formed on the magnetic particles during spray drying. The invention also relates to particles obtainable by said process, to a formulation of said particles in a solvent and to the use of said particles or said formulation for RNA or DNA extraction.