Soft Metal Powder Grinding Below Solvent Melting Point
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Solution Overview
Problem
Existing methods for grinding soft metals like lithium are unsafe, require high energy input, and are difficult to scale due to safety risks and limited stirring speeds, especially when using open handling of hot molten metals in organic solvents.
Innovation Solution
A method involving a mixture of soft metals and solvents with a vapor pressure of at least 0.002 bar at 20 °C, ground at a temperature at least 10 °C below the solvent's melting point, followed by solvent evaporation, using grinding processes like vibrating mills and inert atmospheres.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the Droplet Emulsion Technique is used to grind soft metals like lithium, then metal powder can be produced, but safety risks increase due to open handling of hot molten metals in organic solvents
Solution Approach 1:
The patent replaces the open handling of hot molten metals with a closed ball mill system operating in an inert atmosphere (argon or nitrogen). The ball mill is sealed and purged with inert gas before introducing the metal and grinding media, eliminating the safety risks associated with open handling while maintaining the ability to produce metal powder effectively.
Solution Approach 2:
The patent replaces the mechanical stirring system (with its high-speed stirring element) with a ball mill grinding system. The ball mill uses rotating balls or cylinders to grind the metal in a closed environment, eliminating the need for high-speed stirring and open handling of molten metal while achieving the same powder production goal.
2Manufacturing precision
If high stirring speeds are used in the Droplet Emulsion Technique, then metal droplets are effectively broken down, but energy input increases significantly
Solution Approach 1:
The patent replaces the high-speed mechanical stirring system with a ball mill grinding system. The ball mill achieves metal particle breakdown through the mechanical impact and friction of rotating balls or cylinders, consuming significantly less energy while achieving comparable or superior particle size control and distribution.
3Productivity
If the Droplet Emulsion Technique is scaled up using a reactor system, then production capacity increases, but device complexity increases due to pressure stability requirements and inerting infrastructure
Solution Approach 1:
The patent extracts the metal from the molten state and processes it in a solid or semi-solid state within a ball mill. This eliminates the need for high-temperature processing, pressure stability systems, and complex inerting infrastructure required by the Droplet Emulsion Technique, while still enabling scaled-up production through the use of larger ball mill units.
4Ease of manufacture
If classic grinding processes are used on soft metals, then simple equipment is required, but the soft metal is not suitable for these processes due to its softness
Solution Approach 1:
The patent changes the physical state parameters of the metal during processing. By cooling the metal to below its melting point (or processing it in a cryogenic environment), the metal becomes sufficiently hard to withstand ball mill grinding while maintaining its soft metal properties. This enables the use of simple, reliable ball mill equipment on soft metals that would otherwise be unsuitable for classic grinding processes.
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 produces high-purity metal powder efficiently, eliminating the need for complex purification steps and enabling scalable production with improved yield and safety.
Implementation Method 1
the at least one solvent is separated from the mixture by evaporation
Data Source
Figure 1~2
AI summary
The present invention relates to a process for producing metal powder, in which a mixture comprising at least one metal material and at least one solvent is provided, the mixture is subjected to at least one grinding process, and the at least one solvent is separated from the mixture by evaporation. The at least one metal material is selected from the group consisting of alkali metals, indium, and mixtures and alloys thereof. The at least one solvent has a vapor pressure of at least 0.002 bar at 20 °C and is selected from the group consisting of aliphatic hydrocarbons, aromatic hydrocarbons, and mixtures thereof. The at least one grinding process is carried out at a temperature that is at least 10 °C below the melting point of the at least one solvent. The present invention further relates to a metal powder and its use.