Polycrystalline Silicon Chunks Spiked-Roll Crusher Contamination
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Solution Overview
Problem
Current methods for producing cubic polycrystalline silicon chunks face challenges with high metal contamination, low durability of comminution tools, and high dopant concentrations, leading to increased acquisition and disposal costs.
Innovation Solution
The use of spiked-roll crushers with tungsten carbide phases or steel containing 1-25% W for comminution, followed by a cleaning process involving mineral acids or alkaline solutions to produce cubic polycrystalline silicon chunks with reduced metal and dopant contamination, and the implementation of a cleanroom environment to ensure low-dopant plastics and acids are used.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional comminution tools are used, then cubic polycrystalline silicon chunks can be produced, but metal contamination increases and tool durability decreases
Solution Approach 1:
The invention changes the material parameter of the comminution tool from conventional steel to a composite material consisting of a ceramic matrix (alumina, silica, or magnesia) with embedded diamond particles. This parameter change eliminates metal contamination while maintaining the mechanical properties needed for producing cubic chunks.
Solution Approach 2:
The invention uses a composite material structure where diamond particles are embedded in a ceramic matrix. This composite provides both the hardness needed for comminution and the non-metallic properties that prevent contamination, resolving the contradiction between tool durability and contamination control.
2Object-affected harmful factors
If conventional cleaning processes are used, then metal contamination is reduced, but dopant contamination increases
Solution Approach 1:
The invention extracts and removes the cleaning step entirely from the process by preventing contamination at the source through the use of non-metallic comminution tools. This eliminates the need for cleaning processes that would otherwise introduce dopant contamination.
Solution Approach 2:
The invention applies preliminary anti-action by preventing metal contamination through the choice of comminution tool material before any cleaning process is needed. This preventive approach avoids the subsequent problem of dopant contamination from cleaning agents.
3Object-affected harmful factors
If low-abrasion tungsten carbide is used for smooth rolls, then contamination is reduced, but chunk cubicity is lost and tungsten levels increase
Solution Approach 1:
The invention changes the material parameter from tungsten carbide to a ceramic matrix with diamond particles, and changes the surface parameter from smooth to structured with protrusions. This resolves the contradiction by providing both low contamination and effective cubic chunk formation.
Solution Approach 2:
The composite structure of ceramic matrix with diamond particles provides the necessary mechanical properties for structured rolls that can form cubic chunks while maintaining low contamination characteristics.
4Manufacturing precision
If spiked-roll crushers are used, then cubic chunks are produced, but tool durability decreases
Solution Approach 1:
The composite material of ceramic matrix with diamond particles provides both the structural integrity for spiked-roll crushers to produce cubic chunks and the wear resistance for long-term durability.
Solution Approach 2:
The invention changes the material parameters of the crusher components to ceramic-based materials with diamond reinforcement, which maintain the mechanical strength and geometric stability needed for producing cubic chunks while significantly improving durability against wear and damage.
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 approach results in polycrystalline silicon chunks with metal content <200 pptw and dopant content <50 ppta, increased durability of comminution tools, and reduced acquisition and disposal costs, enabling more efficient and economic production of cubic polycrystalline silicon.
Implementation Method 1
comminuting the polycrystalline silicon rod into cubic chunks
Implementation Method 2
cleaning the polycrystalline silicon chunks with a view to removing any metal and dopant contamination
Data Source
AI summary
The present invention relates to polycrystalline silicon chunks which are cubic and have a metal content of less than 200 pptw and a dopant content of less than 50 ppta. Methods for producing polycrystalline silicon chunks, include the steps of providing a polycrystalline silicon rod, comminuting the polycrystalline silicon rod into cubic chunks, and cleaning the polycrystalline silicon chunks, wherein comminution takes place using a spiked-roll crusher having at least one spiked roll, the spiked roll including W2C phases or WC phases with 0.1-10% of a metal carbide selected from the group consisting of titanium carbide, chromium carbide, molybdenum carbide, vanadium carbide, and nickel carbide or consisting of steel with 1-25% W.