VRM Grinding Additives for Mill Stability Without Cement Pre-Hydration
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Solution Overview
Problem
Vertical Roller Mills (VRMs) face milling instability, leading to vibrations that can damage the mill and affect cement properties, as current stabilization methods like water spraying pre-hydrate cement, reducing its strength and requiring chemicals that can stabilize the mill with minimal water usage.
Innovation Solution
The use of amino acid derivatives, such as ethanol diglycine (EDG) and its salts, as grinding stabilizing additives in VRMs, which include a carboxyl group, an amine, and an alcohol group, to reduce milling instability and enhance cement strength without pre-hydration issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If water is sprayed onto the material layer to stabilize the VRM, then vibrations are reduced, but cement strength decreases due to pre-hydration
Solution Approach 1:
The patent introduces amino acid derivatives (EDG, IPDG) as intermediary substances that mediate between the grinding process and the cement material. These additives stabilize the mill vibrations without causing pre-hydration, thus resolving the contradiction between milling stability and cement strength by providing an alternative stabilization mechanism that does not involve water addition.
Solution Approach 2:
The patent changes the chemical parameters of the grinding system by introducing specific amino acid derivatives with particular molecular structures (containing carboxyl, amine, and alcohol groups). This parameter change allows stabilization through chemical interaction rather than physical water addition, thereby maintaining cement strength while achieving milling stability.
2Stability of the object's composition
If water spray is increased to control vibrations, then milling stability improves, but energy consumption increases
Solution Approach 1:
The patent replaces the mechanical water spray stabilization system with a chemical stabilization system using amino acid derivatives. Instead of using water to dampen vibrations mechanically, the additives chemically interact with the grinding process to reduce vibrations, thereby eliminating the energy associated with water spraying while maintaining stability.
3Loss of substance
If amino acid derivatives are used as stabilizing additives, then water usage is reduced, but additive cost increases
Solution Approach 1:
The patent uses amino acid derivatives at very low concentrations (0.001-0.05% by weight) to achieve stabilization, changing the dosage parameter from significant water amounts to trace additive amounts. This minimal dosage requirement keeps additive costs low despite the higher unit cost of the specialized chemicals, thereby reducing overall water usage without significantly increasing manufacturing costs.
Data Source
AI summary
A method for grinding a solid in a vertical roller mill (VRM), comprising grinding at least one solid in the presence of a grinding stabilizing additive, wherein the grinding stabilizing additive comprises an alkanol amino acid compound or a disodium or dipotassium salt thereof having the structural formula (I): The definitions of variables R1, R2, and R3 are provided herein.