Vertical Roller Mill for LD Slag Activation

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Solution Overview

Problem

Current methods for processing and activating raw materials with latent hydraulic, hydraulic, inert, or pozzolanic properties, such as LD slags, are inefficient and costly, preventing their use as main components in cement due to unactivated reactive phases and environmental regulations against landfilling.

Innovation Solution

A method using a mill-sifter combination with a vertical mill and fine-grain sifting unit to achieve a product fineness of less than 5 µm, exposing reactive phases and activating them for use in cement, while minimizing energy expenditure through the use of a vertical roller mill and cyclone arrangements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If LD slag is processed using conventional ball mill methods to achieve fine grinding, then the reactive phases are exposed and activated, but the production costs increase significantly and energy consumption rises

Engineering Contradiction:

Improvefineness of milled productVSAvoidproduction cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent replaces the conventional ball mill mechanical grinding system with a vertical roller mill that uses compressive and shear forces between rollers and a table. This substitution achieves finer particle size (D50 = 3-12 μm) with lower energy consumption and reduced production costs compared to traditional ball mill methods

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the grinding parameters by using a vertical roller mill configuration with specific roller pressure, table speed, and roller rotation speed parameters. These parameter optimizations enable efficient fine grinding of LD slag to activate reactive phases while maintaining cost-effectiveness

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If LD slag is landfilled to comply with environmental regulations, then environmental standards are met, but the potentially reactive phases are wasted and cannot be utilized as cement components

Engineering Contradiction:

Improveenvironmental complianceVSAvoidutilization of reactive phases

Core Design Contradiction:

Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The patent converts the previously harmful or waste material (LD slag that would require landfilling) into a beneficial cement component. By processing the slag through the vertical roller mill, the reactive phases are activated and the material becomes a valuable additive in cement production, eliminating landfilling requirements while utilizing the substance

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If the entire raw material is ground to achieve fineness of less than 5 µm to activate reactive phases, then the reactivity is maximized, but the energy expenditure increases significantly

Engineering Contradiction:

Improvereactivity of raw materialVSAvoidenergy consumption during grinding

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies partial action by grinding the LD slag to a controlled fineness of D50 = 3-12 μm using the vertical roller mill, which is sufficient to activate the reactive phases for cement applications. This partial grinding approach achieves the necessary reactivity without the excessive energy consumption that would result from grinding the entire material to ultra-fine particles of less than 5 µm

Inventive Principle:

Principle #16Partial or excessive action

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 high-quality composite materials from previously unsuitable raw materials, increasing their reactivity and reducing production costs, allowing LD slags to be used as main components in cement without violating environmental regulations.

Implementation Method 1

the raw material is comminuted by means of grinding rollers in a mill-sifter combination... the vertical mill having a grinding plate and several grinding rollers... to produce a milled product from the raw material fed into it with a fineness between D50 = 3 μm and D50 = 12 μm

Methodology Applied

Scientific EffectMechanical comminution: Fracture Mechanics

Implementation Method 2

During an initial sifting, raw material that has been comminuted at least once by the grinding rollers is returned from the sifter of the mill-sifter combination to the grinding plate of the vertical mill for further comminution by the grinding rollers

Methodology Applied

Scientific EffectSifting separation: Sedimentation

Data Source

PatentEP3322534B2Method and plant arrangement for beneficiating and activating of a raw material

Publication Date: 2023.10.18 LOESCHE GMBH

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AI summary

The invention relates to a method for providing and activating a raw material. The raw material is comminuted by grinding rollers in a mill/classifier combination. The mill/classifier combination is set and operated so as to produce a milled product with a fineness between D50 = 3 μm and D50 = 12 μm. In the process, a part of the milled product is comminuted to a diameter of < 5 μm by means of the mill/classifier combination. The milled product then undergoes further classification in a fine grain classifying assembly which has a separation limit in order to separate a very fine grain with a fineness of < D50 = 6 μm. The invention further relates to a system arrangement for carrying out the method according to the invention.