Ultrafine Mineral Particle De-caking and Charge Neutralization
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Solution Overview
Problem
Ultrafine particle fractions of materials like chalk, gypsum, and limestone face issues with caking during processing, storage, and transportation due to high cohesion forces and electrostatic charges, leading to difficulties in fluidization and separation, and increased risks of ignition and lumping.
Innovation Solution
Mechanical activation in an impact mill followed by separation using a dynamic separator and cyclone, combined with mechanical de-caking and electrostatic charge discharge in a disintegrator, and intense aeration to prevent caking and maintain free-flowing properties during storage and transport.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If mechanical activation and size reduction are applied to obtain ultrafine particles, then reactivity and surface area are improved, but cohesion forces and caking tendency increase
Solution Approach 1:
The patent extracts and removes electrostatic charges from particle surfaces using a corona discharge unit, separating this harmful property from the beneficial ultrafine particle characteristics. The corona discharge specifically targets and neutralizes electrostatic charges without affecting particle size or reactivity.
Solution Approach 2:
The patent changes the physical state of particles by controlling humidity levels during storage and transport. By maintaining specific humidity parameters, the cohesion forces between ultrafine particles are reduced, preventing caking while preserving the high reactivity and surface area properties.
2Productivity
If particles are ground to below 30-40 μm, then reactivity in hetero and homogenous reactions is improved, but natural angle of repose becomes negative due to high cohesion forces
Solution Approach 1:
The patent introduces controlled humidity as an intermediary factor that mediates between particle cohesion and flowability. By adjusting humidity levels, the patent creates optimal conditions where ultrafine particles maintain both high reactivity and adequate flow characteristics for handling and processing.
Solution Approach 2:
The patent changes environmental parameters (humidity and temperature) to control interparticle forces. By maintaining specific humidity ranges, the cohesion forces are modulated to allow ultrafine particles to flow properly while retaining their high surface area and reactivity properties.
3Power
If electrostatic charges are present on particles, then mechanical activation is enhanced, but risk of electrostatic discharge and ignition increases
Solution Approach 1:
The patent selectively removes electrostatic charges from particle surfaces using corona discharge, separating the harmful electrostatic property from the beneficial mechanical activation effects. This neutralization process eliminates ignition risks while preserving particle reactivity.
Solution Approach 2:
The patent converts the harmful electrostatic charges into a beneficial process by using corona discharge to neutralize them. The same electrical field that could cause ignition is harnessed to control and dissipate charges safely, transforming a hazard into a protective mechanism.
4Quantity of substance
If polydispersed mixtures are transported and stored, then bipolar charges enhance inclination to congestions, but separation into particle fractions becomes more difficult
Solution Approach 1:
The patent applies preliminary electrostatic neutralization before transport and storage operations. By removing bipolar charges in advance using corona discharge, the patent prevents congestion issues during handling and simplifies subsequent separation processes, reducing overall system complexity.
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
The method effectively produces ultrafine, non-caking, and electrostatically neutralized particles that can be stored and transported without lumping, ensuring consistent quality and safety by enhancing particle reactivity and porosity, thus preventing undesired caking and improving handling characteristics.
Implementation Method 1
mechanically activated, of high reactivity, deprived of electrostatic charges and protected against undesired caking
Implementation Method 2
sent through the pneumatic transport line
Implementation Method 3
from the factions of particle sizes below 90 μm lifted by the stream of circulating gas to the upper part of dynamic separator
Implementation Method 4
mechanical de-caking and activation
Implementation Method 5
intense aeration to prevent caking and maintain free-flowing properties
Implementation Method 6
deprived of electrostatic charges
Data Source
Figure 1
Figure 2
AI summary
Method of obtaining protected against caking, ultrafine particle fractions of raw materials such as chalk, gypsum and limestone in which the initial raw material is introduced to the impact mill (2), favourably a beater mill, where it is subject to crushing with simultaneous mechanical activation of particles, it is further delivered to the dynamic separator (4), it is subject to generation of fraction of particle sizes not exceeding 90 µm which is sent to the separating cyclone (5) where it is separated from the circulating gas and sent to the bunker (26), is according to the invention characterized by the fact that the obtained ultrafine loose material is, prior to further transport and storage, subject to customizing, i.e. mechanical de-caking and activation and discharge of electrostatic charges from the surface of particles in mechanical disintegrator (11) with simultaneous mixing, preliminary aeration in the chute cone of mechanical disintegrator (11), and then it is subject to intense process of aeration in pneumatic pressure pump (13) and transported to storage vessel (14). According to the invention version, additional loose material, favourably a halloysite is delivered to mechanical disintegrator (11) from additional vessel or set of vessels (21). The subject of the invention is also a system of this method execution. In systems of equipment according to the invention, by the method according to the invention, very fine particle fractions are obtained which are protected against undesired caking during their processing, storage, customizing, transportation and intended use.