Dry Surface Modification of Alkaline Earth Metal Carbonates
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Solution Overview
Problem
Current processes for preparing alkaline earth metal carbonate-containing materials face challenges such as high costs, volatility of additives, foaming issues, and incompatibility with acid-sensitive materials, which hinder their effective modification for improved wetting properties and reduced VOC content.
Innovation Solution
A dry process involving the dry blending and grinding of alkaline earth metal carbonate materials with organophosphonic acids or their derivatives, which form chelate or salt complexes on the material surface, reducing moisture content and enhancing wetting properties without the need for aqueous suspensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional additives (glycols, lignin sulfonates, amines) are used for dry grinding and surface treatment, then the process can be carried out, but the additives are expensive, volatile (below 250°C), cause foaming, or darken white minerals
Solution Approach 1:
The patent changes the chemical parameters of the surface-modifying agent by using organophosphonic acids with high boiling points (>250°C) instead of conventional volatile additives. This parameter change eliminates VOC emissions and foaming while maintaining effective surface modification and wetting properties of the alkaline earth metal carbonate materials
Solution Approach 2:
The patent employs organophosphonic acids that are cost-effective alternatives to expensive conventional additives like glycols and lignin sulfonates. These compounds provide durable surface modification without the recurring costs associated with volatile, foaming, or mineral-darkening additives
2Reliability
If aqueous suspensions are used for surface treatment, then wetting can be improved, but the process becomes complex and requires dewatering steps
Solution Approach 1:
The patent extracts the water component from conventional aqueous suspension processes, implementing a purely dry process for surface modification. The organophosphonic acids are applied in dry blended form, eliminating the need for aqueous suspensions, dewatering equipment, and complex processing steps while achieving equivalent or superior wetting properties
Solution Approach 2:
The patent replaces the mechanical/chemical system of aqueous suspension and dewatering with a purely mechanical dry blending and grinding system. This substitution simplifies the overall process by eliminating liquid handling, drying, and dewatering operations
3Reliability
If strong acids and aluminium salts are used for surface treatment, then dispersion can be improved, but acid-sensitive materials like alkaline earth metal carbonates are damaged
Solution Approach 1:
The patent introduces organophosphonic acids as intermediary compounds that bridge the gap between the mineral surface and the desired dispersion properties. These compounds adsorb onto the alkaline earth metal carbonate surfaces through chelation, providing effective surface modification and improved dispersion without requiring strong acids or aluminium salts that would damage the material
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 process achieves alkaline earth metal carbonate materials with improved wetting properties, reduced foaming, and lower VOC content, enabling their efficient use in applications like paper, plastics, and paints while minimizing environmental impact and costs.
Implementation Method 1
organophosphonic acids or their derivatives, which form chelate or salt complexes on the material surface
Implementation Method 2
dry grinding the blend in at least one grinding unit during and/or after step (c)... wherein the blend has a total moisture content of less than 1.5 wt.-%
Data Source
AI summary
The present invention relates to a process to modify at least part of the surface of an earth alkaline metal carbonate-containing material in a dry blending process as well as to a mineral product obtainable by the inventive process and uses thereof.