Everything you want to know about surface modification of quartz sand powder is from modified silica micro powder manufacturers

1. Why is surface modification necessary for quartz sand powder

(1) Change the surface hydrophilicity, wettability, oil absorption, viscosity, etc. of quartz sand powder;

(2) Improve the compatibility, affinity, dispersibility, and flowability of quartz sand powder as a filler with organic polymers;

(3) Improve the bonding strength between quartz sand powder filler and organic polymer interface;

(4) Improve the performance of composite materials.

2. Surface coating modification of quartz sand powder

Surface coating modification of quartz sand powder is the use of resins or polymers to "coat" the surface of quartz sand powder, such as coating quartz sand with furan resin, which can increase the production of oil wells during drilling; Coating quartz sand with phenolic resin can improve the bonding performance of fine casting sand. Coating modified casting quartz sand not only has a higher investment casting speed, but also maintains high anti cracking and anti roll shell performance of the mold and mold core in production.

Before coating modification, it is generally necessary to scrub and dry the quartz sand powder, which can be divided into two types: cold coating and hot coating.

3. Chemical modification of quartz sand powder surface

(1) Dry surface chemical modification of quartz sand powder

Dry surface chemical modification of quartz sand powder involves high-speed stirring and dispersion of the dried quartz sand powder with a modifier treatment solution, followed by heating treatment.

This process has the characteristics of simple process, flexible operation, low investment, and good applicability of modifiers.

(2) Wet surface chemical modification of quartz sand powder

Wet surface chemical modification of quartz sand powder is a treatment solution prepared by mixing pre configured surface modifiers and additives, which is stirred, dispersed, and subjected to certain temperature conditions for surface modification of quartz sand powder, followed by dehydration and drying.

Compared with the dry process, the wet process has the characteristics of good dispersion of modifiers and uniform coating on the powder surface. However, the wet process requires dehydration (filtration and drying), so it is suitable for various water-soluble or hydrolyzed modifiers, as well as the process flow where the first stage is wet grinding and the second stage requires drying.

(3) Mechanical grinding and chemical coating modification of quartz sand

Mechanical grinding and chemical coating modification of quartz sand refer to the addition of modifiers during mechanical force or fine or ultrafine grinding processes, and surface modification of quartz sand particles as their particle size decreases.

The characteristic of this composite modification process is that the process is relatively simple, and some modifiers also have a grinding aid effect, which can improve the crushing efficiency. However, the temperature is difficult to control, and the particles are constantly crushed, producing new surfaces. The coating of modifiers is difficult to achieve uniformity. In addition, the grinding equipment generates local high temperatures during the process of strong mechanical force, causing some modifiers to decompose or their molecular structures to be destroyed.

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