Direct answer: “silica sand” is not one single product for paint and resin
For paint, resin or an industrial coating, asking simply for “silica sand” is not precise enough.
The first step is to distinguish the silica form required:
| Form | Typical use | Priority controls |
|---|---|---|
| Quartz flour / micronized powder | Paints, coatings, some resins | particle-size distribution, dispersion, colour, moisture |
| Fine graded quartz | Filled resins, resin mortars, self-levelling layers | fraction, moisture, cleanliness, consistency |
| Graded quartz sand | Broadcast resin floors, anti-slip systems, mortars | grading envelope, drying, cleanliness, lot |
| Functional quartz or cristobalite | Targeted technical formulations | mineralogy, surface, particle size, binder compatibility |
Industrial literature confirms that mineral fillers for paints and polymers are supplied in very different particle sizes and can even be surface-modified to match polymer systems [4–5].
In Morocco, the key requirement is therefore not to find a generic label but to define the form, particle size and level of control required by the formulation.
For a general overview of industrial grades, see our silica sand guide.
Quartz flour and graded sand: do not treat them as the same material
The word silica covers very different products.
A liquid or powder coating can use a very fine filler. An epoxy floor, by contrast, may require granular quartz to fill the resin, build system thickness or create a broadcast surface.
This distinction changes:
- dosing method;
- viscosity;
- dispersion;
- texture;
- application behaviour;
- storage;
- dust generation;
- particle-size control.
A 0.3–0.8 mm sand and micronized quartz flour can both be rich in SiO₂, but they do not perform the same role in a formulation.
Particle size: the first parameter to lock down
Particle size directly affects how a filler is incorporated into the system.
For a fine powder, the formulator may monitor a particle-size distribution or indicators such as D50, D90 or sieve residue. For sand used in a resin floor, it is often more useful to work with a defined graded fraction.
Commercial systems clearly show this diversity.
In one documented Sikafloor epoxy system, Sika uses, depending on the layer:
- 0.1–0.3 mm quartz as filler in certain layers;
- 0.3–0.8 mm quartz for certain broadcast layers;
- 0.7–1.2 mm quartz for other configurations [6].
These values are examples from one specific system, not universal specifications.
The purchasing rule is therefore:
particle size should be derived from the paint or resin system, not selected independently.
Why particle size must be tested in the actual resin
A study published in the International Journal of Adhesion and Adhesives compared several quartz-powder fractions in epoxy coatings on concrete. The authors showed that particle size and quartz loading are variables that need to be evaluated in the actual formulation; their testing used loadings up to 29% by mass [8].
This does not mean that 29% is suitable for every resin.
It shows that a supplier cannot predict finished-product performance from the mineral name alone.
Behaviour also depends on:
- binder;
- filler volume fraction;
- wettability;
- dispersion method;
- substrate surface;
- applied thickness;
- other pigments and additives.
Paints and coatings: when fine silica is used
Mineral fillers can perform several functions in a paint or coating formulation.
Depending on the formulation, they can contribute to:
- film build;
- surface hardness;
- wear resistance;
- texture;
- matting;
- volumetric cost control;
- selected mechanical or chemical properties.
A Moroccan university source on mineral engineering cites finely divided quartz and cristobalite as fillers in paints and plastics, particularly for hardness and resistance to abrasion and chemical attack [3].
Quarzwerke also documents mineral fillers in paints, lacquers and coatings and emphasizes consistent quality and application-specific filler selection [4].
The practical consequence is important:
for paint, the word “sand” can be misleading when the formulation actually requires quartz flour or a micronized filler.
Resin flooring: quartz also becomes a functional aggregate
In epoxy flooring and thick coatings, quartz can be used in a different way from powder.
It can serve as:
- filler blended into resin;
- aggregate for resin mortar;
- material broadcast over a fresh layer;
- component used to create anti-slip texture.
The Sika Quartz 02 IN data sheet, for example, describes graded, cleaned and dried quartz developed for broadcast flooring systems and selected epoxy repair applications [7].
Here, cleanliness and drying are not minor logistics details: they are preparation characteristics of the product.
Moisture: define a limit instead of asking only for “dry sand”
For resin systems, “dry” should become a measurable specification.
Moisture can affect:
- the actual mineral mass dosed;
- sand flowability;
- dispersion;
- mixing repeatability;
- storage and agglomeration;
- some resin systems that are sensitive to water.
The acceptable limit depends on the binder and process.
It is therefore not appropriate to impose one universal value. The formulator should define:
- measurement method;
- maximum limit;
- control frequency;
- lot-acceptance basis.
For broadcast sand or resin mortar, it is also useful to verify that the material arrives clean, with no visible contamination and with a stable fraction.
Whiteness, colour and iron: criteria tied to the finished product
Whiteness is often presented as an absolute sign of quality.
It is not.
For a white, light-coloured or translucent coating, the intrinsic colour of the filler can affect the finished appearance. In a heavily pigmented resin or dark system, this criterion can become secondary.
The same caution applies to iron.
A higher iron-oxide content can influence the colour of some silica materials, but there is no single Fe₂O₃ limit that applies to every paint and resin system.
A serious specification should therefore define, when colour is critical:
- whiteness or colour measurement method;
- target value or tolerance;
- reference sample;
- control frequency;
- iron or other oxide content where the formulation justifies it.
Chemical purity: important, but not sufficient
Two fillers with similar SiO₂ content can behave differently.
Qualification may require:
- SiO₂;
- Fe₂O₃;
- Al₂O₃;
- CaO;
- MgO;
- loss on ignition where relevant;
- mineralogy;
- particle size;
- moisture;
- colour;
- bulk density.
Chemistry should be selected according to the finished product.
In many resin systems, particle size, dispersion and lot consistency can be as important as small differences in overall SiO₂ content.
Quartz, cristobalite and surface treatment
The word “silica” also does not define the mineral phase.
Quartz and cristobalite have different properties. Specialist suppliers also offer fillers whose surfaces are modified to improve behaviour in selected polymer systems [5].
That does not mean a treated filler is always better.
It must be compatible with:
- binder chemistry;
- curing system;
- pigments;
- additives;
- target viscosity;
- application conditions.
For an initial purchase, it is therefore useful to ask whether the filler is:
- natural or transformed;
- quartz, cristobalite or a mixture;
- surface-treated or untreated;
- micronized or simply screened.
Morocco context: a real industrial application without inventing a market
Morocco’s Ministry of Industry and Trade lists chemical and para-chemical industries among national industrial sectors and names Atlas Peintures among sector companies [1].
An institutional publication linked to the 2014–2020 Industrial Acceleration Plan also identified resins and technical paints, historically, among targeted organic-chemistry value chains [2].
These sources show that paint and resin formulation has an industrial context in Morocco.
They do not support claims about:
- current market size;
- current silica consumption volume;
- Minerallum production capacity;
- any specific customer;
- a defined local origin for the quartz.
We therefore do not turn these sources into commercial numbers that they do not provide.
Lot reception: a technical data sheet may not be enough
For recurring purchases, it is preferable to define an incoming-inspection sheet.
| Parameter | Why control it |
|---|---|
| Particle size | Maintain viscosity, texture and system behaviour |
| Moisture | Avoid dosing and handling variations |
| Colour / whiteness | Stabilize appearance when the finished product is sensitive |
| Chemistry | Control the oxides or elements that actually matter |
| Cleanliness | Reduce contamination, foreign matter and irregularity |
| Packaging | Protect the material from moisture and contamination |
| Lot number | Ensure traceability and compare deliveries |
A quarry average or old analysis does not replace a representative control of the delivered lot.
Formulation trial: the final step before qualification
A certificate of analysis confirms raw-material characteristics.
It does not by itself confirm:
- paint viscosity;
- ease of dispersion;
- levelling;
- gloss or matting;
- texture;
- adhesion;
- wear resistance;
- hardener compatibility;
- cured-floor behaviour.
For a sensitive formulation, the sound sequence is:
- review documentation;
- obtain a representative sample;
- measure incoming parameters;
- prepare a pilot mix;
- compare against the reference filler;
- validate before moving to industrial volume.
Crystalline silica: build prevention into the specification
As particle size decreases, dust control becomes increasingly important.
INRS notes that inhalation of dust containing respirable crystalline silica can have serious health effects and that exposure should be reduced [9].
For fine powders, particular attention should therefore be given to:
- bag opening;
- dosing;
- transfer;
- mixing;
- cleaning;
- spill recovery.
Prevention measures should be adapted to the site, process and applicable regulations.
This does not change the technical selection of the filler, but it can change the packaging, handling and transfer equipment required.
Purchasing specification: information to provide
To assess silica for paint, resin or coating use in Morocco, provide at least:
- final application;
- binder type;
- micronized powder or graded sand;
- required particle-size distribution or fraction;
- maximum moisture;
- colour or whiteness where critical;
- required chemistry;
- any surface treatment;
- quantity per order;
- frequency;
- bags, big bags or other packaging;
- delivery city;
- customer test method or internal reference.
Quality therefore does not come down to “high SiO₂.”
For this family of applications, the right material is the one whose form, particle size, moisture, appearance and consistency genuinely match the formulated system.