How We Eliminated Dusting and Airborne Dust Issues in Dry Mortar Mix Processing
Dust generation during handling of dry mortar mixes increases the risk of contamination, material loss, and endangers workers' health. Learn how we helped a manufacturer reduce dust levels by over 80% using targeted additives and process optimization.
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The production of dry mortar mixes is a process where even small details determine the quality of the final product. One of the most common problems faced by manufacturers is excessive dustiness during mixing, packaging, or application. Dust not only worsens the working environment but can also lead to the loss of valuable raw materials, contamination of surrounding equipment, or even violations of hygiene standards. In this article, we will look at a specific case where we helped a client identify the causes of dustiness and implement a solution based on the correct selection of additives and modification of the technological process. The result was not only significantly lower dustiness but also more stable mix quality and reduced equipment maintenance costs.
The problem of dusting and dustiness: How we identified it
The production of dry mortar mixtures is a process where high efficiency meets stringent quality and safety requirements. At one of our facilities, we faced excessive dusting and airborne dust, which complicated not only working conditions but also the production itself. The problem was particularly evident during the mixing, dosing, and packaging of mixtures, when a significant amount of fine particles was released into the air. This led to more frequent equipment cleaning, increased consumption of filtration systems, and the risk of exceeding dust exposure limits for workers according to REACH and CLP regulations.
The first step toward a solution involved a detailed analysis of the process. We found that the key factor was the particle size and distribution in raw materials, particularly in fillers such as hydrated lime or silica sand. Fine fractions below 60 micrometers tend to be easily released into the air, while coarser particles remain more stable. We also identified that the moisture content of raw materials plays a crucial role—even small deviations from the optimal value (typically 0.1–0.3%) can significantly increase dustiness.
Selecting suitable additives to reduce dustiness
After identifying the causes, we focused on selecting additives that would help reduce dustiness without negatively affecting the properties of the final product. The primary candidates were anti-dust additives based on mineral oils, fatty acid esters, or special polymers. These substances work on the principle of agglomerating fine particles—they form a thin film on the surface of particles, increasing their cohesion and reducing the tendency to be released into the air.
During testing, we focused on compatibility with the mortar mixture formulation. For example, mineral oil-based additives are effective but may affect the adhesion of mortars to the substrate or slow down cement hydration. Therefore, we selected a combination of low-viscosity mineral oil and fatty acid ester, which provided an optimal balance between dust reduction and preservation of technical properties. The dosage ranged from 0.1–0.3% of the mixture weight, which is sufficient to achieve the desired effect.
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Optimization of Process Parameters and Technological Adjustments
In addition to using additives, we made adjustments to the production process itself. A key step was the introduction of controlled moistening of raw materials before mixing. By adding a small amount of water (0.2–0.5% by weight) to the mixture, we achieved better particle agglomeration without premature cement hydration. This step was implemented using precise dosing equipment, which ensured even moisture distribution throughout the entire mixture volume.
Another modification was reducing the mixing speed and raw material dosing rate. High mixer speeds led to excessive swirling of fine particles, increasing dustiness. After reducing the speed by 20–30%, we observed a significant improvement. At the same time, we optimized the filtration systems in the plant – we increased filter capacity and introduced regular maintenance to prevent clogging and subsequent dust leakage back into the workspace.
Results and long-term benefits of the solution
After implementing the above measures, dust levels in the plant were reduced by more than 70%, significantly improving working conditions and reducing equipment maintenance requirements. Control measurements showed that airborne dust concentration dropped below the hygiene limits set by regulations, eliminating the risk of worker exposure. At the same time, production efficiency increased – the frequency of shutdowns for cleaning and filter replacement decreased, leading to time and cost savings.
In the long term, we have also achieved additional benefits. A more stable mixing and dosing process led to more consistent quality of the final mortar mixtures, which was particularly appreciated by customers in the construction industry. Furthermore, the additives used did not affect the mechanical properties of the mortars, such as compressive strength or adhesion, as verified by standard testing methods. This example demonstrates how a systematic approach to solving operational issues can bring comprehensive improvements across the entire production chain.
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Impact of Humidity and Temperature on the Effectiveness of Dust-Suppression Additives
When reducing dustiness in dry mortar mixtures, not only the selection of the right additive plays a key role, but also the control of ambient conditions during processing. Humidity and temperature in the production facility can significantly affect the effectiveness of dust-suppressing additives, particularly those based on mineral oils or polymers. The ideal relative air humidity ranges between 40–60 %, where lower values can lead to excessive evaporation of volatile components of the additive, while higher humidity causes particle agglomeration and impairs the dispersibility of the mixture.
The temperature in the production facility should be maintained between 15–25 °C to prevent degradation of the additive or changes in its viscosity. For example, in the case of additives based on polyglycols, temperatures above 30 °C can reduce their tackiness and thus their effectiveness. It is therefore recommended to monitor the microclimate in the facility using data loggers and, if necessary, adjust ventilation or heating. In practice, preheating raw materials to a stable temperature before mixing has also proven effective, ensuring consistent distribution of the additive throughout the mixture.
Practical experience with dosing and mixing of additives
Dosing dust-suppressing additives requires a precise approach, as even small deviations can lead to insufficient effectiveness or, conversely, excessive tackiness of the mixture. In our case, we tested dosing in the range of 0.1–0.5 % of the mixture weight, with the optimal amount varying depending on the type of additive and the composition of the mortar mixture. For additives based on mineral oils, the ideal dosage was around 0.2 %, while for polymeric additives, 0.3–0.4 % proved effective.
A key factor is also the method of additive application. The most effective method has proven to be spraying the additive during mixing in a rotating drum or continuous mixer, where uniform coating of the particles occurs. In batch processes, it is necessary to ensure sufficient mixing time (at least 3–5 minutes) and monitor the homogeneity of the mixture visually or using standard test methods. In some cases, it may be advantageous to pre-dilute the additive with a suitable solvent to improve its distribution.
Long-term stability and compatibility with other additives
When introducing dust-suppressing additives into the production process, it is essential to verify their compatibility with other components of the mortar mixture, especially with hardening accelerators, plasticizers, or hydrophobic additives. Some additives may negatively affect the reactivity of cement or slow down hydration, leading to deterioration in the mechanical properties of the final product. In our case, we therefore conducted long-term stability tests of mixtures with various combinations of additives, including compressive strength and moisture resistance tests.
Another important aspect is the shelf life of mixtures with dust-suppressing additives. Some additives based on organic substances may degrade over time or lose effectiveness, especially when stored under unsuitable conditions (high temperature, direct sunlight). It is therefore recommended to perform regular quality checks of stored mixtures and adhere to the recommended shelf life. In practice, additives with REACH certification and verified stability, which guarantee consistent performance throughout the product's lifespan, have proven effective.
Need a Custom Solution?
Every production line has its specific requirements. GCG Group always provides detailed technical data sheets and safety data sheets with the supplied raw materials, and our experts will help you select the optimal solution for your application – whether it’s reducing dustiness, improving processability, or increasing the durability of the final product. Contact us – or browse our catalog of over 1,300 products right away.
