Optimizing Crushed Sand Production for the Dry-Mix Mortar Industry

The production of dry-mix mortar aggregate requires effective interaction of suitable comminution and sizing machines. For this purpose, experimental tests on pilot or large-scale are essential. Of considerable importance for the design of the plant configuration is also consideration of the influence of mineralogical-petrographic rock properties of the raw material deposit, in order to develop for the plant operator a flexible equipment concept for long operating lifetime with high equipment availability

The production of high-quality dry-mix mortar requires precise control over aggregate properties. With increasing demand for consistent and sustainable mortar solutions, optimizing the production of crushed sand has become a critical factor in the construction industry.

Natural sands, while commonly used, present challenges such as impurities, inconsistent particle size distributions, and high processing costs. As a result, manufacturers are increasingly turning to mechanical processing of solid rock to produce crushed sand that meets the high standards required for mortar applications. This newsletter explores key strategies and innovations in optimizing crushed sand production.

Understanding Mortar and Aggregate Requirements

"Mortar" is a fundamental building material composed of a binder (e.g., cement, lime), mineral aggregate with a maximum particle size of 4.0 mm, necessary additives, and mixing water. Given the diverse applications of mortar, the quality and quantity of mineral aggregates must meet stringent requirements.

The demand for mortar aggregates can be met either through natural sand deposits or via mechanical processing of solid rock. However, natural sands present several limitations, including deposit-specific particle size distributions and impurities such as loamy and clayey fines, alkali-reactive components, and brittle rock fragments. These impurities must be eliminated through extensive washing and sorting processes, increasing production complexity.

In contrast, producing mortar aggregate from solid rock—though requiring a relatively higher processing effort—offers greater flexibility. This involves multi-stage, stationary crushing and classification systems that allow precise control over the grain composition. Such a process ensures adaptability to market demands, optimizing the production of high-quality aggregates.

The Need for Optimized Crushed Sand

For dry-mix mortar production, the right combination of crushing and screening technologies is essential to achieve:

• Controlled Particle Size Distribution – Ensuring the right mix of fine and coarse particles for workability and durability.
• Minimal Impurities – Removing loamy fines and other contaminants that can affect mortar quality.
• High Efficiency – Reducing energy consumption and machine wear while maintaining high throughput.

Key Considerations in Crushed Sand Production

For the production of mortar aggregates <4 mm, rock must be extracted from suitable deposits by means of drilling and blasting. The large lumps of blasted rock with a particle size of around 0/1500 mm are then processed in a precrushing installation by means of multistage comminution and sizing processes. For the production of mortar aggregate 0/2 mm (0/4 mm), the particle fraction 0/22.4 mm from the precrushing installation is comminuted further in a downstream dry-mix mortar plant and the crushed material separated into particle fractions, which then, depending on the mortar quality, are combined to defined particle size curves.

For realization of the “comminution” and “sizing” processes, a wide range of machines and equipment is available from different manufacturers. For optimum selection of the necessary comminution and sizing technology, various criteria must be taken into consideration, e.g.:

The properties of the material to be comminuted and sized (e.g. mineralogical and chemical composition, feed size, abrasiveness, strength properties and hardness, apparent and bulk density, surface moisture, etc.)

? Granulometric aspects, e.g. the number and particle ranges of the required particle fractions as well as their yield (quantities). The particle shape is not a factor in mortar aggregates

? Stress and separation conditions and the possibilities for their mechanical realization in the design and selection of the working tools (e.g. size and shape of the comminution and sizing tools; stress type and velocity, etc.

1. Rock Selection and Characterization

Soft to medium-hard sedimentary rocks such as limestone and dolomite are commonly preferred due to their ease of crushing and consistent composition. Advanced petrographic, mineralogical, chemical, and physical analyses help in selecting the best raw materials o ensure they meet industry standards. Petrographic characterization primarily involves evaluating the rock type and its mineralogical composition. This method helps determine rock crushability, particle size and shape distribution, wear potential on machinery, and energy input required for comminution. Such data is essential for optimizing the processing of aggregates.

rom a geometric perspective, DIN EN 13139 specifies preferred particle size fractions such as 0/1 mm, 0/2 mm, 0/4 mm, 0/8 mm, 2/4 mm, and 2/8 mm. However, dry-mix mortar producers often require finer particle distributions to enhance packing density, minimize water demand, and improve mortar performance. To maintain quality, oversize particles should be limited to 15% mass, while undersized particles should not exceed 6–8% mass. Though no specific shape requirements exist for aggregates smaller than 4 mm, optimizing particle shape enhances material flow and final product quality.

Chemical composition also plays a significant role in aggregate selection. EN 12620 and EN 13139 set strict limits on chemical contaminants that can impact mortar solidification, strength, or appearance. Notable restrictions include:

• Chloride content: ≤ 0.04% mass
• Water-soluble sulfate (SO3): ≤ 0.8% mass
• Sulfur content: ≤ 1.0% mass
• Organic impurities: ≤ 0.5% mass

Aggregates are typically analyzed for their oxide composition, measuring elements such as SiO2, TiO2, Al2O3, Fe2O3, FeO, MnO, MgO, CaO, K2O, and Na2O. While these values may not directly affect mechanical processing, they can indicate changes in rock strength, hardness, and abrasiveness, which in turn influence wear rates on processing machinery.

The physical-technical properties of aggregates further determine their suitability for dry-mix mortar applications. These properties include:

• Density & Water Absorption – Affects mortar consistency and workability.
• Rock Hardness & Strength – Determines how aggregates behave during processing.
• Abrasiveness – Influences machine wear and maintenance requirements (limestone is mildly abrasive, while quartzites are highly abrasive).
• Fracture Toughness – Higher values require greater energy input for crushing.

2. Advanced Raw Material Screening Tests

To develop optimal plant configurations, extensive comminution and screening tests are essential. At Haver & Boecker Niagara we conduct those tests at our own Research and Development Center, Haver Engineering, in Freiberg, where we also perform feasibility studies to determine the best processing solutions for each application. The primary goal of these tests is to determine the most efficient operating parameters for the crushing systems being evaluated. This ensures maximum production of high-quality limestone aggregates with minimal energy consumption and reduced machine wear.

Once crushed, the material undergoes precise screening to separate it into specific particle size fractions according to customer requirements. These fractions are stored in dedicated bins, while any oversized materials are recirculated back into the comminution system for further refinement. This closed-loop process optimizes material flow, enhances plant efficiency, and minimizes waste. The lower the recirculated material volume, the higher the overall plant throughput, ensuring consistent and cost-effective production.

3. Advanced Crushing Technologies

The raw materials usually used in the production of mortar aggregates require the use of suitable machines for mediumhard comminution (Mohs hardness of 2…5). Impact crushers and hammer mills are often used to achieve the required particle sizes. The choice of crushing equipment depends on factors such as feed size, abrasiveness, and desired end-product quality. At Haver & boecker Niagara we work we proved crushing providers that are able to ensure you the perfect process flow.

To optimize the crushing process, different size fractions of pre-screened limestone need to be tested in various crushers. Impact crushers process material sized 0/22 mm, while hammer crushers and high-pressure piston-die presses work with 0.7/10 mm fractions. The main focus should be on adjusting rotor circumferential speed in impact and hammer crushers to control product fineness, while in pressure comminution, pressure levels should range between 100 MPa and 200 MPa.

After crushing, the material needs to be analyzed using HAVER & BOECKER EML-200-T sieves to determine particle size distribution. The goal is to produce mortar aggregate fractions of 0.15/0.5 mm, 0.5/0.71 mm, 0.71/1.2 mm, and 0/1.2 mm to meet industry specifications. Additionally, the fine content (<0.075 mm) must be measured, as it plays a crucial role in determining mortar workability.

Results indicate that pressure comminution generates excessive fines while failing to yield enough usable mortar aggregate. On the other hand, impact and hammer crushers provide well-balanced particle size distributions. This data should be used to create machine-specific product curves, forming the basis for plant design.

For successful full-scale production, certain conditions must be met:

• Machine and operating parameters should remain consistent with those defined in testing.
• Raw material homogeneity is essential to maintain steady output quality.
• Mineralogical and petrographic consistency in the deposit prevents fluctuations in crushing efficiency and machine wear.

By fine-tuning crushing parameters and selecting the right equipment, Haver & Boecker Niagara ensures efficient, high-quality crushed sand production tailored to dry-mix mortar applications.

4. Efficient Screening and Classification

Proper screening ensures that the sand meets the required size specifications. The selection of a screen and the definition of its configuration depend on a number of influencing factors. To guarantee high product qualities and quantities, it is necessary to define:

• A sufficiently large screening area and
• An optimum screen aperture (size and shape) for every cut-point.

For high throughput rates, the largest possible screen aperture is advantageous. For accurate screening, relative to the respective cut-point, narrow screen apertures are useful, to keep any misplaced particles in the screen oversize and undersize within the prescribed limits. With the selection of such a mesh width, oversize particles in the undersize can be reduced or even completely excluded, as a result of which, however, misplaced (undersize) particles in the screen oversize can increase to impermissible values. As a result, the yield of fines is reduced considerably.

The multi-deck screening systems and advanced classifiers of Haver & Boecker help achieve precise separation and grading of sand particles, improving overall efficiency and reducing material wastage.

5. Process Optimization Through Simulation

For the design of crushed sand plants, mass flow calculations need to be performed while considering machine-specific operating parameters of the selected comminution technology. Additionally,it is useful to analyse particle size distributions of the mortar products. Innovative process simulation software like NIAflow, developed by Haver & Boecker Niagara, enables manufacturers to model crushing and screening circuits, optimize material flow, and reduce waste. By using NIAflow, operators can ensure consistent quality and maximize plant productivity.

6. Plant Configurations

The dry-mix mortar aggregates are generally produced in stationary crushing and sizing plants. As raw materials, suitable soft to medium-hard rocks (e.g. limestones, dolomites, anhydrites and gypsums) are used, which can be comminuted with relatively low energy input and machine wear. For the comminution part of the dry-mix mortar plant, usually machines with impact and percussion-type stresses (e.g. impact and hammer crushers) are used. In the selection of the crushing system, it is necessary to consider advantages and disadvantages in respect of

• Yield of product grades,
• Production of excess grades,
• Specific work requirement,
• Wear of relevant plant components and
• Guarantee of a stable throughput rate.

Comprehensive Solutions from Haver & Boecker Niagara

At Haver & Boecker Niagara, we are not just a supplier of individual machines—we are a full-scale plant manufacturer and process engineering partner. We specialize in designing, engineering, and implementing complete turnkey processing plants for the dry-mix mortar industry, ensuring seamless integration of all components for maximum efficiency and performance. We develop integrated solutions that optimize efficiency and performance at every stage of the process flow.

Our ProCheck Approach ensures that we analyze, plan, and deliver customized solutions that encompass:

• Complete Prinary Crushing & Screening Plants – End-to-end solutions tailored to specific requiremets.
• Vibrating Screens – High-performance screening technology for accurate particle separation.
• Screen Media – Durable and efficient screen panels tailored to specific applications.
• Aftermarket Service – Dedicated support for maintenance, training, and troubleshooting.
• Spare Parts – Reliable supply of high-quality components to maximize uptime.
• Pulse Condition Monitoring – Advanced diagnostic technology to monitor screen health and predict maintenance needs, reducing unexpected downtimes.

The Impact of Optimized Crushed Sand

By implementing these strategies and leveraging Haver & Boecker Niagara’s cutting-edge solutions, dry-mix mortar manufacturers can achieve:

• Higher product consistency and quality
• Improved sustainability with reduced raw material waste
• Lower operational costs and increased equipment lifespan
• Optimized plant performance through digital process modeling
• Reduced unplanned downtimes through Pulse Condition Monitoring

Case Study: Optimized Crushed Sand Production in a Dry-Mix Mortar Plant

A leading dry-mix mortar manufacturer partnered with Haver & Boecker Niagara to optimize their crushed sand production. The plant was facing challenges with inconsistent particle size distribution, excessive fines generation, and high recirculation rates.

Challenges:

• Excessive fines affecting mortar performance
• High wear rates on screening equipment
• Inefficient recirculation leading to energy losses

Solution Implemented:

Haver & Boecker Niagara provided a tailored solution based on comprehensive testing at Haver Engineering in Freiberg. The key improvements included:

• Optimized Impact Crushers – Adjusted rotor speeds to control fines production
• Precision Screening – Achieved accurate separation of required particle size fractions
• NIAflow Simulation – Enabled fine-tuning of process parameters for maximum efficiency
• Reduction of Recirculation Rates – Improved plant throughput and energy efficiency

Results Achieved:

• 40% reduction in fines generation
• 20% increase in plant efficiency
• Lower maintenance costs due to optimized wear part usage
• Consistent and improved mortar quality

This case study underscores how Haver & Boecker Niagara’s expertise, turnkey solutions and ProCheck approach drive efficient and high-quality crushed sand production, ensuring optimal performance for dry-mix mortar manufacturers, while reducing operational costs.

Conclusion

The optimization of crushed sand production is a game-changer for the dry-mix mortar industry. With the right combination of material selection, advanced processing techniques, and data-driven optimization, manufacturers can ensure high-quality mortar that meets modern construction demands. By integrating Haver & Boecker Niagara’s solutions, companies can stay ahead in the competitive landscape, improve operational efficiency, and maximize uptime through smart condition monitoring and proactive maintenance.

Stay ahead in the industry by investing in smarter sand production solutions with Haver & Boecker Niagara!