Silica Sand Beneficiation – Testwork & Process Evaluation
Mineral Processing Testwork | Gravity & Magnetic Separation | Chemical Purification | 2025
Specialist mineral processing testwork facility in China, where silica sand beneficiation trials were conducted in April 2025. MCS attended the programme to observe testing, evaluate processing technologies and review the results.
Project Overview
Mittermaier Consulting Services (MCS) participated in a preliminary technical evaluation of silica sand beneficiation technologies for a proposed mineral processing development in Southeast Asia.
The objective was to investigate processing methods capable of improving silica sand purity by reducing iron-bearing and other mineral impurities, providing a technical basis for subsequent processing plant development.
During April 2025, a laboratory testwork programme was undertaken at a specialist mineral processing equipment manufacturer’s testing facility in China.
MCS provided technical input, coordinated with the specialist equipment supplier, and participated directly in the evaluation. MCS’s Principal Consultant attended the testwork in person to observe processing performance, discuss technical alternatives and review the findings.
MCS Scope of Services
MCS’s involvement included:
- Preliminary assessment of silica sand beneficiation requirements and product specifications.
- Coordination of laboratory testwork with specialist processing equipment suppliers.
- Technical evaluation of material preparation, classification and impurity-removal processes.
- Assessment of gravity separation and magnetic separation technologies.
- Direct attendance and technical participation during testing in China.
- Review and interpretation of laboratory results.
- Evaluation of additional chemical purification requirements.
- Preliminary assessment of processing plant concepts and potential equipment configurations.
Testwork & Process Evaluation
The testwork investigated a multistage beneficiation process to improve the quality of the silica sand concentrate.
Material preparation and classification
The initial stages included screening, preparation of the required particle-size fractions, scrubbing and desliming to remove unwanted fine material and surface contamination.
Gravity separation
Gravity separation was investigated using a shaking table to evaluate the removal of heavier mineral impurities.
Magnetic separation
Successive magnetic separation stages were investigated, including belt magnetic separation, wet high-intensity magnetic separation (WHIMS) and slurry magnetic separation.
These processes were assessed for their effectiveness in reducing iron-bearing contaminants while maintaining acceptable silica sand recovery.
Additional chemical purification
Mechanical beneficiation achieved a substantial improvement in product quality but did not fully meet the specified iron-oxide requirement.
Additional acid-washing trials were consequently evaluated to determine whether remaining impurities could be removed through chemical treatment.
Technical Results & Findings
The mechanical beneficiation testwork produced a silica sand concentrate containing approximately 99.64% SiO₂, with a reported mass yield of 86.82%.
However, the resulting iron-oxide concentration remained above the required product specification.
Subsequent chemical purification testing demonstrated the potential to achieve approximately 99.9% SiO₂, while reducing Fe₂O₃ to below 120 ppm under laboratory conditions.
The evaluation established that mechanical separation alone was insufficient for the intended product specification and that an additional chemical purification stage would be required.
Engineering Considerations
The testwork highlighted several important considerations for potential commercial plant development:
- Selection and integration of gravity and magnetic separation equipment.
- Optimisation of the process flowsheet to balance product purity and recovery.
- Assessment of multistage magnetic separation performance.
- Evaluation of chemical purification requirements and associated operating costs.
- Consideration of water, reagent handling, effluent treatment and supporting infrastructure.
- Requirement for further engineering and economic evaluation before finalising a commercial processing plant configuration.
Project Outcome
The preliminary investigation established a technical basis for comparing physical beneficiation and additional chemical purification routes.
The findings demonstrated the importance of structured laboratory testwork and specialist equipment evaluation before committing to processing plant design and capital expenditure.
The assignment also demonstrates MCS’s capability to coordinate international technology suppliers, participate in mineral processing testwork and translate laboratory findings into practical engineering considerations.
Project status: Preliminary technical evaluation and laboratory testwork completed in 2025. No commercial plant construction or commissioning was undertaken as part of this assignment.
Project Gallery
Selected photographs from the silica sand beneficiation testwork programme, illustrating sample preparation, scrubbing, gravity separation and multistage magnetic separation, including wet high-intensity magnetic separation (WHIMS).
