Reliable slurry density measurement is essential for process monitoring in mining and mineral processing. However, highly abrasive materials, high viscosity, and challenging pipeline configurations can make stable, representative measurements difficult to achieve.
In this tungsten ore processing application, the material was fine slime—a high-viscosity slurry containing extremely fine, abrasive particles—flowing vertically downward through a pipeline. These conditions demanded a measurement solution that could address material wear, flow-related uncertainty, and operational safety without disrupting the production process.

The Na22 Density Meter combines non-contact clamp-on installation, advanced energy spectrum detection, and an exemption-level gamma radiation source to address these application requirements.

High-Viscosity, Abrasive Tungsten Slurry
Avoiding Wear and Clogging
Tungsten ore fine slime presents significant challenges for conventional wetted sensors. Continuous contact with abrasive particles can accelerate component wear, while viscous material may accumulate around sensing elements and increase the risk of clogging, depending on the sensor design.

These issues can lead to more frequent maintenance, additional production interruptions, and higher operating costs. For plant engineers, the challenge is not simply measuring density, but maintaining a practical measurement arrangement in demanding process conditions.

The Na22 Density Meter addresses this challenge through non-contact, clamp-on installation. Mounted on the outside of the pipeline, it measures without direct exposure to the abrasive slurry.
This approach offers three practical benefits:
· Reduced abrasive exposure: Measurement components remain outside the slurry, avoiding direct contact with abrasive tungsten particles.
· Simplified installation: The clamp-on configuration requires no pipe cutting for installation.
· Less intrusive maintenance: No in-line sensing element is introduced into the process stream, helping reduce maintenance associated with wetted components.
By eliminating direct sensor contact with the material, the Na22 helps address wear-related concerns while supporting production continuity.

The Flow Challenge: Vertical Downward Movement
Factors Affecting Slurry Density Measurement
The second challenge was the pipeline orientation: the slurry was flowing vertically downward.
Although gravity assists bulk flow in this configuration, actual material distribution depends on viscosity, flow velocity, solids concentration, and particle characteristics. Local flow disturbances and entrained gas, where present, can further complicate measurement conditions.

For high-viscosity slurry, these factors make it important to select an appropriate measurement location and ensure that the resulting data represent the process material reliably.

Radiometric Density Measurement Technology
The Na22 Density Meter uses highly sensitive NaI/synthetic crystal detectors and advanced energy spectrum detection technology to support radiometric density measurement.

Energy spectrum detection helps distinguish the measurement signal from background radiation interference, supporting more reliable signal interpretation. This capability is particularly relevant when engineers need consistent density information in challenging industrial environments.

The Na22 has a specified measurement accuracy of ≤ ±1%, subject to applicable measurement conditions and installation requirements.

While no instrument can eliminate every uncertainty caused by changing flow conditions, sensitive detection and background interference discrimination help address signal-related challenges. Correct installation and application-specific commissioning remain essential to achieving representative results.

Addressing Mining-Site Safety and Regulatory Requirements
Density monitoring must also fit the site's safety procedures and regulatory framework. Traditional radiometric instruments can introduce additional considerations involving radiation-source management, approvals, and operating procedures.

The Na22 Density Meter uses an exemption-level gamma radiation source with an activity below 1,000 kBq. Its low source activity is intended to reduce radiation-related management and regulatory burdens.

Actual exemption status depends on local regulations, source classification, and site requirements. The relevant authorities or radiation-safety team should confirm applicable obligations before installation.

This approach allows engineers to consider measurement performance alongside operational practicality and radiation-safety requirements.

Need Help with Slurry Density Measurement?
Every mineral processing application has different material properties, flow conditions, and installation requirements. Contact RETTAR technical team to discuss your slurry density measurement challenges and evaluate whether the Na22 Density Meter is suitable for your process.