DebTech
Courtesy of De Beers and photographer Simphiwe Nkwali

The RhoVol densimetric measurement system from DebTech gives process plants fast and accurate data on material density profiles. This vital information can inform timeous plant adjustments that make for better plant performance and higher recoveries.

The system allows plant operators to conduct density tests on-site and to generate the data they need within about an hour, rather than sending samples to third-party laboratories and waiting days or even weeks for the results.

This article first appeared in Mining Review Africa, Edition 4 2018

Grant High, research and development manager at De Beers Technologies SA (DebTech), says the usual delay in getting results presents a real lost opportunity for metallurgical plants.

He points out that by the time the results of the sample tests are returned to the plant, it is often too late to adjust the set-up of a process with sufficient effect.

Furthermore, the density profile of the material passing through the plant may have changed since the last sample was taken.

“The metallurgical industry has, for many years, been looking for the ability to measure the density of incoming material in real time, so that the plant’s settings can be optimised in time to make a difference,” says High.

In the RhoVol, DebTech has combined its vision size frequency distribution (VSFD) technique – which is a camera-based system for measuring the size of particles – with a rapid weight measurement device. This allows both the mass and the volume to be determined with great accuracy and speed, providing data from which the density of each particle can be calculated.

The system’s software creates a 3D model of each particle, so that any physical dimensions or ratios can be derived; information about the shape of the particle – such as elongation, flatness and compactness – can be very valuable in understanding the particular behaviour of a metallurgical process.

“The simplicity of operation of the RhoVol means that a plant does not require any specialised laboratories on site, and a relatively unskilled operator can conduct the measurements,” he says.

High emphasises that plants can use the RhoVol to audit the density profile of the run-of-mine material entering the plant, as well as material on the output side, facilitating more effective monitoring of plant performance.

The machine – which comes in two sizes to accommodate two size fractions – has an optional sorting functionality, and can even raise the resolution of the 3D models by accommodating multiple passes of material through the system; by ‘matching and merging’ images of the same particle, a very high fidelity 3-D model can be generated.

RhoVol facts

The RhoVol densimetric measurement system determines the density of an ore sample by measuring the mass and volume of individual particles.

Key features of the machine include:

  • Accurate measurement of mass, volume, density and shape of particles;
  • Applicable across a range of different commodities – any mineral or material can be measured for its volume and mass, as the density measurement range is not restricted and can be programmed to suit the product;
  • Quick turnaround time for results – allowing for real-time adjustment of plant processes;
  • Data is displayed live as it is captured – and made available in a standard spread sheet format on a per particle basis;
  • Process rate of 1 000 particles per hour;
  • High levels of measurement repeatability;
  • Two machine sizes – one for material sized 3 – 8 mm, and another larger machine for 8 ‑ 24 mm material;
  • Small footprint – no complex laboratory facilities necessary;
  • Simple operation – tests can be conducted by semi-skilled operator;
  • Small sample size;
  • No consumables required in the testing process; and
  • No toxic liquids involved in the testing.

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