Industrial Products for Advanced Control of Mineral Processing Plants - Advanced Control and Supervision of Mineral Processing Plants - page 291

Below we briefly describe FrothMaster™ 2 (Outotec) [12], JK FrothCam 3 (JK-
Tech Pty. Ltd.) [16] and VisioFroth 4 (Metso Minerals Cisa) [17], three industrial
products based on the foregoing principles.
Outotec's FrothMaster™ is a tool for real-time froth surface analysis. It measures
several essential properties of froth appearance including froth speed and direction,
bubble size distribution and froth stability, and generates a froth color histogram
(RGB). The product also provides statistical data related to these variables. The froth
measurements plus on-stream analyzer assays provide the information necessary for
expert control of the flotation circuit by means of a hierarchical and multivariable
system (FrothCon™) that controls three froth properties - speed, stability and color
- and dynamically maximizes cell efficiency. FrothMaster™ also detects abnormal
situations such as froth collapse. Finally, FrothMaster™ includes web server tech-
nology.
JK Frothcam employs a statistical approach known as the texture spectrum
method to measure both bubble size and froth structure. A classification algorithm
using patterns of texture spectra recognises froth structures that can be related to
variations in flotation process performance. The height of the middle peak of the
texture spectrum provides a means of estimating the average bubble size of the froth
image. Froth speed is measured using an object-matching algorithm called pixel
tracing. The technique assumes that both froth shape and light intensity remain un-
changed during measurement.
VisioFroth, developed by Metso Minerals Cisa, furnishes mean and standard de-
viation measures of froth speed (in cm/s), froth stability (in %), bubble size dis-
tribution, color and brightness indexes and froth texture. It is typically installed to
stabilize the froth speed by manipulating level and/or airflow set-points using the av-
erage speed signals from the OCS © statistical module. The product offers 20 meth-
ods for calculating the froth speed based on correlation, masking and fast Fourier
transforms. The bubble size measurement employs a watershed-based approach.
In addition to these products, other commercial sensors based on the same tech-
nology include the PlantVision™ 5 image analysis system for flotation (Knowl-
edgeScape) [7] and WipFroth (WipWare) [9]. There has been extensive research
and publications on the subject. Morar et al. [18] present the results of test work
conducted at Rio Tinto's Kennecott Utah Copper Concentrator on the application
of SmartFroth, developed at the University of Cape Town investigating the relation-
ship between froth color and concentrate grade. Morar et al. show that models can
be developed to predict concentrate grade based on color information and velocity
and stability information. Kaartinen et al. [19] describe a novel approach in which
2 FrothMaster is a registered trademark of Outotec Riihitontuntie 7 D, PO Box 86, FI-02200 Espoo,
Finland, www.outotech.com
3 FrothCam is a registered trademark of JKTechPty. Ltd. 40 Isles Road, Indooroopilly. QLD 4068
Australia, www.jktech.com.au
4 VisioFroth is copyright of Metso Minerals Cisa BP 6009, 45060 Orlans Cedex 2, France,
www.svedala-cisa.com
5 PlantVision is a registered trademark of KnowledgeScape 254 South 600 East, Suite 202, Salt
Lake City, UT, 84102, USA, www.kscape.com