WHITE PAPER 1 – Lessons from Thickener Pilot Plant Testing: Experiences shared

S. Meiring – PasteTech, Australia

Abstract

Copper tailings may be extremely difficult to thicken; therefore, an entirely holistic system design approach needs to be taken. Both upstream and downstream aspects of the flowsheet, as well as the actual paste production process have to be considered.

A number of pilot tests were performed on 1-6 metre tall pilot thickeners. Findings and experiences from copper paste pilot trials are presented in this paper, to demonstrate, different concerns arising from pilot plant results.

A number of lessons have been learnt from recent pilot plant trials, where operators have not given consideration to relevant occurrence and piloting observations; these include:

Continued…

  1. Running the pilot to hydraulic overload and the unit’s full potential, i.e. why a pilot thickener must be “red lined”.
  2. The importance of dilution water addition and how this can have a detrimental effect on a small pilot unit.
  3. Sizing a paste thickener, the impact of different aspect ratio (diameter versus height).
  4. The understanding of pilot limitations i.e. does the physical height of the pilot thickener permit high unit loadings and high residence time to operate simultaneously.
  5. Why the underflow yield stress is significantly different between pilot plant results compared to a full-scale units.

The suitability of paste applications for copper tailing involves the review of data from a copper tailings pilot test program. Different ore bodies, particularly those containing clay, presented a challenge as too many thickeners would be required.

After initial review of unit area versus underflow solids data, further analysis with consideration of retention time and bed depth was required to further extrapolate the data.

This paper shares the experiences gained from these thickener pilot plant tests.

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WHITE PAPER 2 – Thickeners versus centrifuges – a coal tailings technical comparison

S. Meiring – PasteTech, Australia

Abstract

Both high-rate thickeners and dewatering centrifuges are used in the application of dewatering coal tailings. Both applications are well advanced and accepted as means to dewater coal.

This paper compares a high-rate thickener to a solid bowl centrifuge with respect to numerous process, mechanical, electrical, control, layout and operator variables. Process variables include feed, effluent water discharge, retention time, and centrifuge cake moisture/thickener underflow percent solids.

A comparison of a 33 m diameter thickener and a 1.117 m diameter solid bowl centrifuge with respect to g square meters is shared.

The suitability of the dewatering application is governed by the properties of the resultant solids mixture. Different ash tailings, particularly those containing clay, presented a challenge to both the operations of the thickener and the centrifuge. A holistic view to the entire process is required.

Interested in this paper,  request the full paper now by filling out the contact form below.

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