1. THE USE OF DESIGN OF EXPERIMENTATION
SOFTWARE IN APPLIED FLOTATION TESTING
CAMP
Corby G. Anderson and Todd S. Fayram, The Center for Advanced Mineral and Metallurgical Processing
Montana Tech of the University of Montana, Butte, Montana USA
Introduction
While flotation technology is now one hundred years old, the testing, interpretation and application of lab results can be tedious, costly and time consuming requiring extensive sample collection and preparation. In addition, applied industrial flotation still remains more of an art than a quantifiable science. This poster and the paper will elucidate the application of STAT-EASE Design-Expert software to minimize required laboratory flotation testing while rapidly optimizing multiple results and outcomes in a statistically valid manner. The STAT-EASE program is based on proven design of experiment statistical fundamentals. In this paper, the real world application of this methodology to flotation of a copper and gold ore and a copper, cobalt and gold ore will be cited.
Abstract
The successful application of flotation is now over one hundred years old. However in a practical industrial sense, it still remains predominantly an art rather than a quantifiable science. Moreover, the laboratory testing, interpretation and application of the technology can still be tedious, time consuming and costly. This poster illustrates outlines the use of proven statistical design of experimentation software for rapid optimization of flotation testing with limited representative sample utilization. This results in less costly required testing, a more thorough understanding of results and the ability to simultaneously optimize several variables and outcomes at once. At the Center for Advanced Mineral and Metallurgical Processing, this testing methodology has been used successfully in many metallurgical development and plant optimization projects thereby confirming its real world utility and application.
Table 1. Illustrative STAT-EASE design of experiment ¼ matrix for 6 variables.
Table 3. Illustrative STAT-EASE gold recovery fitted model analysis of variance data.
Table 4. Illustrative STAT-EASE fitted model gold recovery equation in actual factors.
Materials and Methods
All flotation testing in the paper was guided and completed using STAT-EASE diagnostic software. The testing of two ores is illustrated. STAT-EASE software requires the development of a statistically valid design of the experiment matrix using several variables and outcomes. In the case of the Mt. Hagen copper gold deposit testing, the variables used were grind time, pH, flotation time, and the addition or not of sodium sulfide. In addition, four outcomes were simultaneously evaluated: gold and copper grade and recovery.
For the Formation cobalt, copper and gold ore, partially illustrated in this poster, a statistically valid test matrix was setup using STAT-EASE modeling software. Testing was then carried out on a representative ore sample. Variables tested included grind time, rougher collector type and dosage and scavenger collector type and dosage and the use or not of copper sulfate as an activator. Cobalt, copper and gold recovery and grade were then evaluated. Not including replicates, full factorial flotation testing would require sixty four tests to validly determine the affects of these variables. A statistically valid one quarter STAT-EASE test matrix of sixteen tests was set up along with midpoints and replicates. This amounted to only twenty tests. The flotation test matrix details for the cobalt and copper ore are shown in Table 1. Because of limited space, only gold recovery modeling results are shown. Tables 2, 3 and 4 illustrate one application of the STAT-EASE model for gold recovery. For further data, applications and illustrations please see the published paper.
Summary
This poster has illustrated the successful use of statistically valid design of experiments using STAT-EASE software. This proven methodology based on well known statistical fundamentals provides a low cost and rapid process for real world laboratory flotation testing, optimization, application and flow sheet development. This is particularly important when minimal financial resources, time and representative samples are a constraint. At the Center for Advanced Mineral and Metallurgical Processing, this testing methodology is used successfully in many metallurgical development and plant optimization projects thereby confirming its real world utility and application.
Table 2. Illustrative gold recovery data versus the STAT-EASE fitted model prediction.
Contact
Corby G. Anderson, Ph.D., Director
Center for Advanced Mineral and Metallurgical Processing
Montana Tech, 1300 West Park Street
Room 221 ELC Building
Butte, Montana USA 59701
Telephone: ; Facsimile:
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