One of the more common classes of ores containing gold is when gold is associated with pyrite, pyrrhotite, and arsenopyrite. This is the area of gold recovery that has probably received the most research and plant optimization support especially in light of the long history of South African industrial practice. From a reagent viewpoint, charged water soluble collectors such as xanthates, dithiophosphates, some thiophosphate analogs including phosphinates, and some recent adaptations of nitrogen based collectors starting from either urea and/or amines, are the most successful reagents used, e. g. Klimpel (1994). Pyrite as it occurs in sulfide mineral systems requires a collector to float. There is a great deal of fundamental research currently going on in the flotation of pyrite with various chemical structures.
Experience has shown that in the acid pH range of 4 to 5, almost all standard thio collectors are effective as pyrite collectors. Xanthates are not stable at these acid pH’s, e. g. Harris (1988), so that they are used in pyrite flotations only at alkaline pH’s. Collectors such as mercaptobenzothiazole, dithiophosphates, monothiophosphates, thionocarbamates, and dialkly sulfides all have the capability of functioning effectively in neutral to acid side flotations.
Figures 8 and 9 show a recent data ….Read more
The Microcel™ sparger consists of in-line static mixers and a centrifugal pump. Tailings slurry is pumped from the base of the column through the static mixers, where air and slurry are mixed under high-shear conditions to create the bubble dispersion.
As the air-slurry mixture passes through the stationary blades located inside the mixer, the air is sheared into very small bubbles by the intense agitation.
ERIEZ Flotation Column cells
ERIEZ column cells have a similar system called “Cavitation System”
Non-metallic Mineral Flotation by Microcel Column
Many investigators have conducted hydrodynamic analyses of the bubble-particle collision process. Conclusions of these studies can be summarily represented by the following equation:
in which Pc, is probability of collection, Dp ….Read more
COARSE FLOTATION OFFERS IMPORTANT SAVINGS THROUGH REDUCED OPERATING COSTS
Grinding cost varies greatly depending upon the size reduction required. For example, it takes approximately 50% less horsepower to grind from ½” to 48 mesh than it does to grind the same material from ½” to 100 mesh.
Many minerals are liberated at a coarse mesh and middling particles often can be recovered at a much coarser grind than would be required for total liberation. Flotation of coarse middling particles permits regrind and reflotation involving only a fraction of the original tonnage.
“Sub-A” Flotation has the unique ability to handle coarse particles. This coarse flotation makes possible important savings through reduced operating costs as indicated in the following table of horsepower required for grinding:
Coarse flotation is practiced at many mills. This 34,000 ton per day mill uses “Sub-A” Free-flow Flotation Machines to float at 20 mesh. Rougher concentrates are then reground and flotation cleaning raises concentrate grade to meet specifications.
The flowsheet in this study illustrates the general practice in the United Kingdom. A large number of coal preparation plants have been established by the National Coal Board during the past 10 years. The primary consideration is to achieve a maximum recovery of low ash coal. The secondary consideration is to reclaim the plant water and avoid pollution of streams or rivers in the area. The flowsheet incorporates three stages of treatment for the various size ranges, namely, Dense Medium for the — 8″, +2″ fraction, Baum Jigs for the —2″, +½ mm. fraction, and “Sub-A” Flotation for the — ½ mm. fraction. In addition to the low ash coal fines recovered, flotation is an essential part of the flowsheet for preparing coal flotation tailings for media use in the dense medium separation and also to enhance the disposal of the fine refuse or tailing.
Breaking and Sorting: The run-of-mine coal as received from the colliery is reduced by means of Bradford Breakers to approximately 8″ and then screened into plus and minus 2″ fractions.
Dense Medium Section: The —8″, 2″ material is delivered to the Dense Medium Separators which are generally of the ….Read more
Floatability of arsenopyrite as a function of initial concentration of sodium isopropyl xanthate at various pH values.
Recovery of arsenic as a function of pH in flotation of an arsenopyrite ore assaying 12.5% As (27.2% FeAsS) using 30 and 60 g/ ton sodium isopropyl xanthate and 70 g/ton frother.
For a flotation circuit, material balance calculations define an engineering problem where flow parameters between unit operations are partly known. The purpose of a material balancing is to mathematically examine the known flow parameters to solve for the unknown flow parameters. Two main types of material balances are commonly made:
- design material balance
- operating plant material balance.
The design material balance is typically faced during plant design when the flotation test work results and a flowsheet diagram are the only known values. Design material balance purpose is to find values for the unknown flow parameters.
Operating flotation circuits material balances contains large amount of data and helps produce a picture of the state of an operating plant. Here is a procedure of how to do balancing for an operating flotation circuit using Microsoft Excel Solver on Excel spreadsheet. An example solving a copper concentrator flotation circuit is presented and the process flow diagram is given below.
In this video EMC Supasim flotation simulation program is used to simulate the performance of a copper lead zinc plant in southern Spain. Flotation kinetics of key streams are generated by conducting bench scale rate tests on either a laboratory prepared sample of mill feed or grab samples of pulp taken from the plant. And this type of rate test is known as a hot float. A grab sample may or may not be representative and if not, the flotation kinetics it generates will not be a true reflection of the streams floatation characteristics.
- If this happens and you cannot repeat the test, what do you do?
- How to use flotation kinetics to determine what is required to improve plant recovery?
What you see here is a flow sheet for the copper lead zinc plant where you have the copper circuits on your left, the zinc circuit on your right; both have reground mills. It looks very congested that is because it’s got a lot of options. These are valves where you can operate the circuit, in open circuit or in close circuit. And there’s a lead upgrade here. You produce copper concentrate ….Read more
This is an overview of setting up and conducting a flotation rate test. The test is a means of determining the flotation characteristics of an ore. It is conducted in a laboratory scale cell usually with a volume of two point five litres. The intention is to generate relationships of cumulative recovery, mass pull and grade versus time and use these to evaluate the floatability of metal, mineral and gang. The video is not intended to be a detailed explanation of how to conduct a rate test. For that, download the test procedure shown here below. The purpose of this video is to outline the important aspects of setting up the test to ensure that flotation characteristics are correctly measured and the resulting data can be properly interpreted. How the data is used to determine flotation kinetics is a subject of a separate video. The key aspects are:
- the types and setup of the laboratory cell;
- sample to be tested,
- test conditions and
- how the test is conducted.
The standard laboratory cell and cell ….Read more