Blogs
China Currency War
Is this a China Currency War on US or China on all others? What’s China’s End-Game: China is perhaps looking to have the Renminbi ultimately being managed against a basket of currencies as opposed to just being managed against just the USD. This could provide for more volatility going forward between the Renminbi vs. the USD.
Thickener Safety
The last thing that I would like to mention about thickeners is to do with their safety. In some plants fire a worker who wears his hard hat or takes foreign objects onto the catwalks above the thickeners. The reason is that if, by accident, his hard hat ended up in the thickener that thickener may be down for days
Thickener Torque -Rakes & Drive
A little earlier I talked about the rakes of the thickener, these are long arms that extend off of the bottom of the DRIVE SHAFT. As the shaft turns the rakes will sweep the entire bed of the thickener thereby applied Torque. Each rake arm is higher at its far end than it is where it joins the drive shaft.
Thickener Operating pH and Lime for Flocculation & Improved Settling
If, for some reason, the thickener’s settling rate is too slow, as in the case of the grind being so fine or you are dealing with clay rich ore and now the concentrate stays in suspension. The thickener could be “sliming” and will produce a dirty overflow combined with a low density underflow. If this is a problem, a reagent called
Feeding a Thickener for Good Settling and Underflow Density & Overflow Clarity
How much you feed a thickener and how/where you feed it will determine how well slurry or concentrate settles it it as well as the level of ease or difficulty you will have at obtaining a good underflow density and overflow clarity. By using the head assay of the concentrator, and the metallurgical test results that determined the percentage of
Concentrate Thickener Operation
In mining, when flotation is finished with the ore, and a final concentrate has been produced, often, both products will go to a concentrate thickener before it is dried for shipping. This is a very important step so here we discuss Basic Concentrate Thickener Operation. For the mine to get its concentrate to the smelter it will have to be transported,
Merrill Crowe Flowsheet
Here is a common and classic merrill crowe process flowsheet with a simple zinc precipitation chemistry. Some of the flows in this design: Too much dilution water is used Zinc dust is added after the pump No mechanical seal is present on the pump to prevent O2 entry. Learn more about the Merrill Crowe Flowsheet.
Processing Pregnant Solution from Gold Leaching via Merrill Crowe
In processing gold, once it is completely dissolved the solution that is formed by that dissolved gold is called the ‘PREG’ or short for PREGNANT SOLUTION. In other words solution that is full of gold and is accordingly yellow in shade/colour. The solids are now considered the waste and the liquid is the concentrate. To separate the two the solids
Gold Cyanidation Process
The Cyanidation Process or CYANIDE LEACHING is ‘most notably used in the recovery of gold. Safety and environmental concerns are of prime importance in the operation of a cyanidation plant. As we get farther into this type of recovery you will see why. The preparation of the ore for processing is similar to flotation. The ore must be ground to
Basic Flotation Circuit Design
Let’s, proceed to Basic Flotation CIRCUIT DESIGN. To understand flotation it is necessary to learn some new terminology. To do this let’s look at a simple schematic of the circuit we were just working with. Let’s start with the CLASSIFIER OVERFLOW, once the classifier is finished with it enters the CONDITIONER TANK. This tank is there to allow the
Zn Assays: Compare 2 & 4 Acid Digestion
When doing a ICP assay, you can choose between 2 or 4 Acid Digestion. Here is the basic difference: 2-acid digestion is good for sulfide and carbonate material but does not digest the more resistant minerals such as unaltered silicates and some oxides. The 4-acid digestion is a near “total” digestion and will digest almost everything except for the very
Adjust Weir Gate Level on Flotation Cell/Bank
If we examine the froth column of this bank of cells you will notice that the column becomes SHALLOWER from cell to cell. This is to capture the particles that are lightly mineralized, and is floating very low in the froth. The last cell will have the shallowest froth column, in fact in many cases, the pulp level will be so
Flotation Cell/Bank Sand Port
In every cell there is the need to allow the SANDS to escape. The sands are the particles that didn’t become ground fine enough. NO matter how efficient the classifier is it will not be one hundred percent effective. There will always be aware factor, where in the circuit that the cell is, and operator error to introduce the coarser
Adjusting Pulp and Air Levels to Troubleshoot Flotation Cell Froth Movement
Any time that you have an overloaded froth condition the OVERFLOW that is going over the side of the cell will slow down as the froth column begins to collapse under the weight of the mineral. The first corrective reaction is to raise the pulp level or add air to the cells to quickly increase the overflow. As a band
Optimum Flotation Reagent Addition Rate (Dosage)
By now you are aware of the importance of the effect that the reagents have on single bubbles. Now we will begin to show you how the bubbles effect each other. In the cell the air, the reagents, the mineral and the impellor agitation all combine to create what is known as a FROTH COLUMN. The froth column is the
Flotation Frother Dosage
Now for the FROTHER, if there is TOO LITTLE frother the bubbles will become small and the speed of the overflow will be slow. If this condition continues the speed will become slower and slower as the collector overloads the bubble. Soon the froth won’t move at all. The colour will remain correct. On the other hand if there is
Flotation Collector Dosage – Over/Under Collection of Froth
What happens when there is too much flotation collector, how do you know and how can to estimate? The bubble will react as if there is too little depressant. Froth bubbles will get smaller and closer together, but the unlike the depressant it won’t cause the mineral to fall off of the bubble due to overloading. Remember there is enough depressant
Flotation Depressants
Table of ContentsSodium cyanideZinc sulphate First let’s change the amount of the Flotation Depressants used. The valuable mineral that isn’t liberated from the unwanted mineral will begin to be depressed along with the waste. For the floatation operator, the change that will become most apparent is, that the color of the froth will begin to reflect more of the wanted mineral’s
Chemical Reaction of Copper Minerals and Cyanide
In discussing the Reaction Products from Copper Minerals and Cyanide you will find that when an excess of copper mineral is acted upon by cyanide solution, dissolution of copper continues at a decreasing rate until equilibrium is established and no more copper goes into solution. The rate will vary with the particular mineral used as shown by the data in
MgO in Zinc Sphalerite Concentrate Contamination
Here is how Mg is often present as Mg (magnesium oxide) in a Zinc Sphalerite Concentrate produced by froth flotation. According to typical mineralogy data obtained from Zinc concentrate (P80=90um), the MgO is located in 2 opposite regions. This concentrate contained 0.3% Mg total. Unless you want to give away your concentrate to Doe Run, you need to clean up this concentrate.
Froth Flotation Entrainment -Types and Forms
Commonly, none sulphide particles like MgO, being an oxide (or silica gangue), does not respond to flotation. For example, when MgO is found in a sulfide flotation concentrate it is either for it is associated/locked with another sulfide (pyrite/sphalerite) which has and did respond to flotation, or it has been entrained into the froth along with sulfide. Flotation via sulfide
Cyanide Concentration and pH to Depress Sulphides
The chart displays how the Cyanide Concentration (how much NaCN) is needed to effectively Depress Sulphides like Pyrite, Sphalerite, Chalcopyrite but not Galena at various pH. It is pH that affects/impact the required effective concentration of cyanide. The higher the pH, the less NaCN is needed as CaO/Lime also acts as a Sulphide depressant. The use of cyanide complements it will in
DRAEGER Breathing Apparatus Price
If you are wondering about the Price of a DRAEGER Breathing Apparatus you are likely in for a surprise. A new units cost around $11,000 while a used BG 4 (2013 vintage) will price in at around $5000 US.
The Importance of pH in Flotation
In flotation, pH control is a vital method to control selective mineral separation. A standard depressant that is used is an Alkali. An Alkali is any substance that when mixed with Acid will neutralize each other and form a new chemical substance called a BASE. This is very important. The ore may be either alkaline or Acidic. To have a