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Grinding Aid Dosage (9 replies)
Liquid - Small metering pump will work for adding liquid grinding aid.
Making the Solid & Semi-Solid as emulsion, dispersion or solution and adding with metering pump may permit good control. Can add solid as fine powder and use small volumetric feeder.
However:
- What dosage are you interested in adding?
- What is total TPH of feed rate to grinding?
it may be more easy to control low dosages using a diluted form.
I've never heard of a solid grinding aid. Liquid grinding aid added with a small metering pump, measured in drops/minute. Trial and error to determine the least amount of grinding aid required to give you the result you are looking for. My experience is in operating a air-swept dry grind ball mill producing mesh and micronised industrial minerals with throughput rates of 300-700kg per hour.
What type of grinding aid are you trying to use? Are you trying to modify surface chemistry of minerals or change the viscosity within the mill to move the toe and heel? your description is vague in regards to iron ore.
Metering pump is the best facility for dosing the grinding aid in a solution form. You can have a precise control on the dosages and can optimise the dosage as per your requirement.Many metering pumps are available depending on your capacities.
My experience is in ground calcium carbonate using both dry and wet grinding to produce ultra fine products. We used poly acrylates for wet grinding dispersants. Changing the PPM addition rate effects both viscosity at a given % solids and the grinding efficiency. Dosing is carried out using flow meters on incoming feed to determine dmT/hr and variable speed piston pump to regulate the PPM addition rate of liquid dispersants. You need to monitor closely the viscosity and particle size distribution to optimize. Different grades of dispersant can also effect the steepness of the curve. The company I worked for at the time used mainly E & H instrumentation. Hope this helps?
I heard of a project a few years ago where they intended to wet grind the iron ore and pump it many km's in slurry form to the shipping port. Certainly viscosity would be an issue and possibly the need for dispersants/grinding aid to avoid settling and too much duty on the pumps.
Have used sodium silicate as a dispersant for clay in ore, not so much as a grinding as a method of improving grade of concentrate. Other wise never had much luck as to increasing throughput.
It's really about where the circuit operating conditions lie with respect on a curve of % solids - viscosity - grinding efficiency / cyclone efficiency. Truly the answer will be found through experimentation. the lab can only answer part of the question.
Please what is the best way of measuring the dosage of a semi-solid, solid, and liquid chemical grinding aid during wet grinding?
Is it not possible to have a grinding aid (to be used for wet grinding of an ore) in solid form?My interest is on batch grinding test. I'm a bit confused on how to test for the material. How do I check for the dosage if it works and affects viscosity?