what kind of polyacrylamide(flocculant) we use for coal washing?
1. Product characteristics—anionic and nonionic polyacrylamide
After the coal is mined and sized it is then ground down by ball mills and then separated from the waste by gravity in a medium of water. The coal floats and the waste sinks with the subsequent coal again sized and separated into the finished product.
During the process fine coal particles are generated which require further processing to recover these fine coal particles. This is normally achieved by a flotation process where a flotation agent is added to promote the separation of coal from waste. Again the coal floats and the waste sinks.
The fine coal is then recovered by sedimentation and then by filtration or centrifugation. Flocculants are used in the sedimentation process to promote solid-liquid separation and subsequent rapid settlement in the thickeners so by producing clean water from the overflow of the thickeners for recycling back to the preparation plant. The fine coal, which settles, is subsequently recovered by filtration/centrifugation as the fine grade coal product. Again during the filtration/centrifugation process flocculant is added to enhance the separation process.
When processing brown coal, or coal with high clay content, it is sometimes necessary to use a coagulant prior to the addition of a flocculant for settlement applications so as to achieve efficient solids capture and an acceptable overflow clarity.
2. Quality index--- anionic and nonionic polyacrylamide
Hydrolysis degree (%)
Residual monomer content (%)
3. Application--- anionic and nonionic polyacrylamide
(1)Settlement/clarification of fine coal slurry in the thickening vessels. (2)Enhancing solid-liquid separation of the fine coal (from the thickener underflow) normally by filtration /centrifugation.
(3)Settlement/clarification of the waste slurry (tailings) in the thickening vessels.
(4)Enhancing solid-liquid separation of the tailings (from the thickener underflow) normally by filtration /centrifugation.
4. Instruction for use
(1)It's very important to make the efficient dispersion during using, otherwise will cause agglomerate and "fish eyes", dissolving time will be longer.
(2)Low-hardness water for use; avoid adopting such tank or pool, which will influence on water quality.
(3)Improve the water temperature to accelerate the dissolving velocity, but not exceed 50.
(4)Stirring will accelerate dissolving, but tough stirring will make the dispersant chain broken and degradation. Shipshape agitator with 200 - 500 rpm is the best choice.
(5)Commonly mix the product into 0.05%--0.5%(w/w)solution as reserve.
(6)Adjust the optimum dosage of product according to application condition.
5. Product package
25 Kg paper plastic three-in-one compound woven bags, or according to users’ requirement; Its shelf life is 2 years.
The product is moisture absorbent, thus to protect from damp and moist for conservation. It should be stored in a dry and ventilate storehouse, and not be exposed to air and sunshine.