Polymer hydrocyclone

The potash contains clay minerals, often as slime. This clay represents a large surface area and adsorbs the alkylamine collector. This is detrimental to the potash flotation, and therefore several methods are used to dispose of the clay. Mechanical de-sliming using hydrocyclones and hydroseparators is common practice. Slime flotation is often used. In this, the clay minerals are separated in a pre-flotation step by using a polymer and a non-ionic surfactant, for example, polyacrylamide and ethoxylated fatty acid, respectively. An alternate way is to depress the clay minerals with polymers such as sodium carboxymethyl cellulose (CMC), potato starch and lignosulfonate. 

A carpet separation process is illustrated in Fig. 13.1. First the carpet is sorted by face fiber. A near infrared sensor can identify the face fiber within a second even though nylon 6 and nylon 66 have similar infrared spectra. These two types of nylon carpet must be separated since they are incompatible. Next a guillotine is used to cut the carpet into small enough pieces to feed a shredder. After shredding some of the latex, calcium carbonate and dirt will separate from the carpet. To improve the purity of the carpet, fine grinding is necessary. Then a density separator can be used to remove more filler and dirt. Since there is a significant difference in the densities of nylon and polypropylene, a density separator can be used to separate nylon face fibers from polypropylene backing fabrics. Hydrocyclones can separate these polymers rapidly. Sink-float baths can accomplish this... 

The separation in a hydrocyclone, which works based on the principle of sorting by a centrifugal force field, using density difference of the various pol5rmers is one possible solution/ Sometimes, prior to separation, it becomes necessary to clean the polymer waste to remove contamination like dirt, food, and paper. 

Hydrocycloning will separate polymers with densities >1 such as PS, PVC, polyethyleneterephthalate The separation of PP from LDPE is not a viable process. 

Liu, S., Zhao, X., Dong, X., Miao, B., and Du, W. 2005. Treatment of Produced Water From Polymer Flooding Process Using a New Type of Air Sparged Hydrocyclone. Paper SPE 95343 presented at the SPE Asia Pacific Health, Safety and Environment Conference and Exhibition, Kuala Lumpur, 19-21 September. DPI 10.2118/95343-MS. 

A magnetic polymer lacking functional groups has been prepared in hydrophilic form from a vinyl chloride/vinyl acetate copolymer for use as a reusable filter aid in small-scale water treatment (11). Styled on diatomaceous earth, which must be disposed of after the filter bed is saturated, the particles can be separated from the impurities with a hydrocyclone and reused. 

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