Hydroseparators

In hydroseparator tests, it is necessaiy to measure solids concentrations and size distributions of both the supernatant sample withdrawn and the frac tion remaining in the cylinder. The volume of the latter sample should be such as to produce a solids concentration that would be typical of a readily pumped underflow shiny. 

Hydroseparator The hvdroseparator is merely a thickener-type machine receiving more flow than can be clarified in the area provided, Thus the overflow contains fine solids, and the greater the feed rate per unit of area the coarser the solids in the overflow, ... 

In modern iustaUatious wet grinding is sometimes accomphshed in ball mills alone, operating with excess water in closed circuit with classifiers and hydroseparators. 

Hydroseparator The efllnent from the oxidizer column next flows to a hydroseparator in which any lime grit, catalyst, or coke lines are physically removed. The solids are sent to a horizontal vacnnm belt filter, and the overhead liquor from this separator will be further treated to reclaim most of the process liquor and to produce a filter cake for disposal. 

Waste Clarifier This clarifier will treat the overhead liquor from the hydroseparator to concentrate any solids and to reclaim process liquor for reuse in the process. The overflow from this clarifier will be retnrned to the process and the underflow will be filtered to prodnce a filter cake for disposal. The filtrate from the filter press will be returned to the process. 

Horizontal Belt Vacuum Filter The final piece of equipment is the horizontal belt filter, in which the nnderflow from the hydroseparator (basically gypsum diluted with process liquor) will be filtered to produce marketable gypsum of -12% moisture. The filter cake will be washed to reduce the amount of dissolved solids and will be conveyed to a prodnct gypsnm storage area. Filtrate from this filter will be disposed of as an aqneons pnrge stream. 

The hot product from the kiln is quenched in water (e), passed via classifiers and hydroseparators (f) into thickeners (g), filtered on rotary filters (b2), and washed until salt-free. The dried product is ground in high-intensity mills (g) and may undergo organic treatment (with a polyalcohol) depending on the application. 

Classification efficiency of the hydroseparator compares with that of the cone classifier and is appreciably lower than that obtained from mechanical or hydraulic units. The chief virtue of the hydroseparator is its ability to receive and slough off great quantities of water at low per-unit-volume cost. 

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. 

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