Washing centrifugal

The product stream from the kilns is collected in storage bins. Black ash from the bins is fine-ground in a ball mill and fed to a leacher circuit, which is a system of stirred tanks, where it is dissolved in water and the muds are separated by countercurrent decantation. The solution from the decantation is passed through filter presses the muds are washed, centrifuged, and discarded. The filtered product, a saturated solution containing 12—13 wt % strontium sulfide, is sent to an agitation tank where soda ash is added to cause precipitation of strontium carbonate crystals ... 

Manufacture. PVBs are manufactured by a variety of two-stage heterogeneous processes. In one of these an alcohol solution of poly(vinyl acetate) and an acid catalyst are heated to 60—80°C with strong agitation. As the poly(vinyl alcohol) forms, it precipitates from solution (77). Ethyl acetate, the principle by-product, is stripped off and sold. The precipitated poly(vinyl alcohol) is washed to remove by-products and excess acid. The poly(vinyl alcohol) is then suspended in a mixture of ethyl alcohol, butyraldehyde, and mineral acid at temperatures above 70°C. As the reaction approaches completion the reactants go into solution. When the reaction is complete, the catalyst is neutralized and the PVB is precipitated from solution with water, washed, centrifuged, and dried. Resin from this process has very low residual vinyl acetate and very low levels of gel from intermolecular acetalization. 

All samples were submitted to post-treatment with mineral acid. The purpose of the acid post-treatment was to eliminate the ZnO phase in the materials obtained from the thermally treated LDH and a similar procedure was also performed on the other samples for comparison purposes. Hence, 400 mg of each sample was added under stirring to 50 cm3 of a 1 mol dm 3 HCI (Merck) solution at 25 °C under stirring. After a contact period of 2 hours, the residual solid material was separated and washed, centrifuged, and dried at 120 °C for 12 hours. 

If necessary, centrifuge at slow speedfor -2 min to separate the phases. After the last wash, centrifuge as above and remove the lower DCM phase to a clean glass vial (caps should be Teflon-lined). 

Red cell hemolysates were prepared by washing centrifuged red cells twice with a 0.87% saline solution and then mixing one volume of distilled water to one volume of packed red cells. 

Sodium silicate neutralization also has shown promise as a potential commercial method. The resulting soaps form a granular agglomerate, which can be removed by filtration to produce oil containing less than 100-ppm soaps. Thus, the costs of purchasing and maintaining primary and water-wash centrifuges, and wash water disposal are avoided. 

The ester contains about 0.5 per cent of free fatty acid, and for some purposes this is not objectionable, particularly if the acid itself is desired. It is recommended, therefore, that this step be omitted where possible since the yields, particularly from the small batches, may be as low as 80 per cent of the crude ester used. In the absence of an alkaline wash, centrifuging is not necessary, as water alone causes no emulsions to form. 

Refining. The water wash centrifuge stage is, at times, susceptible to oU breakover because of back pressure control. Many plants have a method to monitor or control this other than visual. These breakover conditions can represent substantial quantities of free neutral oil. A secondary gravity separator should be used in-line on the wash water stream to recycle the floatable refined oU directly to the crude oil stream, rather than allowing it to downgrade as acidulated material. 

Water washing Soaps Pumping From primary centrifuge to water wash centrifuge 88 (190) Ambient to 50 (122) Nitrogen or air... 

The acid NG from the centrifuge runs to an injector where it is mixed with 8% aqueous solution of sodium carbonate. It is transported to a special degassing vessel, where CO2 is evolved. After that the emulsion passes to two wash columns provided with perforated discs made of stainless steel. Mixing is achieved by air inlet to the column, from the second column the emulsion runs to a specially designed wash centrifuge. The stabilized nitrate ester runs to an injector and is transported as a non-explosive aqueous emulsion to a separate storage building. 

Assay of polymer was by precipitation with Isopropyl alcohol. Procedures varied in detail from time to time, but in general, biomass was removed by centrifugation before precipitation. Biomass was taken to be "volatile suspended solids," the weight loss of the washed centrifugate between 102°C and 550°C. 

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