Grainer

This type of evaporator is used in the pulp and paper industry to recover 

Tha operating tamparatura may ba varied over a wide range. Efficiency is high and no steam or cooling water is required. 

Ball mills ara somatimas used for batch processes whan tha product is a solid. Tha feed enters tha ball mill and is concentrated as evaporation occurs and tha vapor is removed. Tha ball mill prevents tha haat transfer surface from becoming fouled. The solid product is periodically removed. Residence times ara 

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Significant improvements over the PPG process involve reaction of lime with concentrated HOCl (50%) and drying of the resultant slurry in a spray grainer or fluidized-bed spray dryer to produce hydrated product with av CI2 as high as 82% (126,127,129,210,211). 

There are three important methods of salt isolation and purification brine solution, rock salt mining, and the open pan or grainer process. The percentages of these methods have not changed dramatically in the last few years and are 54% brine, 32% rock salt, and 14% grainer salt. 

Hot brine solution is held in an open pan approximately 4-6 m wide, 45-60 m long, and 60 cm deep at 96°C. Flat, pure sodium chloride crystals form on the surface and fall to the bottom. The crystals are raked to a centrifuge, separated from the brine, and dried. A purity of 99.98% is obtained. Grainer salt dissolves more readily and is preferred in some applications, such as the butter and cheese industries. It is more expensive because of energy use for the hot brine. Its cost can be as much as six times that of rock salt and 20 times that of brine. 

Grainer salt is made by surface evaporation of brine in flat pans open to the atmosphere. Heat usually is furnished by steam pipes located a few inches below tlie tank bottom. Crystals form at the surface of the brine and are held tliere temporarily by surface tension. Thus, they grow laterally for awhile and form thin flakes. But, as they grow, they tend to sink and this process imparts a peculiar, hollow pyramid-like structure to them. Such crystals are called hopper crystals. Ultimately, the crystals sink to the bottom where they are scraped to one end of the pan. The crystals are fragile and during handling they break up, finally assuming a flake-like shape. Thus, tlie term flake salt. 

Sodium chloride (salt, common salt, rock salt, and grainer salt) is a naturally occurring mineral. 

There are three methods of salt production and purification brine solution, rock salt mining, and the open pan or grainer process. 

A continuous mixer is used to dissolve nitrocellulose in ethyl acetate to form lacquer. Lacquer pumps transfer lacquer from the continuous mixer to the grainers. The temperature of the lacquer is already above ambient and any unwanted frictional heat can cause a temperature excursion and possible ignition. 

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