Hickman still

The submitters used a still of the evaporative type, such as a Hickman still. The checkers used a similar still modified to include a magnetic stirring bar. This modification greatly decreases the time required for removal of the last traces of solvent, minimizes the danger of bumping just before evaporative distillation occurs, and increases the rate of distillation of the product. 

The checkers report yields as high as 84% and believe that the use of magnetic stirring in the Hickman still is responsible for the higher yield. 

Figure I. No. 5 Badger-Hickman still installed at International Nickel Co. test facility, Wrightsville Beach...

Table 1. Typical Operating Data for No. 5 Badger-Hickman Still ...

Figure 3. Dependence of yield and heat transfer coefficients with operating temperature of Badger-Hickman still...

The objectives of this phase of the program were to determine the maximum heat transfer coefficient that may be expected with a rotating surface and to devise an inexpensive method of packing such surfaces into a vapor compression still. The model available for this study was the No. 4 Badger-Hickman still, shown in diagrammatic elevation in Figure 5, as received and before various modifications were made. 

Figure 11 Schematic of the single-element Hickman still.

Figure 12 (a) Schematic of the multiple-disc Hickman still, (b) Full-scale Hickman still. 

For further purification, the product may be distilled at a pressure of less than 0.1 mm. (preferably in a Hickman still). Over-all yield is 74%. 

Hickman still, molecular distillation, 427 HIGEE fractionator, 399 Homogeneous gas reactions, 592 HTU (height of a transfer unit), 401,404, 422... 

Mixers. See also Agitation blend time, 290 dimensionless groups, 290 gas dispersion, 296-301 in line type, 300,301 liquids, power and speed need, 293,295 powders and pastes, 301,303,304 power number, 290-292 quality characterization, 290-292 suspension of solids, 295-299 tank desien. 287.288 Moisture c tent, critical, 237 Molecular distillation, 425-427 equipment sketches, 427 Hickman still, 427 operating conditions, rate of evaporation. 

For ordinary laboratory work, a modified Hickman still (Fig. 1-39) is convenient. Volatile impurities and gases present in the liquid to be distilled must first be removed so that frothing wiU not occur in the still. This is done by placing the liquid in an ordinary flask, which is then evacuated and gently warmed. After all of the volatile impurities have been removed, the liquid is transferred to the still. The latter is connected to the vacuum system by means of a large connector in order to minimize pressure drop in the system. The still is heated by an aluminum block which is bored to accommodate the bottom of the still to a depth of about 15 mm and which is wrapped with nichrome wire serving as a heater. The wire is best insulated from the block by asbestos paper, and a layer of asbestos paper should be placed between the still and the aluminum block. As the liquid is heated, it evaporates and collects on the condenser from which it drips... 

I ve put drawings of microscale equipment I ve had occasion to use in this section, along with some discussion ofthe 0-ring seals, conical vials, drying tubes, and so on. I ve put full descriptions of certain microscale apparatus with the operations they re used in. So Craig tubes show up with recrystallization the Hickman still is with distillation. 

Unfortunately, you can t drop an O-ring and cap over a water-jacketed condenser, Hickman still, and so on. What to do Using the water-jacketed condenser as an example, go from the bottom up ... 

If you have only 1-2 ml to distill, then the Hickman still is probably your only way out (Fig. 107). 

Get a clamp ready to accept the Hickman still at about the position you want just open and loosely clamped—horizontally—to the ringstand. Scrunch the conical vial down into the sand, and push it to where you want it to be. Hold the vial at the top. 

Put the Hickman still on the vial. Now, even though you have a sand buttress, this baby is still top heavy and can fall. Hold the vial and the still somewhere about where they meet. 

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