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ZONE REFINING

Reu~ri/le~t,~rom: John D. Christian, J. CHEM. EDUC.33, 32 (1956), by Robert Grew, Far Eastern Highland Mission Island Academy, Agana, Guam PREPARATION the mounted coil, provide a 1-in. circumference bushing over the hour hand shaft (a piece of wooden dowell Prepan* a samplr for refining by dissolving a trace or a piece of heavy walled rubber tubing). Connect of methyl red indicator in 6-8 g of molten naphthalene the tuhe containing the ingot by means of a string to (if only indicator solution is available, a few drops may the shaft of the hour hand and adjust so that the ingot he carefully evaporated and then the naphthalene will he pulled through the heating coil a t a rate of melted in the same evaporating dish). The resulting 1 in. per hr. l'rovide a 10 v power supply (a variable liquid sl~ouldbe a light red-orange in color. Prepare transformer is useful). an elongatrd ingot of the sample drawing the melt into a 1;-20 cni length of 6-mm Pyrex tubing and allow DEMONSTRATION it to solidify and sealing one end. The sample should Connect the furnace t o its source of power and start not be drawn closer than : 3 4 cm from the end of the the clock. As the ingot is raised through the heating tube tn be sealed. element, a molten zone is formed, and recrystallizaWrap one layer of asbestos paper around a piece tion occurs a t the upper end as the material cools. of 8-1nn1 Pyres tubing 8-10 cm long. Wrap '/sof a The rccrystallized material will be colorless, and the 4.75 ft lrngtl~of 1-0. 30 nichrome wire tightly around color impurities will collect in the molten zone. the asbestos to form a coil 1 in. in length near the center of t,hr asbrstos covered tube. Cover the coil with a REMARKS second layer of asbestos and wind the balance of the \vim ove~.tlic first coil. Cover the finished coil with The process is readily adaptable t o the purification of another layer of ashest,os. a variety of substances, and the required temperature Clamp thr coil in a vcrtical position, arrange a can be readily attained by adjusting the voltage applied clock mechanism (electric or spring above to the coil. Jovrr~do l Chemrol Edueolton

M o y 1963

PARAMAGNETISM Suhmitt~dby: Checked by:

Yu-tsai Peng, Chinese Militsly Academy, Fengslia~i, Itepul~lic of China Robert Greve, Far Eastern Highland Mission Island Academy, Agana, Guam

PREPARATION

Providc a n Alnico magnet (Cenco 78236-C or equivalent), a glass dish, distilled water, dropper, and a freshly prepared mixturc made by mixing equal volumes of 0.5 A t FeCl, and 0.5 M K4Fe(CN)6. Also provide two droppers calibrated t o deliver 0.04 ml per drop and a piece of glass tubing 8 X 200 mm with a right angle hend approximately 2 cm from each end. DEMONSTRATION

I'lace the magnet in the glass dish, add a thin laycr of water, and allow to stand a t rest for approximately 10 mins. Add one drop of the freshly prepared blue mixturc approximately 1 cm from the poles of the magnet. The blue complex mill diffuse into the magnetic field. Mount the glass tube in a horizontal position so that it is level. Fill the tube with distilled ~vateruntil it just enters the bent portion a t each end. Carefully add one drop of FeCI3 and one drop of IWe(CiY)s to opposite ends. Observe the position of the blue ring formed as the result of thc diffusion. As soon as the blue hand forms, position the Alnico magnet adjacent t,o the tuhe and to the right of the band. The band will slowly move into the magnet,ic field. REMARKS

The position of formation of the blue ring call be displaced by placing a strong magnet a t oue end of the glass tube. . J o u m d 01 Chcmirnl Rdmalion

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