Chlorine cell

Zinc chloride cell Zinc-chlorine cell Zinc chromate... 

Eig. 3. Expandable anode for diaphragm chlorine cells (a) clamped and (b) expanded. 

In 1885, Charles Martin Hall invented his aluminum process and Hamilton Young Castner in 1890 developed the mercury-type alkali-chlorine cell, which produced caustic (sodium hydroxide) in its purest form. Edward G. Acheson in 1891, while attempting to make diamonds in an electric furnace, produced silicon carbide, the first synthetic abrasive, second to diamond in hardness. Four years later, Jacobs melted aluminum oxide to make a superior emeiy cloth. Within two decades, these two abrasives had displaced most natural cutting materials, including naturally occurring mixtures of aluminum and iron oxides. 

In an alkali-chlorine cell a saturated (about 6 N) solution of sodium chloride is electrolyzed at ordinary temperatures, between a steel cathode (hydrogen overvoltage 0.2) and a graphite anode (oxygen overvoltage 0.6 volt chlorine overvoltage negligible). The nature of the electrode process. Explained ... 

The terms included in brackets and the succeeding terms are less reliable than the others. R. C. Tolman and A. L. Ferguson measured the e.m.f. of the same type of cell at 18° F. Dolezalek measured the e.m.f. of hydrogen-chlorine cells with cone, hydrochloric acid at 30° as electrolyte. G. N. Lewis and H. Storch have measured the free energy of hydrogen bromide inO l A-soln. and G. N. Lewis and M. Randall, that of hydrogen iodide. For HBr gas, at 25°, the latter give —12 592 Cals., and for HI gas, 310 cals. 

Fig. 8.9 Schematic diagram of a vertical experimental lithium-chlorine cell...

Chlorine Anodes. In chlorine manufacture, anode operating life is limited by coaling wear. The wear rate varies according to cell type. The longest anode coaling life has been achieved in diaphragm chlorine cells. 

Because mercury chlorine cells operate at higher current densities and because the mercury cell antxle can be adjusted during operation to minimize the unode-to-ealhode gap. anode coating life in these cells is much shorter, Because of limited commercial experience with anode coinings in membrane cells, commercial lifetimes have yet to be defined. Expected lifetime is 7- 12 years. 

Each electrolytic application demands a unique approach to anode structure design and fabrication. Factors such as current distribution, gas release, ability to maintain structural tolerances, electrical resistance, and the practicality of recoaiing must be taken into account. The most commercially accepted design for diaphragm chlorine cells is that of the expandable anode (Fig. I). 

In mercury chlorine cells, it has been found that cells operate at lower voltages when filled with anode structures comprised or triangular rods or of vertical blades. 

The dimensionally slahle characteristic of the metal anode made the development of the membrane chlorine cell possible. These cells arc typically arranged in ail electrolyzer assembly which docs not allow for anodc-ro-cathode gap adjustment alter assembly. Also, very close tolerances are required. The latitude that titanium affords the cell designer has made a wide variety of monopolar and bipolar membrane cell designs possible. 

Fig. I. Expandable anode fnr diaphragm chlorine cells mi clani ied and (by expanded...

Figure 13 Voltage characteristics of a rotating chlorine cell. 

After listening intently, the operating foreman explained that mere traces of chrome salts in the brine system could create an explosive situation within the electrolytic chlorine cells. Traces of chrome salts in the feed brine to the chlorine cells liberate hydrogen gas in the chlorine cell gas. Hydrogen in the chlorine cell gas has a very wide explosive range. Installation of stainless steel equipment in sodium chloride brine systems has devastated chlorine processing equipment within other similar chlorine manufacturing plants. The maintenance foreman had the improper pump impeller removed immediately before any problems occurred. 

The 140 liters of solution obtained from an alkali-chlorine cell, operating for 10 hours with a current of 1250 amps., contained on the average 116.5 g. of sodium hydroxide per liter. Determine the current efficiency with which the cells were operating. 

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