Molten NaCl

Molten lithium fluoride and sodium chloride have easily measured electrical conductivities. Nevertheless, these conductivities are lower than metallic conductivities by several factors of ten. Molten sodium chloride at 750°C has a conductivity about IQ-5 times that of copper metal at room temperature. It is unlikely that the electric charge moves by the same mechanism in molten NaCl as in metallic copper. Experiments show that the charge is carried in molten NaCl by Na+ and Cl- ions. This electrical conductivity of the liquid is one of the most characteristic... 

Sodium is prepared by electrolysis of molten NaCl (giving chlorine as a by-product) or of molten NaOH. 

Chlorine is prepared by the electrolysis of molten NaCl or of aqueous NaCl. 

Early experimental work in electrorefining at Los Alamos by Mullins et-all ) demonstrated that americium could be partitioned between molten plutonium and a molten NaCl-KCl salt containing Pu+3 ions, and Knighton et-al(8), working at ANL on molten salt separation processes for fuel reprocessing, demonstrated that americium could be extracted from Mg-Zn-Pu-Am alloys with immiscible molten magnesium chloride salts. Work... 

C19-0129. The sketch below shows a cell set up to electrolyze molten NaCl. 

Simulation Results for Shear and Bulk Viscosities of Molten NaCl and KCI... 

Simulation Results for the Thermal Conductivity of Molten NaCl and KCP"... 

We have learned (Chap. 7) that some reactions occur under one set of conditions while an opposite reaction occurs under another set of conditions. For example, we learned that sodium and chlorine combine when treated with each other, but that molten NaCl decomposes when treated with electricity ... 

Although more important as a means of producing sodium, the electrolysis of molten NaCl is carried out on an industrial scale. 

Elemental chlorine is produced by the electrolysis of molten NaCl in the Downs Cell. The other product is sodium metal. The products must be separated because the reaction between metallic Na and gaseous Cl2 is very rapid, spontaneous and explosive. The product, Cl2, is poisonous. 

A few larger-scale tests were planned wherein a larger mass of water would be driven into a mass of molten NaCl. All tests were negative and photography showed that a few leading drops of water would always contact the salt, explosively boil, and drive the descending water column back so as to prevent it from contacting the salt ... 

Anderson, R. P., and Bova, L. (1975). Final Report on the Small Scale Vapor Explosion Experiments Using a Molten NaCl-HjO System, ANL/RAS 75-6. Argonne Natl. Lab., Argonne, Illinois. 

In the electrolysis of molten NaCl, if 23.0 grams of sodium metal is obtained when 1.0 Faraday of electricity passes through the cell, how many grams of sodium are obtained if 1.5 Faradays pass through the cell ... 

Lantelme, R, Turq, R, Quentrec, B., and Lewis, J.W.E., Application of the molecular dynamics method to a liquid system with long range forces (Molten NaCl), Mol. Phys., 28,1537-1549, 1974. 

We shall see later that the differences are not evidence against the correctness of the theory, but follow logically from the theory of the electrostatic bond. The reason why the molecules in molten NaCl dissociate into ions, but those in CC14 do not, is immediately apparent... 

Rh compounds exhibit valences of 2, 3, 4, and 6. The tnvalent form is by far the most stable. When Rh is heated in air, it becomes coated with a film of oxide. Rhodium(III) oxide, Rh Os, can be prepared by heating the finely divided metal or its nitrate in air or O2. The rhodium IV) oxide is also known. Rhodium trihydroxide may be precipitated as a yellow compound by adding the stoichiometric amount of KOH to a solution of RhCb. The hydroxide is soluble in adds and excess base. When the freshly precipitated Rh(OH) is dissolved in HC1 at a controlled pH, a yellow solution is first obtained in which the aquochloro complex of Rh behaves as a cation. The hexachlororhodatetHI) anion is formed when the solution is boiled for 1 hour with excess HC1. The solution chemistry of RI1CI3 is often very complex. Two trichlorides of Rh aie known The trichloride formed by high-temperature combination of the elements is a red, crystalline, nonvolatile compound, insoluble in all aads. When Rh is heated in molten NaCl and treated with Clo, Na RJiClg is formed, a soluble salt that forms a hydrate in solution. Rhodium(III) iodide is formed by the addition of KI to a hot solution of tnvalent Rh. 

All the free halogens are produced commercially by oxidation of their anions. Fluorine and chlorine are both produced by electrolysis fluorine from a molten 1 2 mixture of KF and HF, and chlorine from molten NaCl. 

How many hours are required to produce 1.00 X 103kg of sodium by the electrolysis of molten NaCl with a constant current of 3.00 X 104 A How many liters of Cl2 at STP will be obtained as a by-product ... 

Figure 2. Cation-cation and cation-anion radial distribution functions for molten NaCl, obtained from simulation (force field given in Ref. [285]). Charge ordering is clearly visible, as described in the text.

Figure 2-17 Raman spectra of molten NaCl-KCl-CaCl2 containing (a) 4.3%, (b) 8.8%, (c) 17.8%, (d) 21.0%, and (e) 30.8% MgCl2. (Reproduced with permission from Ref. 30.)...

Figure 7 Dependence of the equivalent electrical conductivity of molten NaCl on the strength of the applied electric field [54,55] at 1223 (1), 1049 (2) and 1003 K (3).

Cathodic deposition of magnesium from various chloride melts on different substrates has been studied by several authors [288-290], In dilute solutions of Mg(II) species the cathode process has been found to be controlled by diffusion of the reactant. Alloy formation has been observed on platinum, as reported by Tunold [288] and Duan et al. [290], The rate constant of the charge transfer process on a Mg/Ni electrode in molten NaCl-CaCl2-MgCl2 was reported by Tunold to have a value of about 0.01 cm s 1. This author also reported underpotential deposition of a monolayer on iron electrodes, at potentials approximately 100 mV positive to the Mg deposition potential. 

In the last section, we looked at an electrolytic cell containing molten NaCl. Very high temperatures are needed to melt sodium chloride, so you might ask, Why can t we just dissolve it in water and do the same thing Before answering that question, you may wish to consider a procedure that you may have seen demonstrated for you (or even performed) in an... 

D) If the molten NaCl is replaced by an 1.0 M aqueous sodium chloride solution, how much sodium can be collected if a current of 1.0 A is applied for 1.0 hour ... 

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