Experiences in the development of magnesium cell technology at Central Electrochemical Research Institute, Karaikudi

Research activities on the preparation of magnesium metal by molten salt electrolytic process were initiated in CECRI as early as in 1958. CECRI started its experiments on a bench scale level and further developed into pilot plant scale and finally to the scale of semicommercial unit. Various types of electrolytic cells were developed at CECRI which include externally heated cells with different design modifications, modular cells, bipolar/multipolar cells and new modified monopolar ceUs. The primary aim of each development was aimed at high current efficiencies energy efficiencies and space time yields. Various types of raw materials like magnesite, sea bitterns, and byproduct MgCl2 from ZrrTi plants etc. were utilised during the investigations. These studies were carried out with financial grants from Govt. of Tamil Nadu, CSIR, DRDO and Nuclear Fuel Complex. The paper illustrates the design and operational features of different electrolytic cells with consequent gradual decrease in specific energy consumption for magnesium production and increased space time yields with improvement in cell design and operational parameters

Phase behaviour of some mixed chloride salt systems

Phase behaviours of two different series of chloride salt mixtures, viz (a) equimolecular (NaCI + KCI), MgCI,, BaCI, and (b) [NaCI + KCI], MgCI,, CaClz have been studied. The percentages of MgCI2 in the salt mixtures were kept fixed at four different valuesviz 10,20,30 and 40in these studies where other components vary. It has been found that the replacement of CaCI, with BaC12 in the four component salt mixtures does not change the shape and the temperature of the liquidus curve significantly except in the cases when the percentage of BaCI, in the mixture is more than 50

Fusibility and density studies of some fluoride mixtures related to electrorefining of aluminium

Fusibility and density of some salt mixtures formed among NaF, AIF, (the two constituents of cvloite o r e ) and an equimolecular haCI-KC1 mixture have been experimentally determined. It has been found that the primary crystallization point of the mixture comes down rapidly with the addition of equirnolecular NaCI-KC1 to cryolite and goes even below 700" when the proportion of NaC1-KC1 in the mixture is kept 50 mole percent and above. It has also been found that the primary crystallization temperature of the salt mixture does not change significantly when the molar ratio of NaF to AIF, in the four component salt mixture was changed from 3:1 (as in natural cryolite ore) to 3:2 The density of thc system decreases with increasing among of NaCl -KC1 in the mixture

A new electrorefining system for aluminium

Super pure aluminium is at present produced on commercial scale by three layer electrorefining process which has several drawbacks. A new nonalloying refining system was hence developed and tried in laboratory scale cells. The performance of the new system and the results obtained therein are discussed in this pape