BEXD Process Description

    Basic Principle:

    The process is based on exchange distillation of Boron Tri-fluoride Diethyl Ether Complex BF3O(C2H5)2. The process involves two important steps, i.e. Raw Material Purification and Exchange Distillation.

    Step-1: Raw Material Purification:

    Commercial grade boron-ether complex with about 20% 10B concentration (natural) is used as the feed material .It contains certain high boiling impurities which are detrimental to the process and as such need to be removed at the beginning. Therefore, the feed material is purified in purification evaporator. The purified feed is condensed and taken to feed receiver.

    Step-2: Exchange Distillation:

    The process of exchange distillation is basically a chemical exchange process, distillation is used as a method of obtaining chemical reflux. BF3.O (C2H5)2 is largely dissociated in the vapor phase and on cooling BF3 gas and di-ethyl ether recombine to form the complex. The chemical exchange of boron isotopes takes place between BF3 in gas phase BF3 di-ethyl complex in the liquid phase.

    The exchange reaction is:

    10BF3 + 11BF3.O(C2H5)2 11BF3 + 10BF3.O(C2H5)2

    The reflux reaction is


    BF3.O (C2H5)2 BF3 + O (C2H5)2


    The exchange process is carried out in a packed column where BF3 gas and BF3.O (C2H5)2 complex are contacted in counter current manner. The reflux is obtained by conventional distillation technique. The distillation is necessarily to be carried out under partial vacuum to reduce the boiling point so as to reduce excessive decomposition of BF3 -ether complex. The operation is carried out at condenser vacuum. The columns are operated in total reflux mode till the desired enrichment is achieved. After the plant operation is carried to the equilibrium state, the waste and product withdrawal are started from condenser and reboiler respectively.

    Last updated on: 04-Feb-2019