Abstract: Chlorine is produced by electrolysis of aqueous HCl, in a membrane electrolyzer, using cathodic mediators such as Fe(III) and/or Cu(II) chlorides and a non-catalysed 3-dimensional cathode, with the real surface area at least ten times higher than its projected area. The HCl electrolysis section is combined with an oxidizer for regeneration of the mediator, product water removal step and optional HCl recovery step. Under optimized conditions chlorine can be produced at very high current densities of 30 kA/m2, without initiating undesired H2 evolution reaction at the cathode.

Abstract: A method for the reduction of soluble aluminum species in an evaporated salt alkali metal halide brine containing up to 500 ppb aluminum species to provide a brine feedstock suitable for use in a chlor-alkali membrane cell process, said method comprising treating said brine with a magnesium salt in an amount to provide a Mg to Al molar ratio selected from 5-20 to 1 at a Mg concentration selected from 0.5-10 ppm, and sufficient alkali metal hydroxide to provide an excess alkalinity concentration of between 0.1-0.5 g/L alkali metal hydroxide to effect precipitation of a magnesium aluminum hydroxide complex; and removing said complex to provide said brine feedstock.

Abstract: Chlorine is produced by electrolysis of aqueous HCl, in a membrane electrolyzer, using cathodic mediators such as Fe(III) and/or Cu(II) chlorides and a non-catalysed 3-dimensional cathode, with the real surface area at least ten times higher than its projected area. The HCl electrolysis section is combined with an oxidiser for regeneration of the mediator, product water removal step and optional HCl recovery step. Under optimised conditions chlorine can be produced at very high current densities of 30 kA/m2, without initiating undesired H2 evolution reaction at the cathode.

Abstract: A method for determining the concentration of hydrogen ion, organic anionic species and anionic species selected from the group consisting of OH−, CO3═, HS−, ClO3−, SO4═, S2O3═, polysulphide and peroxide in an aqueous sample solution, said method comprising subjecting said solution to near infrared radiation at a wavelength region of wave numbers selected from about 7,000 to 14,000 cm−1 through a solution path length of at least 3 mm to obtain spectral data for said solution; obtaining comparative spectral data for said anionic species at known concentrations in aqueous solutions; and correlating by multivariate calibration the relationships between said spectral data of said sample solution and said comparative spectral data to determine said concentration of said anionic species in said sample solution.

Abstract: A column to regenerate methanol from a methanol-water mixture includes a circular column having two contact beds with a plurality of gas inlets connected thereto to split the entering feed gas so that approximately equal portions are fed through each bed. An inlet near the top of the column allows a methanol-water mixture to be introduced to flow down through the two contact beds, countercurrent to the feed gas.