September 2011

This spring issue of your favourite technical magazine has a wealth of articles from our talented young engineers from our local universities, as well as one by a team from the CSIR. First up, as our feature article in the Water treatment section, is the article on removal and recovery of Ni, Cu and Fe from heavy metal effluent by reduction crystallization, written by Tebogo Phetla, (supervised by F Ntuli and E Muzenda), all from the University of Johannesburg's Department of Chemical Engineering.

The paper on which it is based won Tebogo and her co-authors the Water category award in our recent ‘Chemical Technology' awards. This study investigated the use of hydrazine as a reducing agent to remove and recover Ni, Cu and Fe from wastewater. Feasibility studies were carried out to test the efficiency and find the optimum operating conditions for this method and generate an understanding of the chemical and particulate process occurring.

"A case study for treating a reverse osmosis brine using Eutectic Freeze Crystallization - approaching a zero waste process" by Dyllon Randall, Alison Lewis, both of the Crystallization and Precipitation Research Unit at the University of Cape Town, and Jeeten Nathoo from GrahamTek NuWater, in Cape Town, was one of the co-winning papers in the Postgraduate category of our awards. This article (in the Separation and filtration technologies feature) describes a case study in which EFC was used to treat the liquid waste obtained from a Reverse Osmosis (RO) plant, the eMalahleni Water Reclamation Plant (EWRP), which uses a Hi recovery Precipitating Reverse Osmosis (HiPRO) process technology and produces 25 000m³/d of potable water with recovery rates in excess of 99%.

In our article in the Mining and minerals processing section of the mag, PhD student David Lokhat of the School of Chemical Engineering at the University of KwaZulu-Natal, discusses gas-phase epoxidation of hexafluoropropylene

The beneficiation of domestic fluorspar and the development of the local fluorochemical technology base are the major objectives of the Fluorochemicals Expansion Initiative, a priority government strategy within the Departments of Minerals and Energy, Trade and Industry and Science and Technology.

‘In-situ crack repair by laser cladding' is the title of our Materials of construction feature article. It comes to us from Corney van Rooyen, Herman Burger, Maritha Theron, all of the National Laser Centre, CSIR, Pretoria, South Africa and Philip Doubell, Eskom ERID, Johannesburg. The authors evaluated laser cladding crack repair of austenitic stainless steel vessels subjected to internal water pressure in order to develop process parameters for in-situ repair of through-wall cracks in components or vessels which contain water under pressures of up to 2 bar.

For all those coffee-lovers among you, Gavin Chait's article will be of especial interest! Enjoy the issue.

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