With conventional landfills becom ing both scarce and costly and deep well injection being highly
restricted, controlled high temperature incineration is playing an increasingly important role in waste
management and at the same time generating power for industry / consumer use. Depending on the
chemical make-up of the waste (both municipal and hazardous industrial waste) and combustion
conditions, a multitude of harmful acidic gases and deposits are produced which lead to a variety of high
temperature severe corrosive environments resulting in accelerated metal wastage. The acidic gases
produced during incineration of the chlorinated hazardous wastes must be scrubbed out or neutralized
prior to release to the atmosphere. Typically most of the modern incineration systems consist of a high
temperature incinerator chamber, a heat recovery system, a quench section to further reduce the
temperature of the flue gas stream and a host of pollution control equipment to scrub acidic gases and
control the particulate emissions. Hence reliability of high temperature section components and pollution
control section components becomes a major concern. This paper discusses the contributions of nickel
alloys in providing the necessary reliability in combating the corrosion problems.
Another area of concern in the industry has been with the management of nuclear waste via vitrification
technology. Research in USA has shown that alloys containing 50 wt% Nickel, 25 wt% Chromium and
additions of 2 to 3% of either Aluminum or Silicon performed comparably or slightly better than alloy 690 (
UNS N06690), the current material of choice in glass melters. Cogema / Framatome in France have
been successfully using a Ni-Cr-Al Alloy 602CA (UNS N06025) as fusion pots for their vitrification plant at
La Hague in Europe.
This paper gives a brief description of various nickel alloys, their corrosion resistance properties,
fabricability and case histories in these industries.