Authors:
A. Sadri, P. Gebski, D. Olmedo Rojas, G. Zamorano, M. Escudero and J. Araya
MAPLA 2010; 7th International mining plant maintenance meeting, Santiago, Chile, September 1-3, 2010
Abstract
The resulting gases from smelting sulfide based products such as copper and nickel are converted to sulfuric acid to be used in the industrial processes. The gases contain both SO2 and SO3 which are passed through absorption towers where the reaction with water results in production of highly concentrated sulfuric acid. The absorption towers are lined with special acid resistance refractory, however, frequent acid leaks occur through the lining either because of presence of discontinuities or castable failure at the nozzles. The leaked acid eventually finds its way out of the tower and can be identified visually. To repair the leak, the source must be identified since the castable at the nozzles are repairable but the inner lining can only be replaced and repairs are not possible.
This paper discusses the application of Non-destructive testing (NDT) techniques to detect and locate the source(s) of sulfuric acid leak(s) of an Absorption Tower in Chile. In this exercise, a set of NDT techniques was implemented to assure the most comprehensive possible evaluation of the current condition of the Tower. It was decided that a combination of Infrared thermography (IR), Acoustic Emission (AE) and Acousto Ultrasonic – Echo (AU-E) testing will be used to provide results, including the type of flaws, their physical locations and their severity. These NDT techniques are suitable for detecting sources of leaks and to identify local problems with refractory lining that could be the root cause of the Absorption Tower malfunction.
In this paper, the principles of all three techniques (IR, AE and AU-E), and their relevance to this particular project objectives, are briefly discussed. Finally, the results of the NDT exercises were presented.
