Corrosion and Protection of Concrete in an Ammonium Nitrate Environment

A brief description of the compound fertiliser plant and its recycle loop is given. Several items of equipment suffer significant wear. These are the blunger, the drier feed screw, the drier exhaust fan and the oversize pulveriser.

Several attempts have been made to solve the problems of rapid wear on these items. Hard surfacing by welding has been found to be most effective in our case. Weld surfacing has the advantage that worn components may be reclaimed by further weld surfacing. The lives of the various items have been increased significantly, in some cases components last from one annual shutdown to the next.

The problem can never be considered fully solved for two reasons. Firstly, new surfacing materials are being introduced which may offer advantages over those being employed; and secondly, changes in fertiliser formulation can significantly alter the type of wear taking place.