Economic Benefits and Practical Aspects of Converting to the Hemihydrate Route for Phosphoric Acid

There is a trend in the fertilizer industry to convert existing dihydrate phosphoric acid plants to hemihydrate technology. This results in improved ease of operation, enrgy savings and increased P205 recovery for a relatively low capital investment. Most converted plants utilise Norsk Hydro technology and three recent examples are examined in this paper. Details of the conversions of the full-scale commercial plants by the Royster Company, USA, Supra AB, Sweden and Belledune Fertilizers, Canada are provided. Operating data where available are also given. Following from the details of the conversion, a review of capital cost is presented. In addition, a production cost comparison for the hemihydrate, hemidihydrate and dihydrate process is provided. This shows a saving of between US $ 24-35 per tonne P205 when using economic benefits is explained.