Mineralogical characterisation and techno-economic prospects of the Aydag deposit natural zeolite, Azerbaijan

The mineralization of the Aydag deposit, situated in the Tovuz district in the Western part of Azerbaijan, is one of the most well studied occurrences of natural clinoptilolite in the South Caucasus, but its industrial potential is dispersed in mineralogical, process-performance and market distribution studies. The paper presents a pre-feasibility techno-economic screening, combining published mineralogical results, gas purification, catalysis experiments that were conducted on the Aydags, up-to-date natural-zeolites market statistics and adsorption and hydroponic comparative results. The average X-ray content of clinoptilolite in the samples published in the literature ranges from about 70–80%, and the CIS resource synthesis reports 55–65%, material heterogeneity has been confirmed which is why it is necessary to have a grade control based on domains. Field experience in the use of Aydag zeolite in dehydration of gas to low dew points has proven that this zeolite retains acceptable adsorbent capacity after 46 months of operation and is referenced in the literature to adsorbent-cost range of USD 120-230/t compared with USD 2,500-4,000/t for synthetic NaA. The study recently published by Azerbaijani researchers also shows that Aydag zeolite is a heterogeneous catalyst for transesterification of grape-seed-oil. However, many of the resource estimates have been published in the last number of years, with recent official and technical sources showing 20-25 Mt, and historical sources estimating 100 Mt, making this impossible to valuate as a bankable resource. Based on the evidence, a staged development strategy is applicable, starting with gas treatment, water-treatment media and catalyst-grade products and moving on to agricultural and/or hydroponic validation.

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