General Description of the Production Technology
Potassium sulfate is produced from primary and secondary sources.
— Primary sources include natural brines (very limited reserves), as well as minerals including polyhalite.
— Secondary source is potassium chlorine. The production method in case of secondary sources is the Mannheim process, in accordance with which fertilizers are produced from potassium chloride by exposing it to sulfuric acid and as a result of simple replacement of chlorine with sulfate. This is a more expensive method due to consumption of additional electric power and sulfuric acid.
KGDI experts in cooperation with the K-UTEC AG Salt Technologies' specialists have developed variants of the scoping level original technology for polyhalite treatment. It adapts the baseline scheme to the specificity of polyhalite ores of Severo-Krasnoborsky mining field, which allows for reducing the cost of treatment by 70% as compared with other SOP producers that utilize the Mannheim method to produce SOP.
The first commercial scenario for the product is direct sales of polyhalite fertilizers. The only required treatment stages are ragging, milling, and granulation.
Sedimentation in the form of gypsum is generated in the process of production, which may be treated into an end marketable product, such as gypsum and anhydrite for construction purposes.
After torrefaction and dissolution yet another commercial scenario is possible – schoenite. It may be considered as a fertilizer. However, due to the high content of water in it the supply and demand for schoenite remain quite low. Further treatment is therefore a recommended option.
Schoenite is a base material for the production of the end products – potassium sulfate and magnesium sulfate (epsomite), which are considered to be high grade potassium fertilizers.