Elixsys, Inc.

Lucien Papouchado

Joseph D Preston

Barry E Scheetz

Barry E Sheetz

Leonard Passmore

Disclosed herein are systems and methods from processing flue gas desulfurization (FGD) gypsum feedstock and ash feedstocks, either separately or together. FGD gypsum conversion comprises reacting FGD gypsum (calcium sulfate) feedstock or phosphogypsum, in either batch or continuous mode, with ammonium carbonate reagent to produce commercial products comprising ammonium sulfate and calcium carbonate. A process to separate the impurities and convert the calcium carbonate to a pure precipitated calcium carbonate is disclosed. These impurities include a concentrate of valuable Rare Earth Elements, and radioactive thorium and uranium. A process to convert calcium sulfite to calcium sulfate using oxygen and a catalyst is also disclosed. Ash conversion comprises a leach process followed by a sequential precipitation process to selectively precipitate products at predetermined pHs resulting in metal hydroxides which may be converted to oxides or carbonates. The processes may be controlled by use of one or more processors.

Systems and methods to recover value-added materials from gypsum

Disclosed herein are system and methods for producing a high purity ammonium sulfate product as well as either a lower or a high purity calcium carbonate product by reacting flue gas desulfurization (FGD) gypsum feedstock in batch or continuous mode using synthesized ammonium carbonate from ammonia and carbon dioxide gases. The high purity calcium carbonate is obtained by using a precipitation catalyst, filtering out the impurities, then precipitating a high purity calcium carbonate. Alternatively, the lower purity calcium carbonate may be dissolved in acid, impurities filtered out, then a high purity calcium carbonate is precipitated out using a soluble carbonate salt.

Systems and methods to treat flue gas desulfurization waste to produce ammonium sulfate and calcium carbonate products

Disclosed herein are system and methods to effectively leach coal ash with hydrochloric acid and separate an insoluble silica product and then selectively precipitate, from the leachate, a number to value-added, strategic, marketable products using a hydroxide reagent. The resulting precipitated products include iron, aluminum, magnesium, calcium, and a mixture of rare earth elements and transition metals. These can be separated as hydroxides or converted to oxides or carbonates. Using hydrochloric acid for leaching and converting the chloride to sodium chloride in the final step results in practically no waste for this process. The silica can be further purified using sodium hydroxide fusion or caustic leach methods and some minor streams from this process are recycled to minimize any waste stream. These systems and methods can be applied to a number of other industrial waste products such as red mud from the aluminum process, slag from steel furnaces, mine tailings, and other metal-bearing waste streams.

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Aiken, SC, United States of America

Lucien Papouchado