A method for the management of phosphogypsum consists in that a reactor (2) is charged with apatite and/or phosphorite phosphogypsum and with an aqueous or ammoniacal solution of ammonium carbonate and/or bicarbonate from a pre-reactor (1), at 1: (0.1-4) ratio of phosphogypsum to the aqueous or ammoniacal solution of ammonium carbonate and/or bicarbonate, the entire contents are stirred at 10 C. to 200 C. for at least 2 minutes, CO.sub.2 being released in the course of the process is directed to the pre-reactor (1), and the post-reaction mixture is directed to a filter (3) to obtain an aqueous ammonium sulphate solution, whereas the precipitate from the filter (3) is heat-treated, followed by dissolving it in nitric acid in a reactor (5), and the resultant suspension is filtered through a filter (6) to obtain an aqueous calcium nitrate solution, and CO.sub.2 being released in the reactor (5) is recirculated to the pre-reactor (1) wherein CO.sub.2 is reacted with ammonia in an aqueous solution to obtain the aqueous or ammoniacal solution of carbonate and/or bicarbonate which is directed to the reactor (2), with the process for obtaining the aqueous or ammoniacal solution of ammonium carbonate and/or bicarbonate being conducted until the pH 7-12 of the solution is reached.

A method for the management of phosphogypsum consists in that a reactor (2) is charged with apatite and/or phosphorite phosphogypsum and with an aqueous or ammoniacal solution of ammonium carbonate and/or bicarbonate from a pre-reactor (1), at 1: (0.1-4) ratio of phosphogypsum to the aqueous or ammoniacal solution of ammonium carbonate and/or bicarbonate, the entire contents are stirred at 10 C. to 200 C. for at least 2 minutes, CO.sub.2 being released in the course of the process is directed to the pre-reactor (1), and the post-reaction mixture is directed to a filter (3) to obtain an aqueous ammonium sulphate solution, whereas the precipitate from the filter (3) is heat-treated, followed by dissolving it in nitric acid in a reactor (5), and the resultant suspension is filtered through a filter (6) to obtain an aqueous calcium nitrate solution, and CO.sub.2 being released in the reactor (5) is recirculated to the pre-reactor (1) wherein CO.sub.2 is reacted with ammonia in an aqueous solution to obtain the aqueous or ammoniacal solution of carbonate and/or bicarbonate which is directed to the reactor (2), with the process for obtaining the aqueous or ammoniacal solution of ammonium carbonate and/or bicarbonate being conducted until the pH 7-12 of the solution is reached.

The present invention is a process, a method, and system for recovery and concentration of dissolved ammonium bicarbonate from a wastewater containing ammonia (NH3) using gas separation, condensation, and crystallization, each at controlled operating temperatures. The present invention includes 1) removal of ammonia from waste (sludges, semi-solids, and solids and liquids) without the use of chemicals at a temperature of at least 80 degrees Celsius, 2) condensing the gaseous containing ammonia, carbon dioxide and water vapor to remove water vapor concentrating the amount of gaseous ammonia and carbon dioxide, 3) concentrating the ammonia and carbon dioxide in the water by established means, such as concentrating the gas using partial condensation followed by passing the concentrated gas through an absorption column at a temperature of between about 20 and 50 degrees Celsius to form dissolved ammonium carbonate and ammonium bicarbonate, or total condensation followed by dewatering using reverse osmosis, and 4) crystallizing concentrated dissolved ammonium carbonate and ammonium bicarbonate at a temperature of less than about 35 degrees Celsius to form solid ammonium bicarbonate and ammonium carbonate.

The present invention is a process, a method, and system for recovery and concentration of dissolved ammonium bicarbonate from a wastewater containing ammonia (NH3) using gas separation, condensation, and crystallization, each at controlled operating temperatures. The present invention includes 1) removal of ammonia from waste (sludges, semi-solids, and solids and liquids) without the use of chemicals at a temperature of at least 80 degrees Celsius, 2) condensing the gaseous containing ammonia, carbon dioxide and water vapor to remove water vapor concentrating the amount of gaseous ammonia and carbon dioxide, 3) concentrating the ammonia and carbon dioxide in the water by established means, such as concentrating the gas using partial condensation followed by passing the concentrated gas through an absorption column at a temperature of between about 20 and 50 degrees Celsius to form dissolved ammonium carbonate and ammonium bicarbonate, or total condensation followed by dewatering using reverse osmosis, and 4) crystallizing concentrated dissolved ammonium carbonate and ammonium bicarbonate at a temperature of less than about 35 degrees Celsius to form solid ammonium bicarbonate and ammonium carbonate.

The present invention relates to processes and systems for basic gas, e.g., ammonia, recovery and/or acid-gas separation. In some embodiments, a system for acid gas separation may be integrated with an ammonia abatement cycle employing a high temperature absorber. In some embodiments, a system for acid gas separation may employ a higher temperature absorber due to the lower energy consumption and cost of the integrated ammonia abatement cycle. Advantageously, heat may be recovered from the absorber to power at least a portion of any acid gas desorption in the process. Reverse osmosis or other membranes may be employed.

The present invention is a production method for ammonia and ammonia derivatives in a Multi-Reaction Zone Reactor. Said production method comprising the steps of: a) producing at least some section of ammonia as a result of balance reaction of ammonia by means of nitrogen and hydrogen catalyst in at least one primary reaction zone (RZ-1), b) realizing absorption by means of chemical or physical absorbents of at least some section of ammonia which is in gas form and which is produced in primary reaction zone (RZ-1) in at least one secondary reaction zone (RZ-2) which is not separated by discrete physical barriers with the primary reaction zone (RZ-1).

The present invention is a production method for ammonia and ammonia derivatives in a Multi-Reaction Zone Reactor. Said production method comprising the steps of: a) producing at least some section of ammonia as a result of balance reaction of ammonia by means of nitrogen and hydrogen catalyst in at least one primary reaction zone (RZ-1), b) realizing absorption by means of chemical or physical absorbents of at least some section of ammonia which is in gas form and which is produced in primary reaction zone (RZ-1) in at least one secondary reaction zone (RZ-2) which is not separated by discrete physical barriers with the primary reaction zone (RZ-1).

A process for reducing nitrogen oxides in an exhaust stream, such as a vehicle exhaust stream, and apparatus for carrying out the process. The process comprises providing a first composition comprising aqueous urea, a second composition comprising ammonium carbamate and an exhaust stream comprising nitrogen oxides. A process for producing the ammonium carbamate is also provided. The second composition may be introduced into the exhaust stream (10) when the exhaust stream has a temperature below a threshold temperature and the first composition may be introduced into the exhaust stream when the exhaust stream has a temperature at or above the threshold temperature.

A process and system for removing ammonia from ammonia-containing purge gas of a urea plant, the process comprising: contacting said ammonia-containing purge gas with carbon dioxide at a low temperature, reaction of ammonia to form crystals of ammonium salts in a multiphase stream, and removal of the solid ammonium salts from the multiphase stream.

A process and system for removing ammonia from ammonia-containing purge gas of a urea plant, the process comprising: contacting said ammonia-containing purge gas with carbon dioxide at a low temperature, reaction of ammonia to form crystals of ammonium salts in a multiphase stream, and removal of the solid ammonium salts from the multiphase stream.