A process and system are disclosed for producing lithium oxide from lithium nitrate. In the process and system, the lithium nitrate is thermally decomposed in a manner such that a fraction of the lithium nitrate forms lithium oxide, and such that a remaining fraction of the lithium nitrate does not decompose to lithium oxide. The thermal decomposition may be terminated after a determined time period to ensure that there is a remaining fraction of lithium nitrate and to thereby produce a lithium oxide in lithium nitrate product. The lithium oxide in lithium nitrate product may have one or more transition-metal oxides, hydroxides, carbonates or nitrates added thereto to form a battery electrode. The lithium oxide in lithium nitrate product may alternatively be subjected to carbothermal reduction to produce lithium metal.

A process and system are disclosed for producing lithium oxide from lithium nitrate. In the process and system, the lithium nitrate is thermally decomposed in a manner such that a fraction of the lithium nitrate forms lithium oxide, and such that a remaining fraction of the lithium nitrate does not decompose to lithium oxide. The thermal decomposition may be terminated after a determined time period to ensure that there is a remaining fraction of lithium nitrate and to thereby produce a lithium oxide in lithium nitrate product. The lithium oxide in lithium nitrate product may have one or more transition-metal oxides, hydroxides, carbonates or nitrates added thereto to form a battery electrode. The lithium oxide in lithium nitrate product may alternatively be subjected to carbothermal reduction to produce lithium metal.

Disclosed is an exhaust gas purification system, including: a cathode unit including a first accommodation space, a first aqueous solution, and a cathode at least partially submerged in the first aqueous solution; an anode unit including a second accommodation space, a second aqueous solution which is basic, and a metal anode at least partially submerged in the second aqueous solution; and a connection unit configured to connect the cathode unit and the anode unit. The anode is made of aluminum (Al) or zinc (Zn), a gas containing nitrogen oxide (NO.sub.x) is injected into the first aqueous solution, the nitrogen oxide injected into the first aqueous solution reacts with water to produce nitric acid (HNO.sub.3), the nitric acid supplies hydrogen ions, and the hydrogen ions and electrons of the cathode react to produce hydrogen.

A dual pressure plant for the production of nitric acid, comprising: an air compressor; a converter, operating at a low pressure (LP), operable to be fed with a stream of an ammonia/pressurized air mixture to produce an LP gaseous NOx gas/steam mixture, comprising water, NO, NO.sub.2 and N.sub.2O.sub.4; a NOx gas compressor; an absorber unit (6); and a bleacher unit;
wherein the plant comprises means for directing the NOx-loaded stripping gas to the downstream side of the NOx gas compressor;
the plant being characterized in that it further comprises a high-pressure (HP) water electrolyser, in fluid communication with the bleacher unit.

A dual pressure plant for the production of nitric acid, comprising: an air compressor; a converter, operating at a low pressure (LP), operable to be fed with a stream of an ammonia/pressurized air mixture to produce an LP gaseous NOx gas/steam mixture, comprising water, NO, NO.sub.2 and N.sub.2O.sub.4; a NOx gas compressor; an absorber unit (6); and a bleacher unit;
wherein the plant comprises means for directing the NOx-loaded stripping gas to the downstream side of the NOx gas compressor;
the plant being characterized in that it further comprises a high-pressure (HP) water electrolyser, in fluid communication with the bleacher unit.

The disclosure pertains to a nitric acid production process and plant. The process involves supplying an oxygen gas stream and ammonia feedstock to the burner section. In embodiments, a part of the tail gas stream (4) is heated in a tail gas heating section (7) and supplied to the burner section (1).

The disclosure pertains to a nitric acid production process and plant. The process involves supplying an oxygen gas stream and ammonia feedstock to the burner section. In embodiments, a part of the tail gas stream (4) is heated in a tail gas heating section (7) and supplied to the burner section (1).

In a method for oxidizing 1,1-bis-(3,4-dimethylphenyl)-alkane with nitric acid in a pressure vessel to produce 3,3′,4,4′-benzophenone tetracarboxylic acid with concurrent formation of nitric oxide, passing nitric oxide from the pressure vessel into an absorption vessel and reacting nitric oxide in the absorption vessel with molecular oxygen and water to produce an aqueous nitric acid solution prevents discharge of nitric oxide, avoids the risk of oxygen inhibiting the nitric acid oxidation and reduces nitric acid consumption when the nitric acid from the absorption vessel is used for oxidizing the 1,1-bis-(3,4-dimethylphenyl)-alkane.

In a method for oxidizing 1,1-bis-(3,4-dimethylphenyl)-alkane with nitric acid in a pressure vessel to produce 3,3′,4,4′-benzophenone tetracarboxylic acid with concurrent formation of nitric oxide, passing nitric oxide from the pressure vessel into an absorption vessel and reacting nitric oxide in the absorption vessel with molecular oxygen and water to produce an aqueous nitric acid solution prevents discharge of nitric oxide, avoids the risk of oxygen inhibiting the nitric acid oxidation and reduces nitric acid consumption when the nitric acid from the absorption vessel is used for oxidizing the 1,1-bis-(3,4-dimethylphenyl)-alkane.

A vertical bleaching tower for removing dissolved nitrogen oxides from an aqueous nitric acid solution using a stripping gas such as air, nitrogen, oxygen or combinations thereof in a process for producing nitric acid, comprising a structured packing; a liquid distributor comprising a feed box having a serrated weir for distribution of the aqueous nitric acid solution comprising the dissolved nitrogen oxides through upward-pointing serrations of the serrated weir into perforated trays of the liquid distributor and located above the structured packing for distributing the aqueous nitric acid solution comprising the dissolved nitrogen oxides to the structured packing; an inlet and outlet, both suitable for aqueous nitric acid solution; and an inlet and outlet, both suitable for the stripping gas. The present invention further comprises a bleaching method for removing dissolved nitrogen oxides from an aqueous nitric acid solution in a vertical bleaching tower