The disclosure provides seven integrated methods for the chemical sequestration of carbon dioxide (CO.sub.2), nitric oxide (NO), nitrogen dioxide (NO.sub.2) (collectively NOR, where x=1, 2) and sulfur dioxide (SO.sub.2) using closed loop technology. The methods recycle process reagents and mass balance consumable reagents that can be made using electrochemical separation of sodium chloride (NaCl) or potassium chloride (KCl). The technology applies to marine and terrestrial exhaust gas sources for CO.sub.2, NOx and SO.sub.2. The integrated technology combines compatible and green processes that capture and/or convert CO.sub.2, NOx and SO.sub.2 into compounds that enhance the environment, many with commercial value.

The invention belongs to the technical field of the resource treatment of industrial wastes, and particularly relates to a method for preparing a cementing material using smelting industrial waste slag after utilizing the simultaneous removal of SO.sub.2 and NO.sub.x in flue gas and an application of the cementing material obtained by the same. According to the invention, SO.sub.2 and NO.sub.x in the flue gas can be treated with the smelting industrial waste slag, meeting requirement of flue gas desulfurization and denitration; moreover, the smelting industrial waste slag can be purified and separated by means of waste gas resources to obtain a cementing material, realizing the resource utilization of the smelting industrial waste slag and waste gas.

One aspect of the invention relates to a method comprising a single stage conversion of an atmospheric pollutant, such as NO, NO.sub.2 and/or SO.sub.x in a first stream to one or more mineral acids and/or salts thereof by reacting with nonionic gas phase chlorine dioxide (ClO.sub.2.sup.0 , wherein the reaction is carried out in the gas phase. Another aspect of the invention relates to a method comprising first adjusting the atmospheric pollutant concentrations in a first stream to a molar ratio of about 1:1, and then reacting with an aqueous metal hydroxide solution (MOH). Another aspect of the invention relates to an apparatus that can be used to carry out the methods disclosed herein. The methods disclosed herein are unexpectedly efficient and cost effective, and can be applied to a stream comprising high concentration and large volume of atmospheric pollutants.

One aspect of the invention relates to a method comprising a single stage conversion of an atmospheric pollutant, such as NO, NO.sub.2 and/or SO.sub.x in a first stream to one or more mineral acids and/or salts thereof by reacting with nonionic gas phase chlorine dioxide (ClO.sub.2.sup.0 , wherein the reaction is carried out in the gas phase. Another aspect of the invention relates to a method comprising first adjusting the atmospheric pollutant concentrations in a first stream to a molar ratio of about 1:1, and then reacting with an aqueous metal hydroxide solution (MOH). Another aspect of the invention relates to an apparatus that can be used to carry out the methods disclosed herein. The methods disclosed herein are unexpectedly efficient and cost effective, and can be applied to a stream comprising high concentration and large volume of atmospheric pollutants.

The present disclosure provides a system and a method for calcining coal gangue, which belongs to the technical field of coal gangue treatment and resource utilization. The system for calcining coal gangue provided by the present disclosure includes a pretreatment system (1), a crusher (4), a screening system (5), an elevator (6-1), a screw feeder (6-2 ), a rotary kiln (7), and an exhaust gas treatment system (8). The crusher 4 includes a hammer crusher or an impact crusher. The screening system 5 includes a flip-flow screen or a vibrating screen. Both the flip-flow screen and the vibrating screen are of double-layer screen mesh structures. The mesh size of an upper-layer screen f a double-layer screen mesh structure is 25 mm, and the mesh size of a lower-layer screen of the double-layer screen mesh structure is 0.5 mm.

The present disclosure provides a system and a method for calcining coal gangue, which belongs to the technical field of coal gangue treatment and resource utilization. The system for calcining coal gangue provided by the present disclosure includes a pretreatment system (1), a crusher (4), a screening system (5), an elevator (6-1), a screw feeder (6-2 ), a rotary kiln (7), and an exhaust gas treatment system (8). The crusher 4 includes a hammer crusher or an impact crusher. The screening system 5 includes a flip-flow screen or a vibrating screen. Both the flip-flow screen and the vibrating screen are of double-layer screen mesh structures. The mesh size of an upper-layer screen f a double-layer screen mesh structure is 25 mm, and the mesh size of a lower-layer screen of the double-layer screen mesh structure is 0.5 mm.

Method and installation for treating a CO.sub.2- and H.sub.2O-containing flue gas generated by an industrial process unit before CCUS, whereby the flue gas evacuated from the unit is subjected to cooling to a temperature T2 between 100 and 600° C., whereby the cooled flue gas is pretreated in one or more particle removal and/or gas cleaning and/or drying stages and the temperature of the cooled flue gas is further reduced to a temperature T3<T2, before a first part of pretreated flue gas is subjected to CCUS, a second part of the pretreated flue gas being recycled at temperature T3 as a cooling agent and mixed with the flue gas during the controlled cooling thereof, partially or fully purified CO.sub.2 from the CCUS may be recycled at temperature T4<T2 may be recycled as a cooling agent and mixed with the flue gas during the controlled cooling.

Method and installation for treating a CO.sub.2- and H.sub.2O-containing flue gas generated by an industrial process unit before CCUS, whereby the flue gas evacuated from the unit is subjected to cooling to a temperature T2 between 100 and 600° C., whereby the cooled flue gas is pretreated in one or more particle removal and/or gas cleaning and/or drying stages and the temperature of the cooled flue gas is further reduced to a temperature T3<T2, before a first part of pretreated flue gas is subjected to CCUS, a second part of the pretreated flue gas being recycled at temperature T3 as a cooling agent and mixed with the flue gas during the controlled cooling thereof, partially or fully purified CO.sub.2 from the CCUS may be recycled at temperature T4<T2 may be recycled as a cooling agent and mixed with the flue gas during the controlled cooling.

A desulfurization and denitration method includes adding an aqueous solution of a chlorate, an aqueous solution of a peroxide, and an aqueous solution of sulfuric acid to a chlorine dioxide generator to obtain gaseous chlorine dioxide, and mixing the gaseous chlorine dioxide with air to obtain a mixed gas. The gaseous chlorine dioxide is 4-10 vol % of the mixed gas. The method includes letting the mixed gas come into contact with a flue gas to obtain an oxidized flue gas. A molar ratio of the gaseous chlorine dioxide in the mixed gas to nitric oxide in the flue gas is 1-1.8. The final step includes passing the oxidized flue gas to the desulfurization and denitration tower and mixing the oxidized flue gas with a spray of an alkaline absorbent dry powder, and spraying water into the desulfurization and denitration tower to obtain a desulfurized and denitrated flue gas.

A desulfurization and denitration method includes adding an aqueous solution of a chlorate, an aqueous solution of a peroxide, and an aqueous solution of sulfuric acid to a chlorine dioxide generator to obtain gaseous chlorine dioxide, and mixing the gaseous chlorine dioxide with air to obtain a mixed gas. The gaseous chlorine dioxide is 4-10 vol % of the mixed gas. The method includes letting the mixed gas come into contact with a flue gas to obtain an oxidized flue gas. A molar ratio of the gaseous chlorine dioxide in the mixed gas to nitric oxide in the flue gas is 1-1.8. The final step includes passing the oxidized flue gas to the desulfurization and denitration tower and mixing the oxidized flue gas with a spray of an alkaline absorbent dry powder, and spraying water into the desulfurization and denitration tower to obtain a desulfurized and denitrated flue gas.