Oxides of Manganese Processed in Continuous Flow Reactors

Abstract

Methods and systems for regenerating and pretreating oxides of manganese and precipitation of oxides of manganese from manganese salt solutions. Oxides of manganese, a slurry containing oxides of manganese or manganese salt solutions are mixed with heated aqueous oxidizing solutions and processed in a continuous process reactor. Temperature, pressure, Eh value, and pH value of the mixed solution are monitored and adjusted so as to maintain solution conditions within the MnO2 stability area during processing. This results in regenerated, pretreated and precipitated oxides of manganese having high or increased pollutant loading capacities and / or oxidation states. Oxides of manganese thus produced are, amongst other uses; suitable for use as a sorbent for capturing or removing target pollutants from industrial gas streams. Filtrate process streams containing useful and recoverable value present as spectator ions may be further processed to produce useful and marketable by-products.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a divisional of U.S. patent application Ser. No. 10 / 767,460, filed Jan. 28, 2004, which claims priority to U.S. Provisional Application No. 60 / 443,302, filed Jan. 28, 2003.FIELD OF THE INVENTION[0002]The invention relates to systems and processes for pretreatment, regeneration and formation of oxides of manganese that have high oxidation states and / or high pollutant loading capacities which are suitable, amongst other uses, as a sorbent for capture and removal of target pollutants from industrial and other gas streams. Further, the invention relates to oxides of manganese so treated, regenerated or formed.BACKGROUND OF THE INVENTION[0003]Oxides of manganese are utilized for a number of industrial applications, such as pollution control systems, steel manufacture, batteries and catalytic converters, to name a few. Of particular, but not exclusive, interest to Applicants is the use of oxides of manganese in pollution con...

AI Technical Summary

Benefits of technology

The invention relates to methods and systems for regenerating and pretreating oxides of manganese for use as sorbents for the removal of target pollutants from gas streams. The methods involve heating and mixing a manganese containing solution with an aqueous oxidizing solution, and then feeding the mixture into a continuous flow reactor where it is processed to produce the desired oxides of manganese. The methods can be adapted to produce different forms of oxides of manganese, such as regenerated, precipitated, and rinsed oxides. The invention also includes the use of heated continuous flow reactors and the separation and further processing of the oxides of manganese from the processing solution. The technical effects of the invention include improved pollutant removal efficiency, rapid and adaptive processing, and the ability to produce high-purity oxides of manganese.

Problems solved by technology

The most common form of NMD is pyrolusite (β-MnO2), which is inexpensive, but has rather low chemical activity and therefore low pollutant loading capacity.

Though useful as sorbent, characteristics such as low surface area and large compact particle size make EMD somewhat inferior to CMD for gas removal applications, despite its good electrochemical activity.

Oxides of manganese have the ability to capture target pollutants from gas streams, however, the low pollutant loading rates achieved with various prior art oxides of manganese have made some industrial applications of this ability uneconomical.

The large quantity of sorbent that would be required to capture NOX and / or SO2 could result in an overly costly pollutant removal system and sorbent regeneration system.

Further, the oxidation state and thus the loading capacity of the oxides of manganese below the surface of the reaction product coating may be reduced during the pollutant removal, thus diminishing the loading capacity of sorbent even after the reaction product have been removed or disassociated into an aqueous solution.

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