Metal ferrite oxygen carriers for conversion of CO2 to CO and fuel to syngas or CO

Abstract

The invention provides a use of metal ferrite oxygen carrier for converting carbon dioxide to carbon monoxide or synthesis gas via three processes: catalytic dry reforming of methane, chemical looping dry reforming of fuel and promoting coal gasification with CO.sub.2. The metal ferrite oxygen carrier comprises M.sub.zFe.sub.xO.sub.y, where M.sub.zFe.sub.xO.sub.y is a chemical composition with 0<x4, z>0 and 0<y6 and M is one of Ca, Ba, and/or combinations thereof. For example, M.sub.zFe.sub.xO.sub.y may be one of CaFe.sub.2O.sub.4, BaFe.sub.2O.sub.4, MgFe.sub.2O.sub.4, SrFe.sub.2O.sub.4 and/or combinations thereof. In catalytic dry reforming, methane and carbon dioxide react in the presence of metal ferrites generating a product stream comprising at least 50 vol. % CO and H.sub.2. In another embodiment, chemical looping dry reforming process where metal ferrite is reduced with a fuel and then oxidized with carbon dioxide is used for production of CO from carbon dioxide. In another embodiment, the metal ferrite is used as a promoter to produce CO continuously from coal gasification with CO.sub.2.

Claims

1. A method for chemical looping dry reforming of methane comprising: delivering a metal ferrite oxygen carrier comprising MzFexOy to a fuel reactor, where 0<x4, z>0 and 0<y6, and where M is at least one of Mg, Ca, Ba, Sr or combinations thereof; delivering a fuel stream to the metal ferrite oxygen carrier in the fuel reactor and maintaining the fuel reactor at a reducing temperature, where the reducing temperature is sufficient to reduce some portion of the metal ferrite oxygen carrier and oxidize some portion of the fuel stream, and generating gaseous products containing H2, CO or CO2 gas in the fuel reactor; delivering the reduced metal ferrite to an oxidation reactor; oxidizing the reduced carrier by contacting the reduced carrier and carbon dioxide at an oxidizing temperature, where the oxidizing temperature is sufficient to generate an oxidizing reaction, where reactants of the oxidizing reaction comprise some portion of the carbon dioxide, some portion of the M component, and some portion of a FecOd component, where c>0 and d0 and where a product of the oxidizing reaction is CO and a re-oxidized carrier, where the re-oxidized carrier comprises some portion of the MzFexOy; and withdrawing a product stream CO from the oxidation reactor, where the gaseous products comprise the product stream, and where at least >50 vol. % of the product stream consists of CO.

2. The method of claim 1 where the reducing temperature ranges from about 500 C. to about 1100 C.

3. The method of claim 1 where 2>z>0, 2x3 and 3y5.

4. The method of claim 1 where the MzFexOy comprises at least 30 wt. % of the metal ferrite oxygen carrier.

5. The method of claim 1 where the metal ferrite oxygen carrier further comprises an inert support, where the inert support comprises from about 5 wt. % to about 70 wt. % of the metal ferrite oxygen carrier.

6. The method of claim 1 wherein the inert support contains at least one of alumina, silica, zirconia, clay, titania, monolith or combinations thereof.

7. The method of claim 1 where the mixing the fuel stream and the metal ferrite oxygen carrier in the fuel reactor step generates a reduced carrier, where the reduced carrier comprises an M component and an FecOd component, where the M component comprises some portion of the M comprising the MzFexOy, and MO and where the FecOd component comprises some portion of the Fe comprising the MzFexOy, where c>0 and d0.

8. The method of claim 7 where the FecOd component comprises Fe.sup.0, FeO, Fe3O4 or Fe2O3 and M component comprises MO or MCO3.

9. The method in claim 1 where the fuel in the fuel reactor is coal, methane or bio mass.

10. The method of claim 9 wherein the methane concentration may be greater than 5 vol %.

11. The method of claim 1 wherein oxidization of the reduced carrier occurs in an oxidizing reactor, and further comprising: transferring the reduced carrier from the fuel reactor to the oxidizing reactor; supplying the carbon dioxide containing gas stream to the oxidizing reactor, thereby generating the re-oxidized carrier, producing carbon monoxide; transferring the re-oxidized carrier from the oxidizing reactor to the fuel reactor; and repeating the delivering the metal ferrite oxygen carrier to the fuel reactor, introducing methane or coal to the metal ferrite oxygen carrier in the fuel reactor, and the withdrawing the product stream from both the fuel reactor and the oxidizing reactor.

12. The method of claim 11 where the oxidizing temperature ranges from about 500 C. to about 1100 C.

13. The method of claim 11 wherein the carbon dioxide gas stream may be provided by carbon dioxide separated from fuel combustion streams with air or fuel chemical looping combustion streams.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 depicts a catalytic methane/CO.sub.2 dry reforming process using Group II metal ferrites producing synthesis gas;

(2) FIG. 2 depicts a chemical looping dry reforming process using Group II ferrites using a fuel reactor to produce reduced metal ferrite and synthesis gas, and in an oxidation reactor for oxidation of reduced metal ferrite with CO.sub.2 to produce CO;

(3) FIG. 3 depicts a process of CO production from CO.sub.2 gasification of coal promoted with Group II ferrite;

(4) FIG. 4 depicts the effluent concentrations of CO, H.sub.2, CH.sub.4, CO.sub.2, O.sub.2 produced during dry reforming of 12% methane/11% CO.sub.2 with calcium ferrite/zirconia (25 sccm, 12 hours at 900 C.);

(5) FIG. 5 depicts the effluent concentrations of CO, H.sub.2, CH.sub.4, CO.sub.2, O.sub.2 produced during dry reforming of 12% methane/11% CO.sub.2 with calcium ferrite/Alumina (25 sccm, 12 hours at 850 C.);

(6) FIG. 6A, FIG. 6B and FIG. 6C depict data during chemical looping dry reforming tests with coal/CO.sub.2 where FIG. 6A depicts effluent concentrations of CO, H.sub.2, CO.sub.2 produced during temperature ramp of Wyodak coal (0.6)/calcium ferrite (4.5 g) in Helium from ambient temperature to 850 C. and introduction of 10% CO.sub.2 at 850 C.; FIG. 6B depicts effluent CO.sub.2 and O.sub.2 concentrations during introduction of air at 850 C.; FIG. 6C depicts moles of CO produced during coal gasification and CO.sub.2 oxidation;

(7) FIG. 7A and FIG. 7B depict data on coal gasification with Ca ferrite/CO.sub.2 where FIG. 7A depicts comparisons of CO concentrations during the temperature ramp to 850 C. of Wyodak coal/10% CO.sub.2/He with and without calcium ferrite and FIG. 7B illustrates effluent gas concentrations during air oidation at 850 C.

DETAILED DESCRIPTION

(8) The following description is provided to enable any person skilled in the art to use the described embodiments and sets forth the best mode. Various modifications, however, will remain readily apparent to those skilled in the art, since the principles relate to conversion of CO.sub.2 to CO or synthesis gas streams using Group II metal ferrites. More specifically, one or more embodiments relate to the development of novel Group II metal ferrites such as Mg, Ca, Ba and Sr ferrites, for conversion of CO.sub.2 to CO or synthesis gas. In one embodiment, the Group II metal ferrites are used as catalyst in a methane dry reforming process with CO.sub.2 to produce synthesis gas; while in another embodiment Group II metal ferrites are used in a chemical looping dry reforming process with CO.sub.2 to produce CO. In another embodiment Group II metal ferrites are used in coal gasification with CO.sub.2 to produce CO.

(9) In one or more embodiments, Group II ferrites such as Ba, Ca, Mg and Sr ferrites are used as catalysts in the methane dry reforming process are described. These ferrites are inexpensive and environmentally safe.

(10) In at least one embodiment Group II metal ferrite oxygen carriers are used for chemical looping dry reforming to convert CO.sub.2 to CO. Very high conversions of CO.sub.2 to CO were observed via reaction [6].

(11) In one or more embodiments Group II metal ferrites are used as promoters for the CO.sub.2 conversion to CO via coal gasification reaction [7]. The metal ferrites may promote the CO.sub.2 conversion to CO via reactions [3] and [6]. The metal ferrites may be added to coal separately without impregnating the coal with metal ferrite solutions making it a simple process for operation.

(12) Another embodiment relates to a catalytic process using Group II ferrites combined with methane and carbon dioxide gas streams to produce a continuous stream of synthesis gas stream free of nitrogen. Group II metal ferrites such as barium and calcium ferrites have unique properties. They react with methane to produce CO and H.sub.2 reducing the metal ferrites while being oxidized with carbon dioxide. The Group II metal ferrites have lower reaction rates with the CO and H.sub.2, making it easier to control the reaction at the synthesis stage.

(13) In another embodiment, Group II metal ferrites are oxygen carriers for chemical looping dry reforming to produce CO from CO.sub.2. In this process, oxidized Group II metal ferrite reacts with a fuel such as coal or methane to form reduced metal ferrite and oxidation of reduced metal ferrite with CO.sub.2 produces CO.

(14) In another embodiment, Group II metal ferrites are promoters for the coal gasification reaction with carbon dioxide.

(15) Embodiments provide a metal ferrite oxygen carrier having improved durability and reactivity over metal oxides currently used in the dry reforming of methane, chemical looping dry reforming of fuels such as coal and methane and coal gasification with CO.sub.2. The metal ferrite oxygen carrier comprises MzFexOy with 0<x4, z>0 and 0<y6 where M is one of Ca, Ba, Mg, Sr and/or combinations thereof.

(16) In another embodiment, the metal ferrite oxygen carrier comprises MFe.sub.2O.sub.4. In particular embodiments, the MzFexOy comprises at least 30 wt. % of the metal ferrite oxygen carrier. In certain embodiments, the metal ferrite oxygen carrier further comprises an inert support. The inert support material does not participate in the oxidation and reduction reactions of the MzFexOy comprising the metal ferrite oxygen carrier. In an embodiment, the inert support comprises from about 5 wt. % to about 70 wt. % of the metal ferrite and the MzFexOy comprises at least 30 wt. % of the metal ferrite oxygen carrier. Dry reforming of methane or coal with the metal ferrite and CO.sub.2 generates a product stream of CO or syngas comprising at least 50 vol. % of the product stream.

(17) A system 100 within which the Group II metal ferrite catalyst disclosed here may be utilized is illustrated in FIG. 1 which illustrates a catalytic dry reforming methane/CO.sub.2 system including catalytic reactor 101. Metal ferrite catalyst 102 is placed in the catalytic reactor 101. Methane 103 and CO.sub.2 105 gaseous streams are introduced to the catalytic reactor 101 for the dry methane reforming reaction with metal ferrite 102. Catalytic reactor 101 is at a temperature sufficient for metal ferrite 102 to react with methane and CO.sub.2. In an embodiment, the temperature in the catalytic reactor ranges from about 500 C. to about 1100 C.

(18) The reaction involved in the catalytic reactor 101 between methane 103 and carbon dioxide 105 in the presence of metal ferrites 102 is described in reaction [1]. Within the catalytic reactor 101 metal ferrites 102 may be used in the oxidized form or in the reduced form where the metal ferrite is MzFexOy with 0<x4, z>0 and 0<y6 where M is at least one of Ca, Ba, Mg, Sr and/or combinations thereof. For example, the metal ferrite catalyst 102 comprises CaFe.sub.2O.sub.4 on the inert support or CaFe.sub.2O.sub.4 may be mixed with inert material in the reactor bed. The metal ferrite catalyst 102 may also comprise reduced forms of CaFe.sub.2O.sub.4 which is a mixture of CaO, CaFe.sub.2O.sub.5, Fe, and FeO. In the catalytic reactor 101, the reaction between methane 103 and carbon dioxide 105 in the presence of metal ferrites 102 produces syngas comprises of CO and H.sub.2 104. At the exhaust, at least 50 vol. % of the product stream comprises CO and H.sub.2. In an embodiment, at least 90 vol.+% of the product stream comprises CO and H.sub.2.

(19) A system/process 200 within which the Group II metal ferrite oxygen carrier disclosed here may be utilized is illustrated in FIG. 2 which illustrates a chemical looping dry reforming of fuel with carbon dioxide system includes fuel reactor 201. Metal ferrite oxygen carrier 204 is placed in the fuel reactor 201. Fuel 205 (e.g. coal or methane) is introduced to the fuel reactor 201 for the reduction of metal ferrite oxygen carrier 204. Fuel reactor 201 is at a reducing temperature sufficient to reduce at least a portion of the metal ferrite oxygen carrier 204. In an embodiment, the reducing temperature is from about 500 C. to about 1100 C. The reactions involved in the fuel reactor 201 between metal ferrites 204 and fuel 205 are described in reactions [3-5]. When the fuel 205 is a solid fuel such as coal, steam may also be introduced with the fuel 205 to the fuel reactor 201 to promote the reduction reaction of metal ferrite 204.

(20) Within fuel reactor 201, metal ferrite oxygen carrier interacts with fuel 205, and the MzFexOy comprising the metal ferrite oxygen carrier that reduces to a reduced carrier comprising one or more M components and a FecOd component. The M components comprise some portion of the M comprising the MzFexOy and MO. The FecOd component comprises some portion of the Fe comprising the MzFexOy, with c>0 and d0. For example, the FecOd component may be Fe or may be an iron oxide such as FeO, Fe.sup.0, and Fe.sub.3O.sub.4, among others. In an embodiment, the FecOd component is FeOt, where 0t1.5. For example, in an embodiment where the metal ferrite oxygen carrier is CaFe.sub.2O.sub.4 on the inert support, the CaFe.sub.2O.sub.4 interacts with fuel 205 in reactor 201 and generates a reduced carrier comprising CaO, Fe, Fe.sub.3O.sub.4, and Ca.sub.2Fe.sub.2O.sub.5. In this embodiment, the M components CaO and Ca.sub.2Fe.sub.2O.sub.5 generated by the reduction comprises some portion of the Ca comprising the CaFe.sub.2O.sub.4, and Fe and Fe.sub.3O.sub.4 comprise the FecOd component FeOt where 0O1.5. In an embodiment, the M components comprise some portion of the M comprising the MzFexOy and having an absence of the Fe comprising the MzFexOy, such as for example CaO.

(21) The reducing temperature is sufficient to reduce some portion of the MzFexOy oxygen carrier and oxidize some portion of methane, generating products CO.sub.2, CO or syngas 206 in the fuel reactor 201. The CO.sub.2, CO or syngas products 206 are withdrawn from fuel reactor 201 as a product stream at exhaust, and the reduced carrier 203 may exit the fuel reactor. The reduced carrier 203 exiting fuel reactor may subsequently enter oxidation reactor 202. Oxidation reactor 202 further receives a flow of carbon dioxide 206 and facilitates contact between the reduced carrier 203 and carbon dioxide, generating a re-oxidized carrier 204 and a product stream CO 207 as shown in reaction [6].

(22) The product of the oxidizing reaction is the re-oxidized carrier 204, where the re-oxidized carrier comprises MaFebOc on the inert support. Generally, the MaFebOc comprising the re-oxidized carrier 204 is substantially equivalent to the MzFexOy comprising the metal ferrite oxygen carrier. For example, when the metal ferrite oxygen carrier comprises CaFe.sub.2O.sub.4 on the inert support and the reduced carrier 203 comprises CaO, CaFe.sub.2O.sub.5, Fe, and FeO, then the oxidation reaction generates a re-oxidized carrier 204 comprising CaFe.sub.2O.sub.4 on the inert support. Oxidation reactor 202 is at an oxidation temperature sufficient to oxidize at least a portion of the reduced carrier by carbon dioxide. In an embodiment, the oxidizing temperature ranges from about 500 C. to about 1100 C.

(23) Within embodiments described herein, to reduce some portion of the metal ferrite oxygen carrier refers to the loss of oxygen from the MzFexOy comprising the metal ferrite oxygen carrier. For example, the reduction of a MzFexOy composition to FeO, Fe.sub.3O.sub.4, and/or Fe and an M component, where the M component comprises some portion of the M comprising the MzFexOy, or alternatively, the reduction of a MzFexOy composition to a MaFebOc composition, where y/(z+x)>c/(a+b). In an embodiment, MzFe.sub.xO.sub.y is one of CaFe.sub.2O.sub.4, BaFe.sub.2O.sub.4, and/or combinations thereof. The inert support when present does not participate in the oxidation and reduction reactions of the MzFe.sub.xO.sub.y. In an embodiment, the inert support is alumina or zirconia.

(24) Another system 300 within which the Group II metal ferrite oxygen carrier disclosed here may be utilized is illustrated in FIG. 3. In this process, Group II metal ferrites perform as promoter for coal gasification with carbon dioxide. The coal or solid carbonaceous fuel 303 and Group II metal ferrites 302 are introduced to the reactor 301. A flow of carbon dioxide 304 is introduced to produce CO 305. Reactor 302 is at a temperature sufficient to convert coal 303 to produce gas CO 305 in the presence of the metal ferrite oxygen carrier 302 as shown in reaction [7]. In an embodiment, the reaction temperature ranges from about 500 C. to about 1100 C. Both coal 303 and CO.sub.2 304 may be continuously added and Group II metal ferrite 302 placed in reactor 301. The metal ferrite oxygen carrier comprises MzFexOy with 0<x4, z>0 and 0<y6 where M is one of Ca, Ba, Mg, Sr and/or combinations thereof. In another embodiment, the metal ferrite oxygen carrier comprises MFe.sub.2O.sub.4. In particular embodiments, the MzFexOy comprises at least 30 wt. % of the metal ferrite oxygen carrier. In certain embodiments, the metal ferrite oxygen carrier further comprises an inert support. The inert support material does not participate in the oxidation and reduction reactions of the MzFexOy comprising the metal ferrite oxygen carrier. In an embodiment, the inert support comprises from about 5 wt. % to about 70 wt. % of the metal ferrite and the MzFexOy comprises at least 30 wt. % of the metal ferrite oxygen carrier.

(25) CaFe.sub.2O.sub.4 was prepared by mixing metal nitrate precursors. The mixture was heated in an oven to 1000 C. at a ramp rate of 3 C./min in air and kept at 1000 C. for 6 h. These oxygen carriers can also be prepared mixing CaO and Fe.sub.2O.sub.3 instead of nitrate precursors.

(26) In order to demonstrate the catalytic dry reforming methane with CO.sub.2 in the process 100 illustrated in FIG. 1, fixed bed flow reactor studies were conducted in a laboratory-scale fixed-bed reactor (Micromeritics model Autochem 2910 atmospheric flow reactor) at 14.7 psi (1.01105 Pa). The calcium ferrite oxygen carrier (500 mg) was diluted with zirconia (500 mg) or alumina (500 mg) was placed in the reactor and heated to 800-900 C. in a flow of Helium. At the final reaction temperature, 20% methane in Helium was introduced for 45 minutes. Then 12% methane and 11% CO.sub.2 were introduced for 12 hours at 800-900 C. for the dry reforming reaction. The outlet gas stream from the reactor was analyzed using a mass spectrometer (PfeifferVacuum Thermostar).

(27) Performance data on catalytic dry reforming methane with CO.sub.2 with calcium ferrite diluted with zirconia at 900 C. is shown in FIG. 4. When 12% methane and 11% CO.sub.2 were introduced at 900 C., H.sub.2 and CO were formed. CH.sub.4 and CO.sub.2 concentrations were near zero indicating that both these gases were fully consumed to produce H.sub.2 and CO. The performance was very stable during the 12-hour test.

(28) Performance data on catalytic dry reforming methane using CO.sub.2 with calcium ferrite diluted with alumina at 850 C. is shown in FIG. 5. When 12% methane and 11% CO.sub.2 was introduced at 900 C., H.sub.2 and CO were formed. CH.sub.4 and CO.sub.2 concentrations were near zero indicating that both these gases were fully consumed to produce H.sub.2 and CO. The performance was very stable during the 12-hour test.

(29) In order to demonstrate the chemical looping dry reforming process 200 in FIG. 2, fixed bed flow reactor studies were conducted in a bench scale flow reactor. Bench-scale fixed-bed flow reactor (inner diameter 7 mm) tests were conducted with a 4.5 g sample of calcium ferrite oxygen carrier and 0.6 g of Wyodak coal. The outlet gas compositions (CO.sub.2, H.sub.2, CH.sub.4, and CO) from the reactor were measured using a MS (Pfeiffer Omnistar). The metal ferrite-coal sample was heated in Heat a flow rate of 100 cm3/min (0.1 L/min) from ambient to 850 C. (ramp rate of 4 C./min) and 10% CO.sub.2 in He was introduced at 850 C. and was kept isothermal at 850 C. until the CO concentration reached zero. After the reduction step, the sample was exposed to air for 30 min at 750 C.

(30) The performance data of chemical looping dry reforming with calcium ferrite is shown in FIG. 6A, FIG. 6B and FIG. 6C. During the initial temperature ramp from ambient to 850 C. in helium, coal and Ca ferrite reacted to form CO and CO.sub.2, and CO was the main peak as shown in FIG. 6A. All gas concentrations reached near zero at the end of the temperature ramp at 850 C. When 10% CO.sub.2 was introduced at 850 C. after the temperature ramp, CO.sub.2 concentration decreased with a simultaneous increase in the concentration of CO as also shown in FIG. 6A. Formation of CO continued for 110 minutes. The data indicated that the calcium ferrite that was reduced by coal during the temperature ramp was oxidized by CO.sub.2 at 850 C. to form CO. After the CO.sub.2 introduction, air was introduced at 750 C. to determine the amount of coal that was left in the reactor and the amount of calcium ferrite that was not oxidized by CO.sub.2 and the results are shown in FIG. 6B. The amount of CO.sub.2 was very low indicating that all the coal was consumed and oxygen consumption was also low indicating that the reduced Ca ferrite was mostly oxidized with CO.sub.2. The moles of CO produced during the initial temperature ramp for coal gasification with calcium ferrite and during oxidation of the reduced Ca ferrite with CO.sub.2 are shown in FIG. 6C. There is a very high amount of CO produced during oxidation with CO.sub.2 indicating that reduced Ca ferrite is oxidized by CO.sub.2 while producing CO.

(31) In order to demonstrate the process 300, gasification of Wyodak coal with CO.sub.2 was conducted in the presence of calcium ferrite in a fixed bed flow reactor. The fixed-bed flow reactor (inner diameter 7 mm) tests were conducted with a 4.5 g sample of calcium ferrite and 0.6 g of Wyodak coal. The metal ferrite-coal sample was heated in in 10% CO.sub.2 in He at a flow rate of 100 cm3/min (0.1 L/min) from ambient to 850 C. (ramp rate of 4 C./min). For comparisons, coal without the oxygen carrier was used in another experiment. The outlet gas compositions (CO.sub.2, H.sub.2, CH.sub.4, and CO) from the reactor were measured using a MS (Pfeiffer Omnistar). The effluent CO concentrations during the temperature ramp in 10% CO.sub.2 with and without Ca ferrite are shown in FIG. 7A. The CO concentration peak maximum was higher with coal/Ca ferrite/CO.sub.2 than that with coal/CO.sub.2 which indicated that Ca ferrite promotes the coal gasification with CO.sub.2. After the temperature ramp of coal/Ca ferrite with CO.sub.2, air was introduced at 850 C. and the effluent concentrations are shown in FIG. 7B. The CO.sub.2 peaks are very low indicating most of the coal was gasified with CO.sub.2 during the temperature ramp. The oxygen uptake was also very low indicating that the Ca ferrite remains in the oxidized state after the temperature ramp with CO.sub.2.

(32) Embodiments of the present invention provide one or more of the following:

(33) Conversion of greenhouse gas, CO.sub.2 to useful chemical precursors such as CO and syngas using Group II metal ferrites are described in this invention;

(34) Use of Group II metal ferrites as a catalyst to produce synthesis gas continuously via dry reforming of methane and carbon dioxide is described. Complete consumption of methane and CO.sub.2 to produce syngas was observed and the process demonstrated for 12 hours without any deactivation. Group II metal ferrites are low cost and environmentally safe unlike the Ni based materials reported for the process in the past;

(35) Use of Group II ferrites in chemical looping dry reforming of fuel and CO.sub.2 to produce syngas and CO is also described. The process involves reacting the Group II ferrites with methane or coal to form synthesis gas and reduced metal ferrite in the fuel reactor followed by oxidation of the reduced metal ferrite with carbon dioxide to form CO in the oxidation reactor. Production of CO with Wyodak coal/calcium ferrite and oxidation of reduced calcium ferrite with carbon dioxide to from CO was demonstrated. High CO yields were obtained in the process;

(36) Use of Group II ferrites for promotion of CO.sub.2 gasification of coal to produce CO is described. Production of CO at higher rates with Wyodak coal/CO.sub.2/Ca ferrite than that with Wyodak coal/Ca ferrite was demonstrated.

(37) In addition to improved performance, Group II metal ferrites are low cost and environmentally safe as compared to materials previously used for these processes.

(38) Having described the basic concept of the embodiments, it will be apparent to those skilled in the art that the foregoing detailed disclosure is intended to be presented by way of example. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations and various improvements of the subject matter described and claimed are considered to be within the scope of the spirited embodiments as recited in the appended claims. Additionally, the recited order of the elements or sequences, or the use of numbers, letters or other designations therefor, is not intended to limit the claimed processes to any order except as may be specified. All ranges disclosed herein also encompass any and all possible sub-ranges and/or combinations of sub-ranges thereof. Any listed range is easily recognized as sufficiently describing and enabling the same range being broken down into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each range discussed herein may be readily broken down into a lower third, middle third and upper third, etc. As will also be understood by one skilled in the art all language such as up to, at least, greater than, less than, and the like refer to ranges which are subsequently broken down into sub-ranges as discussed above. As utilized herein, the terms about, substantially, and other similar terms are intended to have a broad meaning in conjunction with the common and accepted usage by those having ordinary skill in the art to which the subject matter of this disclosure pertains.

(39) As utilized herein, the term approximately equal to shall carry the meaning of being within 15, 10, 5, 4, 3, 2, or 1 percent of the subject measurement, item, unit, or concentration, with preference given to the percent variance. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the exact numerical ranges provided. Accordingly, the embodiments are limited only by the following claims and equivalents thereto. All publications and patent documents cited in this application are incorporated by reference in their entirety for all purposes to the same extent as if each individual publication or patent document were so individually denoted.