Process for manufacturing an absorbent composition

A process for manufacturing a composition for use as a sulfur oxide absorbent which comprises:

• blending water;
• about two molar parts of a divalent metal compound which is not a salt and includes a divalent metal selected from the group consisting of magnesium, calcium, zinc, strontium and barium;
• about one molar part in sum of an aluminum compound which is not a salt and a trivalent metal compound which is not a salt and includes a trivalent metal selected from the group consisting of cerium, lanthanum, iron, chromium, vanadium, and cobalt;
• about 0.01 to less than two molar parts of a metalate salt containing vanadate, tungstenate, or molybdate anions;
• and an amount of an alkalinity control agent appropriate to stabilize the anions in monometalate, dimetalate, trimetalate or tetrametalate form to produce a mixture;
• heating the mixture to a temperature in the range of about 50.degree. to about 100.degree. C. for at least about one hour;
• recovering from the mixture an anionic layered mixed hydroxide;
• and calcining the recovered layered mixed hydroxide for not less than about one hour at a temperature of about 450.degree. C. or hotter, to produce an at least partially collapsed composition for use as a sulfur oxide absorbent which is substantially composed of solid solution microcrystallites having aluminum oxide dispersed in an oxide of the divalent metal and of spinel phase microcrystallites, each of the microcrystallites having the greatest linear dimension in the range of about 0.1 to about 30 nanometers.

A process for manufacturing a composition which comprises:

• blending water;
• about two molar parts of a divalent metal compound which is not a salt and includes a divalent metal selected from the group consisting of magnesium, calcium, zinc, strontium and barium;
• and about one molar part in sum of an aluminum compound which is not a salt and a trivalent metal compound which is not a salt and includes a trivalent metal selected from the group consisting of cerium, lanthanum, iron, chromium, vanadium, and cobalt;
• and about one-half to about one molar part of a water soluble interstitial anion precursor selected from the group consisting of carbonates, hydroxides, sulfites, sulfates, chlorides, and nitrates to produce a mixture;
• heating the mixture to a temperature in the range of about 50.degree. to about 100.degree. C. for at least about one hour;
• recovering from the mixture an anionic layered mixed hydroxide having an interstitial anion selected from the group consisting of CO.sub.3.sup.2-, OH.sup.-, SO.sub.3.sup.2-, SO.sub.4.sup.2-, Cl.sup.- and NO.sub.3.sup.- ;
• calcining the recovered layered mixed hydroxide for not less than about one hour at a temperature of about 450.degree. C. or hotter, to produce a dehydrated material which is essentially devoid of the anions selected from the group consisting of CO.sub.3.sup.2-, OH.sup.-, SO.sub.3.sup.2-, SO.sub.4.sup.2-, Cl.sup.- and NO.sub.3.sup.- ;
• mixing the dehydrated material with an aqueous solution including about 0.01 to less than two molar parts of a metalate salt containing vanadate, tungstenate, or molybdate anions to produce a slurry, the solution also including an amount of an alkalinity control agent appropriate to stabilize the vanadate, tungstenate, or molybdate anions in monometalate, dimetelate, trimetalate or tetrametalate form;
• and
• recovering solids from the slurry and calcining the solids to produce an at least partially collapsed composition for use as a sulfur oxide absorbent which is substantially composed of solid solution microcrystallites having aluminum oxide dispersed in an oxide of the divalent metal and of spinel base microcrystallites, each of the microcrystallites having the greatest linear dimension in the range of about 0.1 to about 30 nanometers.