Catalyst for reducing the toxic contaminants of combustion engine exhaust gas

Claim 2

A process for making a catalyst reducing the toxic contaminants of combustion engine exhaust gases, which comprises: heating the honey comb carrier to temperatures within the range 300° and 400° C; introducing the hot carrier into a concentrated solution of an aluminum salt of a volatile acid for a period within the range 15 and 60 minutes; expelling excess liquid from the honey comb carrier and drying it at room temperature; heating the dry carrier for a period within the range 1 and 4 hours to temperatures within the range 350° and 450° C and then calcining it for a period within the range 2 and 6 hours at temperatures within the range 500° and 700° C with the resultant formation of an intermediary layer pg,16 of aluminum oxide on the honey comb carrier; heating the carrier to temperatures within the range 300° and 400° C; dipping the hot carrier in a hot concentrated aqueous solution of catalytically active copper, nickel and manganese salts of volatile acids and allowing it to remain therein for a period within the range 15 and 60 minutes; expelling excess liquid from the honey comb carrier and drying it for a period within the range 1 and 4 hours at temperatures within the range 350° and 450° C; and calcining it for a period within the range 5 and 20 hours at temperatures within the range 700° and 1000° C.

Claim 3

The process as claimed in claim 1, wherein the honey comb carrier having the intermediary layer and the catalytically active ingredients deposited thereon is heated for a period within the range 1 and 3 hours to temperatures within the range 400° C and 500° C, in a slightly reducing atmosphere.

Claim 4

The process as claimed in claim 2, wherein the honey comb carrier is heated in an hydrogen/nitrogen mixture containing approximately 5% of hydrogen.

Claim 5

The process as claimed in claim 1, wherein aluminum nitrate is used as the aluminum salt.

Claim 6

The process as claimed in claim 1, wherein aluminum hydroxychloride is used as the aluminum salt.

Claim 7

The process as claimed in claim 1, wherein nitrates are used as the copper, nickel and manganese salts.

Claim 8

The process as claimed in claim 1, wherein the aqueous solution contains said catalytically active copper, nickel and manganese salts of volatile acids in a ratio by weight of 0.1 to 1 : 0.1 to 1 : 0.1 to 1.

Claim 9

The process as claimed in claim 7, wherein the ratio by weight is 1:1:1.

Claim 10

Catalyst for reducing the toxic contaminants in the exhaust gas of combustion engines, the catalyst having been prepared by a process comprising heating a honey comb structure of ceramic material to temperatures within the range 300° to 400° C; introducing the honey comb structure into a concentrated solution of an aluminum salt of a volatile acid and allowing it to remain therein for a period within the range 15 to 60 minutes; blowing out the honey comb structure and drying it at room temperature; heating the dried honey comb structure over a period within the range 1 to 4 hours to temperatures within the range 350° to 450° C and then calcining it for a period within the range 2 to 6 hours at temperatures within the range 500° to 700° C with the resultant formation, on said honey comb structure, of an intermediary layer of aluminum oxide constituting between 5 and 15% of the total weight of the final catalyst; heating the honey comb structure so treated to temperatures within the range 300° and 400° C and dipping it in a hot concentrated solution of copper, nickel and manganese salts of volatile acids so as to impregnate the honey comb structure therewith; blowing out, drying and heating the honey comb structure to temperatures within the range 350° to 450° C and calcining it for a period within the range 5 to 20 hours at temperatures within the range 700° to 1000° C; and finally heating the honey comb structure so impregnated for a period within the range 1 to 3 hours in a slightly reducing atmosphere to temperatures within the range 400° to 500° C.

Claim 11

Catalyst for reducing the toxic contaminants in the exhaust gas of combustion engines, the catalyst having been prepared by a process comprising heating a honey comb structure of ceramic material to temperatures within the range 300° to 400° C; introducing the honey comb structure into a concentrated solution of an aluminum salt of a volatile acid and allowing it to remain therein for a period within the range 15 to 60 minutes; blowing out the honey comb structure and drying it at room temperature; heating the dried honey comb structure over a period within the range 1 to 4 hours to temperatures within the range 350° to 450° C and then calcining it for a period within the range 2 to 6 hours at temperatures within the range 500° to 700° C with the resultant formation, on said honey comb structure, of an intermediary layer of aluminum oxide constituting between 5 and 15% of the total weight of the final catalyst; heating the honey comb structure so treated to temperatures within the range 300° and 400° C and dipping it in a hot concentrated solution of copper, nickel and manganese salts of volatile acids so as to impregnate the honey comb structure therewith; blowing out, drying and heating the honey comb structure to temperatures within the range 350° to 450° C and calcining it for a period within the range 5 to 20 hours at temperatures within the range 700° to 1000° C; and finally heating the honey comb structure so impregnated for a period within the range 1 to 3 hours in a slightly reducing atmosphere to temperatures within the range 400° to 500° C.