Patent Description:
A CO<NUM>/O<NUM> remover is required for example in a semiconductor manufacturing process where an inert gas atmosphere containing nitrogen, helium or argon is used. Active gas components such as CO<NUM> and O<NUM> need to be removed to make the gas inert.

<CIT> discloses a CO<NUM> sorbent, the CO<NUM> sorbent comprises (i) a magnesium salt, and (ii) at least one salt of a Group IA element wherein (i) said magnesium salt and (ii) said Group IA element salt are present in a molar ratio of from about <NUM>:<NUM> to <NUM>:<NUM>.

<NPL> concerns the preparation of Ni-MgO-Al<NUM>O<NUM> materials with varying Ni/Mg ratios. Such materials are investigated with respect to their surface area properties by adsorbing and desorbing CO<NUM> molecules.

The invention relates to a method of removing CO<NUM> and O<NUM> from a gas comprising the steps of: placing a CO<NUM> and O<NUM> remover in a container, wherein the CO<NUM> and O<NUM> remover comprises <NUM> to <NUM> weight percent (wt. %) of a nickel oxide (NiO) and <NUM> to <NUM> wt. % of a magnesium oxide (MgO) and <NUM> to <NUM> wt. % of Al<NUM>O<NUM>, wherein the weight ratio of the nickel oxide and the magnesium oxide (NiO/MgO) is <NUM> to <NUM>, and wherein the wt. % is based on the weight of the CO<NUM> and O<NUM> remover; and passing the gas through the container.

CO<NUM> and O<NUM> can be sufficiently removed from a gas by the present invention.

The CO<NUM>/O<NUM> remover and the method of manufacturing thereof are explained below.

The CO<NUM>/O<NUM> remover comprises <NUM> to <NUM> weight percent (wt. %) of a nickel oxide (NiO) and <NUM> to <NUM> wt. % of a magnesium oxide (MgO) and <NUM> to <NUM> wt. % of Al<NUM>O<NUM> based on the weight of the CO<NUM>/O<NUM> remover. The NiO is <NUM> wt. % or more in an embodiment, <NUM> wt. % or more in another embodiment, <NUM> wt. % or more in another embodiment, <NUM> wt. % or more in another embodiment, <NUM> wt. % or more in another embodiment, <NUM> wt. % or more in another embodiment, based on the weight of the CO<NUM>/O<NUM> remover. The NiO is <NUM> wt. % or less in an embodiment, <NUM> wt. % or less in another embodiment, <NUM> wt. % or less in another embodiment, <NUM> wt. % or less in another embodiment, <NUM> wt. % or less in another embodiment, <NUM> wt. % or less in another embodiment, based on the weight of the CO<NUM>/O<NUM> remover.

The MgO is <NUM> wt. % or more in an embodiment, <NUM> wt. % or more in another embodiment, <NUM> wt. % or more in another embodiment, <NUM> wt. % or more in another embodiment, <NUM> wt. % or more in another embodiment, <NUM> wt. % or more in another embodiment, <NUM> wt. % or more in another embodiment, based on the weight of the CO<NUM>/O<NUM> remover.

The MgO is <NUM> wt. % or less in an embodiment, <NUM> wt. % or less in another embodiment, <NUM> wt. % or less in another embodiment, <NUM> wt. % or less in another embodiment, <NUM> wt. % or less in another embodiment, <NUM> wt. % or less in another embodiment, <NUM> wt. % or less in another embodiment, <NUM> wt. % or less in another embodiment, <NUM> wt. % or less in another embodiment, <NUM> wt. % or less in another embodiment, based on the weight of the CO<NUM>/O<NUM> remover.

The weight ratio of NiO and MgO (NiO/MgO) is <NUM> to <NUM>. The weight ratio of NiO and MgO (NiO/MgO) is <NUM> or more in an embodiment, <NUM> or more in another embodiment, <NUM> or more in another embodiment, <NUM> or more in another embodiment, <NUM> or more in another embodiment, <NUM> or more in another embodiment, <NUM> or more in another embodiment. The weight ratio of NiO and MgO (NiO/MgO) is <NUM> or less in another embodiment, <NUM> or less in another embodiment, <NUM> or less in another embodiment, <NUM> or less in another embodiment, <NUM> or less in another embodiment, <NUM> or less in another embodiment, <NUM> or less in another embodiment. The CO<NUM>/O<NUM> remover comprising NiO and MgO within the range at the weight ratio above sufficiently removes both CO<NUM> and O<NUM> from a gaseous composition. The CO<NUM>/O<NUM> remover further comprises one or more of other metal oxide selected from the group consisting of a silicon oxide (SiO<NUM>), a sodium oxide (Na<NUM>O) and a mixture thereof in an embodiment.

The CO<NUM>/O<NUM> remover comprises SiO<NUM> in another embodiment. The SiO<NUM> is <NUM> wt. % or more in an embodiment, <NUM> wt. % or more in another embodiment, <NUM> wt. % or more in another embodiment, <NUM> wt. % or more in another embodiment, <NUM> wt. % or more in another embodiment, <NUM> wt. % or more in another embodiment, <NUM> wt. % or more in another embodiment, based on the weight of the CO<NUM>/O<NUM> remover. SiO<NUM> is <NUM> wt. % or less in an embodiment, <NUM> wt. % or less in another embodiment, <NUM> wt. % or less in another embodiment, <NUM> wt. % or less in another embodiment, <NUM> wt. % or less in another embodiment, <NUM> wt. % or less in another embodiment, <NUM> wt. % or less in another embodiment, based on the weight of the CO<NUM>/O<NUM> remover.

The CO<NUM>/O<NUM> remover comprises Al<NUM>O<NUM>. The Al<NUM>O<NUM> is <NUM> wt. % or more, <NUM> wt. % or more in another embodiment, <NUM> wt. % or more in another embodiment, <NUM> wt. % or more in another embodiment, <NUM> wt. % or more in another embodiment, based on the weight of the CO<NUM>/O<NUM> remover. The Al<NUM>O<NUM> is <NUM> wt. % or less, <NUM> wt. % or less in another embodiment, <NUM> wt. % or less in another embodiment, <NUM> wt. % or less in another embodiment, based on the weight of the CO<NUM>/O<NUM> remover.

The CO<NUM>/O<NUM> remover comprises an alkali metal oxide in an embodiment. The alkali metal oxide is selected from the group consisting of a sodium oxide (Na<NUM>O), a potassium oxide (K<NUM>O), a lithium oxide (Li<NUM>O) and a combination thereof in another embodiment. The alkali metal oxide comprises a sodium oxide (Na<NUM>O) in another embodiment. The alkali metal oxide is <NUM> wt. % or more in an embodiment, <NUM> wt. % or more in another embodiment, <NUM> wt. % or more in another embodiment, <NUM> wt. % or more in another embodiment, <NUM> wt. % or more in another embodiment, <NUM> wt. % or more in another embodiment, <NUM> wt. % or more in another embodiment, based on the weight of the CO<NUM>/O<NUM> remover. The alkali metal oxide is <NUM> wt. % or less in an embodiment, <NUM> wt. % or less in another embodiment, <NUM> wt. % or less in another embodiment, <NUM> wt. % or less in another embodiment, <NUM> wt. % or less in another embodiment, based on the weight of the CO<NUM>/O<NUM> remover. The CO<NUM>/O<NUM> remover comprises no alkali metal oxide or Na<NUM>O in another embodiment.

The CO<NUM>/O<NUM> remover compositions described herein, including those listed in Table <NUM>, are not limiting; it is contemplated that one of ordinary skill in the art of chemistry could make minor substitutions or additional ingredients and not substantially change the desired properties of the CO<NUM>/O<NUM> remover. For example, substitutions such as oxides of iron (Fe), calcium (Ca), titanium (Ti), cerium (Ce), zinc (Zn), zirconium (Zr) in an amount of <NUM> to <NUM> wt. % based on the weight of the CO<NUM>/O<NUM> remover may be used either individually or in combination to achieve similar performance. The CO<NUM>/O<NUM> remover composition can be determined by a fluorescent X-ray analysis (XRF analysis).

The shape of the CO<NUM>/O<NUM> remover is not limited. The CO<NUM>/O<NUM> remover can be any shape as long as it generates sufficient removal capacity and strength as a CO<NUM>/O<NUM> remover. The CO<NUM>/O<NUM> remover is present in form of particles in an embodiment. The CO<NUM>/O<NUM> remover has a cylindrical or spherical shape in another embodiment. Cross section of the cylindrical CO<NUM>/O<NUM> remover is selected from the group consisting of round, ellipse, polygon, rectangle and polylobe in an embodiment. Cross section of the cylindrical CO<NUM>/O<NUM> remover is round, ellipse or polylobe in another embodiment, polylobe in another embodiment, trilobe in another embodiment.

An example of the cylindrical CO<NUM>/O<NUM> remover <NUM> having a round cross-section is shown in <FIG>. Diameter <NUM> of the cylindrical CO<NUM>/O<NUM> remover <NUM> is <NUM> to <NUM> in an embodiment, <NUM> to <NUM> in another embodiment, <NUM> to <NUM> in another embodiment, <NUM> to <NUM> in another embodiment. Length <NUM> of the cylindrical CO<NUM>/O<NUM> remover <NUM> is <NUM> to <NUM> in an embodiment, <NUM> to <NUM> in another embodiment, <NUM> to <NUM> in another embodiment, <NUM> to <NUM> in another embodiment. The diameter of CO<NUM>/O<NUM> removers having elliptic rectangular cross-sections is defined as the major axis. For CO<NUM>/O<NUM> removers having a polylobed or polygon cross-section the diameter is defined as the diameter of the circumcircle. An example of the cylindrical CO<NUM>/O<NUM> remover <NUM> with a trilobed cross-section is shown in <FIG>. The diameter of the cylindrical CO<NUM>/O<NUM> remover <NUM> is defined as the diameter <NUM> of the circumcircle <NUM> of the trilobe cross-section. The diameter <NUM> of the trilobe CO<NUM>/O<NUM> remover <NUM> is <NUM> to <NUM> in an embodiment, <NUM> to <NUM> in another embodiment, <NUM> to <NUM> in another embodiment, <NUM> to <NUM> in another embodiment. The length <NUM> of the trilobe cylindrical CO<NUM>/O<NUM> remover <NUM> is <NUM> to <NUM> in an embodiment, <NUM> to <NUM> in another embodiment, <NUM> to <NUM> in another embodiment, <NUM> to <NUM> in another embodiment. The CO<NUM>/O<NUM> remover is porous in an embodiment. The pore volume is <NUM><NUM>/g to <NUM><NUM>/g in an embodiment. The pore volume can be measured with an automatic pore size distribution measure instrument for example BELSORP-mini-II from MicrotracBEL Corporation. Surface area (SBET) of the CO<NUM>/O<NUM> remover is <NUM> to <NUM><NUM>/g in an embodiment, <NUM> to <NUM><NUM>/g in another embodiment, <NUM> to <NUM><NUM>/g in another embodiment, <NUM> to <NUM><NUM>/g in another embodiment, <NUM> to <NUM><NUM>/g in another embodiment, <NUM> to <NUM><NUM>/g in another embodiment, <NUM> to <NUM><NUM>/g in another embodiment. The surface area could be measured by a BET method (a single-point method) with a N<NUM> gas absorption at a liquid nitrogen temperature. A surface area analyzer such as Macsorb® Model-<NUM> from MOUNTECH Co. could be used.

The CO<NUM>/O<NUM> remover is made by a precipitation method or a dry method in an embodiment. A Ni compound, a Mg compound, an Al compound and optionally a Si compound and/or a Na compound are provided. The compounds are mixed and calcined to form the CO<NUM>/O<NUM> remover. The Al compound can be added to the mixture of the Ni compound and the Mg compound before the step of calcining or after the step of calcining in an embodiment.

For the raw materials of the CO<NUM>/O<NUM> remover such as the compound of Ni, Mg, Al, Si and Na, any compound which provides the metal oxide thereof after calcination can be used.

The Ni compound could be an oxide, a salt or a mixture thereof. The Ni compound could be selected from the group consisting of a nickel oxide, a nickel nitrate, a nickel nitrite, a nickel hydrosulfate and a combination thereof in an embodiment.

The Mg compound could be an oxide, a salt or a mixture thereof. The Mg compound could be selected from the group consisting of an oxide, a magnesium nitrate, a magnesium nitrite, a magnesium hydrosulfate and a combination thereof in an embodiment.

The Si compound could be selected from the group consisting of a silica, a diatom earth, a sodium silicate and a combination thereof in an embodiment.

The Al compound could be selected from the group consisting of a boehmite, an alumina sol and a combination thereof in an embodiment. The Al compound could also function as a binder for the Ni compound and the Mg compound. As the Al compound could function as a binder of the precipitate, the Al compound could be separately mixed with the precipitate in another embodiment.

The Na compound could be a sodium carbonate in an embodiment.

The metal compounds could be mixed through a precipitation method where a solution dissolving the Ni compound and the Mg compound is prepared in an embodiment. The Ni compound and the Mg compound can be soluble salts, such as nitrates, nitrites and hydrosulfate in another embodiment. The Ni compound is nickel nitrate in another embodiment. The Mg compound is magnesium nitrate in another embodiment. The Si compound and/or the Al compound could be added to dissolve in the solution in another embodiment. The Si compound could be dissolved in the solution in another embodiment. In the precipitation method, the solution can be separately prepared as an acidic solution and an alkaline solution in an embodiment. The acidic solution is prepared by dissolving the Ni compound and the Mg compound in a solution in an embodiment. An alkaline solution is prepared by dissolving the additional metal compound such as a Na compound in a solution in an embodiment. The Si compound could be dissolved in the acidic solution in an embodiment. The acidic solution is incrementally fed to the alkaline solution until the mixed solution indicated about pH <NUM> in an embodiment. The precipitate is separated from the mixed solution and afterwards calcined.

The solvent is water in an embodiment. The solution is heated at <NUM>° C or higher for <NUM> hour or more in an embodiment to generate a precipitate. The precipitate was taken out by filtering in an embodiment. The precipitate is fine powder or coarse-particle in an embodiment. The precipitate is optionally mixed with the Si component and/or the Al component in another embodiment.

The metal compound mixture is calcined. The calcination is carried out after the step of shaping the metal compound mixture in another embodiment. The calcination temperature could be <NUM> to <NUM>° C in an embodiment, <NUM> to <NUM>° C in another embodiment, <NUM> to <NUM>° C in another embodiment, <NUM> to <NUM>° C in another embodiment. The calcination time is <NUM> minutes or more in an embodiment, <NUM> hour or more in another embodiment. The calcination time is <NUM> hours or less in an embodiment, <NUM> hours or less in another embodiment.

The mixture of the metal compounds can be shaped into a desired form in an embodiment. The shaping method is not limited but in an embodiment the mixture of the metal compounds is shaped by extruding or molding. The shaped metal compound mixture could be calcined in an embodiment. The CO<NUM>/O<NUM> remover is reduced by exposing to a hydrogen gas in an embodiment. The hydrogen gas is provided with a gas flow at <NUM> to <NUM>° C for <NUM> to <NUM> hours in an embodiment. After the reduction, an oxide layer is formed at the surface of the CO<NUM>/O<NUM> remover for stabilization by for example exposing to a gas containing O<NUM> in an embodiment.

In another embodiment, a method of manufacturing a CO<NUM> and O<NUM> remover comprises the steps of: mixing a nickel compound and a magnesium compound,
shaping the mixture of the nickel compound and the magnesium compound, and calcining the shaped mixture.

In another embodiment, a method of manufacturing a CO<NUM> and O<NUM> remover comprises the steps of: mixing a nickel compound and a magnesium compound,
calcining the mixture of the nickel compound and the magnesium compound, and shaping the calcined mixture.

The CO<NUM>/O<NUM> remover can be also prepared by a dry method in another embodiment. The Ni compound and the Mg compound are mixed and calcined in another embodiment.

The CO<NUM>/O<NUM> remover is used any places where CO<NUM> and O<NUM> are undesired in an atmosphere. For example, the CO<NUM>/O<NUM> remover is applied to a gas purification system at a semiconductor manufacturing site.

The method of removing CO<NUM> and O<NUM> from a gas comprises the steps of: placing the CO<NUM> and O<NUM> remover in a container, and passing the gas through the container in an embodiment. There is no limitation on the kind of the gas. The gas could be selected from a group consisting of nitrogen, helium, argon and a mixture thereof in an embodiment. The CO<NUM> content in the gas is <NUM> ppm or lower in an embodiment, <NUM> ppm or lower in another embodiment, <NUM> ppm or lower in another embodiment, <NUM> ppm or lower in another embodiment. The O<NUM> content in the gas is <NUM> ppm or lower in an embodiment, <NUM> ppm or lower in another embodiment, <NUM> ppm or lower in another embodiment, <NUM> ppm or lower in another embodiment. The CO<NUM>/O<NUM> concentration in the gas after removal is lower than the original gas at any rate. The CO<NUM> content in the gas after CO<NUM> removal is <NUM> ppm or lower in an embodiment, <NUM> ppm or lower in another embodiment, <NUM> ppm or lower in another embodiment, <NUM> ppm or lower in another embodiment, <NUM> ppb or lower in another embodiment, <NUM> ppb or lower in another embodiment. The O<NUM> content in the gas is <NUM> ppm or lower in an embodiment, <NUM> ppm or lower in another embodiment, <NUM> ppm or lower in an embodiment, <NUM> ppm or lower in another embodiment, <NUM> ppb or lower in another embodiment.

The CO<NUM>/O<NUM> remover was prepared by the following method. An acidic solution was prepared by dissolving <NUM> of nickel nitrate hexahydrate, <NUM> of magnesium nitrate hexahydrate and <NUM> of diatom earth in <NUM> of ion-exchanged water. Separately, an alkaline solution was prepared by dissolving <NUM> of sodium carbonate in <NUM> of pure water. The acidic solution was fed to the alkaline solution until the mixed solution indicated neutrality. The generated precipitate was taken out by filtering and washing. The precipitate was dried and calcinated at <NUM>° C for two hours. The precipitate powder and boehmite were mixed at a weight ratio (precipitate powder:boehmite) of <NUM>:<NUM>. The CO<NUM>/O<NUM> remover was formed by extruding the powder mixture with a vertical extruder. The extruded precursor of the CO<NUM>/O<NUM> remover had a trilobed cross-section shape as the remover <NUM> in <FIG> with <NUM> of diameter <NUM> and about <NUM> of length <NUM>.

The CO<NUM>/O<NUM> remover with a bulk volume of <NUM><NUM> was filled in a quartz tube (<NUM> inner diameter and <NUM> long) having an inlet and an outlet. The CO<NUM>/O<NUM> remover was reduced by exposing to a pure hydrogen gas. Then the hydrogen gas switched to a nitrogen gas at room temperature. Afterwards a nitrogen gas containing oxygen was flown in the tube to stabilize the CO<NUM>/O<NUM> remover by making the oxide layer at the surface.

The surface area SABET was <NUM><NUM>/g measured by Macsorb® Model-<NUM> from MOUNTECH Co.

The composition of the formed CO<NUM>/O<NUM> remover was analyzed by a X-ray fluorescence spectrometer (XRF, Supermini-<NUM>, RIGAKU Corporation), the result is shown in Table <NUM>.

The CO<NUM>/O<NUM> remover was formed in the same manner as of Example <NUM> except that the amount of magnesium nitrate hexahydrate was <NUM>, and the amount of the diatom earth was <NUM>.

The surface area SABET was <NUM><NUM>/g.

The CO<NUM>/O<NUM> remover was formed in the same manner as of Example <NUM> except that different quantities of raw materials were used resulting in a different chemical composition of the remover. The compositions of the CO<NUM>/O<NUM> remover are shown in Table <NUM>. The surface area SABET was <NUM><NUM>/g.

A quartz tube (inner diameter <NUM>, height <NUM>) was charged with a bulk volume of <NUM><NUM> of the CO<NUM>/O<NUM> remover each obtained above. The tube had an inlet at the top and an outlet at the bottom. A reduction was conducted to remove the oxide layer. After the reduction of the CO<NUM>/O<NUM> remover, a <NUM> ppm CO<NUM> gas (CO<NUM>/N<NUM>) flowed from the inlet to the outlet through the CO<NUM>/O<NUM> remover at a space velocity of about <NUM>,<NUM>-<NUM>. The CO<NUM> gas flow was stopped when the CO<NUM> concentration at the outlet increased from zero to <NUM> ppm.

The CO<NUM> concentration of the outlet gas was measured with a gas chromatograph analyzer with a flame-ionization-detector (FID) and a methanizer (GC-8A/MTN-<NUM>, SHIMADZU CORPORATION).

A <NUM> ppm O<NUM> gas (air/N<NUM>) flowed from the inlet to the outlet through the CO<NUM>/O<NUM> remover at SV of about <NUM>,<NUM>-<NUM>. The O<NUM> gas flow was stopped when the O<NUM> concentration at the outlet increased from zero to <NUM> ppm. The O<NUM> concentration of the outlet gas was measured with a trace oxygen analyzer (Model <NUM>-RS, Advanced Micro Instruments, Inc.

The CO<NUM> absorption and O<NUM> absorption were calculated by the equations below. <MAT> <MAT>.

Results are shown in Table <NUM> below. The CO<NUM> removal was sufficiently over <NUM>×<NUM>-<NUM> m<NUM>/kg and the O<NUM> removal was sufficiently over <NUM>×<NUM>-<NUM> m<NUM>/kg in Example (Ex. ) <NUM> and <NUM>. The O<NUM> removal was insufficiently <NUM>×<NUM>-<NUM> m<NUM>/kg in Comparative Example (Com.

Claim 1:
A method of removing CO<NUM> and O<NUM> from a gas comprising steps of:
placing a CO<NUM> and O<NUM> remover in a container,
wherein the CO<NUM> and O<NUM> remover comprises <NUM> to <NUM> weight percent (wt. %) of a nickel oxide (NiO),
<NUM> to <NUM> wt. % of a magnesium oxide (MgO) and <NUM> to <NUM> wt. % of Al<NUM>O<NUM>,
wherein the weight ratio of the nickel oxide and the magnesium oxide (NiO/MgO) is <NUM> to <NUM>, and
wherein the wt. % is based on the weight of the CO<NUM> and O<NUM> remover; and passing the gas through the container.