The present disclosure provides a method of producing an aluminum salt, comprising reacting activated aluminum metal (Al.sup.(0)) with an anion donor. Also provided are aluminum salts prepared by the disclosed methods.

The present disclosure provides a method of producing an aluminum salt, comprising reacting activated aluminum metal (Al.sup.(0)) with an anion donor. Also provided are aluminum salts prepared by the disclosed methods.

The invention relates to a method for producing coagulant aluminium salts. Raw material comprising at least one aluminium oxide compound is mixed with a process acid or a base to form a reaction mixture, which is heated to a reaction temperature of at least 100 C. at a reaction pressure. The aluminium oxide compound is allowed to react with the process acid or the base. The aluminium oxide compound is selected from a group consisting of amorphous aluminium oxide, -aluminium oxide, -aluminium oxide, -aluminium oxide, or any of their mixtures. The reaction pressure is at least 2 bar(g).

The invention relates to a method for producing coagulant aluminium salts. Raw material comprising at least one aluminium oxide compound is mixed with a process acid or a base to form a reaction mixture, which is heated to a reaction temperature of at least 100 C. at a reaction pressure. The aluminium oxide compound is allowed to react with the process acid or the base. The aluminium oxide compound is selected from a group consisting of amorphous aluminium oxide, -aluminium oxide, -aluminium oxide, -aluminium oxide, or any of their mixtures. The reaction pressure is at least 2 bar(g).

The present invention relates to a system and method for desulfurization and denitrification integrated treatment and recycling of flue gas by using red mud, and belongs to the recycling and environmental protection technology field. The system includes a desulfurization spray tower, an ozone generator, a denitration spray tower, a slurry mixing tank, a slurry storage tank, a vacuum filter, an ammonia water neutralization tank, an aluminum hydroxide precipitation tank, an ammonia water tank, an aluminum hydroxide storage tank, a filter press, an ammonia distillation tower, a dephlegmator, a cooler, a concentrated ammonia water storage tank, a gypsum precipitation tank, and an anaerobic biochemical pool. In the present invention, red mud slurry is used for desulfurization and denitrification treatment of flue gas to remove SO.sub.2 and NO in the flue gas, so that SO.sub.2 and NO in the flue gas reach an emission standard.

The present invention relates to a system and method for desulfurization and denitrification integrated treatment and recycling of flue gas by using red mud, and belongs to the recycling and environmental protection technology field. The system includes a desulfurization spray tower, an ozone generator, a denitration spray tower, a slurry mixing tank, a slurry storage tank, a vacuum filter, an ammonia water neutralization tank, an aluminum hydroxide precipitation tank, an ammonia water tank, an aluminum hydroxide storage tank, a filter press, an ammonia distillation tower, a dephlegmator, a cooler, a concentrated ammonia water storage tank, a gypsum precipitation tank, and an anaerobic biochemical pool. In the present invention, red mud slurry is used for desulfurization and denitrification treatment of flue gas to remove SO.sub.2 and NO in the flue gas, so that SO.sub.2 and NO in the flue gas reach an emission standard.

The present disclosure provides a universal preparation method for in-situ growth of a layered double hydroxide (LDH) layer on a substrate surface, and belongs to the technical field of material synthesis. In the present disclosure, an LDH protective layer is grown in situ on a surface of a substrate by means of electrodeposition combined with hydrothermal treatment. Specifically, a seed crystal layer of the LDH is formed on the substrate surface by the electrodeposition, and then obtained LDH seed crystals are crystallized and grown by Ostwald ripening through the hydrothermal treatment. In this way, the LDH protective layer is formed in which an interlayer anion is a nitrate. The protective layer protects the substrate against corrosion. Moreover, since the interlayer anion is the nitrate, the protective layer can be exchanged with other corrosion-inhibiting anions, and is modifiable.

The present disclosure provides a universal preparation method for in-situ growth of a layered double hydroxide (LDH) layer on a substrate surface, and belongs to the technical field of material synthesis. In the present disclosure, an LDH protective layer is grown in situ on a surface of a substrate by means of electrodeposition combined with hydrothermal treatment. Specifically, a seed crystal layer of the LDH is formed on the substrate surface by the electrodeposition, and then obtained LDH seed crystals are crystallized and grown by Ostwald ripening through the hydrothermal treatment. In this way, the LDH protective layer is formed in which an interlayer anion is a nitrate. The protective layer protects the substrate against corrosion. Moreover, since the interlayer anion is the nitrate, the protective layer can be exchanged with other corrosion-inhibiting anions, and is modifiable.

A process for preparing particles of a layered double hydroxide of the general formula

[M.sub.p.sup.z+M.sub.q.sup.y+(OH).sub.2].sup.a+(X.sup.n).sub.a/n.bH.sub.2O(I)

wherein M.sup.z+ and M.sup.y+ are metal cations or mixtures of metal cations, z=1 or 2; y=3 or 4; p+q=1; b=0 to 10, X.sup.n is an anion, n is 1 to 5 and a is determined by p, q, y and z such that a=zp+yq2, comprises (a) mixing, in aqueous solution, M.sup.z+ cations, M.sup.y+ cations and X.sup.n anions, with a base; and (b) allowing the layered double hydroxide of formula (I) to precipitate from the solution mixed in step (a).

Preferably, M is Li, Mg, Zn, Fe, Ni, Co, Cu, Ca, or a mixture of two or more. Preferably, y is 3, and M is Al, Ga, In, Fe or a mixture of two or more thereof. Also provided are particles obtainable by the process, especially wherein M is Ca, M is Al, and X.sup.n is NO.sub.3.sup.. Particles of a layered double hydroxide wherein the particles have a particle size of not greater than 2000 nm, preferably not greater than 300 nm and especially not greater than 100 nm, are also provided. The layered double hydroxides according to the invention are useful in certain applications, for example, as adsorbents, coatings and catalyst supports.

A process for preparing particles of a layered double hydroxide of the general formula

[M.sub.p.sup.z+M.sub.q.sup.y+(OH).sub.2].sup.a+(X.sup.n).sub.a/n.bH.sub.2O(I)

wherein M.sup.z+ and M.sup.y+ are metal cations or mixtures of metal cations, z=1 or 2; y=3 or 4; p+q=1; b=0 to 10, X.sup.n is an anion, n is 1 to 5 and a is determined by p, q, y and z such that a=zp+yq2, comprises (a) mixing, in aqueous solution, M.sup.z+ cations, M.sup.y+ cations and X.sup.n anions, with a base; and (b) allowing the layered double hydroxide of formula (I) to precipitate from the solution mixed in step (a).

Preferably, M is Li, Mg, Zn, Fe, Ni, Co, Cu, Ca, or a mixture of two or more. Preferably, y is 3, and M is Al, Ga, In, Fe or a mixture of two or more thereof. Also provided are particles obtainable by the process, especially wherein M is Ca, M is Al, and X.sup.n is NO.sub.3.sup.. Particles of a layered double hydroxide wherein the particles have a particle size of not greater than 2000 nm, preferably not greater than 300 nm and especially not greater than 100 nm, are also provided. The layered double hydroxides according to the invention are useful in certain applications, for example, as adsorbents, coatings and catalyst supports.