KR830000019B1 - Method of manufacturing alumina - Google Patents

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Description

Method of manufacturing alumina

The present invention relates to a new method for producing alumina using a variety of orphans containing alumina, such as bauxite and non-boxite based minerals as raw materials.

Conventionally known methods for manufacturing alumina are US Patents 3295923, 3323865, 331662, 3346335, 3390954, 3393975, 3394990, 3397951, 3406610, 3408159, 3421852, 3436176, 3427126, 3429660, 340008, 3442606, 3443894, 3443895, 3445187, 3346585, 3449071, 3457502, 3466142, 3462625, 3477813, 3480388, 3479136, 3480389, 3484196, 348886849, 348666856, 3488147, 3497317, 3497318, 3497318, 3520654, 3532460, 3545923, 355666723, 3560148, 3594122, 3600129, 2620671914 3630670, 3694122, 3694271, 3632310, 3642433, 3674372, 3647373, 3649184, 3649185, 3652208, 3653339, 3664809, 3666411, 3667905, 3672831,3681012, 3681013, 3698861, and Japanese Patent Application Publication 45-20961, So 45-25762, So 47-2121, So 47-40628, So 48-758, So 48-1595, So 48-41157, So 49-29821, So 50-33591, So 51-41600, So 52-46194,

In addition, there are Korean Patent Application Publication No. 78-287, but they use alkali method, acid method or alum method. In this case, a lot of heat energy is consumed or the process is complicated and the recovery of treatment agent is difficult, resulting in high production cost. There are other problems such as pollution factors.

燒)하여야하므로 많은 열에너지가 필요하며 시리케이트의 분리가 곤란하고 알루미네이트의 가수분해가 복잡한 등의 문제점ㅇ 잇으며, 삼법의 경우에는 황산사용으로 용기등이 부식되기 쉽고 달라서 이를 방지하기 위하여서는 고가의 시설비가 소요될뿐 아니라 황산으 회수가 어렵거나 이에 많은 부대시설이 소요되며 철분의 분리가 복잡한등의 문제점이 있으며, 또 명반법의 경우에는 400-500℃에서 배소시킬때 SO₂개스가 많이 발생되므로 공해용인이 되며 반응이 잘 진행되지 않아서 암모니아와 산의 손실량이 많아지는 등의 문제점이 있다.For example, in the case of alkali method, calcining at about 1200

燒) It requires a lot of heat energy, so it is difficult to separate the silicate and complicated hydrolysis of the aluminate. In the case of the three methods, sulfuric acid is used to easily corrode containers, so it is expensive to prevent it. In addition to the cost of facility, it is difficult to recover sulfuric acid or many additional facilities, and the separation of iron is complicated. In the case of alum, SO ₂ gas is generated when roasting at 400-500 ℃. Therefore, there is a problem such as tolerate pollution and the reaction is not well progressed, so that the loss of ammonia and acid increases.

Specifically, for example, in the alumina extraction method such as U.S. Patent No. 3,594,122, first, a process in which ammonium sulfate in a stoichiometric ratio is added to clay or similar alumina-containing minerals to the amount of alumina present in the mineral. a), the step of ferretizing the resulting mixture to make a pellet in the range of about 0.25-1.25 inches in diameter, and (b) heating the ferret to a temperature above the decomposition temperature of iron sulfate and below the decomposition temperature of aluminum sulfate. Step (c), step (d) of cooling the ferret, and step (e) of immersing the cooling ferret in water for a sufficient time to dissolve all the aluminum sulfate present in the ferret and the solution obtained Filtering (f), reacting the filtered solution with ammonia gas to form a precipitate of aluminum hydroxide (g), and It is supposed that the alumina is extracted from the alumina-containing ore by the eight steps of the known step (h) made of alumina.

In the step (e), the ferret is preferably supplied in a flow furnace to heat the ferret at 600 ° C., in which the ferret moves toward the heat flow of the gas, and the temperature of 600 ° C. in the step (d). After reaching the ferret is cooled by a cooling air stream and discharged at substantially lower temperatures, and the gas from the furnace's government will contain all of the ammonia gas obtained from the reaction with the ore of aluminum sulfate. have.

However, in this case, since the raw material mixture is carried out in the solid phase, the siliceous mixture is difficult to be crosslinked, and because it must be processed at a relatively high temperature (600 ° C.), a lot of energy is required, or a relatively large amount of pollution gas (NH ₃ , SO ₂ ) is generated. There is such a problem.

In this case, the generation process of pollution gas is as follows.

Al₂(SO₄)₃+ 6NH₃+ 3H₂O 또는3 (NH ₄ ) ₂ SO ₄ +

Al ₂ (SO ₄ ) ₃ + 6 NH ₃ + 3 H ₂ O or

Fe₂(SO₄)₃+ 6NH₃+ 3H₂O3 (NH ₄ ) ₂ SO ₄ + Fe ₂ O ₃

Fe ₂ (SO ₄ ) ₃ + 6 NH ₃ + 3 H ₂ O

Of course, Al ₂ O ₃ or Fe ₂ O ₃ is contained in the clay.

In this case, SO ₂ gas is generated in the step (g) of filtering the obtained solution and reacting this filtrate (a mixed solution of aluminum sulfate + iron sulfate) with ammonia gas to obtain precipitation of Al (OH) ₃ .

Al ₂ (SO ₄ ) ₃ + Fe ₂ O ₃ + SO ₂ ↑

(NH₄)₂SO₄+Al(OH)₃↓Al ₂ (SO ₄ ) ₃ + NH ₃

(NH ₄ ) ₂ SO ₄ + Al (OH) ₃ ↓

In this case, since the cooling ferret should be immersed in water for a long time in order to dissolve all aluminum sulfate present in the ferret in the process (e), there are problems such as a relatively long time.

In the present invention, since the aqueous solution of ammonium hydrogen sulfate, which is a concentrated (70-80%) acid sulfate, is used to solve the problems of the conventional method, the corrosiveness of the installation is less than that of the three methods, thus reducing the production cost. Since it is processed by low temperature heating (140 ℃), there is no need for high temperature sintering, so it can greatly reduce thermal energy compared to alkali method, etc. Also, because it uses a single treatment agent, it is easy to recover and uses salt. In addition to the above, it is possible to reduce the uniformity of the raw material mixture by liquid mixing compared to the ferret method, and to reduce the thermal energy significantly because of low temperature treatment. There is also an advantage that can achieve the desired purpose with a simple facility, the first configuration of the present invention When the above-described embodiment gyeomhayeo follows.

I. The bauxite or non-boaksite-based raw ore is treated according to a known pretreatment method to obtain about 80 meshes.

An aqueous solution (concentration 70-80%) of acid sulfate (such as ammonium hydrogen sulfate) in excess of the equivalent ratio of the alumina content of the pulverized product is added to the crushed ore raw material and heated at a temperature near 140 ° C. while stirring, and then insoluble. Remove and remove residues such as silica gel, which is water.

At this time, the following chemical reaction occurs.

2(NH₄)₂SO₄+ 2NH₄Al(SO₄)₂12H₂O (1)6 NH ₄ HSO ₄ + Al ₂ O ₃

2 (NH ₄ ) ₂ SO ₄ + 2NH ₄ Al (SO ₄ ) ₂ 12H ₂ O (1)

2(NH₄)₂SO₄+ 2NH₄Fe(SO₄)₂12H₂O (2)6 NH ₄ HSO ₄ + Fe ₂ O ₃

2 (NH ₄ ) ₂ SO ₄ + 2 NH ₄ Fe (SO ₄ ) ₂ 12H ₂ O (2)

Of course, Al ₂ O ₃ or Fe ₂ O ₃ is included in the raw ore.

II. Ammonia water or aluminum pieces are added to the extract filtrate to adjust and concentrate the acidity of the extract filtrate to separate the alumina component and other components and to prevent mixing between them.

This is one of the features of the present invention.

In other words, first, the following reactions (3) and (4) occur.

NH ₄ Fe (SO ₄ ) ₂ 12H ₂ O + NH ₄ Al (SO ₄ ) ₂ 12H ₂ O + NH ₄ OH = (NH ₄ ) FeSO ₄ 6H ₂ O + NH ₄ Al (SO ₄ ) ₂ 12H ₂ O ( 3)

That is, by changing Fe ₂ Al ₂ (SO ₄ ) ₄ ㆍ 24H ₂ O of trivalent Fe ⁺⁺⁺ to Fe ⁺⁺ Fe (NH ₄ ) ₂ ㆍ (SO ₄ ) ₂ or FeSO ₄ , alumina-containing components and iron It is one of the features of the present invention to separate the other components and to prevent mixing of Al ₂ (SO ₄ ) ₃ and ammonium alum of formula (1).

III. And other solution components such as aluminum sulfate crystals and iron-containing compounds obtained in formulas (3) and (4) are separated by filtration, and the aluminum sulfate obtained by filtration is added with ammonia water to form aluminum hydroxide and ammonium sulfate, and precipitated aluminum hydroxide. Extract it.

_{2NH 4 Al (OS 4) 2} 12H 2 O + 6NH 4 OH = 4 (NH 4) 2 SO 4 + 2Al (OH) 3 (5)

IV. At the same time, ammonia water is added to the ammonium alum of the formula (1) to extract the precipitate of calcium hydroxide.

Al ₂ (SO ₄ ) ₃ + 6 NH ₄ OH = 2Al (OH) ₃ + 3 (NH ₄ ) ₂ SO ₄ (6)

V. Thus, alumina is obtained from the aluminum hydroxide obtained by filtration in the above (5) (6) by a known method. Of course, depending on the nature of the raw ore, a small amount of other components such as titanium oxide and silica gel are produced in addition to the iron-containing agglomerate. These can be separated and removed by a suitable method.

And by treating the aluminum sulfate obtained in the formula (5) (6) by the air method, it is possible to recover the acidic ammonium sulfate, which is one of the starting materials of the present invention.

That is, for example, when ammonium sulfate is heated to 357 ° C. in the atmosphere, ammonium hydrogen sulfate is produced.

For example, the national mine raw material used in the present invention is as follows.

Kaolin in Sechang Mine, Gyeongnam, Korea

These raw ores are roasted at a temperature of about 700 ° C. for about 2 hours according to a known method, and ground to 80 mesh. For example, 50 grams of this solution is added with 250 ° C. in an aqueous 7-% ammonium hydrogen sulfate solution. The average yield of the alumina obtained by treatment with the method of the present invention was about 97-98%.

In addition, the compounding ratio of the present invention and the concentration condition of aqueous ammonium sulfate solution are taken within the range to obtain a good alumina yield as a result of various tests.

Advantages over other well-known methods of the present invention will be omitted since it has already been compared to the prior art at the beginning.

The features of the present invention are summarized as follows.

next

A. The present invention is characterized by the above-mentioned process I, II and process III, IV is known.

N. Since the invention uses HN ₄ HSO ₄ aqueous solution, the ash I and II processes are all conducted in the liquid phase, so that the mixing of the raw materials is easy and uniform. However, the US patent discloses (NH ₄ ) ₂ SO ₄ crystals. In other words, the first and second processes are processed into solid pellets, so that uniform mixing of raw materials is relatively difficult.

C. In the present invention, since NH ₄ HSO ₄ (melting point 146,9 ℃) and clay are mixed in the present invention, it is sufficient if the treatment temperature is low at 140 ℃, but in the US, the crystal (NH ₄ ) ₂ SO ₄ (melting point 513 ℃ ) And clay, etc. must be mixed to process relatively high temperature (600 ℃), so a lot of heat energy is required.

D. In the present invention, two crystals produced as a result of a chemical reaction (addition of ammonia water or aluminum pieces, etc. in order to prevent mixing of the above formulas (1) and (2), are characterized in that acidity is controlled, but in the US patent, There is no such process because the treatment is Sanyon

M. There is almost no generation of pollution gas in the present invention through the process of IV, but in the case of the US patent there is a problem that relatively high pollution gas (NH ₃ or SO _2, etc.) is generated.

Iii. In addition, in the publication (e) of the US patent (part of the above-mentioned I process), it is necessary to immerse the cooling ferret in water for a long time in order to dissolve all aluminum sulfate present in the ferret, so that a relatively long time is required. There is also a problem, but the present invention has the advantage that such a process is not necessary.

Claims (1)

In extracting anlumina from aluminum ore, ammonium bisulfate concentrated solution (concentration 70-80%) was added to the raw ore crushed powder at a slightly higher amount than the equivalent ratio of alumina content, and the mixture was heated at a temperature of about 140 ° C. while stirring to add ammonium. Alum [(NH ₄ ) ₂ SO ₄ ㆍ Al ₂ (SO ₄ ) ₃ ㆍ 24H ₂ O] and iron alum [Fe ₂ Al ₂ (SO ₄ ) ₄ ㆍ 24H ₂ O], and other residues were separated and removed. It is characterized in that the addition of one of ammonia water or a piece of aluminum and to adjust the acidity to prevent mixed crystals, wherein the ammonium alum 2 is obtained by the aluminum hydroxide precipitates, the iron From the alum, aluminum sulfate and other iron-containing substances are formed, and then, the aluminum sulfate separated from the alumina is reacted with ammonia water to produce aluminum hydroxide. Process for producing alumina by treating the aluminum.