JPH0260604B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to a process for deironating red mud and bauxite and producing high quality raw material for the alumina industry. During processing, pentacarbonyl iron, a valuable raw material for powdered gold, is produced as a by-product.

This book details how to supply raw material suitable for use in the alumina industry from the red mud produced during the production of alumina, which contains no iron and has been accumulated over several decades. This is the object of the invention.

It is a further object of the present invention to detail a process for supplying bauxite as a raw material which is completely free of iron and therefore has a low iron content and is enriched in aluminum oxide for the alumina industry.

According to the method of the present invention, the iron content of the bauxite raw material can be reduced by 80-95% or even to a large extent, thus increasing the production capacity of existing alumina plants by as much as 20-25%. .
Another advantage of the process of the invention is that the amount of red mud produced during aluminum production and the amount of waste aluminum oxide can be significantly reduced.

According to the process of the invention, it is possible to remove iron in the form of pentacarbonyl iron from red mud or bauxite and to produce highly pure powdered pentacarbonyl iron from this by-product. In this way, it is possible to supply raw materials for powdered gold, which is rapidly developing, and to reduce the amount of waste materials.

Technical background Aluminum is generally produced by the Bayer process by electrolysis of pure alumina obtained from bauxite. The aluminum oxide content of good quality bauxite is about 50%.
Impurities in the alumina, particularly iron oxides and iron oxyhydrates, present in an amount of about 25%, are removed by treatment with alkali under pressure. The red mud produced at this stage contains 40-45% iron oxide and 10% aluminum oxide.
Contains ~20%. As there is no known suitable technique for processing red mud, millions of tons of red mud accumulate in the vicinity of alumina plants, and the storage and accumulation of huge amounts of red mud causes serious problems.

Low quality bauxite with low aluminum oxide content and high iron oxide content cannot be processed economically in the Bayer process.

Different qualities of red mud and bauxite can be processed in the method of the invention. Thus, the process of the present invention can improve the raw material supply of alumina plants and contribute to reducing the mining of bauxite, and a significant amount of pentacarbonyl iron produced during processing can be converted into iron powder. It can promote the intensive development of financial institutions. On top of that,
A large usable open space currently used for storing red mud can be used for agricultural purposes.

The treatment and utilization of red mud and the problem of making bauxite iron-free are being thoroughly researched all over the world. Several publications and patent specifications address the problem of increasing aluminum oxide and aluminum production by reducing the iron content of bauxite. However, this prior art process has hitherto never been used on an industrial scale, or its use has been very limited.
This is because the known techniques are complex, expensive, produce by-products that cannot be processed, require large amounts of auxiliary agents, have high energy requirements, and the process is not selective. If it is at a point, you can do this.

According to the general opinion, red mud is a promising second raw material source (Sakur, R.
S, Santo, B.R. [Thakur, RS,
Sant, BR]: Chem.Era, 1980
Zimmer, E.: Aluminum ((Dusseldorf))
1980, Volume 56 (No. 10), Pages 639-42).

Other methods (Yoshii Chikao, Ishimra Koutaro), Hokkaido University Faculty of Engineering Research Report [Hokkaido Daigaku]
Kogakubu Kenkyu Hokoku], 1978, (No. 89)
(pages 1 to 6), red mud is calcined at a temperature of 1450°C in the presence of calcium oxide as a slag-forming agent, the calcined product is then treated with molten alkali, and red mud and aluminum is dissolved in the form of NaAl ₂ O ₂ .

Another method (Matyash, VG, Kudinov, BZ, Leontev,
LI]: Transactions of the Institute of Metals [Tr.Inst.Metall],
Akad Nauk U S S R Ural Neutin Tzentl. [AKad.Nauk
USSR.Ural.Neuchn.Tsentr.] 1977, Volume 30,
103-5), the raw material is calcined with calcium oxide at a temperature of 1100 DEG C., and this step is combined with reduction with semi-coke. In this way, 80% of the iron content can be removed.

Yet another method (Ejima Tatsuhiko, Shimakage
Kazuyoshi, Hoshi Nasayoshi [Ejima,
Tatsuhiko, Shimakage Kazuyoshi, Hoshi
Nasayoshi]: Light Metal [Keikinzoku] 1978, No.
According to Vol. 28 (Issue 9), pages 443-9), calcination is carried out at 450° C. using NH ₄ HSO ₄ . Aluminum and iron are dissolved from the calcined product with sulfuric acid.

Yet another method (Logomerac, VG): TRAB.com.int.
Etude Bauxites, Alumine
[Alum.] 1979, Vol. 15, pp. 279-85), firing is carried out in an electric furnace, and then the metal is
% sulfuric acid and extracted with bis-2-ethyl-hexyl phosphoric acid to recover the active ingredient.

According to another method, the calcination is carried out at 400 ° to 1000 ° C in the presence of FeSO ₄ and the sulfates formed are separated from SiO ₂ by dissolving them in water (Mitsui Alumina Seizo Co., Ltd.). KK〕：
Japanese Patent Publication [Jpn.Kokai Tokkyo Koho]
No. 8177309, November 29, 1978).

Some methods are based on the use of strong acids, such as hydrochloric acid, sulfuric acid, or sulfur trioxide (Zimmer, E.: Aluminum ((Düsseldorf)) 1980
, Volume 56 (No. 10), Pages 639-42, Hungarian patent No. 150459, US patent No. 3185545,
Hungarian Patent No. 179799). According to these methods, dried and ground red mud is treated with acid in countercurrent conditions and the metal salts formed are converted into the corresponding oxides by calcination.

British patent no. 2078211 discloses a very interesting method. With the help of a magnet, the neutralized red mud is separated into two fractions, one of which has a high concentration of iron, and the other with a low iron content.

In the Bayer method, the iron content of iron-rich bauxite can be reduced in order to increase the amount of lime by 15-20% (Pauker, V. I., Tubarev, V. Aishimakova, L.G. VI, Zubarev, VI, Simakova, L.
G.〕((USSR))((TSUBETON))TSUBETON. Met. [((USSR))((Tsvetn))
Tsveton.Met.] 1980, (No. 7), pp. 79-83).

According to another group of methods, iron is removed as iron chloride. The bauxite is dried, calcined at high temperatures of 600° to 700°C, ground and treated with hydrochloric acid or gaseous chlorine in alternating current conditions. In the process, aluminum is also converted to chloride and is separated from the chlorides of iron, titanium, magnesium, calcium and silicon by fractional distillation, or selectively dissolved from the above compounds. (Zotikova, AN, Kozlov, VM, Winkelberg, VT, Guseva, NS, Pavlova, LM)
Vinkelberg, VG, Guseva, NS, Pavlova,
LM]: ((USSSR)) Lev.
Two. Metal [Ref.Zh.Metall.] 1979, Abstract [Abstr.] No. 12G175, Fuori, Yi,
Foley, M. Double You [Foley, E.,
Wadsley, MW] British Patent No. 2023113,
December 28, 1979, Zoteykova, A.N.
Binkenberg, V.G., Pavlova, L.M., Minina, K.P.
P〕: ((U.S.S.R.)) Ref.Zh.Khim.〕1982, Abstr No. 1L98, Kapoly L, Suzabo Renée,
Zsegredavi, Stotzker L, Riederauer Suz, Stotzker L [Kapoly
L., Szabo Lne, Czegledi B., Stoker L.,
Riederauer Sz., Stocker L.: “Hazai bauxitok vastalanitase”
Tatabanya], November 1, 1982).

According to a particular approach, the aluminate solution produced by the Bayer process is treated with hydrochloric acid and the iron is separated from this solution with the aid of organophosphates or oxidizing agents (N. L.P., Subtyenko, et al. Ni, LP, Savchenko, AI: ((U.S.S.R.)) Kompleksn.Ispolz. Minor. Silja.
Miner.Syrya], 1980 (No. 6), pages 81-83,
Kotsuko, A, Kortsushi Ai, Kikuki Ai,
Merianis [Cocco, A., Colussi, I.,
Kikic, I., Meriani, S.]: Int. Solvent Extor Conf ((Proc)) [Int.Solvent
Extr.Conf. ((Proc))] 1980, Volume 3, Paper No. 80
~186, page 7).

According to a study published by Hungarian researchers, bauxite with a high iron content, or bauxite with a high concentration of red mud, can be treated with ammonium chloride at high temperatures to remove iron in the form of Fe(OH) ₃ . Zambo, J., Molnar
L., Siklosi P.: Banyasz.Kohasz Lapok
Kohasz], 1980, Vol. 113 (No. 6), No. 270-3
Page, Zahnborg J., Molnár L., Ciclosi P.: Trav.com Int.
etoud bauxites, almaine arum
(1981, Vol. 16, pp. 183-92).

According to this procedure, approximately 70-80% of the iron content can be removed in a very complicated manner and aluminum is obtained in most cases as chloride.

Several publications deal with the production of pentacarbonyl iron. However, not a single reference relates to the production of pentacarbonyl iron from red mud or bauxite.

Pentacarbonyl iron was discovered in France in 1891 by M.Berthelott (Berthelot, M.: Compt.rend., Vol. 112,
Page 1343 (1891), Vol. .，Langer，
C.]: Journal of the Chemical Society [J.Chem.Soc.] Volume 59, Page 1090,
(1891)). To obtain pentacarbonyl iron, iron powder obtained by reducing iron oxalate is reacted with carbon monoxide under atmospheric pressure. To improve low yield,
The CO pressure was increased to 300 bar, but it was not possible to reach 100% conversion.

Mittasch A. (Z.Angew.Chem) Volume 41,
Page 827 (1928)), and Hieber, et al. (Hieber.W.: Metal Carbonyl, F.I.
A.T. Review-in-Organic Mistry Part [Metallcarbonyle, FIAT
Review. Inorg. Chem. Part.] pages 108-145 (1946)), very good results were obtained using Raney-iron as the raw material.

Reppe and others produced carbonyl iron from iron sulfate under high temperature and pressure (Reppe, W.: Ann. Chem., 1953, No. 582, no. pages 116-121).

Industrial-scale production of pentacarbonyl iron is carried out from iron powder - obtained by reducing iron oxide - at 180° to 200°C in CO at a pressure of 200 bar (Szirkin, VG). ]: Karbonylnie Metalli, Mozukuba [Karbonylnie Metalli,
Moszkva], 1978, p. 98).

SUMMARY OF THE INVENTION According to the method of the invention, dried red mud or powdered bauxite is prepared in a hydrogen-containing reducing gas in the presence of activation and carbonylation promoters, so-called "promoters". Activation is preferably carried out at a temperature of 150° to 800°C under a pressure of from 0.1 bar to 100 bar, in a gas stream which preferably does not contain any carbon monoxide, and then this is carried out at a pressure of 25°C.
Carbonylation at temperatures between 50° and 300°C in carbon monoxide at ~300 bar.

The process of the present invention is the only process in the bauxite industry that is capable of selectively removing almost the entire iron content of red mud or bauxite in the form of pentacarbonyl iron. Red mud and bauxite contain several types of metals, but these irons can be reacted with carbon monoxide with the highest reaction rate, and the volatile liquid pentacarbonyl iron formed can be easily removed. Can be done.

DETAILED DESCRIPTION OF THE INVENTION According to the process of the present invention, a powdered solid feed material is used to perform iron removal in a single step without the formation of by-products and in the absence of any solvent. In this way, almost the entire aluminum oxide content of red mud and bauxite can be recovered and the iron content removed in the form of a highly purified product.

Contrary to the majority of processes in the chemical industry, the process of the present invention does not produce any undesirable by-products, and thus the present invention is a good example of a new type of process that avoids environmental pollution.

According to the process of the present invention, dried red mud or powdered bauxite is prepared in a hydrogen-containing reducing gas, preferably in the presence of activation and carbonylation promoters, so-called "promoters". In a gas stream that does not contain carbon oxide, at a temperature of 150°~
Activation is preferably carried out at 800°C under a pressure of 0.1 bar to 100 bar, followed by activation in carbon monoxide at a pressure of 25 to 300 bar and at a temperature of 50° to
Carbonylate at 300℃.

Elemental sulfur, inorganic or organic sulfur compounds (e.g. _H2S , HgS, CuS, FeS, mercaptans) in the procedure
or HgO, CuO, elemental iodine or iodine compounds (e.g. HJ, CuJ) or mixtures thereof as accelerators, calculated relative to the weight of the raw material.
May be used in amounts of 0.5-30%. Accelerators vary based on the composition of the raw material, iron content, alkali metal content, and lime content. For example, red mud has a higher alkali and lime content than bauxite. Therefore, when using red mud as raw material, it is preferable to use acid promoters (eg S, H ₂ S or HJ) or mixtures thereof. On the other hand, when treating bauxite, elemental sulfur, mercaptans, HgO, CuO, FeS, or
Preference is given to using FeCO ₃ or mixtures thereof.

Since the iron compounds are present in the initial raw material, during the activation procedure they undergo thermal decomposition due to the high temperatures. Thus, oxyhydrates, carbonates, hydroxides and other iron compounds decompose to iron oxides, which are reduced with hydrogen to active iron. During the activation stage, the promoter promotes the decomposition and reduction of iron compounds, and during the carbonyl production stage, the promoter increases the production rate of carbonyl compounds.

As reducing gas it is possible to use pure hydrogen, preferably a gas which does not contain any carbon monoxide, a water gas, ammonia or a gas containing hydrogen and/or ammonia. Activation can preferably be carried out under atmospheric pressure. The preferred temperature for this step is between 150° and 300°C.

After the activation stage, the activated red mud or bauxite is cooled from the high temperature of activation to 50°C.
A carbonylation temperature of up to 300°C, preferably from 50°C to 80°C is reached, which is then reacted with carbon monoxide under a pressure of 25 to 300 bar. Pure carbon monoxide, carbon monoxide-containing synthesis gas, generator gas or producer gas can be used for carbonylation. Bauxitization is an exothermic reaction, with an increase in temperature indicating the formation of pentacarbonyl iron. Simultaneously with its formation, the pentacarbonyl iron is condensed under pressure and continuously led out of the reactor into a storage tank in a stream of CO.

Surprisingly, during the activation and carbonyl formation steps, if more than one type of promoter is used simultaneously, i.e. sulfur powder or organic or inorganic sulfur-containing promoters, the effectiveness of the promoters can be reduced. found that it increases. If two or more types of accelerators are used, the effects of individual accelerators cannot be simply reduced, so they mutually contribute to the effects of the other,
You can get synergies that you have never seen before.

When more than one type of promoter is used, it is likely that the iron forms an active intermediate compound with the promoter, and the active compound thus formed is able to react more easily with carbon monoxide. In this case, the carbonylation step involves a ligand exchange process, in which the iron-bound ligand is exchanged for carbon monoxide. The sum of the activation energies of these two processes is much smaller than the activation energy of simply bonding the carbon monoxide ligand to iron, and therefore the promoter greatly facilitates the formation of pentacarbonyl iron.

The optimum synergistic effect of the accelerator will depend on the chemical composition of the raw red mud, so the optimum amount of accelerator will be determined by individual experiments for each red mud raw material. After determining the chemical composition of the red mud or bauxite, preliminary experiments are carried out in a laboratory scale reactor using 100 g of samples with various combinations of promoters and the results of the preliminary experiments are compared.

The following examples are intended to further confirm the details of the invention and are not intended to limit the scope of protection to these examples.

Example 1 In a 500 ml stainless steel reactor, 10 g of dry powder of red mud (aluminum oxide content 15.9 g, iron oxide content 43.1 g ((Fe = 30.1 g))) was stirred in a hydrogen stream. Heating rate 50-60℃/hour
It was activated by heating to 350° C. and stirring at this temperature in the presence of hydrogen for 12 hours under a pressure of 20 bar. The activated red mud is cooled to 150℃,
in carbon monoxide at a pressure of 50 bar with stirring.
Carbonylation was carried out for 10 hours. The liquid pentacarbonyl iron produced is cooled and removed from the reactor. The residue remaining in the autoclave contains 15.2 g of iron. In this way, the total iron content of the raw material
We were able to remove 49.5%. As a result of iron removal treatment, the aluminum oxide content of red mud is 15.9%
It increases from 22.0% to 22.0%.

Example 2 100 g of dry powder of red mud (aluminum oxide content 15.9 g, iron oxide content 43.1 g ((Fe = 30.1 g)))
was thoroughly mixed with 2g of sulfur powder, then the mixture
In a 500 ml stainless steel reactor, in a hydrogen stream with stirring, heat at a heating rate of 50-60 °C/hour to 700 °C, and at this temperature, with stirring.
Activate for 12 hours under 30 bar pressure. The activated red mud was placed in carbon monoxide at a pressure of 150 bar.
Carbonylate at a temperature of 200° to 210°C for 10 hours while stirring. The liquid pentacarbonyl iron produced is removed from the reactor while cooling. The residue in the autoclave contains 8.2 g of iron. Therefore, the Fe removal rate is 72.8%. As a result of iron removal treatment, the aluminum oxide content of red mud is 15.9%
This will increase from 24.3% to 24.3%.

Example 3 100 g of dry powder of red mud (aluminum oxide content 15.9 g, iron oxide content 43.1 g ((Fe = 30.1 g)))
thoroughly mixed with 5.5 g of iron sulfide ((S = 2 g)),
and heated to 400°C in a hydrogen stream with stirring at a heating rate of 50° to 60°C/hour in a 500 ml stainless steel reactor and activated at this temperature for 12 hours in the presence of atmospheric hydrogen. let The activated red mud is carbonylated for 10 hours with stirring in carbon monoxide at 230°C and a pressure of 115 bar. The liquid pentacarbonyl iron produced is removed from the reactor while cooling. The red mud in the autoclave contains 8.5 g of residual iron. The iron removal rate is 71.8%.
As a result of the iron removal treatment, the aluminum oxide content of the red mud increases to 24.2%.

Example 4 100 g of dry powder of red mud (aluminum oxide content 12.9 g, iron oxide content 42.4 g ((Fe = 29.7 g)))
2.7g of iron sulfide ((S=1g)) and 1g of sulfur powder
Mix thoroughly. The mixture was heated to 600°C in a 500ml stainless steel reactor with stirring in a hydrogen stream at a heating rate of 40° to 60°C/h, and at this temperature in the presence of hydrogen at atmospheric pressure for 12 hours. Activate. Activated red mud is heated to 200℃ under pressure.
Carbonylation is carried out in carbon dioxide at 90 bar for 10 hours with stirring. The liquid pentacarbonyl iron produced is removed from the reactor while cooling. The remaining red mud contains 2 g of iron. Iron removal rate is 93.3
%, and the aluminum oxide content of red mud is
This will increase to 21.6%.

Example 5 100 g of dry powder of red mud (aluminum oxide content 12.9 g, iron oxide content 42.4 g ((Fe = 29.7 g)))
2g of sulfur powder and finely powdered pyrite (composition:
H ₂ O = 1.0%, S = 50.6%, Fe = 45.5%, SiO ₂ =
0.9%, Zn=0.10%, Cu=0.31%, Pb=0.2%, As
= 0.09%, Ca = 0.49%, Mg = 0.05%) and mix thoroughly with 4 g. The mixture was heated to 500°C in a 500ml stainless steel reactor with stirring in a stream of hydrogen at a heating rate of 50° to 60°C/hour, and activated at this temperature for 12 hours in the presence of hydrogen at atmospheric pressure. to become The activated red mud is carbonylated in carbon monoxide at a pressure of 90 bar at 200°C for 10 hours with stirring. The liquid pentacarbonyl iron produced is removed from the reactor while cooling. The remaining red mud contains 0.8g of iron, and the iron removal rate is 97.3%.
And the aluminum oxide content of red mud will increase to 22.0%.

Example 6 100 g of dry powder of red mud (aluminum oxide content 12.9 g, iron oxide content 42.4 g ((Fe = 29.7 g)))
1.5g of sulfur powder and finely ground pyrite (composition:
H ₂ O = 1.0%, S = 50.6%, Fe = 45.5%, SiO ₂ =
0.9%, Zn=0.10%, Cu=0.31%, Pb=0.2%, As
= 0.09%, Ca = 0.49%, Mg = 0.05%) and mix thoroughly with 3 g. In a 500 ml stainless steel reactor, the mixture was heated to 500°C in a hydrogen stream with stirring at a heating rate of 50° to 60°C/h, and at atmospheric pressure at this temperature with gradual introduction of hydrogen for 12 hours. Activate time. A total of 2 g of ethyl mercaptan is added to the hydrogen that passes continuously through the red mud. While stirring activated red mud at 200℃,
Carbonylation is carried out for 10 hours in carbon monoxide at a pressure of 90 bar. The liquid pentacarbonyl iron produced is removed from the reactor while cooling. The remaining red mud contains 1.0g of iron, and the iron removal rate is 96.6%.
As a result of the iron removal treatment, the aluminum oxide content of the raw red mud increases from 12.9% to 22.0%.

Example 7 100 g of dry powder of red mud (aluminum oxide content 12.9 g, iron oxide content 42.4 g ((Fe = 29.7 g)))
is thoroughly mixed with 0.75 g of elemental iodine and 1.12 g of CuJ. In a 500 ml stainless steel reactor, the mixture was heated in a hydrogen stream with stirring at a heating rate of 50° to 60°C/hour to 485°C, and at this temperature.
Activate for 10 hours. The contents inside the reactor are heated to 180℃
and carbonylation for 8 hours in carbon monoxide at a pressure of 110 bar. The pentacarbonyl iron produced is condensed under pressure and water cooled, and the produced liquid is continuously removed in a stream of carbon monoxide. The remaining red mud contains 0.95g of iron, and the iron removal rate is 96.8%. The aluminum oxide content of the residue increases to 22.0%.

Example 8 Dry bauxite 100 with particle size 300-400μ
g fraction (aluminum oxide content 50.7%, iron oxide
24.4% ((Fe = 17.1%))) mixed with powdered sulfur 0.5,
and place the mixture into a 500ml stainless steel autoclave. The contents of the reactor are placed in a hydrogen stream,
Heat to 350°C at a heating rate of 50° to 60°C/hour and activate at this temperature for 12 hours. The activated bauxite is cooled to 200° C. and carbonylated at 190° to 210° C. for 10 hours in carbon monoxide at a pressure of 180 bar. The pentacarbonyl iron produced is continuously removed from the system while cooling. The aluminum oxide content of the remaining bauxite reaches 61.9%. Iron content decreased from 17.1% to 6.3%;
The iron removal rate is 63.2%.

Example 9 100 g of dry powder of bauxite (aluminum oxide content 50.7%, iron content 17.1%) are mixed with 2 g of sulfur powder and placed in a 500 ml stainless steel reactor. Heating the mixture in a hydrogen stream at
Heating at 60°/hour to 500°C and pressure at this temperature.
Activate for 12 hours in 25 bar hydrogen. After activation, the reaction mixture is cooled to 200 °C and pressure
Carbonylation is carried out for 10 hours in carbon monoxide at 150 bar. The pentacarbonyl iron formed is continuously removed by condensation under pressure. The remaining bauxite contains 62.7% Al ₂ O ₃ and 5.2% iron. The iron removal rate is 69.6%.

Example 10 100 g of dry bauxite (aluminum oxide content 50.7%, iron oxide content 24.4% ((Fe = 17.1
%))) is thoroughly mixed with 3 g of sulfur powder. The mixture was introduced into a 500ml stainless steel autoclave and heated at a heating rate of 50° to 60°C/h in a stream of hydrogen.
℃ and activate at this temperature under atmospheric pressure for 12 hours. activated bauxite
Cool to 190° C. and carbonylate for 10 hours in carbon monoxide at a pressure of 115 bar. The pentacarbonyl iron produced is continuously removed from the system while cooling. The aluminum oxide content of the remaining bauxite reaches 63.5%. Iron content ranges from 17.1% to 4.3
%. The iron removal rate reaches 74.9%.

Example 11 100 g of dry and crushed bauxite (aluminum oxide content 50.7%, iron oxide content 24.4% ((Fe
= 17.1%))) is thoroughly mixed with 20 g of sulfur powder.
The mixture was placed in a 500 ml stainless steel autoclave and heated at a heating rate of 50° to 60°C/hour in a hydrogen stream.
Heat to 700°C and activate at this temperature for 12 hours under atmospheric pressure with stirring. The activated bauxite is carbonylated at 200° C. in carbon monoxide at a pressure of 90 bar for 10 hours. The pentacarbonyl iron formed is continuously removed from the system while cooling. The remaining bauxite has an aluminum oxide content of 66.0% and an iron content of 1.3%, down from 17.1%. The iron removal rate reaches 92.4%.

Example 12 100g of dry bauxite powder (aluminum oxide content 50.7%, iron oxide content 24.4% ((Fe=
17.1%))) was placed in a 500 ml stainless steel autoclave and heated to 500°C at a heating rate of 50° to 60°C/hour.
and at the same time introduce a mixture of ammonia and synthesis gas. The feed material is activated at this temperature and atmospheric pressure for 12 hours while syngas is continuously passed through the system. 8 g of ethyl mercaptan is added to the syngas stream during activation. The activated bauxite is carbonylated in carbon monoxide at 200° C. and 100 bar pressure for 10 hours. The pentacarbonyl iron produced is continuously removed from the reactor with cooling. The aluminum oxide content of the remaining bauxite is 66.2%, and the iron content is 17.1%.
This will decrease from 1.2% to 1.2%. Iron removal rate is 93.0%
become.

Example 13 100 g of dried and finely powdered bauxite (aluminum oxide content 50.7%, iron oxide content 24.4%)
((Fe=17.1%))) pulverized sulfur ore (composition:
H ₂ O = 1.0%, S = 50.6%, Fe = 45.5%, SiO ₂ =
0.9%, Zn=0.10%, Cu=0.31%, Pb=0.2%, As
= 0.09%, Ca = 0.49%, Mg = 0.05%) and heated the mixture in a 500 ml stainless steel reactor in a hydrogen stream with stirring.
Heat to 500°C at 50°-60°C/h and activate at this temperature in the presence of hydrogen for 12 hours under atmospheric pressure with stirring. activated bauxite
Carbonylation is carried out for 10 hours in carbon monoxide at a pressure of 100 bar with stirring at 200°C. The liquid pentacarbonyl iron produced is removed from the reactor while cooling. The aluminum oxide content of the remaining bauxite reaches 65.6%, and the iron content ranges from 17.1% to 1.8
%. The iron removal rate will be 89.5%.

Example 14 100 g of powdered bauxite (aluminum oxide content 50.7%, iron oxide content 24.4% ((Fe = 17.1
%))) HgO2g and sodium periodate 3.35
g and charge the mixture into a 500 ml stainless steel tubular reactor. The mixture was heated to 650°C at a heating rate of 30° to 50°C/h in a stream of syngas containing no CO and blown ammonia factory gas (150-300 ml/h), and heated to 650°C with stirring at this temperature. Activate for 10 hours under atmospheric pressure.
The activated bauxite is cooled to 100℃,
and the pressure of the carbon monoxide gas stream from 10 bar
Carbonylation was carried out for 11 hours with continuous increase to 160 bar. Temperature increases parallel to the increase in pressure. The production rate of pentacarbonyl iron can be made to follow the rate of increase in temperature. The produced pentacarbonyl iron is condensed under pressure and continuously removed from the reactor with a stream of carbon monoxide gas into a pentacarbonyl iron storage tank. The iron content of the remaining bauxite decreased from 17.1% to 115%,
This corresponds to an iron removal rate of 93.25%. The aluminum oxide content of bauxite remaining in the autoclave increases from 50.7% to 66.6%.

Claims (1)

[Scope of Claims] 1 (a) Red mud or bauxite raw material is activated in the presence of one or more promoters at 150° to 800°C in a stream of reducing gas at a pressure of 0.1 to 100 bar. , and then (b) carbonylating with carbon monoxide or a gas containing carbon monoxide at a temperature of 50° C. to 300° C. under a pressure of 25 to 300 bar and removing the pentacarbonyl iron formed from the system. A method for deironating red mud or bauxite and producing raw material for alumina industry and pentacarbonyl iron, characterized by: 2. Process according to claim 1, characterized in that a hydrogen-containing gas, preferably a gas completely free of carbon monoxide, is used as the reducing gas stream. 3. The method according to any one of claims 1 and 2, characterized in that hydrogen or a gas containing hydrogen and/or ammonia is used as the reducing gas stream. 4. Characterized by the use of sulfur powder, one or more organic or inorganic sulfur compounds, or sulfur-containing minerals, and/or iodine and/or one or more iodine compounds as accelerators. , the method according to any one of claims 1 to 3. 5. Any one of claims 1 to 4, characterized in that the promoter is used in an amount of 0.1 to 30% by weight, calculated on the starting material.
The method described in section. 6. characterized in that the gas containing carbon monoxide is a synthesis gas produced by decomposition of generator gas, blow gas, earth gas, or generator gas;
A method according to any one of claims 1 to 5.