UA53306C2 - Charge for obtaining ferrosilicon - Google Patents

Abstract

Charge for obtaining ferrosilicon includes wastes of production containing silicon and ferric oxides, carbon-containing material, and waste of wood. Additionally charge includes slack lime and slag deoxidizer. As wastes of production containing silicon and ferric oxides ferrosilicon slag is used at the following ratio of components, % by weight: ferrosilicon slag 70-80, carbon-containing material 3-7, slack lime 5-10, slag deoxidizer 2-5, waste of wood 5-10.

Description

The invention relates to ferrous metallurgy, in particular to the production of ferroalloys, more specifically to the production of ferrosilicon.

In the production of ferrosilicon, it is of interest to use in the composition of the charge various wastes that contain the basis of ferrosilicon - iron and silicon or their oxides. Production waste is conventionally divided into "clean", which can be relatively easily processed in metallurgical processes (various metal waste, metal shavings, ore beneficiation waste, etc.), and "dirty", the processing of which causes significant technological difficulties. Ferrosilicon slag is among the "dirty" production wastes that are difficult to process. Over the decades of operation of ferroalloy productions, significant volumes of this slag have accumulated in dumps.

The main components of ferrosilicon slag are: bi? (silicon oxide) - 23-4695, AI2Oz (aluminum dioxide) - 44-5895, CaO (calcium oxide) - 9-1995, ReO (iron oxide) - 0.6-2.095, MdO (magnesium oxide) - 0.5 -1.595.

The content in the slag of "Korolkov" (Eebi ferroalloy) is 10-2095.

Ferrosilicon slag is refractory (melting point about 17007С), characterized by high viscosity (30-35 poise), which leads to "entanglement" of slag and ferroalloy. The inclusion of such slag in the charge for the production of ferrosilicon of known compositions leads to slagging of the furnace, the impossibility of separating the slag from the ferroalloy.

From the point of view of the composition of ferrosilicon slag, as a valuable raw material for the production of ferrosilicon, and the problems of disposal of production waste, the development of the composition of the charge for the production of ferrosilicon based on slags of ferrosilicon production is relevant. 2 A known charge for obtaining ferrosilicon (author's certificate of the USSR Me998558, MKVZ С22С33/04, priority 14.01.82), which includes a carbon reducing agent, metal additive, quartzite, silicate slag, quartzitobarite with the following ratio of components, wt.9o: carbon reducing agent 20-35 metal additive 1-40 silicate slag 1-10 quartzitobarite 0.5-10 quartzite other.

Components of the charge: carbon reducing agent (metallurgical coke or semi-coke of the chemical industry) with a content of 70-9095 fraction 5-25 mm in the amount of 20-3595, metal additive (steel shavings, scrap metal) fraction no more than 150 mm in the amount of 1-4095, silicate slag of our own production with metal inclusions, crushed to a fraction of no more than 150 mm, quartzitobarite, which is a mineral with intergrowths of barite and quartzite (30-6095 VaO., 40-7095 5102) fraction 40-100 mm and quartzite fraction 40-120 mm, are mixed and used for production of ferrosilicon.

The charge is heated and melted in the furnace. The peculiarity of this charge is that silicate slag and quartzitobarite are additionally involved in the interaction of the components. These components of the charge accelerate phase transformations of quartzite and increase its reactivity.

Sulfur compounds released from quartzite barite, as a result of its interaction with silicate slag, destroy carborundum in the upper layers of the charge, thereby contributing to uniform gas evolution on the furnace furnace.

In the lower layers, in the area of the garnish, the destruction of carborundum by silica silicate slag and barium occurs, as a result of which metallic silicon is formed, which is assimilated by the main mass of ferrosilicon.

The obtained ferrosilicon contains 45-9095 51, other - iron and impurities.

Common features of the analogue and the proposed solution are: charge for the production of ferrosilicon, which contains silicon oxides, and carbon-containing. material.

The specified composition of the charge requires the inclusion of metal additives (steel shavings, scrap metal, etc.) in the composition of the charge and does not allow the use of "dirty" production waste, which contains compounds of iron and silicon, but is difficult to process in metallurgical processes, in the composition of the charge for obtaining ferrosilicon. for example, ferrosilicon slag.

A known charge for obtaining ferrosilicon (patent of the Russian Federation Me2109836, MKVU C22С033/04, priority from 04/22/1994). The essence of the invention is that the charge for obtaining ferrosilicon additionally contains a mixture of fluxed iron ore pellets and iron slag in the ratio 1:(1-3) with the following ratio of components, wt.Uo: quartzite 35-55; carbon reducer 20-30; a mixture of fluxed iron ore pellets and iron slag 10-30; steel shavings other.

When using a mixture of pellets and slag as part of the charge for smelting ferrosilicon, the escape of silicon with the exhaust gases is reduced. In addition, the charge allows you to increase the depth of immersion of the electrodes in the charge, which allows you to perform melting at a higher voltage from the low side of the transformer, as well as to perform melting without the use of expensive semi-coke.

The common features of the analog and the proposed solution are: a charge for the production of ferrosilicon containing iron and silicon oxides, as well as carbon-containing material.

The charge for obtaining ferrosilicon does not allow the use as its components of "dirty" production waste, which contains compounds of iron and silicon, but is difficult to process in metallurgical processes, for example, ferrosilicon slag.

A known charge for smelting ferrosilicon (USSR copyright Mob48635, MKVZ C22С033/00, priority 08.02.77), which contains metal waste, quartzite, briquetted hydrolyzed lignin or cellolignin, wood waste, as well as coke introduced in the form of pitch or petroleum coke at to the following ratio of components, wt. 9o: briquetted hydrolyzed lignin or cellolignin 1-51 wood waste 5-70 pitch or petroleum coke 0.5-2.0 metal waste 1-11 quartzite other.

The proposed charge makes it possible to reduce the intake of aluminum oxides and titanium oxides with it, to increase the ratio of the amount of calcium and magnesium oxides to alumina, and therefore to significantly reduce the total amount of slag-forming oxides.

The ratio of the amount of calcium and magnesium oxides to alumina is fundamentally important. If it exceeds 2 kg, and the total amount of alumina in the charge is less than 0.35 kg, then the conditions for obtaining low-melting and fluid-moving slag, which is easily removed from the furnace, are provided.

The batch was tested in industrial production when smelting 6595 ferrosilicon in an electric furnace with a capacity of 110.00kVa.

Common features of the analogue and the proposed solution are: a charge for the production of ferrosilicon containing silicon oxides, carbon-containing material, as well as wood waste.

The batch requires the inclusion of a metal additive (steel shavings, scrap metal) and does not allow the use of "dirty" production wastes, which contain compounds of iron and silicon, but are difficult to process in metallurgical processes, for example, ferrosilicon slag, as part of the batch for obtaining ferrosilicon.

As a prototype, the charge for smelting ferrosilicon, known by the US patent Me5174810, MKV, was chosen

СО01833/02, priority from February 19, 1992. (Smelting of ferrosilicon in a direct current furnace).

The charge includes waste, including oxides of silicon and iron, carbon-containing material, wood waste.

Waste beneficiation, which includes oxides of silicon and iron, is represented by waste beneficiation of ores.

For example, waste from the enrichment of taconite, magnetic iron, hematite and limonite. The preferred material is taconite enrichment waste, which includes, in weight 95: Be2Oz3-18.12, BeO-8.91, 5102-64.61, CaO-1.29, M9O-1.96,

СО»-4,14, other.

Carbonaceous material can be, for example, carbon black, activated carbon, coal, or coke, coke fines. The preferred carbon-containing material is coke fines, as a by-product of coking. Coke fines are an inexpensive source of carbon for this process. The form of carbon-containing material can be, for example, powder, granules, briquettes.

The tailings, including oxides of silicon and iron, can be fed to the furnace alone or mixed with carbonaceous material.

Production of ferrosilicon alloys based on the specified charge includes: - feeding carbon-containing material and enrichment waste, including silicon and iron oxides, into a closed furnace; - heating the mixture in a closed furnace with a direct current arc; - removal of the ferrosilicon alloy from the closed furnace.

The advantage of melting ferrosilicon in a closed furnace with a direct current arc is expressed in the fact that the particle size of the materials fed into the furnace is not critical.

General features of the prototype and the proposed solution are: a charge for obtaining ferrosilicon, which contains production waste, including silicon and iron oxides, carbon-containing material, as well as wood waste.

The ore beneficiation waste included in the charge belongs to the category of "clean" waste, which is relatively easy to process in metallurgical processes. The specified composition of the charge ensures production of commercial ferrosilicon using ore beneficiation waste, but does not allow the use of ferrosilicon slag as components of the charge for obtaining ferrosilicon.

The basis of the invention is the task of improving the charge for the production of ferrosilicon, which, due to the selection of components and their ratio, would provide the possibility of using ferrosilicon slag as part of the charge for obtaining ferrosilicon, as one of the "dirty" production wastes that are difficult to process in metallurgical processes.

The task is solved by the fact that the charge for obtaining ferrosilicon, which contains production waste, including silicon and iron oxides, carbon-containing material, as well as wood waste, according to the invention, additionally contains slaked lime and a slag deoxidizer, and as production waste, which includes oxides of silicon and iron, ferrosilicon slag is used in it with the following ratio of components, in wt.9o: ferrosilicon slag 70-80 carbon-containing material 3-7 slaked lime 5-10 slag deoxidizer 2-5 wood waste 5-10

The specified features constitute the essence of the invention.

It is advisable to use limestone, quicklime, or fluorspar as a slag deoxidizer in the charge.

It is advisable to choose the fractional composition of ferrosilicon slag in the range of up to 10 cm, and the fractional composition of wood waste to choose in the range of 0.1-4.0 cm.

The cause-and-effect relationship of the features that make up the essence of the invention with the technical result (possibility of using ferrosilicon slag as part of the charge for obtaining ferrosilicon) is expressed as follows.

The charge for obtaining ferrosilicon, which includes ferrosilicon slag, carbon-containing material, slaked lime, slag deoxidizer and wood waste in the specified ratio of components, provides the possibility of smelting conditioned ferrosilicon using ferrosilicon as part of the slag charge.

The basis of the composition of the charge for obtaining ferrosilicon are components that include silicon and iron oxides, as well as a reducing agent. In the considered case, such components of the charge are ferrosilicon slag and carbon-containing: material. Taking into account the properties of ferrosilicon slag (primarily refractoriness and high viscosity), the simplest composition of the charge based on ferrosilicon slag does not allow to organize molten ferrosilicon as a result of inevitable slagging of the furnace. Other components contained in the charge ensure a normal process of melting the charge based on ferrosilicon slag and carbon-containing material with the production of a conditioned final product. Thus, the inclusion of limestone, quicklime, or fluorspar (slag deoxidizers) in the specified ratio in the composition of the charge reduces the melting point of the slag and increases the fluidity of the slag. The inclusion of slaked lime in the composition of the charge in the specified ratio ensures the possibility of separation of slag and ferroalloy in the liquid phase before crystallization (prevents "entanglement" of slag and ferroalloy). Wood waste in the composition of the charge in the specified ratio increases the electrical resistance of the charge, which in turn provides the possibility of deeper planting of electrodes and uniform penetration of the charge under the slag layer.

Thus, the composition of the claimed charge provides an effective melting process with the production of conditioned ferrosilicon based on a charge that includes ferrosilicon slag as one of its main components.

The batch for obtaining ferrosilicon includes ferrosilicon slag (70-8Owag.95), carbon-containing material (3-t7wag.9o), slaked lime (5-1Owag.95), slag deoxidizer (2-5wag.95), as well as wood waste ( 5-1 Ovag. 9c). It is advisable to use coke fines as a carbon-containing material. Limestone, quicklime, or fluorspar can be used as a slag deoxidizer in the charge. The fractional composition of ferrosilicon slag is chosen within 10 cm. The fractional composition of wood waste is chosen in the range of 0.1-4.0 cm. The components of the charge are weighed, mixed and fed into a DC electric arc furnace for melting. The charge is heated and melted in the furnace. After melting, the slag is drained from the furnace and the final product is a ferrosilicon alloy.

Below, in tabular form, specific examples of the declared charge are given.

Table

Load charge components, kg 1101 | Ferrosilicon slag //-/-/-://7777777/|Ї777171784 |77771790 77171196 112 |Ugletsevvysmysmateral.o//-/:// | (6 2 MM | DL | In 113 Gashesevalnaya ////////777777777777171717111111111111112 | 960 1161. 00074 0 (/////7711111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111 11111111111136 0016 |Plavykovviyspat/////777777777711111Ї111117 11111111 11111240 00007 IWastewood.//://77777/|7117117112 71196116 1 ,D o -

Claims (2)

The present invention relates to the improvement of the method of carbonylation of methanol for the production of acetic acid. In particular, the improved method according to the present invention allows to reduce the formation of carbonyl impurities during the carbonylation reaction due to the fact that this reaction is carried out in the presence of small amounts of methyl iodide. There are many modern ways of producing acetic acid. Among them, the most widely used in industry is the so-called Monsanto method (Mopzapiso), based on the carbonylation of methanol with carbon monoxide. This method of carbonylation of methanol, as described in the US patent Me3769329 (author Rashciik, the right to the patent has been transferred to the company Mopzapio Sotrapu) |, is used by industry all over the world and gives the largest amount of produced acetic acid. This method uses a catalyst that contains rhodium, dissolved or dispersed in a liquid reaction medium, and a halogen-containing catalyst accelerator, which is preferably methyl iodide. Rhodium can be supplied to the reactor in any of its many forms. An exact determination of the nature of the rhodium moiety in the active catalytic complex is hardly appropriate here, if at all possible. The nature of the halo accelerator is also not critical. A very large number of suitable halide accelerators, most of which are organic iodides, are disclosed in the aforementioned US patent No. 3,769,329. The reaction is usually carried out with a catalyst dissolved in a liquid reaction medium through which carbon monoxide gas is continuously bubbled. In US patent Me3769329 it is noted that the liquid reaction medium here can be any solvent compatible with the catalytic complex and that it can contain, for example, a pure reactant alcohol or a mixture thereof with the target carboxylic acid end product and/or esters thereof two compounds. The best solvent and liquid reaction medium for this method is the produced carboxylic acid itself. It can be, for example, acetic acid, to obtain which methanol undergoes carbonylation. In this case, the reaction medium usually contains rhodium, methanol, methyl iodide, methyl acetate, acetic acid and water. As stated in the above-cited patent, an important circumstance is that in order to ensure a sufficiently high reaction rate, the reaction mixture must contain a significant amount of water. In addition, this patent states that reducing the amount of water in the reaction medium leads to the creation of an ester product in contrast to the carboxylic acid. Indeed, in the application for the European patent 055618, the right to which has also been transferred to the company Mopsapiyuo Sotrapu, it is noted that in the reaction medium of a typical installation for the production of acetic acid in the manner under consideration, the water content, as a rule, is about 14-1595 (wt) . In the work (Niopk)ayeg apa degpep, Ipa. Epd., Spet., Rhod. Waves. YuOeu. 16, 281-285 (1977). it is also claimed that an increase in water from 0 to 1495 (wt.) increases the rate of the methanol carbonylation reaction. In the above-mentioned application 055618, it is noted that rhodium has a tendency to precipitate out of the reaction medium. This tendency takes on the most pronounced forms at the stages of distillation to separate the acetic acid product from the reaction medium, when the content of carbon monoxide in the catalytic complex decreases. The tendency of rhodium to precipitate from the reaction medium increases as the water content in this medium decreases. Thus, as follows from the statements in the US patent Mo3769329 and application 055618, to overcome the tendency of rhodium to precipitate, that is, to maintain the stability of the catalyst, the water content in the reaction medium must be quite large. Industrial acetic acid comes from the manufacturing company in dehydrated or nearly dehydrated ("glacial") form. Extraction of acetic acid in dehydrated or almost dehydrated form from a reaction medium with 14-1595 (wt.) water content, i.e. separation of acetic acid from water, requires considerable energy expenditure for distillation and/or other types of additional processing. Monsanto's basic method has received some improvements, for example, in the aforementioned US patent Mo3769329. Among them, in connection with the present invention, those improvements that allow this method to be carried out with amounts of water below 1495 (mass) are of interest. U.S. patents MeMe5001259, 5026908, 5144068, the rights to which were transferred in the usual order, and European patent Me0161874 B2 offer improved methods for the carbonylation of methanol, where the water content is maintained at a level well below 1495 (wt). According to these patents, acetic acid is produced from methanol in a reaction medium containing methyl acetate, methyl halide, and especially methyl iodide and rhodium, in catalytically effective amounts. These patents also disclose the surprising observation that catalyst stability and carbonylation reactor performance can be maintained at surprisingly high levels even at very low water contents, i.e., 495 (wt) or less, in the reaction medium (whereas conventional industrial practice requires approximately 14-1595 (wt.) of water) by maintaining in the reaction medium, together with a catalytically effective amount of rhodium, at least a limited amount of water, methyl acetate and methyl iodide, as well as a certain concentration of iodide ions in addition to the iodide content in the form of methyl iodide or another organic iodide . The iodide ion is present as a simple salt, with lithium iodide being preferred. According to the claims of these patents, the content of methyl acetate and iodide salts is an important parameter that affects the rate of carbonylation of methanol in the production of acetic acid, and especially at low water content. In general, in US patent Me5144068 and other patents related to this issue, in addition to the basic provisions, it is noted that high levels of methyl iodide are desirable (US patent Me5144068, Figs. 4, 16 and 22, Table 2, column 9, lines 41-54) . US patent Me5281751 discloses the use of methyl iodide in the reaction system, which gives high conversion rates in the acetic acid production system. When using relatively high concentrations of methyl iodide, methyl acetate, and iodide salt, surprisingly high catalyst stability and reactor productivity are obtained even when the reaction medium contains very small amounts of water. Thus, these patented methods make it possible to produce acetic acid at lower water concentrations than in previous known methods. US Patents MoMe5001259, 5026908, 5144068 and European patent Me0161874 B2 are incorporated herein by reference. However, when applying the method of methanol carbonylation at low water concentrations, other problems arose, and in particular, they are related to the fact that in such a low-water mode of the acetic acid production process, the formation of certain impurities increases. As a result, the acetic acid product produced by such low-water carbonylation is often deficient in permanganate time due to the presence of small amounts of residual impurities. Since the test for sufficient permanganate time is an important industrial criterion that this acid product must satisfy in many cases of practical application, the presence of impurities in it that reduce the permanganate time is undesirable. Spitivig,. "Assays Asia" Moishte At, p 56, 5" ed). This applies especially to some carbonyl compounds and unsaturated carbonyl compounds, in particular, acetaldehyde and its derivatives - crotonaldehyde and 2-ethylcrotonaldehyde (which are also called unsaturated impurities). But for permanganate time other known carbonyl compounds, such as acetone, methyl ethyl ketone, butyraldehyde and 2-ethylbutyraldehyde, are also affected. Thus, these carbonyl impurities affect the commercial quality and acceptability of the produced acetic acid. Even with a concentration of carbonyl impurities of only 10-15 x 109 parts, they will already significantly reduce the commercial value of the acetic acid product. As used herein, the term "carbonyl" refers to intermediate compounds that contain an aldehyde or ketone functional group and may or may not have unsaturation. In the article (Muaizop, Tpe Sama "m Rgosev5 Tog pe Rgodisiop oi Aseiys Asii, Spet. Ipa. (OekKeg) (1998) 75 Saiauvyv oi Ogdapis Neasiyop5, pp. 369-380) accelerated rhodium-catalyzed complexes have increased steady-state levels of rhodium-acyl products, which are able to form free acetaldehydes at a higher rate. An increase in the rate of formation of acetaldehyde can lead to an increase in the production of compounds that reduce permanganate. The chemical way in which crotonaldehyde, 2-ethylcrotonaldehyde, and other compounds that reduce permanganate are formed in the process of methanol carbonylation has not been determined exactly. According to one of the theories of the formation of crotonaldehyde and 2-ethylcrotonaldehyde impurities in the process of methanol carbonylation, these impurities are the result of aldol and cross-aldol condensation reactions starting with acetaldehyde. Since these pollutants theoretically originate from acetaldehyde, many known methods of controlling carbonyl pollutants have been based on the removal of acetaldehyde and acetaldehyde carbonyl derivatives from the reactor plant. To remove acetaldehyde and carbonyl derivatives, the most widely used treatment of acetic acid with oxidants, ozone, water, methanol, amines, etc. In addition, these methods could be combined with the distillation of acetic acid. The most typical purification operation is a series of successive distillations of the acetic acid product. Also known are methods of removing carbonyl impurities from organic streams by treating these streams with an amine compound, for example, hydroxylamine, which reacts with carbonyl compounds to form oximes, and subsequent distillation to separate the purified organic product from the products of oxime-forming reactions. But this method of processing the acetic acid product makes industrial processes more expensive. In the US patent Mo5625095 (authors Miga Yei A.) and PCT application Me PCT/O597/18711, publication Me MO098/17619, various methods of removing acetaldehydes and other impurities from the process of producing acetic acid with a rhodium catalyst are disclosed. All these methods are based on the extraction of unwanted impurities from the process streams to reduce acetaldehyde concentrations in the reactor plant. The above-described approaches made it possible to achieve some success in controlling the concentrations of carbonyl impurities in acetic acid obtained by the carbonylation of methanol. But the known methods of removing the source of contamination still do not solve the problem of contamination of the produced by carbonylation of methanol acetic acid with acetaldehyde and carbonyl impurities that are derivatives of acetaldehyde, in particular, crotonaldehyde and 2-ethylcrotonaldehyde. Therefore, there remains an urgent need for a method of controlling carbonyl impurities in the acetic acid product obtained by the carbonylation of methanol, which would be cost-effective and could be carried out without adding impurities to the acetic acid or additional high-cost processing steps. It was found that reducing the amount of methyl iodide can improve product purity profiles. The method proposed by this invention allows you to significantly reduce carbonyl pollutants, in particular, acetaldehyde and carbonyl pollutants derived from acetaldehyde. This method is based on the reduction of the formation of acetaldehyde, and therefore the formation of its derivatives, crotonaldehyde and 2-ethylcrotonaldehyde, and not on the removal of acetaldehyde and carbonyl impurities originating from acetaldehyde from the reactor. Thus, the beneficial effect of the method according to the present invention is associated with a change in the chemical part of the carbonylation reaction aimed at reducing the formation of acetaldehyde, crotonaldehyde and 2-ethylcrotonaldehyde, and not with additional equipment and process steps to remove these impurities after they have already been formed . The method according to the present invention also provides additional effects. One of them is that it allows the process of methanol carbonylation to be carried out in the mode of low water concentration without sacrificing the stability of the catalyst. The improved method does not require changes in the reactor and distillation equipment. The improved method reduces current distillation line equipment requirements, thus eliminating bottlenecks in the distillation and clearing the way for additional product yield. According to the present invention, a method of producing acetic acid is proposed by reacting methanol with carbon monoxide in a liquid reaction medium containing a rhodium catalyst, a catalyst co-accelerator stabilizer, which is an iodide ion stabilizer-co-accelerator catalyst, water, acetic acid, methyl iodide and methyl acetate, with subsequent extraction of acetic acid from the reaction product. Ionic iodide is obtained from any of a number of suitable soluble salts. It is clear that the important factor in such a catalytic complex is the concentration of iodide ions, and not the cations bound to iodide, and that at a given molar concentration of iodide the nature of the cations is not as significant as the effect of the iodide concentration. Any metal salt or organic cation salt can be used, provided that the selected salt is sufficiently soluble in the reaction medium to provide the desired iodide level. The iodide ion stabilizer co-accelerator may also be in the form of a soluble alkali metal or alkaline earth metal salt, or quaternary ammonium or phosphonium salt, which creates an effective amount of iodide ions in the reaction solution. Lithium, sodium and potassium iodides or acetates are particularly suitable. The improvement of this method consists in reducing the contamination of the acetic acid product with carbonyl impurities by maintaining in the reaction medium during the reaction: (a) water concentration from the limit of 0.195 (wt) to less than about 1495 (wt); (p) the concentration of a salt soluble in the reaction medium at the reaction temperature in an amount sufficient to maintain the concentration of ionic iodide in the range of about 2 to 2095 (w/w), which acts as a catalyst stabilizer and co-accelerator; (c) methyl iodide in a concentration of 595 (wt.) or less; (4) methyl acetate in a concentration of approximately 0.595 (wt) to 3095 (wt); and (is) a catalytically effective amount of rhodium. In general, said salt is a quaternary ammonium or phosphonium salt or a Group IA or Group PA metal salt of the Periodic Table of the Elements, which provides an effective amount of ionic iodide. A non-exhaustive list of suitable salts is given, for example, in Table. U.S. Patent No. 5,026,908 (authors of this article), the disclosure of which is incorporated herein by reference. The most acceptable salts are lithium iodide or lithium acetate. Methyl iodide in the reaction medium is maintained, as a rule, in an amount from about 1 to 595 (wt), and more often from about 2 to 495 (wt). The concentration of water in the reactor is maintained in the range of approximately 1.0 to 1095 (wt.) relative to the mass of the reaction medium. In the best embodiments, rhodium is present in the reaction medium in increased amounts of approximately 500 to 5000 x 10'Emas.h. A more typical range of the amount of rhodium in the reaction medium is approximately from 600 to 2000 x 10 Emas.part, and the most often used is from approximately 750 to 1500 x 10: bmas.part. Having achieved some success in the preliminary improvement of the chemical part of the carbonylation reaction and, in particular, in reducing the concentration of water during the reaction, the authors found that as the concentration of water decreases, carbonyl impurities and, in particular, acetaldehyde and carbonyl impurities derived from acetaldehyde, in particular crotonaldehyde and 2 -ethylcrotonaldehyde, sharply increase. Although the exact chemical pathway of formation of acetaldehyde, crotonaldehyde and 2-ethylcrotonaldehyde during the carbonylation reaction was not established, the authors concluded that the formation of these pollutants is a multifaceted problem. Indeed, other factors can also participate in their formation. In connection with the creation of this invention, it was found that the rate of generation of acetaldehyde is greatly influenced by the concentration of methyl iodide in the reactor. As it turned out, if the concentration of methyl iodide is maintained at levels below those specified in known technical solutions, and especially at low concentrations of water, the formation of acetaldehyde and its derivatives - crotonaldehyde and 2-ethylcrotonaldehyde - is sharply reduced. In known methods, the concentration of methyl iodide was maintained at a level of approximately 595 (wt.) or higher. But the authors quite unexpectedly found that maintaining the concentration of methyl iodide in the process of the carbonylation reaction at the level of approximately 595 (wt.) or lower allows to significantly reduce the formation of acetaldehyde, crotonaldehyde and 2-ethylcrotonaldehyde. Therefore, it is preferable if the methyl iodide is present in an amount less than about 595 (w/w). A typical homogeneous reactor installation, in which the method according to the present invention is used, consists of: (a) a liquid-phase carbonylation reactor, (b) a rapid distillation apparatus for light fractions, and (c) a column for the separation of methyl iodide and acetic acid. The carbonylation reactor, as a rule, is an autoclave with a stirrer in which the content of the reaction medium is maintained automatically at a constant level. The reactor is continuously supplied with fresh methanol, water in an amount sufficient to maintain its limited concentration (250 x 10 by mass and better if at least about 0.195 (by mass)) in the reaction medium, recycled catalytic solution from the base of the rapid distillation apparatus and recycled methyl iodide, methyl acetate and water from the upper shoulder of the column separating methyl iodide and acetic acid. A stripping device may be used for further treatment of the stream of condensed top dressing from the rapid distillation apparatus. The residue from the rapid distillation apparatus is again returned to the reactor. Carbon monoxide is continuously introduced into the carbonylation reactor and thoroughly dispersed in it. The gaseous stream of purge products is removed from the main part of the reactor to prevent the formation of gaseous by-products and to maintain the set partial pressure of carbon monoxide at a given total reactor pressure. The temperature and pressure in the reactor are regulated in conventional ways known to those skilled in the art. The crude liquid product is withdrawn from the carbonylation reactor at a rate sufficient to maintain a constant level in it and is transferred to the flash still between its bottom and top. In the rapid distillation apparatus, the catalytic solution is withdrawn in the form of a base stream consisting mainly of acetic acid, which contains rhodium catalyst and iodide salt together with smaller amounts of methyl acetate, methyl iodide and water, while the condensed overhead stream of the rapid distillation apparatus contains mainly thus, the crude product is acetic acid together with methyl iodide, methyl acetate and water. Some of the carbon monoxide, along with gaseous by-products such as methane, hydrogen, and carbon dioxide, leave the top of the flash still. The dry acetic acid product (1500 x 109h4 water) is obtained from the bottom of the methyl iodide and acetic acid separation column (it may also exit as a side stream near the base) and is sent to final purification, which can be accomplished by any method known to those skilled in the art. field and is not covered by the scope of this invention. The overhead from the methyl iodide-acetic acid separation column, which consists primarily of methyl iodide, methyl acetate, and water, is returned to the carbonylation reactor. In order to better illustrate this invention, several specific examples of its implementation are considered below. These examples do not have a limiting direction and should not be considered as defining the conditions, parameters and values that are only acceptable for the practical implementation of this invention. Examples 1-3 Continuous methanol carbonylation processes were carried out in the reactor setup described above, which included a stirred tank reactor, a flash light distillation apparatus, and a methyl iodide-acetic acid separation column. To demonstrate the effect of reducing the amount of methyl iodide on the formation of acetaldehyde, crotonaldehyde, and 2-ethylcrotonaldehyde, the reaction conditions in all of the following examples were the same except for varying the concentration of methyl iodide. The reaction conditions are given in Table 1. In each experiment, before recording data on contaminants, a stable state of the process was established by continuous control of the reactor operation with constant compositions and reaction conditions, as indicated in Table 1. Data were then collected and graphed for at least 12 hours to show that the carbonylation reaction was steady state. The results obtained in Examples 1-3 are shown in Table 1. It can be seen from this that the presented results were taken in the state of balanced masses for at least 12 hours in the stable mode of operation of the reactor. Each of the results according to Examples 1 and C represents a mass-equilibrium process. The results of Example 2 represent the average value of two mass-equilibrium working periods. The concentration of acetaldehyde in the reactor was measured to show that even when it exceeded the level of 500 x 10 h, operating the reactor at a concentration of methyl iodide of about 595 (wt) or less reduced the rate of further formation of acetaldehyde compared to the process at higher concentrations of methyl iodide. The rates of formation of acetaldehyde, crotonaldehyde and 2-ethylcrotonaldehyde pollutants were measured by the values of concentration and flow rate of raw acetic acid product of the reactor plant. This flow was the condensed upper shoulder of the rapid distillation apparatus, that is, the input flow of the methyl iodide and acetic acid separation column. The rate of formation of impurities was expressed as the output in moles for a certain period of time (5TU: vrase-ite uieii) of the formed carbonyl contamination per liter of hot fresh reaction solution in one hour (mol/l/h. X 1075). As can be seen from Table 1, as a result of maintaining the concentration of methyl iodide during the carbonylation reaction at the level of 595 (wt.) and better, if below this level, the rate of formation of acetaldehyde decreases significantly, and the rate of formation of unsaturated compounds - crotonaldehyde and 2- ethylcrotonaldehyde. With the amount of methyl iodide in the reactor at the level of 295, the amount of acetaldehyde formed 1 ev is 2/5 times less than at a methyl iodide concentration of 6.7 (wt), and the formation of unsaturated impurities is reduced by more than 4 times. This decrease in the rate of formation of acetaldehyde is reflected in Table 1 also as the ratio of the rate of formation of acetaldehyde to the rate of formation of acetic acid in various examples and, along with this, as the ratio of the rate of formation of unsaturated impurities to the rate of formation of acetic acid. The term "unsaturated impurities" in Table 1 refers to the sum of crotonaldehyde and 2-ethylcrotonaldehyde. Table 1. Results obtained in a continuous process!? НИ"?"Н"6"тЙ НЙ ТВТТИИТНЙКЩХОООООООВОВООСООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООООО. 6 | 66 (Condensed upper shoulder strap of the rapid lung removal| The rate of formation of unsaturated pollutants, mol/l/h, x fraction of vva | in It is quite clear that the examples of implementation of this invention given here do not in any way limit its scope and essence, which are fully covered by the invention and allow various modifications and variants of its implementation, which do not go beyond their scope, defined by the attached Formula of the invention. 1 The rates of formation of acetaldehyde and unsaturated impurities (the values of which are given in x 10: zmol/l/h.) were measured in the condensed upper run of the apparatus for rapid distillation of light fractions, which was directed to the column separating methyl iodide and acetic acid. 2 The reaction temperature was 1952C at a gauge pressure of 400 psig.