RU2383506C1 - Method for production of portland cement (versions) - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: method for production of portland cement includes production of portland cement clinker, containing tricalcium silicate, bicalcium silicate, tricalcium aluminate and four-calcium alumoferrite, sintering of initial cement raw mix, containing calcium, silica-alumina, ferriferous components and fluorine-containing mineralisator - fluorine-carbon-containing wastes of electrolytic production of aluminium in amount of 0.1-0.25 wt % as equivalent to fluorine from initial raw mix, cooling and grinding of clinker with gypsum. According to another version of invention, fluorine-containing mineralisator is represented by mixture of fluorite and above-specified wastes at their following content, wt % as equivalent to fluorine: specified wastes - 0.1-0.2, fluorite - the rest till content of fluorine in raw mix of 0.15-0.4 wt %. Specified wastes are represented by dust of electric filters or sludge of gas treatment, or flotation tailings of coal froth.

EFFECT: reduced specific consumption of fuel for clinker annealing, improved efficiency and prolonged overhaul life of furnace, efficiency of mills operation in process of clinker grinding, recycling of aluminium production wastes.

8 cl, 27 tbl, 5 ex

Description

The present invention relates to the production of building materials, specifically to a technology for preparing the initial cement raw material mixture, its sintering, followed by grinding of clinker and obtaining Portland cement.

The main redistribution of Portland cement production is firing before sintering of the components of the initial cement raw mix, containing mainly calcium, aluminosilicate and ferrous components. Depending on the requirements for Portland cement, and the composition of the main feedstock, various corrective active additives, including mineralizers, are introduced into the mixture.

Mineralizers are substances that are actively involved in the formation of clinker minerals during firing and are partly part of them themselves. As mineralizers in the cement industry, phosphogypsum, fluorite, sodium silicofluoride Na ₂ SiF ₆ , apatite Ca ₅ (PO ₄ ) ₃ F, gypsum, etc. are used.

Of the fluorine-containing mineralizers, fluorite CaF ₂ (fluorspar), the mineral containing 48.8% F and 51.2% Ca, has found the greatest industrial application. In cement production, fluorite is used with impurities, while the content of the main substance, calcium fluoride (CaF ₂ ) in the fluorine-containing mineralizer, can vary from 30 to 95 wt.%.

The prior art patent of the Russian Federation No. 2060979 known a method of manufacturing Portland cement and a method of manufacturing concrete and reinforced concrete products based on manufactured Portland cement (С04В 7/02, 09/29/1995), in which as a mineralizer used: calcium fluoride, calcium sulfate, silica gel phosphogypsum (see paragraph 12 of the claims).

Also known is the patent of the Russian Federation No. 2304562 a method of manufacturing a quick-hardening Portland cement and a method of manufacturing concrete based on it (С04В 7/42, 04/12/2005). This technical solution was chosen for the prototype (the closest analogue) as the closest in technical essence and the presence of similar features.

In the prototype method, the raw material mixture contains calcium, aluminosilicate and glandular components, includes sodium and potassium oxides, as well as calcium sulfates and calcium fluoride in the form of fluorite. The fluorite content in the feed mixture in terms of fluorine is 0.15-0.4 wt.%. The sulphates of the feed mixture are alkali and / or alkaline earth metal sulfates.

From the position of the proposed method in the method of the prototype, there are a number of disadvantages:

- the use of calcium fluoride in the form of fluorite or its ore is associated with additional costs for its purchase, which, in general, increases the cost of commodity Portland cement compared to the cost of the complete or partial replacement of fluorite with fluorocarbon-containing waste (FUS waste) from aluminum electrolytic production;

- taking into account the above requirements for the composition of fluorite and its ore, the raw material base of this type of mineralizer is significantly reduced;

- the disadvantages of the method of the prototype can also be attributed to the lack of heat entering the preparatory zone of the furnace with a gas-air fuel mixture. The absorption of thermal energy by the calcined material in the preparatory zones of the furnace is significantly higher compared to the sintering zone. As a result of the imbalance in the arrival and consumption of heat in the preparation zone of the furnace, the physicochemical processes in the clinker are not complete, and the resulting clinker may contain an increased amount of free calcium oxide.

The objective of the invention is to increase the technical and economic performance of clinker kilns and mills for grinding the resulting clinker, expanding the raw material base of fluorine-containing mineralizers.

The technical result when implementing the invention:

- reduction of specific fuel consumption for clinker firing;

- increase the productivity of the furnace;

- increase in the overhaul period of the kiln;

- improving the efficiency of the mills when grinding the resulting clinker;

- reduction in the cost of cement;

- Utilization of FUS-waste from the electrolytic production of aluminum.

The technical result is achieved by the fact that in the method for producing Portland cement, which includes the preparation of Portland cement clinker, which mainly contains tricalcium silicate 3CaO · SiO ₂ (C ₃ S), dicalcium silicate 2CaO · SiO ₂ (C ₂ S), tricalcium aluminate 3CaO · Al ₂ O ₃ (C ₃ A) and tetra-calcium aluminoferrite 4CaO · Al ₂ O ₃ · Fe ₂ O ₃ (C ₄ AF), sintering the initial cement raw material mixture comprising calcium, aluminosilicate, ferrous components and a fluorine-containing mineralizer, subsequent cooling and grinding of Portland cement clinker with plaster, as e fluorine-containing mineralizer use either fluorocarbon-containing waste from the electrolytic production of aluminum or a mixture of fluorite and fluorocarbon-containing waste from the electrolytic production of aluminum. Moreover, in the first embodiment of the proposed method, 0.1 ÷ 0.25 wt.% FUS-waste in terms of fluorine is added to the initial raw mix, and in the second embodiment of the proposed method, the total fluorine content in the initial cement raw mix is kept within 0, 15 ÷ 0.4 wt.%, With 0.1 ÷ 0.2 wt.% Fluorine coming from the use of FUS-waste, and the rest of the fluorine comes from fluorite. Moreover, as fluorocarbon-containing waste from the electrolytic production of aluminum, it is also possible to use separately the dust of electrostatic precipitators, or gas treatment sludge, or coal foam flotation tailings.

The technical essence of the invention is as follows.

1. The study of issues related to the theoretical justification and practice of using fluorine-containing mineralizers was carried out by many researchers both in our country and abroad. As a result, it was found that due to the introduction of small additives of fluoride salts into the raw material mixture, an increase in the reactivity of the raw materials components to different degrees at all stages of firing is observed. Fluoride salts during heating interact with calcium carbonate and give intermediate compounds such as double salts having relatively low melting points. Therefore, in the firing process, already in the preparation zones in the presence of fluoride compounds, materials interact with the liquid phase, which intensifies the interaction of lime, silica, aluminum oxides and iron.

A number of researchers have shown that the presence of fluoride compounds in conventional raw material mixtures leads to a change in the mineralogical composition of clinkers — high-iron aluminoferrites C ₈ A ₂ F and low-basic aluminates C ₁₂ A ₇ instead of C ₄ AF and C ₃ A appear. The formation of these compounds suggests that thus liberated free calcium oxide reacts with the dicalcium silicate c ₂ S to form additional amounts of tricalcium silicate c ₃ S. However c ₃ S content increases to 10-12%, improves sinterability granules and cement strength.

In laboratory and industrial conditions, the following fluorine-containing materials were successfully tested as mineralizers during clinker burning:

- technical cryolite - at Pikalevsky and Sukholozhsky cement plants;

- phosphorus-fluorine-containing slag - at JSC "Zhigulevsky building materials";

- aluminum fluoride - at the Novotroitsk cement plant;

- natural fluorspar (fluorite) - at the Angarsk, Gornozavodsky, Nevyansk cement plants.

Through the use of these fluoride salts, a reduction in specific fuel consumption for clinker burning was achieved, increased productivity of rotary kilns, improvement of the coating condition in the sintering zone, which allowed to extend the overhaul period of the kilns.

However, many natural mineralizers are scarce material, their use in factories is limited. Therefore, a large reserve of fluoride mineralizers is cheap technogenic products, for example, fluorocarbon-containing waste (FUS-waste) of aluminum electrolytic production. Over the decades of operation of aluminum plants, sludge fields have accumulated millions of tons of finely dispersed FUS-waste. These wastes represent a mechanical mixture of dust from electrostatic precipitators, gas cleaning sludge, and coal foam flotation tailings.

As already noted, according to the results of numerous scientific studies confirmed by industrial tests, it was found that under the influence of fluorine during firing the temperature of the formation of the liquid phase decreases and the formation of C ₃ S is significantly accelerated. Thus, studies on the use of fluorspar as a fluorine-containing mineralizer showed that both C ₃ S and C ₃ A exist in the presence of CaF ₂ , which may be part of C ₃ S.

At the same time, the fact of decomposition of C ₃ A was established when 5% CaF _{2 was} introduced at high temperatures. Also, at these concentrations, the effect of CaF ₂ on the compounds of a number of ferritic solid solutions was noted, accompanied by decomposition into C ₁₂ A ₇ and ferrite of a composition close to C ₆ AF ₂ (“Chemistry of Cements.” Building Literature Publishing House, Moscow, 1969, pp. .53). As a result of further studies, it was found that reducing the addition of fluoride mineralizer to 1-3% fluorspar ensures the assimilation of free lime at a lower temperature without the harmful effects of CaF ₂ on the mineralogical composition of clinker, and fluoride compounds remain in the clinker.

Thus, the positive effect of fluorine on the firing process is realized under the condition of the optimal content of fluorine-containing mineralizer. With optimal dosing into the raw cement mixture, finely dispersed FUS wastes from the aluminum industry can be considered a full-fledged alternative to natural fluorine-containing mineralizers. Laboratory studies, confirmed by pilot tests, allow us to recommend the introduction of FUS-waste in the initial cement raw material mixture in an amount of 0.1-0.25 wt.% In terms of fluorine when using only FUS-waste as a fluorine-containing mineralizer. When implementing the method, a mixture of fluorite and FUS-waste in the amount of 0.1-0.2 wt.% In terms of fluorine was used as a fluorine-containing mineralizer, while maintaining the total fluorine content in the mixture of 0.15-0.4 wt.%.

Below is the composition and characteristics of the proposed aluminum waste.

The composition and characteristics of dust electrostatic precipitators

The dust of electrostatic precipitators is represented by three main components: aluminum oxide, fluoride salts and carbon. In those plants where aluminum electrolysis is carried out with a reduced cryolite ratio, the dust of electrostatic precipitators is richest in fluorine (F = 18-23%). The poorest dust of electrostatic precipitators contains 13-15% of fluorine. The limits of the content of the main elements in the dust of electrostatic precipitators are presented in Table 1.

Table 1 The chemical composition of the dust of electrostatic precipitators, wt.% F Na Al Ca Mg SO ₄ Fe Si FROM Resin TO 13-23 9-13 9-19 0.4-2 0.1-1.1 1,5-4,5 1.0-2.1 0.07-0.3 20-34 3-8 0.5-1.5

The main dust of electrostatic precipitators is: aluminum oxide Al ₂ O ₃ , mainly α-modifications; fluoride salts, mainly cryolite Na ₃ AlF ₆ and chiolite Na ₅ Al ₃ F ₁₄ ; carbon C; resinous substances and sodium sulfate Na ₂ SO ₄ . The approximate phase composition of the dust of electrostatic precipitators is given in table 2.

table 2 The approximate content of basic compounds in the dust of electrostatic precipitators No. Name of compounds The content of compounds, wt.% one. Cryolite Na ₃ AlF ₆ 12.10 2. Chiolite Na ₅ Al ₃ F ₁₄ 11.00 3. Sodium Fluoride NaF 2.43 four. Aluminum fluoride AlF ₃ 0.71 5. Elpazolite K ₂ NaAlF ₆ 2.79 6. Fluorite CaF ₂ 1.48 7. Magnesium Fluoride MgF ₂ 1.36 8. Alumina Al ₂ O ₃ 30.90 9. Iron oxide Fe ₂ O ₃ 2.00 10. Silica SiO ₂ 0.45 eleven. Sodium Sulfate Na ₂ SO ₄ 4.08 12. Carbon C 26.73 13. Resinous substances 4.68

Dust of electrostatic precipitators is a fine waste, the average particle diameter of which varies from 10 microns to 25 microns. The approximate particle size distribution of the dust of electrostatic precipitators is presented in table.3.

Table 3 Granulometric composition of dust of electrostatic precipitators Fineness class, microns 0-1 1-2 2-3 3-4 4-6 6-8 8-12 12-16 16-24 24-32 32-48 48-64 64-192 d _cp 0 4.9 2,4 0 5.5 3.0 9.0 0 27.0 2,3 24.9 4,5 16.5 22.9 Class content, wt.%

The composition and characteristics of the gas treatment sludge

Due to the specifics of the formation of gas purification sludge, in comparison with the dust of electrostatic precipitators, it is enriched in fluorine, depleted in carbon and aluminum oxide. The limits of variation in the elemental composition of the gas treatment slurry and the approximate content of the main compounds in the slurry are presented in Tables 4, 5.

Table 4 The chemical composition of the gas treatment sludge, wt.% F Na Al Ca Mg SO ₄ Fe Si FROM Resin TO 17-25 15-23 12-22 0.5-1.5 0.2-1.0 3-8 1.0-2.1 0.1-0.5 20-30 3-8 0.5-1.5 Table 5 The approximate content of the main compounds in the sludge gas treatment, wt.% Na ₃ AlF ₆ K ₂ NaAlF ₆ NaAlCO ₃ (OH) ₂ Al ₂ O ₃ CaF ₂ MgF ₂ Fe ₂ O ₃ SiO ₂ Na ₂ SO ₄ FROM Resin 34.97 1.83 2.87 22.67 1,07 1.05 1,64 0.35 6.56 21.46 5.53

The basis of gas treatment sludge is fluoride salts, alumina (mainly α-modifications), carbon, resinous substances and sodium sulfate. Unlike electrostatic dust, gas treatment sludge does not contain chiolite, and some soda hydroalumocarbonate Na ₂ O · Al ₂ O ₃ · 2CO ₂ · nH ₂ O may be present in the sludge.

As a rule, the average particle size of the gas treatment sludge particles is close to or slightly smaller than the dust particle size of the electrostatic precipitators and ranges from 7-20 microns. The data on the particle size distribution of the gas treatment sludge are presented in Table 6.

Table 6 Exemplary particle size distribution of gas treatment sludge Fineness class, microns 0-1 1-2 2-3 3-4 4-6 6-8 8-12 12-16 16-24 24-32 32-48 48-64 64-192 d _cp 2,8 5.7 6.2 5.8 12,2 11.8 20.1 11.6 12.6 5,6 4.2 1,0 0.5 9.25 Class content, wt.%

The composition and characteristics of the flotation tailings

Dry tailings of coal foam flotation are finely divided black powder. In composition, the flotation tailings are a multicomponent mixture based on carbon, fluoride salts and alumina (Table 7).

Table 7 The chemical composition of the flotation tailings, wt.% Items The range of variation, wt.% Approximate composition, wt.% Na 4,5-7,0 6.0 Al 2.5-5.5 4.2 F 6.0-12.0 9.0 FROM 65.0-85.0 80.5 K 0.1-0.5 0.15 Sa 0.4-0.7 0.6 Mg 0.15-0.40 0.25 Fe 0.60-1.0 0.75 Si 0.10-0.25 0.15 S 0.15-0.60 0.45 Resinous 0.7-1.5 1,0

Note: The resinous substances in the flotation tailings are mainly represented by flotation reagents (kerosene + pine oil) used in flotation enrichment of coal foam.

X-ray phase studies of flotation tails showed that they have a very complex composition. Based on the complex of analyzes of the flotation tailings of coal foam, it was found that the main components are: graphite, cryolite, chiolite, weberite, β-alumina, fluellite, williomyite (Table 8); minor ones: gearxsuitite, fluorite, mayenite, sulfagolite, schererite, burkeite, sellait (Table 8); and impurities: hydrohematite (Fe ₂ O ₃ · nH ₂ O); rutile (TiO ₂ ); malladrite (Na ₂ SiF ₆ ); carobbyite (KF); gieratite (K ₂ SiF ₆ ); potassium cryolite (K ₃ AlF ₆ ) and elpazolite (K ₂ NaAlF ₆ ).

Table 8 The approximate content of primary and secondary compounds in the flotation tailings,% Components Connection Name Chemical formula Compound Content The main Graphite FROM 87.4 Cryolite Na ₃ AlF ₆ 5.62 Chiolite Na ₅ Al ₃ F ₁₄ 1.18 Weberit Na ₂ MgAlF ₇ 1.24 β-alumina Na ₂ O · 11Al ₂ O ₃ ; K ₂ O 11Al ₂ O ₃ 0.70 Fluellite Al ₂ (PO ₄ ) F ₂ (OH) 7H ₂ O 0.59 Williomite NaF 0.54 Minor Gearksuit CaAlF ₄ (OH) H ₂ O 0.34 Fluorite CaF ₂ 0.29 Mayenite Ca ₁₂ Al ₁₄ O ₃₃ 0.15 Sulfagolite Na ₆ (SO ₄ ) ₂ FCl 0.33 Shirerit Na ₂₁ (SO ₄ ) ₇ F ₆ Cl 0.31 Burkeite Na ₆ (SO ₄ ) ₂ CO ₃ 0.33 Sellait MgF ₂ 0.39

Studies of the dispersed composition of flotation tailings showed that the average particle diameter in the samples ranges from 35 microns to 75 microns. The size of the flotation tailings is determined mainly by the conditions of coal foam grinding. A typical example of the particle size distribution of flotation tailings is given in Table 9.

Table 9 Granulometric composition of the tailings of the flotation of coal foam Fineness class, microns 0-1 1-2 2-3 3-4 4-6 6-8 8-12 12-16 16-24 24-32 32-48 48-64 64-192 d _cp 1,2 3.2 3.6 2.7 4.8 3.8 5.3 3.9 6.4 5.3 8.1 7.3 42.8 53 Class content, wt.%

The data given in Tables 1–9 show that the basis for the use of FUS waste from the electrolytic production of aluminum is mainly with the exception of flotation tailings of coal foam, fluoride compounds and element oxides traditionally present in the feedstock for cement production. From the point of view of cement production, the new components of FUS-waste are carbon and resinous substances, which are not harmful components for the cement raw material mixture, as they burn out during the firing process, intensifying the clinker sintering process due to the addition of additional heat generated during the combustion of carbon and resinous substances.

It should be noted that as a result of firing the raw mix prepared both according to the first and second variants of the implementation of the proposed method, that is, when all fluorite or part of it is replaced with FUS-waste, a clinker of the same composition as when using natural fluorine-containing is obtained mineralizer - fluorite without the introduction of FUS-waste. The chemistry of the process of interaction of fluorine-containing components introduced with aluminum wastes and calcium oxide is described by the following main reactions:

- for cryolite component:

2Na ₃ AlF ₆ = 6NaF + 2AlF ₃

2AlF ₃ + 3CaO = 3CaF ₂ + Al ₂ O ₃

6NaF + 3CaO = 3CaF ₂ + 3Na ₂ O

2Na ₃ AlF ₆ + 6СаО = 6CaF ₂ + 3Na ₂ O + Al ₂ O ₃

- for chiolite component:

3Na ₅ Al ₃ F ₁₄ = 5Na ₃ AlF ₆ + 4AlF ₃

5Na ₃ AlF ₆ = 15NaF + 5AlF ₃

9AlF ₃ + 13.5 CaO = 13.5 CaF ₂ + 4.5 Al ₂ O ₃

15NaF + 7.5 CaO = 7.5 CaF ₂  + 7.5 Na ₂ O

3Na ₅ Al ₃ F ₁₄ + 21 CaO = 21 CaF ₂ + 4,5 Al ₂ O ₃ + 7,5 Na ₂ O

The above reactions are implemented in the temperature range of 650-1050 ° C, from which it follows that even before the clinker formation process begins, a significant part of fluorine is transferred from sodium fluoroaluminates to fluorite. It should be noted that sodium fluoride formed as a result of thermal dissociation of cryolite, before starting interaction with CaO, performs the function of a mineralizer, more effective than CaF ₂ (B.V. Volokonsky. Mineralizers in the cement industry. M., 1964). In general, the higher mineralizing ability of FUS wastes is due to the formation of a less viscous liquid phase at lower temperatures (compared with CaF ₂ ).

Thus, the firing of a cement raw material mixture containing FUS waste from aluminum production is more efficient than using fluorite, and the composition of the clinker obtained is similar to the composition of clinker obtained when fluorite is used as a fluorine-containing mineralizer.

2. When using FUS waste as an fluorine-containing mineralizer, the electrolytic production of aluminum, it is necessary to take into account the fact that an additional amount of alkali metals, mainly Na, in the form of fluoride salts is added to the waste. The minor constituents of Portland cement materials affect the properties of the product, mainly as a result of ionic substitution in the main phases. Taking into account the fact that fluoride compounds almost completely turn into clinker and all alkaline phases of clinker are not useful, the authors propose introducing FUS waste from aluminum production within certain limits into the initial cement raw material mixture, depending on the content of alkali metals in the feedstock choose the first or second embodiment of the proposed method.

Due to the huge volumes of FUS waste accumulated in the slurry fields of aluminum production plants, the FUS waste from sludge fields, which are a mixture of dust from electrostatic precipitators, gas cleaning sludge and flotation tailings of coal foam, will usually go to the cement industry for processing. But this does not exclude the possibility of separate processing of each of these types of waste. In this case, the newly generated waste will be involved in the processing, which will be removed from the process stream to an independent product.

The amount of introduced mineralizer - one or another type of FUS-waste or its composition - is determined based on the quality indicators of the main components of the initial cement raw material mixture. In the case of easily sintering the basic components of the charge (for example, chalk and clay), the amount of mineralizer introduced into the charge corresponds to the region near the lower declared limit (0.10-0.15 wt.% In terms of fluorine). Upon receipt of clinker from hardly sintered raw materials (marble, fuel ash, etc.), the addition of a mineralizer from FUS-waste will vary in the region of the upper declared limit (0.20-0.25 wt.% In terms of fluorine). It is also necessary to control the total alkali content in the clinker charge. In the case when it is necessary to introduce an increased amount of mineralizer, and the amount of alkali exceeds the permissible limits, it is proposed to use a combined mineralizer, including FUS-waste and fluorite.

With a high content of alkali metals in the feedstock, it is recommended to reduce the content of FUS waste, and the specific content of FUS waste from the intervals stated in the claims is determined individually for each specific production, taking into account the raw materials and technology used.

In the first embodiment of the method, the lower limit of the content of FUS waste - 0.1 wt.% In terms of fluorine - is determined, firstly, from the point of view of economic feasibility of implementing the proposed method. Secondly, laboratory confirmation has been obtained that even when using basic cement raw materials with a high initial content of alkaline and alkaline earth elements, the addition of gas purification sludge as the most saturated waste in the alkali metal part (15-23 wt.% Na, 0.5-1, 5 wt.% K), in an amount of 0.1 wt.% Allows you to get cement consumer quality. The upper limit of the content of FUS wastes (0.25 wt.%) Was also determined during laboratory tests for the similar raw materials mentioned above, but dust of electrostatic precipitators with a content of Na 9-13 wt.% And K 0.5-1 was used as an additive , 5 wt.%.

Exceeding the content of FUS-waste above 0.25 wt.% Reduces the consumer properties of cement due to the negative effects of alkali metals.

In the second embodiment of the method, the upper limit of the fluorine content is increased to 0.4 wt.%, Which is due to the fact that fluorite is less active compared to FUS-waste, a mineralizer, and also because alkali metal content is insignificant in natural fluorite impurities .

Practice has shown that with an increase in the fluorine content in the initial feed mixture above 0.4%, the setting time of cements is lengthened, which is undesirable, because leads to a decrease in early strength and tendency of cements to salt formation.

The compositional options for the chemical composition of FUS-waste with three variable types of waste (gas treatment sludge, electrostatic dust, coal foam flotation tailings), as well as combinations of the main components of the initial cement raw material mixture are endless. Therefore, for each specific cement production, each specific raw material processed at a cement plant, it is necessary to select not only the most optimal of the two proposed options for the implementation of the proposed method, but also, if possible, the optimal type of FUS waste. We repeat that in practice it is most likely to use FUS-waste from the sludge field, which is represented by a mixture of the three wastes listed above.

Below are specific examples of two options for implementing the proposed method using all possible types of FUS-waste.

3. As noted in RF patent No. 2060979, the main feature of the clinker firing process is its high fuel consumption: from 190 to 240 kg srvc. fuel / t clinker with wet and from 130 to 150 kg srvc. fuel / t clinker in the dry production method, and the absorption of thermal energy by the calcined material in the preparation zones of the furnace significantly exceeds the absorption of heat in the sintering zone. A significant amount of carbon (up to 85%) is present in aluminum production waste, especially in the tailings of coal foam flotation, as a result of which an additional energy source enters the preparation zone. Carbon combustion begins at a temperature of 450-500 ° C. This, firstly, reduces the energy intensity of the firing process as a whole, and secondly, increases the productivity of the furnace by increasing the length of the sintering zone.

A comparison of the proposed options for the implementation of the proposed method for producing Portland cement with the closest analogue (prototype) revealed the presence of a number of similar features:

- in both methods, the initial cement raw material mixture includes calcium, aluminosilicate and glandular components;

- both methods are aimed at optimizing the clinker formation process by introducing a fluorine-containing mineralizer into the initial raw cement mixture;

- in both methods, the target components of the clinker are mainly: tricalcium silicate, dicalcium silicate, tricalcium aluminate and tetracalcium aluminoferrite;

- in both methods, the resulting clinker is subjected to cooling, followed by grinding with gypsum;

- in both methods, a fluorine-containing mineralizer is recommended to be introduced within certain limits.

However, the proposed method differs from the prototype primarily by the presence of the variability of its implementation.

The first embodiment of the method is characterized by the following distinctive features from the closest analogue:

- as a fluorine-containing mineralizer use fluorocarbon-containing waste (FUS-waste) electrolytic production of aluminum;

- quantitative input of FUS-waste is regulated by the interval 0.1 ÷ 0.25 wt.% in terms of fluorine;

- as FUS-waste use dust of electrostatic precipitators, and / or gas treatment slurry, and / or coal foam flotation tailings.

The second embodiment of the method, in addition to the above features similar to the prototype, has the following additional similar feature:

- fluorine-containing mineralizer provides a fluorine content in the initial cement raw material mixture of 0.15 ÷ 0.4 wt.%.

The second embodiment of the method is characterized by the following distinctive features from the closest analogue:

- as a fluorine-containing mineralizer, a mixture of fluorite and fluorocarbon-containing waste from aluminum electrolytic production is used;

- quantitatively, the introduction of FUS-waste into the raw material mixture is regulated by the interval 0.1 ÷ 0.2 wt.% in terms of fluorine;

- as waste use dust from electrostatic precipitators, and / or gas treatment sludge, and / or coal foam flotation tailings.

The proposed technical solution is characterized by features similar to those of the closest analogue, and distinctive features, which allows us to conclude that it meets the patentability condition of "novelty."

A comparative analysis of the proposed technical solutions with known solutions in this field of technology in the search process for patent and scientific literature revealed the following:

- in the article "Achievements and Problems of Processing Industrial Wastes of Alumina and Aluminum Production", authors: V.A. Utkov, V.M. St. Petersburg, 2001) considers the problem of processing waste from primary aluminum production. But these authors focus on carbon-containing aluminum electrolysis wastes - spent coal lining of electrolyzers. Coal lining, together with dust, gas treatment slurries and flotation tailings of coal foam, is recommended to be used as slag-forming material in steelmaking in open-hearth furnaces and converters, to save fuel and improve product quality in the production of ceramic materials (brick, tile, etc.), in the production of secondary cryolite using carbon in rotary kilns and for partial replacement of coke in the manufacture of electrode products. The carbon-containing aluminum electrolysis waste in this article assigned the trademarks MIK-4M, MIK-SM. This new type of marketable product is recommended as a mineralizer for use in metallurgy and the production of building materials. This type of marketable product, as indicated above, basically consists of a battle of coal lining and is evaluated in the recommendations for use as a carbon source. In the claimed technical solution, it is proposed to use only finely divided waste from the electrolytic production of aluminum, the complex multicomponent composition of which can significantly change the physicochemical processes of clinker formation without impairing its quality;

- in the patent of the Russian Federation No. 2291208 "Method for producing granulated material" (СВВ 1/245, 2005.02.22), a method for preparing ores and concentrates for further processing, specifically the process of agglomeration of industrial raw materials, is stated. In the mixture containing the agglomerated material, the carbon-containing component and the flux, the flotation tailings of coal foam are added in an amount of 0.3-2.5%. Coal foam flotation tails allow partial replacement of fuel and flux;

- in the copyright certificate No. 979512 "Method for producing pellets of fluorspar" (С22В 1/243, 05.06.81) a method for producing pellets using dust from aluminum smelters, consisting of dust from electrostatic precipitators and gas treatment sludges, is stated.

The analysis showed that at the time of filing the application for the invention, no technical solutions were identified that are characterized by a combination of known and unknown features similar to the proposed solution, which indicates the compliance of the proposed technical solution with the condition of patentability of the invention “inventive step”.

Compliance with the patentability condition “industrial applicability” is proved by experimental data obtained during laboratory studies and industrial tests.

Example 1

Obtaining Portland cement clinker when using FUS-waste from the sludge field in an amount of 0.1-0.25 wt.% In terms of fluorine.

The initial cement raw material mixture was sintered in a laboratory tube resistance furnace at a mixture heating rate of 7 deg / min to a temperature of 1450 ° C and maintaining a slightly oxidizing atmosphere in the furnace (oxygen content 3-5%). Upon reaching the set temperature, the mixtures were kept for 15 min, after which they were cooled to room temperature.

The composition of the raw mix: limestone 79.5%, clay 15.7%, cinder 3.5%, high aluminate clay 1.3%, mineralizer FUS-waste from the sludge field in an amount of from 0.05 wt.% To 0.30 weight .% (tests were also carried out in a prohibitive interval to confirm the optimality of the moisture stated in the formula).

The resulting clinkers were ground together with gypsum in a laboratory mill with an identical sample of clinker = 1500 g, grinding time = 30 min, the same mill rotation speed and ball load.

The results of physical and mechanical tests of cements obtained from clinkers are given in table 15.

The optimal addition of fluorine-containing mineralizer in the form of FUS-waste is 0.1-0.25 wt.% In terms of fluorine. This ensures optimal clinker density, good grinding ability, normal setting time of cement, its high activity at all stages of hardening and a moderate degree of salt formation.

With a decrease in the amount of FUS wastes introduced into the raw material mixture less than 0.1 wt.%, The clinker density decreases, which negatively affects its grindability, cement setting time and its activity.

An increase in the amount of FUS wastes introduced into the raw material mixture over 0.25 wt.% Is impractical because this leads to clinker burning due to the formation of an excess amount of the liquid phase in the furnace. As a result, grindability also worsens and, as a result, the setting time of cement is lengthened with a decrease in its activity. In addition, the degree of salting out of cement increases, as well as the consumption of the mineralizer itself.

Example 2

Obtaining Portland cement clinker when using FUS-waste in the form of electrostatic dust, gas cleaning sludge, coal foam flotation tailings.

Prepared 4 raw mixes for the production of Portland cement clinker using basic raw materials, the amount and composition of which is identical to example 1 (table 10-13).

Raw mix 2.1: fluorite ore with a fluorine content of 18.2 wt.% Was used as a mineralizer. The main impurity components of the ore were CaCO ₃ and SiO ₂ .

Raw mix 2.2: dust of electrostatic precipitators of electrolytic aluminum production (PEF) was used as a mineralizer.

Raw mix 2.3: the slurry was used for gas purification of electrolytic aluminum production (SHGO) as a mineralizer.

Raw mix 2.4: tailings of flotation of coal foam of electrolytic aluminum production (HFUP) were used as a mineralizer.

The dust composition of electrostatic precipitators, gas purification sludge, and carbon foam flotation tailings are presented in Table 16.

The amount of mineralizer introduced into the raw material mixture in all experiments was the same and amounted to 0.15 wt.% In terms of fluorine.

Sintering of raw mixes No. 2.1-2.4 with various mineralizers was carried out in an industrial tubular rotary kiln with a diameter of 5.5 m, a length of 135 m, heated by natural gas. The average water content in the raw mix was 39.1 wt.%. When sintering the raw mix, according to operational technological indicators, the furnace was adjusted in terms of changing the productivity of the raw mix and the consumption of natural gas for the sintering process.

Some technological indicators of the furnace are given in table 17. The chemical and modular composition of the resulting clinkers is presented in table 18, 19.

Table 17 Comparative performance of the sintering furnace using various mineralizers Raw mix Medium produces. clinker furnaces, t / h Average specific gas consumption, m ³ / t clinker Average weight 1 dm ³ clinker, g No. 2.1 (CaF ₂ ) 51.5 171.5 1455 No. 2.2 (PEF) 52.3 170.0 1490 No. 2.3 (ShGO) 53.1 169.0 1495 No. 2.4 (HFUP) 52.0 168.5 1505

Replacing the mineralizer used in the prototype (raw mix No. 2.1, CaF ₂ ) with electrostatic dust (raw mix No. 2.2), gas cleaning sludge (raw mixture No. 2.3), coal foam flotation tailings (raw mixture No. 2.4), provides Portland cement clinkers almost identical composition with close modular characteristics (table 19). With the same fluorine content in the raw material mixture (0.15 wt.%), Replacing fluorite with FUS-waste leads to a slight increase in the content of Na ₂ O in clinker while reducing the content of free calcium oxide.

Table 18 The chemical composition of clinkers obtained using various mineralizers Raw mix F SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ Cao MgO SO ₃ K ₂ O Na ₂ O No. 2.1 (CaF ₂ ) 0.09 21.48 4.68 5.18 65.63 1.15 0.42 0.51 0.27 No. 2.2 (PEF) 0.08 21.45 4.79 5.01 65.56 1.15 0.42 0.52 0.30 No. 2.3 (ShGO) 0.09 21,20 5.00 5.35 65.48 1.15 0.42 0.52 0.31 No. 2.4 (HFUP) 0.09 21,20 5.00 5.35 65.48 1.15 0.42 0.51 0.30 Table 19 The modular characteristics of clinkers and the content of the main clinker minerals Raw mix Kn n p C ₃ s C ₂ S C ₃ A C ₄ AF CaO freedom No. 2.1 (CaF ₂ ) 0.94 2.17 0.90 67 10 3.6 16 0.12 No. 2.2 (PEF) 0.94 2.18 0.96 66 eleven 4.2 fifteen 0.10 No. 2.3 (ShGO) 0.94 2.05 0.93 66 10 4.2 16 0.08 No. 2.4 (HFUP) 0.94 2.05 0.93 66 10 4.2 16 0,07

Due to the stronger mineralizing properties of FUS wastes, in comparison with fluorite, roasting of the raw material mixture, ceteris paribus, provides on average (Table 17):

- increase the specific productivity of the sintering furnace by 1.9%;

- decrease in specific consumption of natural gas by 1.4%;

- an increase in the weight of a liter of clinker by 2.9%.

Example 3

Obtaining Portland cement clinker using a mixture of fluorite and FUS-waste

A combined fluorine-containing mineralizer, consisting of a mixture of fluorite and FUS-waste, can be used when the initial raw material mixture for the production of Portland cement clinker contains an increased amount of alkali, and the addition of a fluorine-containing mineralizer with a high sodium content does not allow to obtain a controlled clinker.

To confirm the above, we give the following example. Table 20 shows the calculation of the composition of the raw material mixture and the resulting clinker when using FUS-waste from the sludge field of an aluminum plant as a mineralizer, the composition of which is given in Table 14, introduced in an amount of 0.25 wt.% In terms of fluorine based on dry weight components of the raw mix.

Table 20 The composition of the starting materials, the raw material mixture and clinker, wt.% Components p.p.p. SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ Cao MgO F R ₂ O Ocher 0.17 1.12 0.49 0.22 0,07 0.06 - 0,07 Limestone 32.21 1,64 0.59 0.36 41.72 0.56 - 0.09 Clay 1.45 10.71 2,37 1.17 1,11 0.50 - 0.52 Fe sod. additive 0.06 0.46 0.11 0.76 0,07 0.01 - 0.02 FUS-waste 0.58 - * 0.28 - * 0.02 - * 0.25 0.18 Raw mix 34.47 13.93 3.84 2,51 42,99 1.13 0.25 0.88 Clinker 21.26 5.86 3.83 65.63 1.73 0.38 1.34 Note: * - the content of the compound is less than 0.01%; R ₂ O is the content of alkaline oxides in clinker.

Due to the fact that the initial raw material mixture (especially clay) contains an increased amount of alkali, the introduction of FUS-waste with a high alkali content into the mixture leads to the fact that the resulting raw material mixture and Portland cement clinker do not meet established standards for alkali oxide content (no more 1.20 wt.% R ₂ O in clinker).

In this situation, when the raw mixture requires an increased amount of mineralizer while limiting the alkali content, it is envisaged to use a combined mineralizer of FUS waste and fluorite.

Table 21 shows the calculation of the composition of the raw mix and the resulting clinker when using a combined mineralizer from FUS waste with a fluorine content of 19.5 wt.% In an amount of 0.10% and a fluorite concentrate CaF ₂ in an amount of 0.17% with a content of the main substance 92 wt.%.

Table 21 The composition of the starting materials, the raw material mixture and clinker, wt.% Components p.p.p. SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ Cao MgO F R ₂ O Ocher 0.17 1.12 0.49 0.22 0,07 0.06 - 0,07 Limestone 32.21 1,64 0.59 0.36 41.72 0.56 - 0.09 Clay 1.45 10.71 2,37 1.17 1,11 0.50 - 0.52 Fe sod. additive 0.06 0.46 0.11 0.76 0,07 0.01 - 0.02 FUS-waste 0.23 - * 0.11 - * - * - * 0.10 0,07 CaF ₂ Concentrate - * - * - * - * 0.21 - * 0.17 - Raw material charge 34.12 13.93 3.67 2,51 43.18 1.13 0.27 0.77 Clinker 21.14 5.57 3.81 65.54 1.72 0.41 1.17 Note: * - the content of the compound is less than 0.01%. R ₂ O is the content of alkaline oxides in clinker.

The initial raw material mixture prepared in accordance with the calculation according to table.21, meet the established standards (not more than 1.20% R ₂ O in clinker) and has the following modular characteristics: KN = 0.930; n = 2.25; p = 1.46. When sintering the mixture, the following mineralogical composition of clinker was obtained: C ₃ S = 65.1%; C ₂ S = 12.1%; C ₃ A - 7.9%; C ₄ AF = 11.6%.

Example 4

Obtaining Portland cement clinker using a mixture of fluorite and FUS-waste in the form of dust from electrostatic precipitators, gas purification sludge, coal foam flotation tailings

Raw mixes were prepared for the production of Portland cement clinker of the same composition using the following raw materials: marble and fuel ash of a thermal power plant + fluorine-containing mineralizer. Marble belongs to difficult to sinter materials, in addition, it contains a significant amount of undesirable impurities - oxides of magic, potassium and sodium and the inclusion of low reactivity silica. Fuel ash, unlike clay used in most plants, prevents the normal formation of granules in rotary kilns, which leads to increased dust removal from the furnaces, and unregulated dust return creates an instability of the clinker firing mode. In addition, significant fluctuations in the chemical composition of ash and the presence of inactive forms of silica in it are also an obstacle to obtaining high-quality clinker.

For such a raw material mixture, an increased amount of a fluorine-containing mineralizer is provided in order to provide better conditions for the interaction of the reacting phases. Given the significant content of alkalis in the components of the raw material mixture, it is possible to use only a combined fluorine-containing additive consisting of FUS-waste and fluorite as a mineralizer.

As FUS-waste, dust from electrostatic precipitators, gas purification sludge, coal foam flotation tailings, the composition of which are given in Table 16, were added to the raw material mixture. Fluorite is represented by a flotation concentrate with CaF ₂ content = 92%. The total amount of mineralizer was chosen taking into account that the raw materials used were difficult to sinter and amounted to 0.30 wt.% In terms of fluorine. Various compositional combinations of the combined mineralizer are given in table.22.

The use of a combined mineralizer from FUS-waste and fluorite provides the necessary conditions for the formation of clinker minerals in the process of firing the raw mix. However, when the content of FUS-waste in the mineralizer is less than 0.10 wt.% (Mixtures No. 1, 2. Table 22) in terms of fluorine, the overall mineralizing effect is reduced, which is expressed in an increase in the specific gas flow rate and a decrease in the sintering furnace productivity.

When the content of FUS-waste is more than 0.20 wt.%, The alkali content in the raw mix and clinker increases, and due to the formation of an excess amount of the liquid phase (due to the low melting point of the FUS-waste), there are risks of obtaining a burnt clinker, as well as the formation of diaphragms ( rings) on the inner lining of the furnace, which can lead to an emergency stop of the furnace.

Example 5

Industrial Test Results

Also, to confirm compliance with the patentability condition “industrial applicability”, we present the results of industrial tests conducted at one of the cement plants using fluorocarbon-containing waste from the Bratsk aluminum plant (BrAZ OJSC).

In January 2004, a pilot batch of clinker was released using fluorocarbon-containing waste from the slurry field of BrAZ OJSC as a mineralizer.

Fluorocarbon-containing waste was introduced into the raw material charge instead of natural fluorite. The composition of the prepared raw material mixture with FUS waste of BrAZ OJSC, given in Table 23, is practically no different from the composition of the raw material mixture with the addition of fluorite and, in terms of basic standardized indicators, meets the requirements of the Technological Regulations in force at a cement plant.

The raw material mixture was fired in rotary kilns with a diameter of 3.6 m and a length of 150 m. Representative clinker samples with different initial CaF ₂ contents were selected during the testing period. Subsequently, a study was conducted of the chemical composition and construction-technical properties of the resulting clinkers.

For comparison, Table 24 shows the results of a chemical analysis of clinkers with the introduction of a different amount (grade F) of fluorocarbon-containing wastes of BrAZ OJSC obtained at two industrial kilns No. 1 and No. 3, and the results of a chemical analysis of a clinker control sample using fluorite . From the data given in the table, it can be seen that clinkers with FUS wastes are quite close in chemical composition and are characterized by the following values of modular characteristics:

KN = 0.92-0.94 n = 2.07-2.13 p = 1.29-1.33

where KN is the saturation coefficient;

n is a silicate module;

p - alumina module.

The estimated content of the main clinker minerals was common for Portland cement for general construction purposes and varied within the following limits:

C ₃ S = 59-63%; C ₂ S = 10-14%; C ₃ A = 6.9-7.6%; C ₄ AF = 13%.

The content of free calcium oxide and iron oxide is negligible, which indicates a satisfactory burning of clinkers. The range of fluctuations in the content of these oxides amounted to:

CaO _cb = 0.09-0.31%; FeO = 0.07-0.28%.

It should be noted that clinkers with sludge from BrAZ OJSC had a higher bulk weight: 1630-1770 g / dm ³ , versus 1470 g / dm ³ for the control clinker, which indicates a denser granule structure due to the increased content of the liquid phase in the process sintering.

The study of the construction and technical properties of cements obtained on the basis of clinkers with sludge from BrAZ OJSC was carried out on laboratory grinding cements with the addition of gypsum in an amount of 2.5% in terms of SO ₃ . The fineness of cement grinding was evaluated by the residue on sieve No. 008 and the specific surface. The following results were obtained:

R ₀₀₈ = 7 ± 0.2%; S _beats = 3000-3130 cm ² / g

Physico-mechanical tests of the obtained cements were carried out in accordance with the requirements of GOST 310.1-76-310.3-76 and GOST 310.4-81 “Cements. Test Methods. " The test results are given in table.25.

An analysis of the results shows that the highest strength indicators have cements with sludge from BrAZ OJSC in the amount of 0.1-0.17% F (samples No. 2, 3, 5 and 6). At the same time, the strength indicators of these cements are quite close to those of the control cement (Table 25).

Tests have shown that an increase in the content of FUS-waste in the initial cement mixture above 0.25%, in terms of F, leads to a sharp decrease in both brand strength of cement and strength after steaming (TBO). The setting time of cements with both FUS-waste BrAZ and fluorite is quite significant (Table 26).

Table 26 Results of mechanical testing of cements Options Strength characteristics of cements, MPa Cements from the initial raw mix containing FUS-waste in an amount of 0.10-0.17% fluorine Control cement with fluorite in an amount of 0.17% by fluorine after TVO 25.5-30.1 27.7 after 3 days of normal. hard. 30.9-35 33.6 after 28 days of normal. hard. 47.8-50.9 50,0 start of setting, hour-min 4.3-5.45 4.4 setting time, hour-min 7.1-8.1 7.2

The setting time of cements using FUS wastes from aluminum production as a mineralizer is comparable with the same indices of the control sample (see Table 26). Longer setting times are typical for the plant where the tests were conducted. This is explained by the features of the main raw materials processed at this enterprise. For comparison, the setting time for cements of most cement plants is within: start - 2-3 hours; the end is 3-4 hours. Practice has shown that with an increase in the fluorine content in the initial feed mixture above 0.4%, the setting time lengthens, which is undesirable and has a retarding effect on hardening processes, especially in the first hours. This leads to a decrease in the early strength and tendency of cements to salt formation.

The degree of salt formation (K v _{/ v} ) of cements was determined by the known Hyprocement technique. According to this technique, the K _{/ V} value is the total content of calcium, sodium, and potassium oxides (mg / dm ³ ) in aqueous extracts from hardening cement slurry samples taken over 4 days. For the final result, which determines the tendency of cements to salt formation, the average value of the 3 values of K _{in / about is} taken. An analysis of the results showed that the degree of salt formation in cements with the addition of waste from BrAZ OJSC exceeds this indicator of the control sample by 10–16% (Table 27), but remains within acceptable limits. The reason for this, as noted above, was the slow hardening in the first 12 hours after the cement was mixed with water and, accordingly, the lower strength characteristics of cement in the early stages of hardening and its increased porosity. This facilitated the migration of water-soluble alkaline salts and Ca (OH) ₂ to the surface of the hardened cement stone and an increase in K _{/ V.}

Table 27 Dependence of salt formation on the addition of a mineralizer Sample Name To _{/ about} , mg / dm ³ With the introduction of FUS-waste in the amount of 0.17% by F 825-867 A control sample with the introduction of fluorite in an amount of 0.17% F 746

At a cement plant, where pilot tests of the proposed method according to the first embodiment were carried out, 600 thousand tons of Portland cement clinker were produced using FUS waste from electrolytic aluminum production as a mineralizer. Over 4 thousand tons of waste was recycled. The fluorine content in the waste was in the range of 15-18 wt.%

According to the current control of cement production, the introduction of waste additives in the raw mix varied from 0.10% to 0.25% in terms of F. Moreover, a slight increase in the content of alkaline oxides was observed in the composition of clinker - by 0.06-0.15% in comparison with clinker obtained using fluorite.

Based on the results of using FUS-waste from BrAZ OJSC in cement production, a feasibility study was carried out for the implementation of the measure, which showed the efficiency and feasibility of using aluminum production waste as a mineralizer.

Thus, by replacing fluorite with FUS-waste from the electrolytic production of aluminum in the raw material mixture for the production of Portland cement clinker, the following are ensured:

- effective disposal of FUS-waste from the electrolytic production of aluminum;

- reduction of anthropogenic pressure on the environment near aluminum smelters;

- expansion of the raw material base of fluorine-containing mineralizers to obtain Portland cement clinker with the replacement of scarce, traditionally used fluorite mineralizers;

- reduction of specific fuel consumption for clinker firing;

- increasing the productivity of the kiln;

- increase in the overhaul period of the kiln;

- a moderate degree of salification of the resulting cement;

- standardized strength indicators of cement throughout the curing period;

- reduction in the cost of cement.

Claims (8)

1. A method of producing Portland cement, including the preparation of Portland cement clinker, which contains mainly tricalcium silicate, dicalcium silicate, tricalcium aluminate and tetracalcium aluminoferrite, by sintering an initial cement raw material mixture comprising calcium, aluminosilicate, glandular, and fluoride-containing mineral compound and fluoride-containing cement clinker with gypsum, characterized in that fluorocarbon-containing waste elec is used as a fluorine-containing mineralizer the trolytic production of aluminum in an amount of 0.1-0.25 wt.% in terms of fluorine from the initial cement raw mix. 2. The method according to claim 1, characterized in that the dust of electrostatic precipitators is used as fluorocarbon-containing waste from the electrolytic production of aluminum. 3. The method according to claim 1, characterized in that as a fluorocarbon-containing waste from the electrolytic production of aluminum, gas treatment slurry is used. 4. The method according to claim 1, characterized in that the flotation tailings of coal foam are used as fluorocarbon-containing waste from the electrolytic production of aluminum. 5. A method of producing Portland cement, including the preparation of Portland cement clinker, which contains mainly tricalcium silicate, dicalcium silicate, tricalcium aluminate and tetracalcium aluminoferrite, by sintering an initial cement raw material mixture comprising calcium, aluminosilicate, glandular and fluoride-containing cementitious fluoride materials raw mix 0.15-0.4 wt.%, subsequent cooling and grinding of Portland cement clinker with gypsum, characterized in that as a fluorine-containing mineralizer present a mixture and fluorite ftoruglerodsoderzhaschih waste electrolytic production of aluminum at the following content of them in the original cement raw meal, the weight% based on fluorine.:
fluorocarbon-containing waste from aluminum electrolytic production 0.1-0.2 fluorite the rest is up to the indicated fluorine content 6. The method according to claim 5, characterized in that the dust of electrostatic precipitators is used as fluorocarbon-containing waste from the electrolytic production of aluminum. 7. The method according to claim 5, characterized in that as a fluorocarbon-containing waste from the electrolytic production of aluminum, gas treatment slurry is used. 8. The method according to claim 5, characterized in that the flotation tailings of coal foam are used as fluorocarbon-containing waste from the electrolytic production of aluminum.