RU2207995C2 - Method of manufacturing low water-demand cement - Google Patents

Abstract

FIELD: manufacture of building materials. SUBSTANCE: method consists in mechanic-chemical treatment, in particular common grinding to specific surface 400- 700 sq.m/kg, of Portland cement clinker with calcium sulfate ingredient and modifier, the latter including hardening accelerator and organic water-reducing agent. More specifically, Portland cement clinker is granulated product of cement raw mill firing comprising alkali metal sulfate and carbonate admixtures, which admixtures are fired in the form of hardened surface granules, drops, and leakages of anhydrous compounds and/or needles and joints of their crystal- hydrates joined during common grinding of the above-indicated ingredients to form salt phase of hardening accelerator in organic reagent in amounts 10 to 50% of the weight of the latter. Common grinding is effected at ratio of the above- indicated ingredients 100:(1-7): (0.6-2.5), respectively, until stoichiometric amount of alite phase in surface layer of cement clinker particles is attained. This moment and, correspondingly, grinding end moment is found from degree of aggregation of cement particles equal to 5-15 vol % at hygroscopic moisture no higher than 3%. Portland cement clinker may contain alkali metal compounds calculated as

Description

 The invention relates to the technology of building materials, mainly to obtain hydraulic binders, namely cements.

The prior art method for the manufacture of cement of reduced water demand by co-grinding Portland cement clinker and a modifier - a liquid substance that includes an organic component - technical lignosulfonate [1]. The main disadvantages of this technical solution include increased aggregation and lower flowability of the specified cement, especially with increased fineness of grinding, corresponding to the specific surface determined by the method of breathability on the instruments of Elaine, Lee-Parker, Sominsky-Khodakov, Tovarov, etc., about 400 m ² / kg and more. Increased aggregability and reduced flowability of cement cause difficulties in transporting and storing the latter both inside the manufacturer and when shipping this cement to the consumer, and after exposure to cement shocks of the vehicle and environmental humidity - difficulties are even more pronounced when unloading cement from the consumer from vehicles that increase the term of the latter under unloading, as well as during transportation and loading of cement to the consumer’s warehouse, and especially after x injuries in the indicated warehouse during transfer to dispensers over concrete mixing devices, leading to a decrease in metering accuracy, fluctuations in the composition of concrete and mortars, and ultimately to an increase in the coefficient of variation of the construction and technical characteristics of the latter, which, in accordance with the current Building Standards and Rules, leads to excessive consumption cement in the manufacture of these building materials to compensate for the increased dispersion of their properties and compliance with the required safety factors.

F₂(фтор)= f; Cl₂(хлор) = с, Н₂О=Н; K₂O=К; MgO=М; Na₂O=N; SiO₂=S;

коэффициент при оксиде в обычной химической формуле становится в сокращенной подстрочным индексом. Так, Са₃SiO₅=3CaO•SiO₂=С₃S и т.д.; тире или запятая между литерами в данной нотации означает переменное мольное отношение, т.е. отсутствие стехиометрии у данного соединения; кроме того, потери при прокаливании сокращенно обозначают п.п.п., а нерастворимый остаток - н.о.These disadvantages are less characteristic of the known method of manufacturing a binder of low water demand from Portland cement clinker, calcium sulfate ingredient, such as gypsum stone, and a dry modifier, including a cement hardening accelerator and an organic water-lowering reagent, by mechanochemical treatment by joint grinding of the listed ingredients to the specific surface of the specified cement about 400 m ² / kg [2]. However, in the manufacture of this cement based on Portland cement clinkers, including impurities of alkali metal compounds, mainly sodium and potassium, in an amount of more than 0.6 wt.%, Calculated on the equivalent content of sodium oxide, i.e. on R ₂ O = Na ₂ O + 0,658K ₂ O, these disadvantages are fully manifested. It should be noted that the scientific council of the X International Congress on Cement Chemistry in Gothenburg (Sweden, 1997) considered it appropriate to change the name of binders of low water demand in the text of the report read at the indicated congress on behalf of the authors, including the authors of the present invention name the latter as low water demand cements [3]. For their detailed characteristics, hereinafter in the description of the invention, a shortened notation of oxides, chlorine and fluorine, adopted in the chemistry of cement, is used: Al ₂ O ₃ = A; CaO = C; Fe ₂ O ₃ = F;

F ₂ (fluorine) = f; Cl ₂ (chlorine) = s, H ₂ O = H; K ₂ O = K; MgO = M; Na ₂ O = N; SiO ₂ = S;

the oxide coefficient in the usual chemical formula becomes an abbreviated subscript. So, Ca ₃ SiO ₅ = 3CaO • SiO ₂ = C ₃ S, etc .; A dash or comma between the letters in this notation means a variable molar ratio, i.e. lack of stoichiometry for this compound; in addition, the loss on ignition is abbreviated as ppt and the insoluble residue is n.o.

Closest to the invention (prototype) is a method of manufacturing cement of low water demand by mechanochemical treatment by joint grinding of Portland cement clinker, calcium sulfate ingredient and a modifier, including a hardening accelerator and an organic water-lowering reagent, to a specific surface of 400-700 m ² / kg, in which modifier before spray drying, i.e. first, a hardening accelerator is introduced, and thus the modifier previously contains in a dry state the corresponding chemical additive with a mass ratio of the latter and organic water-lowering reagent from 3: 7 to 7: 3 [4]. This somewhat reduces the above disadvantages, due to the increased tendency to aggregation and reduced flowability of the cement produced based on highly alkaline Portland cement clinker, which includes more than 0.6% R ₂ O, since it reduces the solubility of alkaline impurities - sulfates, alkali metal carbonates and others - in hygroscopic moisture cement during its grinding, as well as in the liquid phase of mortar and concrete mixtures of the specified cement due to the presence in these liquid phases of counterions from additives - accelerator tv glow of. However, it is not possible to avoid aggregation of particles of known low water demand cement made on the basis of Portland cement clinker, comprising more than 0.6% R ₂ O.

The objective of the invention is to increase the aggregate stability and flowability of cement of low water demand, made from alkali-containing clinkers, practically preventing its clumping and aging, i.e. loss of hydraulic activity during storage, at any possible, in practice, content in the specified cement of alkali metal compounds and even if it contains excess free lime (C _ST ). The solution to this problem is a significant technical achievement, stabilizing the properties of cement of low water demand based on any Portland cement clinker, in particular including more than 0.6 wt.% R ₂ O and / or free calcium oxide in the range of 1-2.5 wt.%. It should be noted that, using the known method (prototype), it is not possible to produce low water demand cement based on the latest clinkers.

This problem is solved by the fact that in the method of manufacturing cement of low water demand by mechanochemical processing by co-grinding to a specific surface of 400-700 m ² / kg of ingredients - Portland cement clinker, calcium sulfate ingredient and a modifier that includes a hardening accelerator and an organic water-reducing reagent, as specified Portland cement clinker uses a granular product of firing a cement raw material mixture, which contains impurities of sulfates and carbonates of alkali metals wherein said impurities are fired in the form of droplets and sag of anhydrous compounds and / or needles frozen on the surface of the granules of the specified product and their crystal hydrates intergrowths bonded during the joint grinding of these ingredients with an organic water-lowering reagent to form the salt phase of the hardening accelerator in an organic reagent in an amount of 10 - 50% by weight of the latter, and joint grinding is carried out with the ratio of these ingredients within the range of max. respectively 100: (1 - 7): (0.6 - 2.5) until stoichiometry of the alite phase in the surface layer of clinker particles of the specified cement is achieved, the moment of this achievement and, accordingly, the end of grinding is set by the criterion of the degree of aggregation of particles of the specified cement equal to 5 -15 vol.% At hygroscopic humidity of not more than 3 wt.%. Portland cement clinker may contain alkali metal compounds in terms of R ₂ O = Na ₂ O + 0.658 K ₂ O in an amount of 0.3 to 1.4 wt. % and sulfur trioxide compounds in an amount of 0.4 - 1.5 wt.%, as an organic water-reducing reagent, 0.6 - 2.5% by weight of Portland cement clinker is used materials from the group of salts of alkaline earth and / or alkali metals of the product of condensation of naphthalene sulfonic acid with formaldehyde or a condensation product of melamine-containing resins with formaldehyde; complex salts of alkaline earth metals and sulfuric and / or nitric and / or formic and / or acetic acids and low molecular weight monosaccharides with the number of C 3-5 atoms, paired mixtures of these materials in a mass ratio of 4: 1 to 1: 4, as calcium sulphate ingredient use two-water gypsum or a mixture thereof with semi-aqueous gypsum in wt. ratio from 1: 0.01 to 1: 2 or a mixture of two-water gypsum with anhydrite in wt. a ratio of from 1: 0.01 to 1: 0.2, or a mixture of two-water gypsum with chemical gypsum from the group of phosphogypsum, borogypsum, titanogypsum, fluorohydrite, the product of purification of flue gases from industrial furnaces and / or limestone reactors, taken in wt. in a ratio of 1: 0.05 to 1: 1, with hygroscopic humidity in an amount of 0.01 - 3 wt.%, an active mineral additive and / or filler are additionally added to the cement composition with joint or separate grinding, followed by mixing at mass. ratios of clinker, additive and / or filler 100: 5 to 100: 850 at hygroscopic humidity of 0.01 - 3 wt.%, as an additive, one or two components from the group of granulated blast furnace slag, fuel slag, fly ash, volcanic ash are used , pumice, tuff, quartz sand, feldspar sand, seeding from granite crushing, ore dressing tailings, cullet, brick fight, expanded clay or glass ceramic dust, or active silica from the group crushed or granular, or ground silicate block in an amount of 0.2 - 20% by weight of cement , silica fume in powder or granular forms in an amount of 0.2 - 10% by weight of cement, the granular form of silica fume containing plasticizing component introduced during granulation in an amount of 0.01 - 0.2%, calculated on the weight of cement.

The essence of the present invention is to use a new aspect of the interaction between the impurities of alkali metal and sulfur compounds by the cement clinker ingredient and the organic modifier water-lowering reagent in the process of mechanochemical activation of these ingredients during joint grinding. In a non-ground clinker, the surface layer of alite crystals (tricalcium silicate, C ₃ S) is characterized by a lack of calcium, or rather, a lower atomic Ca / Si ratio compared with the stoichiometric composition, as indicated by X-ray photoelectron spectroscopy (XPS), often called Auger spectroscopy by the name of the French physicist P. Auger who proposed this method (1925), given in table 1, column 3, line 1. The lack of calcium in the surface layer is also characteristic of other clinker phases - belite (C ₂ S) three lithium aluminate (C ₃ A) and aluminoferrite phase [C ₂ (A, F)]. Due to the indicated non-stoichiometry, which manifests itself in the presence of vacancies (Schottky defects) in the cationic sublattice of the crystal lattices of these clinker phases, in the initial states inside the clinker granules, the crystals of these phases are prone to interfacial aggregation, in which the individual phases are “crosslinked” by oxygen “bridges” that increase strength and microhardness of the clinker ingredient and hindering the grinding of cement.

After joint grinding of Portland cement clinker with a gypsum ingredient in the surface layer of alite, which is the main phase of ordinary Portland cement, on the contrary, an excess of calcium is detected, or rather, an increased value of the atomic ratio Ca / Si compared with the stoichiometric composition (table 1, column 3, line 2) . A detailed analysis of the infrared spectrum of the particles of finely ground cement shows that this excess is due to distortions during grinding of the forms of silicon-oxygen tetrahedra (SiO ₄ ^4- ) in the crystal lattice of tricalcium silicate, which facilitate the accelerated migration of Ca-O ion pairs to the surface of the particles of the cement clinker ingredient. In other clinker phases, these phenomena are observed on a smaller scale, and as a result, the composition of their surface layers in the grinding process approaches stoichiometric. Being essentially plastic deformations of the crystal lattice of alite and other phases at the molecular level, these phenomena, similar to premelting, lead to excessive absorption of the energy of grinding media during grinding and ultimately generate free electronic orbits of superstoichiometric calcium in the interstices of the crystal lattice interstices (Frenkel defects) , which are the basis of dislocation cores on the alite surface, visible under an electron microscope (adsorption tests show that it’s on these the nucleus with excess calcium against stoichiometric composition sorbed acidic surface-active compounds (surfactants) type of higher fatty acids, sulfonic acids, and the like with the group -COOH ^- and accordingly these nuclei are acceptors for electron pairs anionic groups (SO ₄₎ ^{2 -} , (СО ₃ ) ^2- and 2 (ОН) ^- from alkali sulphate, carbonate and hydrosulphate impurities on the surface of clinker particles. These acceptors at the moment of transfer of electron pairs and unpaired impurity electrons to the alite surface form aggregates of cement particles. The latter represent the basis for the initial stage of clumping and other negative phenomena mentioned above.

The presence of alkaline impurities in the clinker ingredient, which serve as accelerators for hardening mortars and concrete after mixing cement with water, and an organic water-lowering component in the modifier, when the clinker cement ingredient and the modifier are combined, changes the situation. It was established that an organic water-lowering reagent, penetrating deep into the crystal lattice of the alite of the clinker ingredient during the grinding process (this follows from a decrease in the intensity of the spectral signal from the aromatic groups of the specified reagent in the ultraviolet range) and forming bonds C (carbon atom from the specified reagent) - O (oxygen atom from alite), recorded on the spectra in the infrared range, inhibits the movement of Ca-O ion pairs to the surface of the alite phase, which prevents plastic deformations of the crystalline Alita lattice in the process of joint grinding of ingredients and reduces the energy consumption for grinding cement. Moreover, the presence on the surface of cement particles of highly ionized anionic groups (SO ₄ ) ^2- , (СО ₃ ) ^2- and 2 (ОН) ^- of the mentioned alkaline impurities of the clinker ingredient binds positively charged functional groups from molecules of an organic water-reducing reagent, preventing aromatic groups of the latter significantly deepen into the crushed particles of cement, which is possible in cement according to the prototype without the mentioned alkaline impurities in clinker. This creates a surface supersaturation of the alite chemisorption capacity with a water-lowering reagent, restricts the useful concentration of the latter in the mixture of ingredients from above, and when the specified reagent is temporarily introduced into the mixture of ingredients (i.e., in the mixture of grinding the specified cement) in excess of the excess of the specified reagent during the grinding of cement it is removed from the surface of this particle of the clinker ingredient and transferred to its other particles, where it takes part in the chemical interaction with the clinker ingredient m. At the same time, the coefficient of use of the organic water-reducing reagent is not only increased, its useful consumption in the composition of the specified cement is reduced, and the grinding of the latter is further intensified with an increase in the productivity of cement mills by 15-20%, but first of all, the shape of the cement particles changes, namely, the proportion of elongated particles decreases ( with a ratio of maximum to minimum size of more than 2-2.5) and the proportion of isometric particles (with a specified ratio in the range 1.1-1.3) in the composition of the specified cement increases. Elongated particles are known to promote aggregation and clumping of cement as a whole due to the concentration of electrostatic charges on their protruding parts [5]. Therefore, the indicated change in particle shape, visible in immersion preparations under an optical microscope, is an additional and very significant factor that reduces the initial level of cement aggregation and increases its flowability, as well as stabilizes its storage properties, i.e. reducing the rate of cement aging. This is especially important for those consumers who lay cement for long periods of storage and then use it without special means of mechanizing loading and unloading operations, namely when constructing buildings and structures in the Far North and the Far East of the country, as well as for building for defense purposes in remote regions countries. In the method according to the prototype, in contrast to the indicated, in addition to the inevitable excessive saturation by the organic of the inner zones of the particles of the clinker ingredient and the associated about twofold overspending of the organic water-lowering reagent - the most expensive of the ingredients of the grinding mixture, the reagent practically does not participate in the intensification of the grinding process and the aforementioned higher than the change in the shape of the particles of the specified cement, reducing their tendency to aggregation, clumping, etc.

The specified complex of phenomena in the manufacture of cement according to the invention leads to balancing the concentration of calcium, namely, increasing it compared to the original within the thickness of the surface layer of alite zones in the particles of the clinker ingredient, limited to fractions of a micron, i.e. several tens of unit cells of the alite crystal lattice (Auger spectroscopy sensitivity interval). The adsorption potential of the interaction between the following reagents: [acidic part of the organic water-lowering reagent] + [alkaline cations of the corresponding impurities of the surface of clinker particles] + [calcium vacancies in the alite lattice] can be calculated using a number of basicity of clinker minerals, major oxides and halogens, including the number of alkali metals, calcium, magnesium, silicon, aluminum, iron, sulfur, and phosphorus from [6]. Calculations show that the values of the indicated potential are sufficient only to eliminate calcium non-stoichiometry in the alite surface layer, which is observed experimentally (table 1, column 3, line 3). In the absence or at a low (less than 0.3 wt.%) Content of alkaline impurities in the clinker ingredient according to the prototype, the acid part of the organic water-lowering reagent is able to “draw” more calcium from the inner zones of the clinker ingredient than is necessary to eliminate the initial non-stoichiometry of the alite phase composition, and then excess calcium in the alite surface layer, in turn, increases the sorption of the indicated reagent, and this iteratively causes a new increase in calcium in the indicated alite surface layer of the clinker ingredient that, etc. The result is an excess of the calcium content in the alite surface layer over the stoichiometric (table 1, column 3, line 4) and the strengthening of the above disadvantages. Moreover, an excess of organic water-lowering reagent on the alite surface subsequently leads to a slowdown in alite hydration and a decrease in the initial cement strength. With a gradual increase in the specific surface area of the cement according to the invention, a sequential approximation of the composition of the surface layer of alite (tricalcium silicate) in the presence of an organic water-reducing reagent and alkaline impurities in the clinker ingredient during co-grinding to a stoichiometric for this phase is observed. This, as already mentioned, limits aggregation of finished cement, unlike cement without a modifier or from control cement with a modifier, but not containing alkaline impurities. It should be noted that the fact that the cement produced according to the invention does not have a transition of the calcium concentration in the surface layer through the stoichiometric level is evidence of the dissolution of alkaline impurities from the clinker ingredient in an organic water-lowering reagent during the mechanochemical activation of this pair of ingredients during joint grinding. However, for low-alkali cement (R ₂ O less than 0.4% of the mass of clinker) this is not significant: the degree of aggregation of low-alkali cement of low water demand according to the prototype does not exceed 20-25%, that is, higher than that of cement obtained according to the invention, but not so large as to prevent the flow of cement. And in the presence of alkaline impurities in larger quantities in terms of R ₂ O, the degree of aggregation increases to 30-40% and begins to impede the transport of cement and loading and unloading operations, and also complicates the storage of cement.

We also note that the content of the salt phase of the hardening accelerator falling into the composition of the specified organic reagent in the amount of 10-50% of the mass of the last of the impurities of alkali metal compounds in the clinker ingredient, precisely within the indicated limits, is due to the fact that, at a lower content, their effect on the action of this reagent slightly, and when the content exceeds the specified, the specific effect of this reagent on the atomic ratio Ca / Si in the clinker ingredient is significantly reduced, which was established using trial experiments on the enrichment of the specified organic reagent with alkaline compounds. As for the degree of extraction of impurities of alkali metal compounds from the clinker ingredient during the grinding process, having previously determined the content of sodium and potassium sulfates and carbonates in the latter completely passing into the specified reagent, it is possible to establish the content of the organic water-reducing reagent in cement, which is required to comply with the specified higher than the fraction of the mentioned alkaline compounds in it, and the estimated specific surface area of cement required for completeness of ab sorption of a specified amount of an organic water-lowering reagent, establishing after this experimentally observed, as a rule, compliance of the indicated technological parameters with a minimum degree of aggregation of the specified cement. Exceptions to this rule are possible only if the clinker ingredient is clearly not burned and contains more than 3% by weight of the marginal phases: RC ₈ A ₃ , C ₂ F, CF, RF, RA. Such Portland cement clinkers are not applicable for the manufacture of cement according to the invention.

It follows from the foregoing that the first novelty element of the present invention is the use of a new phenomenon in the method of manufacturing said cement — changes in the Ca / Si atomic ratio in the surface layer of the alite phase of a cement clinker ingredient in the process of joint grinding of said ingredients with the approximation of the said ratio to the equilibrium stoichiometric in the presence of the specified reagent due to the mentioned dynamic absorption equilibrium, taking into account the presence and dissolution in organic m dewatering reagent impurities alkali metal compounds from the clinker ingredient of said cement during premelting contacting pair of surfaces - the clinker ingredient as the main part and of said reactant as the acid part - at the level of dispersion of said cement, since the specific surface area of 400 m ² / kg or higher , and establishing at the time of equilibrium the minimum degree of aggregation of the specified cement.

 The second novelty element of the present invention is the ability to manufacture cement of low water demand based on highly alkaline clinker, without overspending organic water-reducing reagent, i.e. when its content is not more than 2.5%, unattainable with the prior art, when an organic water-lowering reagent in the amount of up to 3-4% of the mass of the clinker ingredient has to be added to the cement composition to provide reduced water demand. And this is economically unacceptable, since a decrease in the consumption of the specified cement in concrete in comparison with the control cement does not cover the additional costs of the specified, excessively increased consumption of the organic water-reducing reagent in the cement and due to the corresponding increase in the price of the specified cement.

The third element of the novelty of the invention is the selection by criterion of the minimum degree of aggregation of cement of low water demand in the process of grinding it at once three technological parameters:
- optimal grinding time, corresponding to the achievement of stoichiometry of the surface layer in the alite phase of the clinker ingredient;
- the optimum specific surface area of cement of low water demand, corresponding to the completeness of surface coverage with the present amount of organic water-reducing reagent, which corresponds to the maximum achievable degree of stabilization of the aggregative state of cement for a given content of alkaline impurities in the clinker ingredient, i.e. the absence of clumping of the specified cement during its storage during the warranty period, but not less than 12 months;
- the optimal concentration of organic water-lowering reagent in the composition of cement with alite in the clinker ingredient of this abortion tank; excess organic water-lowering reagent at a given specific surface is removed during grinding with aspiration air; therefore, by reducing the dosage or the corresponding concentration of the specified reagent using continuous dosing, you can adjust the content of the latter in the composition of cement, bringing it closer to the optimal iterative method. The above ratio of clinker, sulphate-calcium ingredients and modifier 100: (1-7): (0.6-2.5) taking into account the content (wt.%) Of the indicated clinker ingredient of impurities of alkali metal compounds in terms of R ₂ O about 0.3-1.4 and sulfur trioxide compounds about 0.4-1.5 corresponds to the optimums selected by the above iterative route.

 Embodiments of the invention provide improved properties of the low water demand cement produced according to the invention, characterized by a low degree of aggregation or completely disaggregated.

In an embodiment of the invention, the salts of mono- or divalent metals of the condensation products are selected as the indicated organic water-reducing reagent: naphthalenesulfonic acids and / or melamine-containing resins with formaldehyde; complex salts of alkaline earth metals and sulfuric, nitric, formic or acetic acids with low molecular weight C ₃ -C ₅ monosaccharides, paired mixtures of these materials in a mass ratio of about 4: 1-1: 4, introduced in an amount of 0.6-2.5% of the mass clinker with the selection of their optimal content using any method, for example, petrographic analysis. Moreover, the above iterative method for selecting the composition of the charge of the grinding is supplemented by any other of the methods for selecting the content of the organic water-reducing reagent in the charge of the mixture, including the method of petrographic analysis. This refers to the well-known position from the work [3] on the advisability of the absence in the finished cement of low water demand of an organic water-reducing reagent in a free state. Due to the characteristic spherical shape of the particles of the specified reagent obtained in spray drying devices, these particles are easily detected in the finished cement in immersion preparations using petrographic analysis. In the presence of such a reagent in a free state, it is advisable to reduce its concentration in the mixture of grinding. The experiments of the authors of the present invention show that the optimal levels of the specified reagent, namely, iteratively selected with the specified criterion for the degree of aggregation and the method of petrographic analysis with the criterion for the absence of free organic water-reducing reagent under an optical microscope, practically coincide with the important difference that the second of these optical microscopic methods are not suitable for continuous monitoring of production, while the first with criteria for the degree of aggregation of cement that - it is tested and suitable for industrial quality control of the specified cement.

 The degree of aggregation of the specified cement is determined using a device for determining the specific surface of cement by the method of air permeability, moreover, the cuvette of the specified device is used as the mentioned capacity. For this, the specific surface area of cement is previously determined in a separate sample of cement. Then, based on the known value of the last count, the thickness of the cement layer in the cuvette of the device is calculated after free placement of the cement under the influence of its own weight by shaking (aggregated state) and after compaction by pressing until complete disaggregation when the porosity of the powder layer is about 50 ± 2 vol.%. The degree of aggregation in fractions of a unit is considered to be the deduction from the unit of the ratio of the height difference in the disaggregated compacted and aggregated states of the cement layers. In more detail, with calculation formulas, information on determining the degree of aggregation is given in the description of an example of the use of the invention. From the data given in Table 1, it follows that there is indeed a strict correlation between the approach to the stoichiometry of the Ca / Si atomic ratio in the alite phase of the clinker ingredient according to Auger spectroscopy and the degree of cement aggregation: the closer to three, i.e. stoichiometrically the required value for the alite phase of the clinker ingredient indicated atomic ratio, the lower the degree of aggregation of cement, including the specified clinker ingredient. This natural dependence is manifested in the presence of any of the types of organic water-lowering reagent, calcium sulfate ingredient, and additionally active mineral additives and / or fillers mentioned in the variants of the invention. It is not fully manifested when the hygroscopic humidity of the mixture of grinding is more than 3 wt.%, Which should not be allowed when using the method of manufacturing the specified cement according to the invention.

It should be noted the use, along with the degree of aggregation, of such physical and mechanical characteristics of the specified cement as flowability. The flowability index is defined as the velocity of the powder in m / s under a pressure of 1 Pa, or the surface area in m ² , which can be covered in 1 s with a powder mass of 1 kg at the specified pressure. Details of the methodology for determining this indicator are set forth in an example embodiment of the invention.

 The significance of the present invention is emphasized by the fact that the maximum degree of disaggregation of cement particles achieved during its implementation prior to its mixing with water determines the maximum area of interaction of cement with water immediately after mixing in the construction mortar and concrete mixtures. This ensures that it is not necessary or advisable to use special techniques in the technology of mortars and concretes related to the so-called activation of cement, which are essentially exactly the disaggregation of deliberately aggregated cement in mixing water by mechanical action on cement-water systems. Excluding these technological methods, reducing the consumption of the specified cement in mortars and concrete, as well as reducing the duration or eliminating the heat and moisture treatment of concrete and reinforced concrete products and structures, consumers achieve significant technical and economic advantages using cements made according to the invention, compared with those known from prior art.

 The invention becomes clearer from an example of its implementation.

Example. For the manufacture of a binder of low water demand by the proposed method, the following starting materials are used:
clinker ingredient (CI):
KII: chemical composition, wt. % on major oxides: SiO ₂ 20.99; Al ₂ O ₃ 5.82; Fe ₂ O ₃ 4.75; CaO 64.25; MgO 1.79; SO ₂ 0.63; R ₂ O 1.08; including K ₂ O 0.84 and Na ₂ O 0.53; sum 99.31; silicate modulus n = S / (A + F) = 1.99; alumina module p = A / F = 1.23, lime saturation coefficient (KH) according to V.A. Kindu = (C-1.65A-0.35F) / 2.8S = 0.90; the content of the remaining small components: Li ₂ O≅0, BaO 0.049, SrO 0.002, NiO 0.025, CoO 0.02, Mn ₂ O ₃ 0.09, Cr ₂ O ₃ 0.12, MoO2 0.015, TiO ₂ 0.18; P ₂ O ₅ 0.19, Cl ₂ O, F2 0.N.O .: 0.28. The calculated mineralogical composition of the average sample, wt.%: C ₃ S 56, C ₂ S 18, C ₃ A 7.4, C ₄ AF 14.4, impurities - the rest;
KII: chemical composition, wt.%: On the main oxides: SiO ₂ 21.80; Al ₂ O ₃ 5.29; Fe ₂ O ₃ 5.09; CaO 65.35; MgO 1.1; SO ₃ 0.38; R ₂ O 0.32; including K ₂ O 0.3 and Na ₂ O 0.12; the sum of 99.33, n 2.10; p 1.04; KN according to V.A. Kind: 0.90; the content of the remaining small components: Li ₂ O≅0, BaO 0.07, SrO 0.002, NiO 0.031, CoO 0.02, Mn ₂ O ₃ 0.095, Cr ₂ O ₃ 0.188, MoO 0.054, TiO ₂ 0.02, Ws 0 , 19, Cl 0, F ₂ 0. I.O .: 0.16. The calculated mineralogical composition of the average clinker sample, wt.%: C ₃ S 58, C ₂ S 19, C ₃ A 5.4, C ₄ AF 15.5, impurities - the rest;
KIIII: chemical composition, wt.%: On the main oxides: SiO ₂ 23.59; Al ₂ O ₃ 3.55; Fe ₂ O ₃ 3.39; CaO 66.19; MgO 0.83; SO _∈ 0.74; R ₂ About 1.38; including K ₂ O 0.96 and Na ₂ O 0.75; the sum of 99.67, n 3.4; p 1.05; KN according to V.A. Kind: 0.90; the content of the remaining small components: Li ₂ O≅0, BaO 0.03, SrO≅0, NiO 0.01, CoO 0.01, Mn ₂ O ₃ 0.03, Cr ₂ O ₃ 0.09, MoO 0.02 , TiO ₂ 0.02, P ₂ O ₅ 0.12, Cl ₂ 0, F2 0. I. about. : 0.57. The calculated mineralogical composition of the average clinker sample, wt.%: C ₃ S 63, C ₂ S 20, C ₃ A 3,7, C ₄ AF 10,3, impurities - the rest.

 These clinkers were obtained by calcination before sintering in rotary kilns of cement raw materials based on limestone, clay and a glandular component, including alkali metal compounds - sodium and potassium, as well as small components, which are also part of the granular calcination product - Portland cement clinker.

Calcium Sulphate Ingredient (SI):
SII: gypsum stone, including, wt.%: Two-water gypsum 98.8; impurities - the rest;
CII: a mixture of gypsum stone, including, wt.%: Two-water gypsum 98.8, impurities - the rest, with a product of purification of exhaust sulfur dioxide from industrial furnaces with limestone, including, wt.%: Anhydrite 94.4, semi-aquatic gypsum 1.8, carbonate calcium 3,5, other impurities - the rest, taken in wt. 1: 1 ratio.

Modifier (M), including an organic water-lowering reagent
MI: sodium salt of the product of the condensation of naphthalenesulfonic acid with formaldehyde (plasticizer C-3);
MII: sodium salt of the condensation product of melamine-containing resins with formaldehyde (plasticizer 10-03);
MIII: a mixture of the sodium salt of the condensation product of naphthalenesulfonic acid with formaldehyde (C-3 plasticizer) and a complex salt of calcium and nitric acid with low molecular weight C ₃ -C ₅ monosaccharides, taken in wt. 1: 1 ratio.

Mineral additives: active, 1 - of natural origin:
IA: volcanic ash: p.p.p. 7.42; SiO ₂ 63.38; Al ₂ O ₃ 4.52; Fe ₂ O ₃ 14.40; CaO 2.43; MgO 1.04; SO ₃ 0.67; Na ₂ O 4.19; K ₂ O 1.95;
IB: tuff composition: p.p.p. 9.31; SiO ₂ 64.22; Al ₂ O ₃ 11.77; Fe ₂ O ₃ 1.95; CaO 6.68; MgO 0.92; SO ₃ 1.51; impurities of Na ₂ O and K ₂ O - the rest;
IB: composition pumice: 4.62; SiO ₂ 69.43; Al ₂ O ₃ 12.69; Fe ₂ O ₃ 2,52; CaO 6.70; MgO 0.98; SO ₃ 0.63; impurities of Na ₂ O and K ₂ O - the rest;
II - artificial origin:
IIA: blast furnace granulated slag composition: pp 0.36; SiO ₂ 31.75; Al ₂ O ₃ 10.63; Fe ₂ O ₃ 2.12; MnO 0.30; CaO 50.90; MgO 1.24; S (sulfide ion) 2.09; SO ₃ 0.30;
IIB: ash - ablation of a thermal power plant composition: p.p.p. 0.79; SiO ₂ 30.45; Al ₂ O ₃ 28.25; Fe ₂ O ₃ 13.01; CaO 3.23; MgO 1.59; Na ₂ O 0.74; K ₂ O 0.15; SO ₃ 0.50; TiO ₂ 1.29;
IIB: ash - slag of a thermal power plant composition: p.p.p. 1.16; SiO ₂ 49.24; Al ₂ O ₃ 26.69; Fe ₂ O ₃ 17.53; CaO 2.51; MgO 0.55; Na ₂ O traces; K ₂ O 0.43; SO ₃ 0.77; TiO ₂ 1.13;
mineral additive: III - filler:
IIIA: quartz sand composition: pp 0.23; SiO ₂ 98.07; Al ₂ O ₃ 0.32; Fe ₂ O ₃ 0.28; CaO 0.71; MgO 0.12; SO ₃ 0.18; Na ₂ O 0.05; K ₂ O 0.04;
IIIB: feldspar sand composition: p.p. p. 1.12; SiO ₂ 68.65; Al ₂ O ₃ 15.09; Fe ₂ O ₃ 3.87; CaO 1.91; MgO 0.60; SO ₃ 0.43; Na ₂ O 2.50; K ₂ O 5.83;
IIIB: crushing and sowing waste, fraction less than 7 mm, granite of the following chemical composition: 0.24; SiO ₂ 78.53; Al ₂ O ₃ 10.69; Fe ₂ O ₃ 3.67; CaO 1.92; MgO 0.68; SO ₃ 0.43; Na ₂ O 1.78; K ₂ O 2.06;
IIIГ: tailings of enrichment (quartzite composition) of an iron ore deposit from a mining and processing plant of the following chemical composition: p. 1.34; SiO ₂ 73.12; Al ₂ O ₃ 0.71; Fe ₂ O ₃ 19.06; FeO 2.55; CaO 1.16; BaO 0.17; MgO 0.52; SO ₃ 0.03; Na ₂ O 0.58; K ₂ O 0.76;
mineral additive: IV - active silica:
IVA: ground silicate block;
IVE: silica fume in granular form: dust trapped from the exhaust gases of ferroalloy furnaces, granulated by the addition of technical lignosulfonates - sodium salt, introduced in an amount of 20% by weight of silica fume.

When implementing the method according to the invention in the first series of experiments, the physicomechanical characteristics of cements are determined in laboratory grinding samples, which are carried out in a two-chamber mill of periodic action lined with cast iron armored plates with the dimensions of each chamber: length 0.28 m, diameter 0.5 m, frequency rotation 48 min ^-1 , drive power 1.1 kW, engine speed 930 min ^-1 , grinding load on 1 chamber (with 10 kg clinker mounted in each chamber): balls ⌀ 60 mm approx. 6 kg, ⌀ 50 mm approx. 8 kg, ⌀ 40 mm approx. 8 kg, ⌀ 30 mm approx. 8 kg, tsilpebs ⌀20 mm • L 32 mm 25 kg, total 55 kg. Before weighing, the clinker is crushed to a fraction of 1-2 mm in a laboratory jaw crusher.

In the second series of experiments, cement grinding is carried out under production conditions. Clinkers of various chemical and mineralogical composition obtained are selected and stored, and they are milled in a pipe mill measuring 3.2 • 12 m (diameter • length), operating in an open cycle, three-chamber, with chamber lengths 1 _I = 3,525 m, 1 _II = 1.758 m, 1 _III = 5.78 m, with a living cross-section of 0.7, 3 and 1.5%, respectively, of the cross-sectional area of two inter-chamber partitions and the output grate with the following grinding load: I chamber: balls with a diameter of 80 mm - 11 t, 70 mm - 14 t, 60 mm - 11 t, total 36 t; II chamber: balls with a diameter of 60 mm - 2 t, 50 mm - 7 t, 40 mm - 10 t, 30 mm - 8 t, a total of 27 t; III chamber: cylinders with dimensions (diameter • length), mm: 12 • 25 - 54 t, 16 • 16 - 9 t, 12 • 12 - 4 t, a total of 67 t, total grinding load - 130 t.

The average grinding fineness of the obtained samples of the specified cement was 6-8% of the residue on a sieve with cells of 45 μm, with a specific surface in the range of 448-462 m ² / kg by the method of breathability.

 Determining the degree of aggregation and flowability of the specified cement is carried out on a device of the Sominsky-Khodakov system (type PSX-2) based on the mentioned approach according to the techniques described in [7].

 Other equipment, instruments, and devices for assessing the physicomechanical properties of the specified cement are standard ones used for the preparation and testing of control samples from standard cement dough and mortar.

The test results in the manufacture of the specified cement according to the invention in the first and second series of experiments are presented in table 2. The data obtained indicate that:
1. The cement obtained according to the invention is characterized by a low level of particle aggregation (less than 10 vol.%), Increased flowability at an economical expenditure of an organic water-reducing reagent. It should be noted that this property does not disappear during long-term storage - up to three years in silos and airtight containers. Cement based on high-alkaline clinker, made according to the prototype, and control cement without a modifier, obtained both in laboratory and in production conditions, are characterized by several times increased degree of aggregation, two to three times less friability and significantly reduced by two or three grades - strength values at 28 days of age, as well as delayed hardening in the early stages and during heat and moisture treatment compared to cement made according to the invention.

 2. The latter, including in its particles and somewhat delaying due to the location in the surface layer of particles of the clinker ingredient, the output of alkali metal compounds into the liquid phase of cement paste, mortar and concrete, increases the strength of these materials compared to prior art analogues hardening periods (up to 3 days inclusive), and at 28 days of age. Reduced values of the degree of aggregation of cements, increased values of their flowability and strength, as can be seen from the above data, cannot be obtained by methods known from the prior art.

 3. The application of the method according to the invention and, accordingly, the production of low-water cement in an almost completely disaggregated and, therefore, most active state, is not hindered by differences in the compositions of caustic alkali impurities containing Portland cement clinker, calcium sulphate ingredient, organic water-reducing reagent, and also additionally introduced into the composition cement active mineral additives and fillers.

 Thus, the specified cement manufactured by the method according to the invention has significant advantages compared to those known from the prior art, characterized by novelty elements and being multivariant, not requiring tight binding to a narrow raw material base, which is essential to reduce its cost in a market economy. An additional advantage of said cement made according to the invention is the diversification of its fields of application, i.e. the possibility of using both in high-strength concrete and in low-class concrete, cellular concrete, especially for construction in remote regions of the country, with periodic deliveries of cement and its long-term storage until use, including for defense construction purposes. The specified cement made according to the invention is characterized by a low degree of particle aggregation or its absence, higher flowability compared to the known cements, characteristic of the cement according to the invention both immediately after manufacture and after long-term storage in silos or containers, which facilitates its use, especially in remote areas of the country and after prolonged transportation.

 A method of manufacturing cement according to the invention and cement made by the specified method, have been successfully tested in production conditions. Therefore, the invention is fully prepared for industrial implementation.

List of references
1. Tarnarutsky G. M. Surface-active additives for the industrial production of plasticized cement. Overview. VNIIESM, ser. Cement Industry, 1987, no. 3, p. 1-42.

 2. European Patent (EP) 0081861, CL C 04 B 7/52, 1983.

 3. Toudovitch, B. E., Dmitriev A.M., Zoubekhine, S.A. et al. Low-water requirement binders as new generation cements. 10th International Congress on the Chemistry of Cements (1CCC). Gothenburg, Sweden, 2-6 June 1997. Proceedings, ed. by H. Justnes. Amarkai AB and Congrex Gotenborg AB, 1997, v. 3, 3iii021, 4 pp.

 4. RF patent 2029749, cl. C 04 B 7/52, 1995 (prototype).

 5. Yudovich B.E. Study of the features of grinding, particle size distribution and construction and technical properties of high-strength Portland cement. Abstract of diss. for a job. student step. Cand. tech. sciences. M .: NIIcement, 1972.- 31 p.

 6. Ptitsyn VV et al. Mineralizing effect of multicomponent (complex) additives during firing of plate clinkers. Proceedings of the Research Institute of Cement, 1986, no. 89, p. 28-33.

 7. Vatutina L. S. et al. Determination of the degree of aggregation of cement particles by the method of breathability. Proceedings of the Research Institute of Cement: "The use of physical instruments and methods in the study of clinkers and cements", 1987, no. 91, p. 221-238. See also Yudovich B.E. et al. Determination of flowability of cement using the method of breathability. In the same place, with. 238-245.

Claims (7)

1. A method of manufacturing cement of low water demand by mechanochemical processing by joint grinding to a specific surface of 400-700 m ² / kg of ingredients: Portland cement clinker, calcium sulfate ingredient and a modifier, including a hardening accelerator and an organic water-lowering reagent, characterized in that as the specified Portland cement clinker use a granular product of firing a cement raw material mixture containing impurities of sulfates and carbonates of alkali metals, in which these ropes are burnt in the form of droplets and sagging of anhydrous compounds and / or needles and intergrowths of their crystalline hydrates frozen on the granules of the specified product and bonded during the indicated grinding of the ingredients with an organic water-lowering reagent with the formation of the salt phase of the hardening accelerator in an organic reagent in an amount of 10-50% by weight the latter, and the specified grinding is carried out at a ratio of the specified ingredients in the range respectively 100: (1-7) :( 0.6-2.5) parts by weight until stoichiometry of the alite phase in the surface layer of the particles of the specified clinker is achieved, the moment of this achievement and, accordingly, the end of the grinding is established by the criterion of the degree of aggregation of particles of the specified cement, equal to 5-15 vol.% at hygroscopic humidity of not more than 3 wt.%. 2. The method according to claim 1, characterized in that the Portland cement clinker contains alkali metal compounds in terms of R ₂ O = Na ₂ O + 0,658 K ₂ O in an amount of 0.3-1.4 wt.% And sulfur trioxide compounds in the amount of 0.4-1.5 wt. %  3. The method according to claim 1 or 2, characterized in that as the specified organic water-lowering reagent, materials from the group of salts of alkaline earth and / or alkali metals of the condensation product of naphthalene sulfonic acid, introduced in an amount of 0.6-2.5% by weight of Portland cement clinker, are used formaldehyde or condensation product of melamine-containing resins with formaldehyde, complex salts of alkaline earth metals and sulfuric and / or nitric and / or formic and / or acetic acids and low molecular weight monosaccharides with C 3-5 atoms, pairs nye mixtures of these materials in a mass ratio of 4: 1 to 1: 4.  4. The method according to any one of claims 1 to 3, characterized in that as the calcium sulfate ingredient, two-water gypsum or a mixture thereof with semi-aqueous gypsum in mass is used. ratio from 1: 0.01 to 1: 2, or a mixture of two-water gypsum with anhydrite in wt. a ratio of 1: 0.01 to 1: 0.2, or a mixture of two-water gypsum with chemical gypsum from the group of phosphogypsum, borogypsum, titanogypsum, fluorohydrite, the product of purification of flue gases of industrial furnaces and / or limestone reactors, taken in wt. a ratio of 1: 0.05 to 1: 1 with hygroscopic humidity of 0.01-3 wt.%.  5. The method according to any one of claims 1 to 4, characterized in that an active mineral additive and / or filler are additionally introduced into the composition of said cement with joint or separate grinding, followed by mixing at mass. the ratio of Portland cement clinker and active mineral additives and / or filler from 100: 5 to 100: 850 with its hygroscopic moisture content of 0.01-3 wt.%.  6. The method according to any one of claims 1 to 5, characterized in that active silica from the group crushed, or granular, or ground silicate block is used as an active mineral additive in an amount of 0.2-20% by weight of said cement, silica fume in powder or granular form in an amount of 0.2-10% by weight of the specified cement, and the granular form of silica fume contains a plasticizing component introduced during granulation in an amount of 0.01-0.2% in terms of the weight of the specified cement.  7. The method according to any one of claims 1 to 5, characterized in that one or two components from the group granular blast furnace slag, fuel slag, fly ash, volcanic ash, pumice, tuff, quartz sand, feldspar are used as an active mineral additive sand, seeding from granite crushing, ore dressing tailings, cullet, brick fight, expanded clay or glass expanded clay dust.

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