RU2497767C1 - Method of cement obtaining - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to production of building materials and can be applied in production of cements for different purposes with active mineral additives. In method of cement obtaining, which includes mixing and combined milling of Portland cement clinker with gypsum and active mineral aluminium-silicon-containing additive, as active mineral additive applied are technogenic thermo-processed aluminium-silicon-containing wastes of mineral raw material processing in form of TPP ash-fly from coal burning, thermo-processed at 950-1050° C and/or in from of ashes of waste bank - burnt rock of mine dump of coal fields, thermo-processed at 600-850° C, which are supplied to mixing in quantity 5-25% of clinker weight.

EFFECT: reduction of consumption of Portland cement clinker for cement production, obtaining cement with increased durability and exploitation properties, recycling of technogenic wastes.

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Description

The invention relates to the production of building materials and can be used in the production of additional cements for various purposes.

To reduce the energy and material costs of cement production, composite type cements are made, which, in addition to the clinker part, contain active mineral additives. Replacing part of the clinker with an active mineral additive significantly saves fuel and electricity for cement production. Active mineral additives are introduced into the composition of cements to improve their construction and technical properties. When mixing cement with water, active mineral additives interact with calcium hydroxide released during the hydration of Portland cement. The resulting calcium hydrosilicates are practically insoluble in water. Thus, the soluble component of the cement stone Ca (OH) _{2 is} converted into an insoluble compound. This is the point of using active mineral supplements:

saving the clinker part, they at the same time give the cement a number of special properties.

Rocks are widely used as natural active mineral additives: diatomite, tripoli, flask, burnt clay rocks - gliezha, rocks of volcanic origin: volcanic ash, tuff, pumice, vitrofire, slopes.

Artificial active mineral additives are industrial by-products and waste: quick-cooled (granular) blast furnace slag, belite (nepheline) sludge - waste from alumina production, fly ash - waste generated during coal combustion, waste and mineral production by-products.

From the point of view of affordability, cost and environmental safety, man-made active mineral additives are of interest, which are, in fact, waste and by-products of various mining and processing industries.

Known astringent, consisting of Portland cement clinker, two-water gypsum and additives in the form of an alkaline aluminosilicate rock -synyr in the following ratio of components, wt.%:

Synnyr - 30 - 35

Two-water gypsum - 3

Portland cement clinker - the rest (RF patent No. 2125545, С04В 7/12, 1999, [1]).

The main disadvantages of the known solution are the restrictions on the use as an active mineral additive in the production of cements and an insufficient raw material base (synyr is a by-product in the development of mineral deposits of the nepheline group).

A known method of producing cement, comprising a two-stage processing of cement clinker with grinding in the second stage together with other materials in an open-cycle mill, in which at the first stage the cement clinker is crushed in stages in a vertical rotary mill with preliminary and final classification by screening into pieces smaller than 5 mm . Further, the material is crushed in an impact crusher with a vertical shaft and with an integrated classifier to a particle size of 1.0 mm, and finally, in a horizontal ball crusher with a separator to a specific surface of 2000-3000 cm ² / g according to Blaine or clinker together with quartz sand, taken in a ratio of from 1: 1 to 1: 0.5, crushed by the jet method in an impact crusher with a vertical shaft. However, other cement components are also pre-processed. Blast furnace slag is finely crushed in a ball mill with a separator to a specific surface of at least 1500 cm ² / g according to Blaine, ash and fly ash are grinded in a roller mill to a specific surface of not less than 4000 cm ² / g according to Blaine, limestones and gypsum stone are crushed sequentially a jaw and impact crushers in pieces smaller than 5 mm, and in the second grinding step any previously crushed so domalyvayut materials together in a ball mill to open cycle cement powder specific surface 4000-5000 cm ² / g Bley y (RF patent №2388710, S04V 7/00, 2010. [2]).

The main disadvantage of the known solution is a complex hardware-technological scheme, significant energy costs, which increases the cost of a marketable product.

A known method of manufacturing cement of low water demand by joint grinding to a specific surface of 400-700 m ² / kg of Portland cement clinker ingredients, calcium sulfate ingredient and a modifier including a hardening accelerator and an organic water-lowering reagent, in which a granular cement firing product is used as the specified Portland cement clinker a mixture containing impurities of sulfates and carbonates of alkali metals. These impurities are annealed in the form of droplets and sagging of anhydrous compounds and / or needles and intergrowths of their crystalline hydrates frozen on the surface of the granules of the specified product, connected during the grinding of the ingredients with an organic water-reducing reagent with the formation of the salt phase of the hardening accelerator in an organic reagent in an amount of 10-50% by weight last one. Grinding is carried out with a ratio of these 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 reached, 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.%.

The composition of the specified cement can be additionally introduced an active mineral additive and / or filler in joint or separate grinding, followed by mixing at mass ratios of Portland cement clinker and active mineral additive and / or filler from 100: 5 to 100: 850 at hygroscopic humidity of 0.01 -3 wt.%.

As an active mineral additive, one or two components from the group can be used: granulated blast furnace slag, fuel slag, fly ash, volcanic ash, pumice, tuff, silica sand, feldspar sand, granite seedings, ore dressing tailings, cullet, brick fight, expanded clay or glass ceramic dust (RF patent No. 2207995, C04 B7 / 52, 2003 [3]).

By purpose, technical nature, the presence of similar features, this technical solution is selected as the closest analogue.

The cement obtained by a technical solution has high consumer properties, but at the same time, the active mineral additives used are mostly scarce or require additional preliminary preparation before use, which increases the cost of a marketable product.

The objectives of the proposed technical solution are: reducing the cost and improving the quality of cement, expanding the raw material base for cement production through the use of non-deficient industrial waste processing of mineral raw materials.

Technical results include reduction of the consumption of Portland cement clinker for cement production, production of cement with increased strength and performance properties, processing of industrial waste.

Technical results are achieved by the fact that in the method for producing cement, comprising mixing and co-grinding Portland cement clinker with gypsum and an artificial active aluminum-silicon-containing mineral additive containing ash - ablation of thermal power plants from burning coal, technogenic heat-treated aluminum - silicon-containing is used as an artificial active mineral additive mineral processing waste in the form of ashes - entrainment of thermal power plants from coal burning and / or as heaps of heaps of heaps - burnt rock of mine dumps oil deposits, which are fed for mixing in the amount of 5-25% by weight of clinker.

In addition, according to the proposed technology, cement can be prepared containing Portland cement clinker, gypsum and an active mineral aluminum-silicon-containing additive in the form of ashes - entrainment of thermal power plants from burning coal and / or in the form of heaps of heaps - burnt rock of mine dumps of coal deposits in the following ratio of components , the weight.%:

gypsum 4,5-7,5 ash - entrainment of thermal power plants and / or ash of waste heaps 4,5-18,5 portland cement clinker rest

A comparative analysis of the proposed technical solution with the solution for the closest analogue shows the following.

Known and proposed solutions are characterized by similar common features:

- use for the production of cement Portland cement clinker and gypsum;

- the use of active aluminum - silicon-containing mineral additives containing fly ash;

- mixing and joint grinding of Portland cement clinker with gypsum and active aluminum - silicon-containing mineral additive; containing ash - fly ash.

The proposed solution differs from the known solution in the following features:

- as active aluminum - silicon-containing mineral additives use heat-treated aluminum - silicon-containing waste processing of mineral raw materials;

- as heat-treated aluminum - silicon-containing waste processing of mineral raw materials for mixing and grinding serves:

- ash - ashes of thermal power plants and ashes of heaps - burnt rock of mine dumps of coal deposits;

- ash - ablation of thermal power plants and / or ash of waste heaps - burnt rock of mine dumps of coal deposits in the amount of 5-25% by weight of clinker.

Moreover, a mixture of ash - fly ash and ash of heaps in different proportions in the amount of 5-25% by weight of clinker or ash of heaps in the amount of 5-25% by weight of clinker can be fed to the mixing.

The presence in the proposed solution of signs that are distinct from the signs characterizing the decision taken as the closest analogue allows us to conclude that the proposed technical solution meets the condition of patentability of the invention of "novelty."

The technical essence of the proposed solution is as follows.

Technogenic waste used in the proposed solution is an artificial, heat-treated mineral raw material generated during the extraction and burning of coal. Fly ash is formed as a result of burning coal at thermal stations, is captured by electrostatic precipitators and is used for industrial purposes in a dry state. Ash of heaps - the burnt rock of mine dumps of coal deposits - is a product of natural heat treatment of the rock, extracted from coal mines with coal and stored in the form of artificial embankments - heaps.

In the case of fly ash, the heat treatment of the material occurs at 950-1050 ° C, in the case of ash heaps - at 600-850 ° C. The firing products formed in both cases are rich in dehydrated clay minerals, from which highly active crystal residues are formed. These active compounds based on aluminosilicates when mixing cement with water interact with calcium hydroxide, forming water-insoluble calcium hydrosilicates, and thereby increase the strength and performance characteristics of cement.

When using the proposed technical solution, a closed technological and environmental cycle option is implemented, including coal mining, its use at thermal power plants for generating electricity and heat, and also utilizing both coal mining waste (waste heaps) and its products in the form of thermal fly ash in cement production.

A closed technological cycle: coal mining - production of electricity and heat - utilization of industrial wastes - cement production, from the point of view of logistics, requires the location of these industries quite compactly in the region. As a result, transportation costs are reduced, both for the transportation of coal from coal mines and mines to TPPs or TPPs, as well as waste heaps from dumps of coal mines and ash - the removal of TPPs to cement plants.

The use in the proposed solution as an active mineral additive of technogenic heat-treated aluminum silicon-containing waste processing of mineral raw materials is aimed at solving several problems at once:

- expansion of the raw material base of effective, widely available active mineral additives for cement production;

- improving the quality and reducing the cost of cement production;

- Utilization of large-capacity industrial wastes of mining and processing of coal.

The use of ash - fly ash and / or ash heaps in the amount of 5-25% by weight of clinker due to the following circumstances. The amount of active mineral additive introduced into the additive cement is determined by the quality of the clinker. The higher the quality of the clinker, the greater the amount of additive can be used when grinding cement. With a low clinker activity, the input of an active mineral additive is minimal and can be 5-10% of the clinker weight. High-quality clinker allows you to enter when grinding the maximum amount of active mineral additives: 15-25% by weight of clinker. With the introduction of ash - fly ash and / or ash of heaps in the amount of more than 25% of the weight of the clinker, the activity of the resulting cement decreases below normalized indicators.

A comparative analysis of the proposed technical solutions with other known solutions in this field shows the following.

1. Known sulfate-resistant Portland cement, including Portland cement clinker, calcium sulfate and igneous aluminosilicate rock with a fine crystalline structure, in which the specified rock has a crystal size of up to 20 μm and contains minerals represented by solid solutions of augite-anorthite series. The crystals in the rock structure surrounded by a glassy layers, Portland cement clinker contains tricalcium aluminate C ₃ A in an amount up to 5 wt.%, And the amount of tricalcium aluminate C ₃ A and tetracalcium alyumoferrita C ₄ AF clinker is less than 22 wt.%, With the following ratio components, wt.%:

Clinker of the specified composition 60-90

Calcium Sulphate 2-8

Specified rock - rest

(RF patent No. 2237627, С04В 7/02, 2004, [4]).

In the known solution, as an active mineral additive, an igneous (heat-treated under natural conditions) aluminosilicate rock with a fine crystalline structure is used. The main disadvantage of this solution is the lack of supplements.

2. The well-known "Method for the manufacture of cement, concrete based on it and concrete and reinforced concrete products and monolithic structures from the obtained concrete" (patent EA 002673 B1, С04В 7/00, 2002, [5]), in which cement is made by joint and / or separate grinding, followed by mixing, a gypsum component can be added additionally, and additionally, during grinding and / or mixing, active silica can be introduced as a secondary product of silicon production and / or dust captured from the exhaust gases of ferroalloy production furnaces in the amount of 0.2-10 wt.% from the specified cement (p. 46 claims), can be introduced active mineral additive in an amount of 1-85 wt.% the specified cement (p. 47 claims), can be introduced expansion component in the form of aluminous clinker or alumina slag in the amount of 2.5-50 wt.% of the specified cement (p. 48 claims).

3. Known "Portland cement clinker, cement based on it and a method of manufacturing corrosion-resistant concrete" (RF patent No. 2058952, С04В 7/02, 1996, [6]). In a known solution, cement may contain an active mineral additive in an amount of 5-50% by weight of clinker (Claim 5 according to claims 3,4), as an active mineral additive, cement may contain heat-treated materials: dehydrated kaolin, or dehydrated kaolinite clay, or dehydrated clay, or shale, or burnt rock, or clay (clause 8 according to claim 5 of the claims), the cement may contain artificial material as an active mineral additive: blast furnace granulated slag, or fly ash, or ash-slag of thermal power plants (clause 9 according to claim 5 of the claims).

When grinding clinker (p. 18 according to claim 17 of the claims), an active mineral additive is introduced in an amount of 5-50% by weight of clinker and flask, or tripoli, is used as an active mineral additive (p. 19 according to claim 18) or diatomite, or volcanic ash, or volcanic tuff, or pumice, or traces, or dehydrated kaolin, or dehydrated kaolinite clay, or heat-treated slate, or burnt rock, or slag, or blast furnace granulated slag, or fly ash or fly ash slag of thermal power plants.

4. It is known to mix fly ash having a particle size of not more than 20 μm, in an amount of from 2 to 25% by weight with cement containing cement clinker, including Al ₂ O ₃ and Fe ₂ O ₃ , in which the ratio of Al ₂ O ₃ to Fe ₂ O ₃ ranges from 0.05 to 0.62, and the content of C ₂ S is 35-55% by weight (RF patent No. 2199498, С04 В 7/02, 2003, [7]).

In contrast to the known solutions, the proposed solution uses an integrated component as an artificial active mineral additive - man-made heat-treated aluminum - silicon - containing waste from processing mineral raw materials in the form of ash - thermal power plant entrainment from burning coal and / or in the form of waste heaps - burnt mine coal mine dumps of coal deposits. In addition, active mineral additives are served for mixing and co-milling with Portland cement clinker and gypsum in an amount of 5-25% by weight of clinker. These technogenic heat-treated active mineral additives are effective when used within the specified limits and are affordable large-tonnage industrial waste from coal mining and processing.

As a result of a comparative analysis of the proposed technical solution with other well-known solutions in this area, no technical solutions were identified that are characterized by a combination of features similar to the proposed solution, the use of which allows achieving similar technical and technical and economic results.

Based on the foregoing, we can conclude that the proposed technical solution meets the condition of patentability "inventive step".

The proposed technical solution is implemented as follows.

Portland cement clinker, gypsum in the amount of 4.5-7.5% by weight of clinker and an active mineral aluminum-silicon-containing additive in the form of ash - TPP entrainment from coal burning and / or in the form of waste heaps - burnt rock of mine dumps are fed for mixing and grinding coal deposits in the amount of 5-25% by weight of clinker. As a result of mixing and grinding the components, cement is obtained with the ratio of components specified in paragraph 4 of the claims.

Example 1

The following materials were used to evaluate the effectiveness of using ash of heaps as an active mineral additive: clinker of the Angarsk cement plant, natural gypsum of the Novonukutsk deposit (Irkutsk region), fly ash of the Irkutsk thermal power station - 1 and burned rocks from mine heaps of the Cheremkhov coal basin (Irkutsk region) .

The composition of the starting materials are shown in tables 1-5.

table 2 The average chemical composition of gypsum stone The content of compounds,% weight. Cao SO ₃ MgO SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ Other 30.30 32.25 5.54 5.53 0.55 0.74 25.09

Table 3 The average chemical composition of fly ash CHP-1 The content of oxides,% weight. SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ Cao MgO K ₂ O Na ₂ O MnO TiO ₂ SO ₃ P ₂ O ₅ 60.55 22.39 7.34 4.39 1.96 1.25 0.26 0,038 0.46 0.76 0.05

Table 4 The average chemical composition of waste heaps - burnt rock mine dumps of coal deposits of the Cheremkhovsky coal basin The content of oxides,% weight. SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ Cao MgO K ₂ O Na ₂ O MnO TiO ₂ SO ₂ 65.6 18.7 6.03 2.2 2.6 1.9 0.35 0,027 0.30 0.29

Table 5 Averaged physico-mechanical properties of zo terricone Characteristics, Dimension Values Natural humidity,% weight. 8.8 Bulk density, kg / m ³ 1085 Grain content 0-5 mm,% weight. 58.6 The grain content of 5-70 mm,% weight. 41,4 True density, g / cm ³ 2,58 The strength in the cylinder, g / cm ² 17.7 Water absorption,% weight. 15.3 Softening coefficient 0.69

The effectiveness of using heaps of heaps as an active mineral additive in comparison with fly ash was carried out on laboratory grinding cements with a total content of active mineral additive of 18% by weight of Portland cement clinker (PCC). With this content of active mineral supplements, 5 compositions were prepared. The composition and content of gypsum stone (gypsum stone - KG), the grinding conditions of the samples in all compositions were the same. The sixth composition was prepared without fly ash with ash content of heaps 25% weight. The content of fly ash (ZU) and terricone ash (ZT) in compositions 1-6 varied within the claimed limits (according to claims 1-3 of the claims). The seventh composition also contained only ash heaps in the amount of 28% weight. and gypsum. The results of mechanical testing of cements with various combinations of active mineral additives are presented in table 6.

Table 6 - Change in the mechanical properties of cements from a combination of additives (fly ash and heap ash) No. Mechanical properties The strength of the sample, MPa Composition 1: PCC + 0% ST + 18% memory + 5.2% KG one Steamed at the age of 1 day. when bending 3.57 under compression 19.28 2 Hardening in water, age 7 days. when bending 3.61 under compression 23.02 3 Hardening in water, age 28 days. when bending 6.35 under compression 40,23 Composition 2: PCC + 5.5% ST + 12.5% memory + 5.2% KG one Steamed at the age of 1 day. when bending 3.80 under compression 20.56 2 Hardening in water, age 7 days. when bending 3.77 under compression 23.58 3 Hardening in water, age 28 days. when bending 6.33 under compression 40.56 Composition 3: PCC + 9% ST + 9% memory + 5.2% KG one Steamed at the age of 1 day. when bending 4.14 under compression 22.15 2 Hardening in water, age 7 days. when bending 3.90 under compression 24.58 3 Hardening in water, age 28 days. when bending 6.64 under compression 41.89 Composition 4: PCC + 12.5% ST + 5.5% memory + 5.2% KG one Steamed at the age of 1 day. when bending 4.28 under compression 24.23 2 Hardening in water, age 7 days. when bending 4.41 under compression 26.22 3 Hardening in water, age 28 days. when bending 6.92 under compression 43.56 Composition 5: PCC + 18% ST + 0% memory + 5.2% KG one Steamed at the age of 1 day. when bending 4.37 under compression 28.98 2 Hardening in water, age 7 days. when bending 4,58 under compression 29.56 3 Hardening in water, age 28 days. when bending 7.22 under compression 45.24 Composition 6: PCC + 25% ST + 0% memory + 5.2% KG one Steamed at the age of 1 day. when bending 4.28 under compression 27.05 2 Hardening in water, age 7 days. when bending 4.40 under compression 28.80 3 Hardening in water, age 28 days. when bending 7.02 under compression 44.09 Composition 7: PCC + 28% ST + 0% memory + 5.2% KG Steamed at the age of 1 day. when bending 4.08 under compression 23.60 Hardening in water, age 7 days. when bending 3.89 under compression 26.45 when bending 6.67 Hardening in water, age 28 days. under compression 39.20

From the obtained results of laboratory experiments, it follows that with a decrease in the ratio of fly ash to ash of heaps with the same consumption of active mineral additive, the strength of cement stone in plastic solutions, both in bending and in compression, increases up to 25% of the input of the active additive. An increase in the strength of samples with the addition of ash of heaps is observed at various periods of hardening and after steaming. Moreover, the greatest effect is achieved in the composition, where only ash of heaps is used as an active mineral additive. With the introduction of ash heaps more than 25% weight. (composition 7) decreases the activity of the resulting cement.

Additional quality indicators of cement with the addition of 18% ash of heaps (composition 5, table 6) are shown in table 7.

Table 7 Qualitative indicators of cement with waste heaps as an active mineral additive. Characteristics, Dimension Quality indicators True density, g / cm ³ 3.00 Bulk density, g / cm ³ 1,085 Fineness: grinding residue 0.08,% 13.8 Fineness: specific surface, m ² / kg 326 Normal density,% weight. 28.5 Setting time, min. 220 The end of setting, min. 430 Coefficient of water disposal,% 14.1

Studies confirm the guaranteed reproducibility of the results of the proposed technical solution and the possibility of varying the improved consumer properties of the resulting cement depending on technological capabilities and needs.

Using the proposed technical solution will expand the raw material base of the cement (construction) industry, utilize man-made heat-treated aluminum - silicon-containing waste from mineral processing, improve the environmental situation in the areas of coal mining and the location of thermal power plants, reduce the cost of cement production, improve its quality and operational properties .

Information sources

1. RF patent №2125 545, С04В 7/12, 1999

2. RF patent No. 2388710, С04В 7/00, 2010

3. RF patent №2207995, С04В 7/52, 2003

4. RF patent No. 2237627, С04В 7/02, 2004

5. Patent EA 002673 B1, C04B 7/00, 2002

6. RF patent №2058952, С04В 7/02, 1996

7. RF patent No. 2199498, С04В 7/02, 2003.

Claims (1)

A method of producing cement, comprising mixing and co-grinding Portland cement clinker with gypsum and an active mineral aluminum-silicon-containing additive, characterized in that the active mineral additive uses technogenic heat-treated aluminum-silicon-containing waste from processing mineral raw materials in the form of fly ash from thermal coal burning, heat-treated at 950-1050 ° C and / or in the form of ash heaps-burnt rock mine dumps of coal deposits, heat-treated at 600-850 ° C, which are served on mixing in the amount of 5-25% by weight of clinker.