RU2837020C1 - Method of producing non-fired mineral binder of hydraulic hardening - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to the construction industry, in particular to the production of non-fired inorganic binders from wastes and industrial products of various industries. Method of producing non-fired mineral binder of hydraulic hardening involves grinding, mixing and mixing with water a mixture of an acidic active mineral additive and a lime-containing component. Amount of the active mineral additive added per unit weight of the lime-containing component is calculated by formula AMS = (10±0.4): A_PA × C_CaOact., where AMS is the amount of active mineral additive, g, kg, t; A_PA is the pozzolanic activity of the mineral additive, mg CaO/g AMS, g CaO/kg AMS, kg CaO/t AMS; C_CaOact. – content of active calcium oxide in lime-containing component, wt.%; coefficient ±0.4 corresponds to the confidence interval, which includes results of laboratory experiments with reliability of 95%.

EFFECT: invention enables to reduce specific consumption of components for synthesis of non-fired binder and obtain binder with maximum mechanical characteristics.

1 cl, 2 ex, 5 tbl

Description

The invention relates to the production of building materials and has a resource-saving focus, due to the involvement in the processing of waste and industrial products of various industries. Waste and industrial products are used to obtain non-fired inorganic binders of hydraulic hardening, which can be used as active mineral additives to traditional binders or in the form of independent low-activity binders. The present invention applies to non-fired binders, the basis of which are "acidic" (aluminosilicate) and alkaline (lime-containing) components.

A method is known [A.s. SU No. 1837053 A1, IPC C04B 7/28, published. [30.08.1993] for preparing a binder, including grinding and mixing coal ash, quicklime, gypsum and alkali or alkaline earth metal chloride, in which lump quicklime, 1/4-1/2 of the total amount of coal ash, alkali or alkaline earth metal chloride are first ground together in runners for 10-15 minutes, hardening water is added until a moisture content of 8-13% and a surface-active additive from the group of sodium dihexyl succinate sulfonate, polyethylene glycol monoalkyl phenyl ether is obtained, then the resulting mixture is kept in a reactor for 6-20 hours, after which it is mixed with gypsum and the remaining amount of coal ash in the following ratio of components, wt.% (on dry matter):

quicklime 20-30 alkali chloride or alkaline earth metal 0.6-1.0 gypsum 3.0-5.0 surface-active additive 0.05-0.15 coal ash rest

The disadvantage of the known solution is the preparation of the binder in several successive operations using specific materials and additives.

A method is known for producing a non-fired binder by grinding shell limestone with the addition of 5-15% caustic lime or an aqueous solution of magnesium chloride or sulfite-cellulose lye to the batch [A.s. No. 89980 80b1. Declared 05/09/1950].

The disadvantage of the known solution is the limited scope of application, based on the use of shell limestone.

A binder mixture is known for use in the building materials industry [Patent RU No. 2733365 C1, IPC C04B 40/00, C04B 28/18, C04B 14/04, C04B 18/14, C04B 22/08, published 01.10.2020]. The binder mixture contains, by weight %: 4-45 wt % volcanic rock, from more than 0 to 40 wt % latent hydraulic material, wherein the latent hydraulic material includes one or more of lignite fly ash, anthracite fly ash, kaolin and trass, the volcanic rock has a Blaine grinding fineness of more than 3000, and the latent hydraulic material has a Blaine grinding fineness of more than 3000, 10-45 wt % alkali component, wherein the alkali component contains one or more of alkali metal hydroxide and alkali metal carbonate, 20-90 wt % filler, less than 1 wt % sulfate, wherein the sulfate is present in the binder mixture in the form of impurities, and no more than 5 wt % calcium. The technical result is an increase in strength, including early strength, an increase in resistance to elevated temperatures and low thermal conductivity.

The disadvantage of the known solution is the use of fairly specific components in the mixture (volcanic rock, latent hydraulic material) and wide limits of their dosing in the absence of substantiated optimal mixture compositions.

The closest to the claimed technical solution is the technology for obtaining a non-fired mineral binder of hydraulic hardening, including grinding, mixing, mixing with water an acidic active mineral additive in the form of burnt rock from waste heaps of coal deposits (ash from waste heaps), a lime-containing component in the form of carbide lime - a waste product of acetylene production from calcium carbide and a gypsum-containing component in the form of fluorogypsum - a waste product of hydrogen fluoride production [Levchenko E.A., Vorobchuk V.A., Filonenko E.A., Filonenko K.A. Non-fired binder from technogenic waste. - Bulletin of IrSTU. - No. 10 - 2012 - P.113-117]. According to the technical essence, the presence of similar features, this solution was chosen as the closest analogue.

The disadvantage of the known technology is the fixed ratio of waste heap ash, carbide lime and fluorogypsum 0.8:0.1:0.1. This ratio is set for a specific, fixed composition of the components of the unfired binder. If the composition of waste heap ash and/or carbide lime changes, the optimal ratio of reagents will change. As a result, the strength characteristics of the binder will decrease.

The objective of the proposed technical solution is to develop a universal method for forming a composition of a non-fired binder based on mineral “acidic” (aluminosilicate) and alkaline (lime-containing) components.

The technical result of implementing the invention consists in reducing the specific consumption of components for the synthesis of a non-fired binder, in obtaining a binder with maximum mechanical characteristics.

The technical result is achieved in that in the method for obtaining a non-fired hydraulic hardening mineral binder, including grinding, mixing and mixing with water a mixture of an acidic active mineral additive and a lime-containing component, characterized in that the amount of active mineral additive added per unit weight of the lime-containing component is calculated according to the formula

AMD = (10±0.4) : A _PC × C _CaOact. ,

where AMD is the amount of active mineral additive, g, kg, t;

A _PC – pozzolanic activity of the mineral additive, mg CaO/g AMD, g CaO/kg AMD, kg CaO/t AMD;

С _{СаОакт.} – content of active calcium oxide in the lime-containing component, wt.%;

The coefficient ±0.4 corresponds to a confidence interval that includes the results of laboratory experiments with 95% reliability.

The technical essence of the claimed solution is as follows.

The formation of cement stone from acidic and alkaline components occurs as a result of the synthesis of silicates, aluminosilicates, aluminates, and calcium hydroalumosilicates. Only active components included in the acidic and alkaline components of the binder participate in the synthesis of these complex compounds. As a rule, silicon and aluminum oxides are active in acidic components, and calcium oxide or hydroxide in alkaline components.

The degree of pozzolanic activity is used as an indicator of the activity of the acid component (active mineral additive). Pozzolanic activity is the ability of a mineral additive to bind lime into low-basic calcium hydrosilicates and aluminates. The activity of mineral additives is determined by the amount of CaO and Ca(OH) ₂ that absorbs 1 g of additive from a saturated lime solution at a certain temperature and interaction time.

The indicator of the activity of the alkaline lime-containing component is the concentration of active calcium oxide or hydroxide in it, which is determined by titrating lime dissolved in water with a 1 N solution of hydrochloric acid in the presence of an indicator - an alcohol solution of phenolphthalein.

The optimal ratio of acidic and alkaline components in the mixture for obtaining a non-fired binder is achieved in the case where the concentration of active calcium oxide in the lime-containing component corresponds to the pozzolanic activity of the acidic active mineral additive.

An empirical relationship was obtained linking the pozzolanic activity of the acidic active mineral additive and the content of active calcium oxide in the alkaline lime-containing component. In accordance with the relationship obtained, the amount of active mineral additive added per unit weight of the lime-containing component is calculated using the formula:

AMD = (10±0.4) : A _PC × C _CaOact. ,

where AMD is the amount of active mineral additive, g, kg, t;

A _PC – pozzolanic activity of the mineral additive, mg CaO/g AMD, g CaO/kg AMD, kg CaO/t AMD;

С _{СаОакт.} – content of active calcium oxide in the lime-containing component, wt.%;

The coefficient ±0.4 corresponds to a confidence interval that includes the results of laboratory experiments with 95% reliability.

The variation of the coefficient (10±0.4) within ±0.4 is due to fluctuations in the composition of the binder components, the error in determining the pozzolanic activity of the acidic mineral additive and the content of active calcium oxide in the lime-containing component.

Formation of the mixture composition based on the obtained empirical dependence guarantees the optimal ratio of active compounds in the composition of the binder based on an acidic active mineral additive and a lime-containing component.

Comparison of the proposed solution with the closest analogue shows the following. The proposed solution and the closest analogue are characterized by similar general features:

- obtaining a non-fired mineral binder with hydraulic hardening;

- use of an acidic active mineral additive based on aluminosilicates in the binder;

- introduction of a lime-containing component into the binder composition;

- grinding, mixing and mixing with water a mixture of active mineral additive and lime-containing component.

The proposed solution differs from its closest analogue in the following ways:

- the proposed solution applies to a wide range of compositions of non-fired binders based on acidic active mineral additives and lime-containing components;

- the proposed solution takes into account changes in the content of active compounds in the components of the unfired binder, on the basis of which it recommends different ratios of acidic and basic components in the composition of the binder;

- the amount of active mineral additive added per unit weight of the lime-containing component is calculated using the formula:

AMD = (10±0.4) : A _PC × C _CaOact. ,

where AMD is the amount of active mineral additive, g, kg, t;

A _PC – pozzolanic activity of the mineral additive, mg CaO/g AMD, g CaO/kg AMD, kg CaO/t AMD;

С _{СаОакт.} – content of active calcium oxide in the lime-containing component, wt.%;

The coefficient ±0.4 corresponds to a confidence interval that includes the results of laboratory experiments with 95% reliability.

The presence in the proposed solution of features that differ from the features of the closest analogue allows us to conclude that the proposed technical solution complies with the patentability condition of the invention “novelty”.

A comparative analysis of the proposed technical solution with other known solutions in this area revealed the following.

A binder is known [Patent KZ No. 25103, IPC C22B 1/24, C22B 1/243. Published 15.12.2011. Bulletin 12], containing dusty waste from the production of freshly burned lime and a substance containing active magnesium oxide in the following ratio of components, wt. %:

- dusty waste from the production of freshly burnt lime - 75-85;

- a substance containing active magnesium oxide - 15-25.

As a substance containing active magnesium oxide, dust from the firing of raw dolomite or ground fired dolomite is used. The content of active calcium oxide in the calcium-containing material should be at least 70%.

The known solution does not use acidic components, unlike the proposed solution.

In the work [Selivanov V.M. Non-fired building materials and products based on clinker-free and low-clinker clay-containing binders. Dissertation for the degree of Doctor of Technical Sciences. Abakan 2002] the compositions and technological parameters of non-fired materials and products based on clinker-free and low-clinker clay-containing binders from technogenic raw materials of Khakassia were developed. The features of the formation of the structure of hardening stone in the systems: high-calcium ash (HCA)-water and ash-clay-water were investigated. It has been established that in the hardening ash-clay-water system, physical and physicochemical interaction occurs, manifested in the consumption of physically bound (interlayer and interpacket) water of layered clay silicates for the hydration of ash minerals, causing a damping effect, which is simultaneously enhanced by the replacement of interlayer exchange cations Na+ and K+ of montmorillonite with cations Ca2+ and Mg2+ of ash, which is accompanied by the convergence and "cross-linking" of negatively charged elementary layers of the clay mineral and its lithification.

Based on theory and experiment, the maximum content levels of thermal power plant ash in binders were determined, depending on their activity, which ensured the effective use of the ash-clay system for the development of mixed clinker-free and low-clinker binders. With a high-calcium ash content of 45 to 65% and clay of 15 to 50%, two new types of binders were obtained: SBV Ml00 and SMV M200.M400.

Also developed are unfired building mortars and dry building mixes M4. M50; ready-to-use dry mix for producing cast aerated concrete with a density of up to 170 kg/ ^m3 and a thermal conductivity coefficient of up to 0.07 W/(m⋅°C); ordinary concretes on SMV M100.M300, F50.F100; decorative concretes on SMV M300; concretes for wall stones on SBV M100.M125, F15.F25; wall stones for laying heat-efficient walls.

The compositions of inorganic binders developed in the dissertation are based on the use of acidic aluminosilicate clays and lime-containing ash. The dissertation defines the ranges of component content in the compositions of binders. At the same time, there is no mathematical relationship that determines the ratio of acidic and alkaline components, depending on the pozzolanic activity of acidic mineral additives and the concentration of active lime in the alkaline component.

In the method for producing unfired building products [Patent RU No. 2168481, IPC C04B 28/26. Published 10.06.2001], which includes mixing an alkali metal silicate and a filler, mixing with water, molding the products and drying, liquid sodium glass is used as the alkali metal silicate, and crushed glass cullet or a jointly crushed mixture of glass cullet with sand and/or clay is used as the filler, wherein the filler is mixed with liquid sodium glass, microsiliceous waste from ferrosilicon production is additionally introduced into the resulting mixture, after which mixing with water is carried out in the following ratio of components by weight. h.: broken glass 10-100, sand - up to 90, clay - up to 50, liquid sodium glass by solid residue - 2.5-10, microsiliceous waste from ferrosilicon production - 2-6, water - 5-10, and the molded products are dried first in the air, then in an oven at 200 - 300 ° C for 1-2 hours. When mixing, a heat-resistant blue aluminum-cobalt pigment is additionally introduced, the finished products are glazed by firing in an oven at 600-700 ° C for 5-20 minutes.

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

Consequently, the proposed technical solution meets the patentability requirement of an invention “inventive step” .

The proposed technical solution is implemented as follows.

Example 1

To prepare two mixtures according to the proposed technical solution, the following were used: Mixture No. 1: carbide lime from the Usolye-Khimprom plant + microsilica from JSC Kremniy (Shelekhov, Irkutsk Region). Mixture No. 2: carbide lime from the Oxygen-Acetylene Plant (Zheleznogorsk, Krasnoyarsk Region) + burnt rock from the Borodinsky coal mine.

The pozzolanic activity of acidic active additives: microsilica and burnt Borodino rock, as well as the concentration of active calcium oxide in carbide lime were preliminarily determined. The results are given in Table 1.

Table 1 – Characteristics of active components of mineral additives and lime-containing components

Pozzolanic activity of mineral additives,
Mg CaO/g AMD Concentration of _active CaO in carbide lime, % Microsilica Burnt rock Borodino Carbide lime Usoliekhimprom Carbide lime Zheleznogorsk 99.0 86.9 77.0 62.4

The amount of active mineral additive added per unit weight of lime-containing component for mixture 1:

AMD = 10: _APC × C _CaOact = 10: 99 × 77 = 7.78 g of microsilica per 1 g of Usolye carbide lime.

The amount of active mineral additive added per unit weight of lime-containing component for mixture 2:

AMD = 10: _APC × C _CaOact = 10: 86.9 × 62.4 = 7.18 g of burnt Borodino rock per 1 g of Zheleznogorsk carbide lime.

Mixtures 1 and 2 were prepared from dry components by grinding in a ball mill for 30 min. The weight of each mixture was 1250 g. The composition of the mixtures is given in Table 2.

Table 2 – Composition of mixtures of unfired binders, g/%

Mix 1 Mix 2 Microsilica Carbide lime Usoliekhimprom Burnt rock Borodino Carbide lime Zheleznogorsk 1107.6/88.6 142.4/11.4 1097.2/87.8 152.8/12.2

The mixtures were mixed with water. The resulting dough was used to make beams measuring 40×40×160 mm. After 24 hours, the beams were placed in air-humid conditions for 7 days, then in water for 21 days. The average test results for the samples 28 days after production are shown in Table 3.

Table 3 – Test results of beams made from mixtures 1 and 2

Mixture No. Dimensions, mm Weight, g Density kg/ ^m3 Bending strength of the sample, MPa Compressive strength of the sample, MPa 1 159×39×39 342.2 1415 3.1 9.8 2 159×40×40 367.6 1445 4.0 10.4

Example 2

We prepared two mixtures from the same components, using the same technology as mixture 1 and mixture 2, but with a different ratio of acidic and lime-containing additives.

Mixture No. 3: carbide lime from the Usolye-Khimprom plant + microsilica from JSC Kremniy (Shelekhov, Irkutsk region) in a weight ratio of 30%: 70%.

Mixture No. 4: carbide lime from the Oxygen-Acetylene Plant (Zheleznogorsk, Krasnoyarsk Territory) + burnt rock from the Borodinsky coal mine in a weight ratio of 30%: 70%.

The compositions of mixtures 3 and 4 are given in Table 4.

Table 4 – Composition of mixtures of unfired binders, g/%

Mix 3 Mix 4 Microsilica Carbide lime Usoliekhimprom Burnt rock Borodino Carbide lime Zheleznogorsk 875/70 375/30 875/70 375/30

The mixing of the mixtures with water, the production of beams and the hardening of the mixtures are similar to the experiment described in Example 1. The average test results of samples from mixtures 3 and 4 28 days after production are given in Table 5.

Table 5 – Test results for beams made from mixtures 3 and 4

Mixture No. Dimensions, mm Weight, g Density kg/ ^m3 Bending strength of the sample, MPa Compressive strength of the sample, MPa 1 160×40×39 346.4 1388 2.6 8.7 2 159×39×40 346.0 1395 3.4 9.6

Comparison of the mechanical characteristics of mixtures 1 and 2 with the characteristics of mixtures 3 and 4, prepared with a different ratio of acidic and lime-containing components, confirms the fact of optimization of the composition of unfired binders, manufactured according to the claimed recipe. The results of Example 2 indicate an excess of lime-containing components in mixtures 3 and 4.

Thus, the claimed technical solution provides a universal rule for forming the composition of a non-fired binder based on mineral "acidic" (silicate and aluminosilicate) and alkaline (lime-containing) components. The use of the invention reduces the specific consumption of components for the synthesis of a non-fired binder, ensures the production of a binder with maximum mechanical characteristics.

Claims (6)

A method for producing a non-fired hydraulically hardening mineral binder, including grinding, mixing and mixing with water a mixture of an acidic active mineral additive and a lime-containing component, characterized in that the amount of active mineral additive added per unit weight of the lime-containing component is calculated using the formula AMD = (10±0.4) : A _PC × C _CaOact. , where AMD is the amount of active mineral additive, g, kg, t; A _PC – pozzolanic activity of the mineral additive, mg CaO/g AMD, g CaO/kg AMD, kg CaO/t AMD; С _{СаОакт.} – content of active calcium oxide in the lime-containing component, wt.%; The coefficient ±0.4 corresponds to a confidence interval that includes the results of laboratory experiments with 95% reliability.