ES2402131B1 - NANOMICROCEMENTS - Google Patents

Abstract

Nanomicrocement whose particle size is between 400 nm and 1000 nm (1 micron), obtained by injecting at least one precursor element for cementitious particles in the base material, the at least one precursor element being one of the following: a precursor for cementitious particles of pozzolanic character, a precursor for cementitious particles of latent hydraulic character or a precursor for cementitious particles with hydraulic character.

Description

NANOMICROCEMENTS

FIELD OF THE INVENTION

The present invention relates to nanomicrocement structures, as well as the manufacturing process thereof.

BACKGROUND OF THE INVENTION

For the manufacture of cement materials are used that have the following oxides in their composition: CaO, SiO "AbO, and Fe, O, in certain percentages to obtain two calcium silicates, bicalcium silicate and tricalcium silicate responsible for hardening Cement Oxides Ab03 and Fe20 3 oxides form the compounds tricalcium aluminate and tetracalcium ferrite aluminate and are indispensable for lowering the formation temperatures of calcium silicates.

The materials that supply the above oxides are mainly limestones and clays and as sanding materials for the percentages of some of the above oxides are used sands, iron and aluminum ores. The loam or limestone, after being removed from the quarry by blasting, is subjected to a preliminary crushing in a hammer mill to a size of about 30 mm. They are transported and stored in a pre-homogenization park in which the material is controlled both chemically and granulometrically.

The next phase consists of a dosage of limestone loam I and correctors: sand, iron ores, etc. to a ball mill achieving an intimate mixture of the minerals, a chemical composition and a fineness suitable for the subsequent obtaining of the silicates in the oven. The reduction of the size is carried out by collisions of the balls with the material and the residual gases of the furnace are used in this phase for the drying of the material inside the mill.

,

The mill material is transported to homogenization silos

Pneumatic where it is stored and from which the ovens are fed_ The cooking process (sintering) begins with the feeding of the previous material to the oven and is divided into two stages:

a first stage of heating the material in an exchanger

in countercurrent of cyclones where the material falls and heats and

the gases rise enlriimdose; the cyclones perform the lunction of

gas-solid separation, reaching temperatures of up to BOQee or even 925 ° C at this stage if there is carbon injection in the

tower; and a second stage where the material reaches the furnace tube and at a lower speed the material is heating and reacting until it reaches 1450 'C at the discharge end.

The fuel used is pet-coke, coal or luel-oil (also; n alternative fuels are used). The discharge is carried out in what is considered a third stage to an air cooler that cools the material rapidly in order to freeze the existing crystalline state at 1450 'C which is not stable at room temperature.

Obtaining the cement clinker is achieved by sintering a mixture of precisely specified raw materials containing elements, normally expressed in the form of oxides, CaO, Si02, Ab03, Fe20 3 and small amounts of other materials. The cement clinker is a hydraulic material that must be constituted at least two thirds of its mass by calcium silicates 3CaO.8iO, and 2CaO.Si02, the rest being constituted by aluminum and iron and other compounds. Other types are manufactured in addition to the normal gray clinker such as: Initial High Resistance Clinker, SR Clinker, Low Alkaline Clinker or White Clinker.

The next phase of the process consists in a dosing of the clinker with approximately 5% of plaster that regulates the setting of the cement and prevents

an instant hardening of the same allowing a workability of approximately 2 hours. Cements with clinker and plaster are those considered traditional and are called Type 1. The rest of the cements are made by mixing with the clinker and plaster the additions that are fly ash, blast furnace slags, pozzolans and limestones that improve the properties of Cements for some purposes giving rise to composite cements.

The materials are dosed according to the cements to be manufactured, mixed and ground to a high fineness in mills that are generally balls equipped with third-generation dynamic separators that allow a control of the granulometry of the final product. Subsequently, the cement is stored in silos and sold in bulk or in sacks protected with plastic.

With efficient grinding and high-tech separation procedures (top-down technology) it is possible to manufacture microcements, that is, very fine cements. There are currently three types of microcements: TP 32, TP12 and TP 6 that have all their particles smaller than 32 microns, 12 microns and 6 microns respectively. Two aspects that limit the manufacture of microcements of granulometry lower than the one currently available are energy consumption and separation technology. Without improving these aspects, obtaining these products is at least in an economically reasonable industrial way.

The first key aspect to reduce the price of these products is the reduction of the energy consumption necessary for their production, specifically in relation to the grinding energy. In this respect, it is necessary to consider that the necessary grinding energy increases exponentially as the particle size is reduced. Thus, currently TP32 cement is relatively affordable, with high but reasonable energy consumption of about 150 kw / t, while TP 12 has an energy consumption of the order of 300 Kw 11. The TP6, by far the best performance, It has very high energy consumption, of the order of 1000 kw / t. At this moment, the technical knowledge barrier is in TP6, and getting finer microcements is a great technological challenge.

It would be desirable to be able to manufacture the TP1, with all its particles smaller than 1 micron.

Currently, high performance concrete technology is based on the use of high performance cements to which special additions are added to achieve new properties. The current EHE Structural Concrete Standard has opened a field of these additions and has placed them in great value to extend the durability of concrete in very aggressive environments, especially those exposed to chlorides, de-icing salts and carbonation. Some of the most important are: - Silica smoke, a byproduct of the quartz reduction process, which is used to obtain high strength concrete. -Metacaolin, which is obtained from the thermal activation of the kaolin and the modification of the crystalline structure.

Currently there are many investigations that with the addition of special additions, usually micro and nano, expect to achieve special properties of high mechanical performance, conductivities, oxidizing properties of air pollutants, etc.

In addition, many materials, among which are floors, rocks and even concrete, tend to present porosities that are undesirable from the point of view of their possible uses, either because such porosity decreases the mechanical properties thereof, or because it absorbs water that penetrates the material with swelling and retraction, or because it compromises its durability by leachate (especially in concrete), etc. Porosity is usually macroscopic greater than 1 mm but also microscopic reaching micro and even nano sizes. To reduce this porosity and achieve a stabilization of the material with the desired properties, injections of materials that have a particle size in the case of solids smaller than the size of the porosity are usually carried out. An efficient way to reduce porosity is to inject grouts of normal cements or even mortars first to reduce macroporosity, then finer cements and then the range of microcements that reach TP6 cement, that is, all its particles below 6 microns From this cement it is necessary to resort to liquid resins that in addition to their serious inconveniences of price, toxicity, impact on the environment, also have a great application problem that is usually its high viscosity.

The realization of microinjections is a common practice carried out in a wide range of applications, which can be grouped mainly into three categories: - Waterproofing: intended to prevent the passage of water in tunnels, dams, form screens in contaminated land, protect underground currents, etc. . -Fill: in this case it is intended to fill gaps so that loads are transferred and existing structures are reinforced. -Consolidation: this action joins the cracked material, improving its resistance. It is often used in tunnel and bridge land, but also in old masonry structures.

The ultimate purpose of microinjection is to recreate the monolithic properties of the original material (for example: hardness, stiffness or density). Depending on their use, the requirements for injection materials are different. At the national level, the UNE-EN 1504-5 regulations include the requirements that they must meet, grouping them by their nature into two categories: -Polymeric materials, whose hardening is related to a polymerization reaction. Epoxy resins, polyurethanes and acrylic gels are included here. -Hydraulic materials, whose hardening depends on a hydration reaction. They include fluid cements and microcements.

In general, the field of application of each of the materials used in concrete microinjections is marked according to their permeability. Thus, the smaller the particle size, the better permeability properties are obtained, and consequently it is possible to repair smaller cracks.

With existing materials it is currently possible to penetrate micro porosities of up to 100 ~ m. However, the size and concentration of a large part of the particles do not allow penetration into lower micro porosities. In the microcements that have been developed so far (TP32, TP12 and TP6), the permeabilities that are reached reach levels of 10-6m / s. For lower permeabilities, current approaches have been directed to the use of synthetic materials (resins), and many types of them that offer different solutions for certain problems, such as:

-

Organomineral resins: based on sodium silicates as an inorganic product and an isocyanate as organic. They are the most used in civil works and can be classified into expansive resins (or foams) and not expansive (or consolidation). They solve problems of waterproofing, filling and consolidation of land. -Poliurethanes: they are used both in the sealing of waterways, with aquatreactive resins, and in the consolidation of areas where a product of low viscosity is needed. They are very adherent and elastic. -Metacrilatos: are the resins of lower viscosity and are used for sealing cracks and fissures of small thickness. They are also used in the consolidation of non-cohesive soils. -Other: there are also ureaformaldehyde and phenolic resins, but they are used more in mining than in civil works.

Although these resins are widely used, their synthetic nature and the existence of components that may be harmful to health and the environment are raising suspicion among society. Thus, for example, during the application of these materials and their hardening there is a great risk for both the workers involved, who must be properly protected, as well as for the environment, due to the toxicity of both uncured materials and agents. curing agent or other additives used (for example, solvents to increase the fluidity of the resins). This, together with the high cost of resins, means that today there is a growing demand for products that are capable of replacing polymeric materials, exhibiting behavior similar to these but cheaper and safer. The present invention is therefore oriented to the solution of the aforementioned problems, posing a viable alternative to the polymeric materials currently applied in the repair of small cracks.

It would therefore be desirable to be able to develop a new microcement with a maximum particle size of 1¡.Jm, surpassing the existing particle sizes currently on the market. Microcements are cements whose maximum particle size is very small, and whose main field of application are injection jobs. The application of microcements began in Japan approximately 20 years ago, spreading rapidly to most of the countries in the world where, due to its geology and complexity of works, it has been required. The main characteristic of this type of cement is the low granulometry value they possess, as well as their high durability performance. This new product poses a viable alternative to the polymeric materials currently applied in the repair of small cracks.

With the TP1 whose technology is framed in the so-called top-down it seems that the limit of its possibilities is reached, in terms of the particle size of the materials obtained.

Crystal or vitreous compounds are known in the state of the art as those contained in European Patent No. 07788656.2 or in European Patent No. 07788656.

Thus, it would be desirable to provide microcements, that is, very fine cements, with a very small particle size or particle size in an industrial and reasonable manner, solving the current mentioned problems of energy consumption and separation technology, and providing excellent hardness properties, stiffness and density. Thus, the present invention is aimed at providing microcements whose maximum particle size is very small, whose main field of application are injection jobs, whose main characteristic is the low granulometry value they possess, as well as their high durability performance, in such a way that a viable alternative to the polymeric materials currently applied in the repair of small cracks is provided.

SUMMARY OF THE INVENTION

Thus, the general objective of the present invention is to develop a new range of nanomicrocements whose particle size is between 400 and 1000 nm (1 micron), with an energy efficient manufacturing process as well as economically viable.

These nanomicrocements have been developed for use as microadditions to cause a qualitative leap in the behavior of concrete from the point of view of mechanical properties as well as durability and for use in the microinjections of soils, rocks and concrete in order to achieve improvements in its permeabilities.

To continue with the objective of obtaining materials with smaller particle size, the invention uses down-top technology, that is to say from injections of liquid precursors, in the case of the invention in a high temperature flame, to form cementitious compounds with an innovative technology that will allow a new era in cement manufacturing.

To this end, it has been investigated in precursors that thermodynamically evolve to the known crystalline or vitreous compounds, with the chemical composition required and with the smallest possible particle size, which the invention frames on the scale called nano-micro between 400 and 1000 nm, the nano scale O -100 microns, and the intermediate between 100 to 400 nm.

These nanomicrocements have been developed for use as microadditions to cause a qualitative leap in the behavior of concrete from the point of view of mechanical properties as well as durability and for use in the microinjections of soils, rocks and concrete in order to achieve improvements in its permeabilities.

Other features and advantages of the present invention will be apparent from the following detailed description of an illustrative embodiment of its object in relation to the accompanying figures.

DESCRIPTION OF THE FIGURES

Figure 1 represents a schematic view of the elements that make up the nanomicrocement manufacturing facility according to the invention.

Figure 2 shows a graph showing the result of a nanomicrocement pozzolanicity test according to the invention.

DETAILED DESCRIPTION OF THE 1NVENTION

The objective of the present invention is to develop a new range of nanomicrocements whose particle size is between 400 and 1000 nm (1 micron), obtained by means of an energy efficient manufacturing process as well as economically viable.

These nanomicrocements have been developed for use as microadditions to cause a qualitative leap in the behavior of concrete from the point of view of mechanical properties as well as durability and for use in the microinjections of soils, rocks and concrete in order to achieve improvements in its permeabilities.

The general objective of the invention is broken down into the following specific objectives:

Provoke a qualitative leap in improving the characteristics of the

concretes that are going to use these nanomicrocement in terms of

durability, mechanical resistance, waterproofing, and

especially the permeability of chlorides to increase the durability of reinforced concrete in marine environments, de-icing salts and other aggressive environments. Get an offer of industrialized nanomicroads that reach the real applications of construction in a competitive way and therefore are innovative construction materials of the new century

XXI. Provoke a qualitative leap in the range of microcements with nanomicrocements for their best features and expand their scope. Achieve permeabilities in the products injected with the same better than with resin injections, for use micro porosities that until now cannot be solved with the current cements / microcements. Minimize the energy consumption of the microcement production process with a new technology to make its manufacture economically viable and / or profitable. Obtain a product with adequate characteristics that is capable of replacing the requirement of current concrete regulations (EHE) for the use of silica smoke to increase durability, since silica smoke is a byproduct of limited and very expensive production . Achieve a highly competitive industrial manufacturing process for the new range of microcements. Achieve a new range of completely new nanomicrocements in the cement industry, allowing us to increase the radius of our current market thanks to worldwide export, our market share, expanding the client portfolio, as well as the current sales level.

In order to achieve the general objective and the specific objectives

Previously, it has been necessary to undertake the following operational objectives: Development of precursor materials for cementitious materials that allow to obtain particles of smaller granulometry.

1. Precursors for cementitious particles of pozzolanic character.

These precursors have given as final product the following 5 chemical compositions:

~ Chemical composition formed by at least 40% 5i02, being the

remaining components A1203, Fe203, CaO and MgO, Na20, K20, as well

as small amounts of other items with activity

puzolanica based on the predominant reaction of Si02 with (OH) 2Ca released by cement hydration to form CSH gel with

cementitious properties.

~ Chemical composition formed by at least 20% A1203, being the

remaining components Si02, Fe203, CaO and MgO, Na20, K20, as well

as small amounts of other items with activity

pozzolanic based on the predominant reaction of AI203 with (OH)

2Ca released by cement hydration to form hydrated calcium aluminates.

./ Chemical composition formed by at least 40% 3i02 and at least

20 20% A1203, the remaining components being Fe203, CaO and MgO,

Na20, K20, as well as small amounts of other elements with a mixture of pozzolanic activity based on the reaction of 5i02

with (OH) 2Ca released by cement hydration to form CSH gel with cementing properties of AI203 with (OH) 2Ca released

25 by cement hydration to form hydrated calcium aluminates.

2. Precursors for latent hydraulic cementitious particles

30 These precursors have given as final product the following chemical compositions:

./ The chemical composition that meets the chemical requirements of CaO + Mg / Si02 greater than 1 which has hydraulic activity

latent.

3. Hydraulic particle precursors

These precursors have given as final product the following chemical compositions: ./ The chemical composition that is formed by at least 50% CaO,

the remaining components being Si02, A1203, Fe203, and MgO, Na20,

K20, as well as small amounts of other elements with high cement activity.

To achieve the above chemical compositions, mixtures of the following precursor materials injected according to Figure 1 have been used and which allow to achieve the required chemical composition:

o Sodium silicate or silicic acid solutions as a precursor

of contribution of Si02.

o Solutions of calcium hydroxide or calcium bicarbonate as

CaO contribution precursor.

o Aluminum hydroxide solutions as a contribution precursor

o Solutions of sodium and potassium carbonate as precursors

of A1203.

of contribution of Na20 and K20.

o Acid solutions of cements, blast furnace slags and other slags, limestone, marls and similar materials as precursors of all the previous oxides.

The following tables present the results obtained, according to the

invention.

Hydraulic Material laiente 1 Chemical Analysis (%)> 10, AI ~ O ~ h: O,

Ref Material 9 ~~. 1 6 8.1.1 I, ~ Granulome tria (% Pasa) '"lOO, .., Material of Ref 9 13.1 2ó, r J8,8

e.o: l1l!, 0 SO ".0

~ O.6 "'A." . ", .. '" (l1) '"'" ,, ~ J2

..... 0 e,

OH., "" "" " $ ~. 1 'M

UNCLE:

. " , .. 100. <1

Latent Hydraulic Material 3

Re! Material eleven Granul om e tría () ~ Pass) t..Jlaterial de Re! eleven

.'HO.

F 100 L ~ .9

.u, ~ - ,, -.

1l.h 200 2), 1) -----

. ~ ~! OJ

Or < .11111 ~ I ",

<: '•. 0

J] .. 5 <Or. jO_ ~

; \ 1, 0

6R ': O; ~ Iln : 'Io.?

SW,

0.0 60 'M

K.O

~ -I5 7-0 {/ ~ g..1

~ lIl ()

0.18 or'" ; 9.6

rr uncle.

(l, OI 0.0 ".1000 90.3 100.0

Hydraulic Material 1 Chemical Analysis (%)

Rel 1.2 Material Granulometry a (% Pass) M relial of Rel 12

Pf

:: M lOO "

SIl):

1 '9. ~ '" ,. "

"\ 1: 01

(; 317 300 ,} Y, iI

Ff ': O, e.o

¡; 06;. ~ "","or .19.2 5S, ::

". bear,

2 ~ 6 J.38 '"'" ' ".,;5..!

i \ ~ Q

... '00 8;, 6

"· ...: 0

(1, -3 ,, " 9U

cr

(1.03 1,000 J03J)

Reference

Granulome

Analysis

Material

Malerial

triad

Chemical

PUlolánico

Puzzler

(% Pass)

«, ~)

Sieve (nm)

510,

_ ~ i. ~

10.

one"

. \ 1.0

:: 6.4

tOO

.! 9r

F ,,; or (.))

Jm

6.,

~ ", OR

e.o

49.1

. "

; \ 1.0

OJ

'66' ',, 6'

'' ''

SW,

.00

0.0

'Oit

l.1

'H

""OR

~: It ~ f)

1} .: 2

li, j ".l

".

g

~ t ~

0, '

".

100J)

oo.

OR,,

J006

ES 2 402 131 Al

Chemical Analysis Reference (%)

Pozzolanic material 2 Granulol 11etry (% Pass) Sieve (nm) Pozzolanic material 2

'F 510;

l "'~», 1 "." -... ", 9

..I.} Or ..,

" , .. 30.0

1 '' '; 0

~ .S ... ... 40.1 "'

e.o

: '\ (19' 0,

1.-6 0. ' ..., JO <) J9.:! "',.

"

o.oo ~ &the '9 ~ (

... one

"ALoo.o

5 In the preferred embodiments just described, those modifications within the scope defined by the following claims can be introduced.

Claims (8)

1. Nanomicrocement whose particle size is between 400 nm and 1000 nm (1 micron), obtained by injecting at least 5 a precursor element for cementitious materials that allows to obtain particles of lower particle size, applying this precursor element for cementitious particles in the base material, this precursor element evolving thermodynamically to known compounds with the required chemical composition and the size of The smallest possible particle, the at least one precursor element being one of the following: a precursor for cementitious particles of a pozzolanic character, a precursor for cementitious particles of latent hydraulic character or a precursor for cementitious particles with a hydraulic character.

2.

Nanomicrocenter according to claim 1, wherein the precursor element is liquid and injected into a flame at high temperature.

3.

Nanomicrocement according to any of claims 1-2, in the

20 that the injected precursor element is a precursor for pozzolanic cementitious particles, obtaining as a final product a chemical composition formed by at least 40% Si02, the remaining components being A1203, Fe203, CaO and MgO, Na20, K20, as well as small quantities of other elements with pozzolanic activity 25 based on the predominant reaction of Si02 with (OH) 2Ca released by cement hydration to form CSH gel with cementitious properties. 4. Nanomicrocement according to any of claims 1-2, in the 30 that the injected precursor element is a precursor for pozzolanic cementitious particles, obtaining as a final product a chemical composition formed by at least 20% A1203, the remaining components being Si02, Fe203, CaO and MgO, Na20, K20, as well as . small amounts of other elements with pozzolanic activity based on the predominant reaction of AI203 with (OH) 2Ca released by cement hydration to form hydrated calcium aluminates.

5.

Nanomicrocement according to any of claims 1-2, wherein the injected precursor element is a precursor for pozzolanic cement particles, obtaining as a final product a chemical composition formed by at least 40% 302 and at least 20% A1203, the Remaining components Fe203, CaO and MgO, Na20, K20, as well as small amounts of other elements with a mixture of pozzolanic activity based on the reaction of Si02 with (OH) 2Ca released by cement hydration to form CSH gel with cementing properties of AI203 with (OH) 2Ca released by cement hydration to form hydrated calcium aluminates.

6.

Nanomicrocement according to any of claims 1-2, wherein the injected precursor element is a precursor for latent hydraulic cementitious particles, obtaining as a final product a chemical composition that meets the chemical requirements of CaO + Mg / Si02 greater than 1, with latent hydraulic activity.

7.

Nanomicrocement according to any of claims 1-2, wherein the injected precursor element is a precursor for hydraulic cementitious particles, obtaining as a final product a chemical composition that is formed by at least 50% CaG, the remaining components being Si02, A1203, Fe203, and MgO, Na20, K20, as well as small amounts of other elements with high cement activity.

8.

Nanomicrocemento according to any of the preceding claims, wherein the injected precursor elements are a mixture of at least one of the following elements: sodium silicate solutions or

silicic acid as Si02 contribution precursor, calcium hydroxide or calcium bicarbonate solutions as CaG contribution precursor, aluminum hydroxide solutions as a contribution precursor of A1203, solutions of sodium and potassium carbonate as contribution precursors of Na20 and K20 or acid solutions of cements, blast furnace slags and other slags, limestones, marls and similar materials as precursors of all the previous oxides.