WO2014147282A1

WO2014147282A1 - Ceramic residue for producing cements, method for the production thereof, and cements containing same

Info

Publication number: WO2014147282A1
Application number: PCT/ES2014/070212
Authority: WO
Inventors: María Isabel SÁNCHEZ DE ROJAS; Moisés FRÍAS ROJAS; Eloy ASENSIO DE LUCAS; César MEDINA MARTÍNEZ
Original assignee: Consejo Superior De Investigaciones Científicas (Csic)
Priority date: 2013-03-22
Filing date: 2014-03-21
Publication date: 2014-09-25
Also published as: ES2512065A1; ES2512065B1

Abstract

The invention relates to a ceramic residue produced from construction and demolition residues, as a puzzolanic component of cements. The invention also relates to a method for producing said ceramic residues and to another method of producing cements using said residues. This type of residue is collected in recycling plants, where it is managed. This invention facilitates a potential commercial launch.

Description

USEFUL CERAMIC WASTE FOR THE DEVELOPMENT OF CEMENTS. PROCEDURE OF OBTAINING AND CEMENTS THAT UNDERSTAND IT

SECTOR OF THE TECHNIQUE

The present invention is part of the construction sector, and more specifically in the cement industry, which, forced by a foreseeable decrease in the materials currently used, will demand alternative products that have viable technological, environmental and economic advantages for the sector.

STATE OF THE TECHNIQUE

Construction and demolition waste (RCD) includes different materials, among which the bricks, tiles and other ceramic materials stand out for their quantity, as they represent more than half of the total of this type of waste.

In the manufacturing process of ceramic products, natural materials are used as raw material, which contain a high proportion of clay minerals, which by means of a dehydration process, followed by another controlled cooking at temperatures between 700 ° C and 1000 ° C acquire its characteristic properties of "cooked clay". The incorporation of materials from these construction and demolition wastes in the manufacture of cements would allow the concept of sustainability to be introduced in the construction sector, a sector that is traditionally considered as disrespectful of the environment, thus being consistent with European and national sustainable development policies. In the present invention a new use of these ceramic residues for the manufacture of cements is described.

BRIEF DESCRIPTION OF THE INVENTION

An object of the invention is a ceramic residue useful for the manufacture of cements characterized in that it comprises at least 20% of ceramic material from construction and demolition or manufacturing waste, which possesses a pozzolanic activity and adequate granulometry ( the optimization of the process is sought by applying the materials of lower granulometry, to facilitate subsequent grinding).

Another object of the invention is the process for obtaining the ceramic residue of the invention comprising the following steps:

a) collection of starting waste directly at the recycling and management of construction and demolition waste (RCD recycling plants) or manufacturing plants,

b) waste selection of a) so that there is at least 20% ceramic content,

c) drying the residue of b) in an oven at 105 ° C to constant weight,

d) crushing or grinding the residue of c) the time required to obtain a size smaller than 63 μιη, and

e) sieving the residue of d) with a sieve of 63 μιη to obtain the ceramic residue.

Another object of the invention is cement, hereinafter cement of the invention, which comprises the ceramic residue of the invention as a component in said cement in a percentage of between 0.1% and 55%. In a preferred embodiment of the invention the cement comprises the ceramic residue as the main component in said cement in a percentage of between 6% and 55%. In another preferred embodiment of the invention, the cement comprises the ceramic residue as an additional minor component in said cement in a percentage of between 0.1% and 5%.

Another object of the invention is the process for obtaining the cement of the invention, hereinafter the method of the invention, which comprises the following steps:

a) mixing the ceramic residue of the invention with a cement in a proportion between 0.1% and 55% to ensure proper homogenization, and

b) storage of the mixture of a) in a sealed place to avoid carbonation and humidification thereof.

DETAILED DESCRIPTION The present invention is based on the fact that it has been observed that from a construction and demolition waste (RCD) (Figure 1) it is possible to obtain a ceramic residue that acts as a pozzolanic material useful as an additive for cement manufacturing when it contains at least 20% of this ceramic residue and when prepared as a homogeneous product, with a fine grain size less than 63 μιη (particle size similar to cement) (Figure 2). These ceramic wastes can be obtained from construction and demolition waste recycling plants and their factories and can thus offer a commercial outlet to this waste material.

This ceramic residue (Figure 2), is introduced into the cements as the main component (6-55% by mass) and is framed within pozzolans natural calcined (Q) and also as a minor component (percentages below 5% by mass), provided that it is not already included as a majority component. Different types of cements can be obtained with this product, depending on the dosages made.

The ceramic waste described in the present invention that comes from construction and demolition waste can be considered as calcined natural pozzolans, where according to UNE-EN 197-1: 201 1 (Spanish Standard UNE-EN 197-1: 201 1 " Cement: Part 1: Composition, specifications and conformity criteria of common cements ", December 201 1), calcined natural pozzolans (Q) are defined as materials of volcanic origin, clays, slates or sedimentary rocks activated by thermal and compliant treatments with section 5.2.3.1. (Generalities of pozzolanic materials P, Q).

In this way and according to the UNE-EN 197-1: 201 1 standard, they could be used as the main component (percentages greater than 5% by mass) in the manufacture of cements CEM ll / AQ, CEM ll / BQ, CEM IV / A, CEM IV / B, CEM V / A and CEM V / B, and can also be used as a minor component (percentages below 5% by mass) giving rise to any of the main types of cement (CEM I, CEM II , CEM III, CEM IV and CEM V) provided that it is not already included as a majority component.

The incorporation of materials from these construction and demolition wastes in the manufacture of cements would allow the concept of sustainability to be introduced in the construction sector, a sector that is traditionally considered as disrespectful of the environment, thus being consistent with European and national sustainable development policies.

According to section 5.2.3.1 of the UNE-EN 197-1: 201 1 standard, pozzolans are essentially composed of silicon dioxide (Si0 ₂ ) and oxide of aluminum (AI2O3). The rest contains iron oxide (Fe ₂ Ü3) and other oxides. The reactive silicon dioxide content must be greater than 25%. The composition of the construction and demolition ceramic waste, object of this invention, would meet these requirements.

Thus, an object of the invention is a ceramic waste useful for the manufacture of cements characterized in that it comprises at least 20% of ceramic material from construction and demolition or manufacturing waste, which has a pozzolanic activity and a particle size. adequate (the optimization of the process is sought by applying the materials of lower granulometry, to facilitate subsequent grinding).

An object of the invention is the process for obtaining the ceramic waste of the invention, hereinafter procedure for obtaining the ceramic waste of the invention, which comprises the following steps: a) sample collection directly in the recycling and management plants of construction and demolition waste (RCD recycling plants) or manufacturing plants,

b) waste selection of a) so that there is at least 20% ceramic content,

c) drying the residue of b) in an oven at 105 ° C to constant weight,

d) crushing or grinding the residue of c) the time required to obtain a size of less than 63 μιη, for example, approximately 3 minutes (depending on the amount of material introduced into the ring), and

e) screening the residue of d) with a sieve of 63 μιη to obtain the ceramic residue. The cement with which the invention is to be made is a 42.5 R resistant Portland cement according to UNE-EN 197-1: 201 1, although it is not limiting; the difference in the use of one cement or another will influence the final performance, the final behavior of the invention can be adapted to the characteristics of the cement used.

Also, if the process of incorporating ceramic waste from RCD recycling plants (construction and demolition waste) is carried out directly at the cement factory, these could be added and ground together with the clinker, in the percentages suitable for the manufacture of the different types of common cements of the UNE-EN 197-1: 201 1 standard.

Another object of the invention is cement, hereinafter cement of the invention, which comprises the ceramic residue of the invention as a component in said cement in a percentage of between 0.1% and 55%. In a preferred embodiment of the invention the cement comprises the ceramic residue as the main component in said cement in a percentage of between 6% and 55%.

In another preferred embodiment of the invention, the cement comprises the ceramic residue as an additional minor component in said cement in a percentage of between 0.1% and 5%.

Another object of the invention is the process for obtaining the cement of the invention, hereinafter procedure for obtaining the cement of the invention, which comprises the following steps:

b) storage of the mixture of a) in a sealed place to avoid carbonation and humidification thereof. Another particular object of the invention is the process for obtaining cement where the proportion between the ceramic waste and the cement of a) meets the following formula: mtotal ^- rricemento ⁺ rflresiduo

m _C ement ⁼ mtotal ^* (1 -X)

ITIresiduo = X ^* mtotal

being:

Total mass of the mixture to be made

- m _cement0 : cement mass used

m regular ^' - mass of ceramic waste

X: percentage by one of the ceramic waste.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1. Initial aspect of the RCD sample taken by camera.

Figure 2. Appearance of the milled and screened sample below 63 μιη taken by camera.

EXAMPLES OF EMBODIMENT OF THE INVENTION

In this example of the invention a mixture of cement with ceramic construction and demolition waste is carried out as a component. Ceramic residues (Figure 1), could act in cements as the main component (6-55% by mass) and would be framed within calcined natural pozzolans (Q) and also as a minor component (percentages below 5% by mass), provided that it is not already included as a majority component, according to UNE-EN 197-1: 201 1. With this ceramic residue of the invention, depending on the dosages made, cements of type CEM ll / AQ, CEM ll / BQ, CEM can be obtained IV / A, CEM IV / B, CEM V / A and CEM V / B, or cements of any type (CEM I, CEM II, CEM III, CEM IV and CEM V) if used as minority components. To study the conformity of this ceramic waste with the standard and its possibility of being used as a pozzolanic material, the starting waste was collected from the recycling plant, a ceramic waste was selected and prepared with the proportion of ceramic material indicated (not less than 20%) (Table 2).

It was then conditioned, based primarily on drying the sample in an oven at 105 ° C. Subsequently, the material was crushed, reducing its size and facilitating subsequent grinding in a ring mill. Once this grinding is achieved, the sample is sieved to obtain a homogeneous product, with a fineness lower than 63 μιη, similar to that of cement, as can be seen in Figure 2.

The chemical composition of the ceramic waste studied in Table 1 meets the requirements of the standard referred to, and is similar to that of other widely known pozzolanic materials and collected in the UNE-EN 197-1: 201 standard 1, such as fly ash and silica smoke (Table 1). In addition, these residues meet the specifications of the reactive silica according to UNE-EN 197-1: 201 1, where the content must be greater than 25%.

Table 1. Comparison of the chemical composition of different pozzolanic materials.

Materials Losses Si0 ₂ Al ₂ 0 ₃ Fe ₂ 0 ₃ CaO MgO S0 ₃ Na ₂ 0 K ₂ 0 Pozzolanics by (%) (%) (%) (%) (%) (%) (%) (%) calcination

(%)

Smoke of <4> 85

Silica

Ash 6 32 13 6 35 2 4 <1 1 high flywheel

in lime

Ash 2 51 31 7 3 1 1 <1 3 flywheel

in lime

Residue 2-27 25- 6-12 2-4 12- 1 -10 0-3 0-1 1 -3 Ceramic 61 31

of the

invention ^*

^* , describes the minimum and maximum obtained with the different mixtures described in Table 2.

Substitutions were made in the cement waste with different percentages of ceramic material, shown by way of example in Table 2.

Table 2. Substitutions in the cement with ceramic residue of the invention with different proportion of ceramic material

^" ^ \% Ceramic material in

These mixtures of ceramic waste of the invention and cement, in different proportions, meet the requirements of chlorides and sulfates, whose limit concentrations in the cements are also included in the UNE-EN 197-1 standard, according to the test methodologies of the LINEEN 196-2: 2006 standard (values below 3.5% or 4.0% for sulfates, expressed as SO3 and values below 0.1% for chlorides). Table 3 shows the concentrations of SO3 and chlorides for the ceramic waste from RCD and the cement used as a reference, as well as the cement manufactured with the ceramic waste of the invention in the different percentages shown in Table 2 and the highest percentage of sulfates and chlorides in ceramic waste from RCD.

Table 3. Content in minor components.

^* The cement used is taken into account

In view of the results, and taking into account the aforementioned standard, this type of materials would be in accordance with the limits established by the standard. For physical and mechanical requirements, such as setting time, volume stability and mechanical resistance, according to UNE-EN 196-3: 2005 and UNE-EN 196-1: 2005, values are obtained that would comply with the limits established in the norm UNE-EN 197-1: 201 1, being therefore shown in tables 4, 5 and 6 respectively.

Table 4. Setting times for the different examples performed

Time of

Setting

(min)

M1> 60

M2> 60

M3> 60

M4> 60

M5> 60

M6> 60

M7> 60

M8> 60

M9> 60 i volume for different

Stability of

volume

(mm)

M1 <10

M2 <10

M3 <10

M4 <10

M5 <10

M6 <10

M7 <10 Μδ <10

M9 <10

Table 6. Mechanical compressive strengths for the examples made

^* Results obtained at 28 days according to the specifications of the UNE-EN 197-1: 201 1 standard, and according to the test methodology of the UNE-EN 196-2: 2005 standard

^** Average values of compressive strengths

With respect to its mechanical properties shown above, all CEM ll / A portland cements, which contain as a main component this ceramic material in a percentage between 6% - 20%, could be used to manufacture portland cements with a strength class 32.5 (N and R) and 42.5 (N and R), according to the mechanical requirements established in table 3 of the UNE EN 197-1: 201 1 standard. When its content is between 21% - 35% by mass, portland cements of type CEM ll / B, type CEM IV / A and type CEM V / A could be used to manufacture cements of a strength class 32.5 (N and R), complying with the requirements set out in the table of the standard mentioned above. When the content is between 36% - 55% by mass, CEM IV / B and CEM V / B type cements would be resistant classes of 32.5 N, although not in all cases.

On the other hand, for CEM IV type cements, compliance with the test described in the UNE-EN 196-5: 2000 standard is established, pozzolanicity test, according to this test, the cements with these additions, would comply with this requirement to the age of 8 days, although this result will be affected by the content of ceramic material in the RCD considered, so it is established that this type of ceramic waste from RCD is active additions from the pozzolanic point of view, the results are shown at continued in table 7. Table 7. Pozzolanicity test for the examples performed

* This specification must be met by CEM IV A / B, whose replacement percentages range from 21 -55%.

Claims

one . Ceramic residue useful for the manufacture of cements characterized in that it comprises at least 20% of ceramic material from construction and demolition or manufacturing waste, has a pozzolanic activity and a particle size of less than 63 μιη.

2. Procedure for obtaining the ceramic waste according to claim 1 characterized in that it comprises the following steps: a) collection of starting waste directly in the recycling and construction of demolition waste management plants (RCD recycling plants) or manufacturing plants,

b) waste selection of a) so that there is at least 20% ceramic content,

c) drying the residue of b) in an oven at 105 ° C to constant weight,

d) crushing the residue of c) the time required to obtain a size smaller than 63 μιη, and

3. Cement characterized in that it comprises the ceramic residue according to claim 1.

4. Cement according to claim 3 characterized in that the ceramic residue is comprised between 0.1% and 55% as a component in said cement.

5. Cement according to claim 4 characterized in that the ceramic residue is comprised between 0.1% and 5% as a component in said cement.

6. Cement according to claim 3 characterized in that the ceramic residue is comprised between 6% and 55% as a component in said cement.

7. Procedure for obtaining the cement according to claims 3 to 5, characterized in that it comprises the following steps:

a) mixing the ceramic residue according to claim 1 with a cement in a proportion between 0.1 and 55% to ensure correct homogenization, and

8. Method according to claim 7 characterized in that in the mixing stage the proportions between the ceramic residue and the cement meet the following formula:

mtotal ^- m _C ement ⁺ m _re siduo

mcemento ⁼ mtotal ^* (1 -X)

m _re siduo = X ^* mtotal being:

Total mass of the mixture to be made

m _cemen to ^' - cement mass used

mresiduo- mass of ceramic waste

X: percentage by one of the ceramic waste