METHOD FOR PRODUCING CEMENTING MATERIALS PRODUCED FROM THE RECYCLING OF INDUSTRIAL WASTE FROM THE PROCESSES OF PRODUCING CERAMICS AND BRICKS

Abstract

A method for producing a cementing material from the waste from the brick and ceramics industry is provided, the method being selecting the batches of waste from bricks and ceramics for a subsequent grinding, in which they should achieve a grain size of between 20 and 40 microns, and wherein this waste can be mixed together or used individually to be subsequently included in the cement in a proportion of up to 30%, wherein the mixtures can achieve designs of up to 4000 PSI.

Claims

1. A method for producing cementitious materials made from the recycling of industrial waste from the processes of production of ceramics and brick, comprising: a. selecting structural and nonstructural brick waste or byproducts, which have been fired at a temperature of between 500 and 1000 C. b. selecting ceramic parts waste, which have been fired at a temperature of between 700 and 1200 C. c. separately crushing the waste selected in steps a and b until obtaining particle sizes of between 10 and 80 microns. d. mixing crushed fines resulting from step c, from 40 to 60% of fines from brick waste and 40 to 60% of waste from ceramic parts.

2. The method for producing cementitious materials made from the recycling of industrial waste from the processes of production of ceramics and brick according to claim 1, wherein the material selected from steps a and b have a humidity of less than 1%.

3. The method for producing cementitious materials made from the recycling of industrial waste from the processes of production of ceramics and brick according to claim 1, wherein the cementitious material resulting from step d is incorporated into matrices of cement and/or concrete in a range from 0.5% to 40%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0015] The cementitious materials proposed by the present invention have been designed and developed to resolve the aforestated problems, by virtue of the fact that by using industrial waste from brick and ceramics manufacture, and once having been converted into cementitious materials, they generate less environmental impact by virtue of the fact that less greenhouse gases are emitted and, furthermore, they have a smaller carbon footprint than the manufacture of cement.

[0016] The locations where industrial waste is generated must be identified, whether from bricks and/or ceramics. An initial process of selection must be carried out upon each waste material to verify that it does not contain contaminant particles or materials such as plastics, wood, carbon, ash, metals, others, and, subsequently, materials characterization is carried out to identify the chemical composition, the mineralogical composition, the quantity of amorphous materials, the loss on ignition, and the temperature whereat the initial crystalline structure thereof was modified.

[0017] On having identified the potential use of the waste as cementitious materials, it requires to be passed through industrial processes of crushing, grinding and microgrinding. Once the material achieves the particular grain size fineness, the technical viability of the material must be evaluated in terms of the raw materials required by concretes, mortars or precast products. If the properties of the cementitious material are correct, when compared with those of cement, the appropriate percentage must be determined of substitution for cement in matrices of concrete, mortar and precast products.

[0018] A) Selection of Material [0019] Waste from Brick Works

[0020] Cementitious products must be selected, manufactured from defective fired bricks (structural and nonstructural, roof tiles, pavers). These are silico-aluminous materials fired at temperatures of between 500 and 1100 C., free from contaminants of white or black ash, carbon, refired material, wood, plastic, metal, humidity. The production sheets of these materials must be examined for this purpose. [0021] Ceramic Waste

[0022] Fired ceramic waste (wash hand basins, toilet bowls, cladding, refractory materials, insulant materials, ceiling roses, crockery) shall have the required characteristics, such as being of material fired at temperatures of between 700 and 1300 C., free of contaminants of white ash, metallic materials, wood, plastic, sludge, fine dust from a process of particulate material containment, humidity. The production sheets of these materials must be examined for this purpose.

[0023] B) Crushing [0024] Waste from Brick Works

[0025] The material selected will be passed through mills for the purpose of primary and secondary crushing, concluding with a process of microgrinding whereby a fineness of the material corresponding to less than 10% retained on 325 (45 microns), 400 (38 microns) and 635 mesh (20 microns), and having a humidity lower than 5%, shall be obtained, having the objective of being used as a partial substitute for cement. [0026] Ceramic Waste

[0027] Fired ceramic waste shall have the required characteristics, such as being silico-aluminous material fired at temperatures in a range between 700 and 1300 C., free of contaminants of white ash, metallic materials, wood, plastic, sludge, fine dust from a process of particulate material containment, humidity, and others, and will be passed through processes for particle reduction by means of primary and secondary crushing, concluding with a process of microgrinding whereby a fineness of the material corresponding to less than 10% retained on 325 (45 microns), 400 (38 microns) and 635 mesh (20 microns), and having a humidity lower than 5%, shall be obtained, having the objective of being used as a partial substitute for cement.

[0028] C) Mixing Fines

[0029] Mixing fines from cementitious product waste (defective fired bricks) and ceramic waste (defective fired ceramic parts) at a ratio of between (60:40), (40:60), (50:50), or individually for the generation of the corresponding cementitious material.

[0030] D) Creation of Cementitious Material

[0031] The percentage substitution in concrete matrices lies in the range from 1% to 30% on the basis of designs from 2500 psi to 12 000 psi.

[0032] E) Inhibition of Reactive Aggregate Conditions

[0033] The percentages of addition in concrete matrices are applicable for any type of design, percentages of addition being from 5% upwards, depending on the degree of reactivity of the aggregate contained in the concrete matrix.

Advantages

[0034] Properties of the cementitious materials: great fineness, chemical resistance, mechanical strength, inhibitor of reactive aggregate conditions (alkali-aggregate reaction), and high pozzolanic activity. These materials are deemed to be similar to cement by virtue of:

[0035] I. The chemical composition thereof

[0036] II. The grain size thereof

[0037] III. The pozzolanic index thereof

[0038] IV. The interaction thereof in the concrete matrix

[0039] V. Enduring strength

[0040] VI. The handleability thereof

[0041] VII. Incorporation into the cementitious matrix

[0042] VIII. Inhibition of the alkali-aggregate reaction.

[0043] Depending on the application, these materials may be used both as partial substitutes in cement and in additives for concrete, taking into account that when employed as additives they will act as an inhibitor of alkali-aggregate reactions in the concrete.

[0044] It must be considered that the reactivity of aggregates arises by virtue of: [0045] Environmental conditions [0046] Temperature [0047] External sources of alkalis.

Results

Physical-Chemical Properties

[0048] One of the principal advantages of the new cementitious compositions is the maintenance of similar characteristics to those of traditional cements; in the table below the pozzolanic index thereof stands out, which same, although being variable by virtue of the nature of the materials, always fluctuates at approximately 100%, humidity does not exceed 5%, although habitually it is 1%, grain size is equal to that of traditional cements, as is the setting time thereof.

TABLE-US-00002 Portland Pozzolanic New cementitious Attribute cement cement composition Pozzolanic 100% 100% 85%-140% index: Humidity: <1% <1% <5% 325 mesh, Grain size RM325: RM325: <40% 325 mesh, 8% 8% <50% 400 mesh, <80% 600 mesh Curing time (min) 120 120 120

[0049] In terms of chemical composition, the high content of SiO.sub.2 and Al.sub.2O.sub.3 is emphasized, important for the pozzolanic reaction, although the quantity of CaO is low, for this reason it is important that the cementitious material contain an appropriate quantity of cement in order to be able to react and act in the concrete matrix.

TABLE-US-00003 Cementitious Substance material Cement SiO.sub.2 69.8 22.45 Al.sub.2O.sub.3 23.9 6.55 Fe.sub.2O.sub.3 0.4 2.14 CaO 1.9 54.44 MgO 0.6 0.84 SO.sub.3 2.41 K.sub.2O 1.3 Na.sub.2O 1.2 Free C 0.16 Loss on ignition 9.19 P.sub.2O.sub.5 0.1 TiO.sub.2 0.4

[0050] For better comprehension of the foregoing, the pozzolanic reaction is set out schematically as follows:

Ca(OH).sub.2+H.sub.4SiO.sub.4.fwdarw.Ca.sup.2++H.sub.2SiO.sub.4.sup.2+2 H.sub.2O.fwdarw.CaH.sub.2SiO.sub.4.Math.2H.sub.2O

Performance

[0051] The performance of two compositions containing 7% and 10% of the new cementitious material was compared against a standard of a particular type of cement (for concrete), the balance of the percentage being cement. The test measures the percentage of performance to achieve a specific strength, in this case 4000 psi. In the graph below it may be observed that these new compositions attain the 4000 psi performance level more quickly, presenting an advantage of 4 days in attaining a minimum performance of 100% (4000 psi).

Standard Test for Potential Reactivity

[0052] This test method provides a means to determine the potential of an aggregate for use in concrete, measuring the potentially prejudicial internal expansion thereof. If the concrete expands by more than 0.1% in length at an early stage (first three days) the concrete is deemed to be deficient. Good quality aggregates (natural aggregates, river gravel and sand) prevent concrete being defective, nevertheless these aggregates are increasingly scarce and costly.

[0053] One of the great advantages of this new cementitious material is in that it permits the use of aggregates of lesser quality, such as silicic minerals, and in preventing internal expansion and precluding potential reactivity. In the graph shown below it may be observed how the use of this new cementitious material in different proportions can considerably reduce potential reactivity, particularly those compositions having 15 and 20% substitutions, these demonstrating an expansion of 0.1 after 11 days.

[0054] The foregoing graph is based upon the test according to ASTM C1567 and permits the determination of the efficiency of an additive (silica fume, ash or pozzolana) in minimizing or neutralizing the reaction.