Barium slag-modified aluminate quick-hardening special cementing material and preparation method thereof

Abstract

Disclosed are a barium slag-modified aluminate quick-hardening special cementing material and a preparation method thereof, wherein the raw materials for the preparation of the barium slag-modified aluminate quick-hardening special cementing material includes, in parts by weight: 10-12 parts of aluminate cement clinker, 2-3 parts of barium slag powder, 1.5-2 parts of sulfate material, and 0-1.5 parts of early-setting agent. The present invention, on the basis of ensuring the original advantages of aluminate cement, can increase the long-term strength, durability, and economy, and solve the possible environmental problems caused by the barium slag, making it more suitable for use in various engineering projects.

Claims

1. A barium slag-modified aluminate quick-hardening cementing material, comprising, in parts by weight, following raw materials for preparation of the barium slag-modified aluminate quick-hardening cementing material: 10-12 parts of aluminate cement clinker, 2-3 parts of barium slag powder, 1.5-2 parts of sulfate material, and an early-setting agent; wherein the early-setting agent is present in an amount greater than zero and up to 1.5 parts and wherein the sulfate material and the early setting agent are different; the sulfate material includes at least one of sodium sulfate, calcium sulfate, aluminum sulfate, potassium sulfate, phosphogypsum, and celestite; the early-setting agent comprises at least one of calcium hydroxide, sodium hydroxide, sodium carbonate, sodium sulfate, quicklime, and carbide slag; a mass proportion of tricalcium aluminate in the aluminate cement clinker is 20-40 wt %; a ratio of a molar mass of Ba.sup.2+ in the barium slag powder to a molar mass of SO.sub.4.sup.2?+PO.sub.4.sup.3? ions in the sulfate material is 1:1; wherein a method for preparing the barium slag powder comprises: obtaining a black barium slag powder satisfying that according to GB 5085.3-2007 test, a leaching concentration of Ba.sup.2+ from the black barium slag powder in an acidic solution with a liquid-solid ratio of 10:1 is 1500-2300 mg/L; and subjecting the black barium slag powder to calcining at 800-1200? C., a ball milling and passing through a 200-mesh sieve to obtain the barium slag powder.

2. A method for preparing a barium slag-modified aluminate quick-hardening cementing material, comprising: mixing, in parts by weight, 10-12 parts of aluminate cement clinker, 2-3 parts of barium slag powder, 1.5-2 parts of sulfate material, and an early-setting agent, and then adding water and stirring until uniform to obtain the barium slag-modified aluminate quick-hardening cementing material, wherein the early-setting agent is present in an amount greater than zero and up to 1.5 parts and wherein the sulfate material and the early setting agent are different; and wherein a mass ratio of the added water to solid components is 0.3-0.5.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) In order to more clearly illustrate the technical solutions of the embodiments of the present invention, a brief description will be given below of the accompanying drawings which are required to be used in the description of the embodiments. It is obvious that the drawings in the description below are some embodiments of the present invention, and it would be obvious for a person skilled in the art to obtain other drawings according to these drawings without involving any inventive effort.

(2) The FIGURE is a flowchart of a method for preparing barium slag-modified aluminate quick-hardening special cementing material provided in Example 6 of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(3) The following will elaborate on the present invention in conjunction with specific embodiments and examples, and the advantages and various effects of the present invention will be presented more clearly. Those skilled in the art should understand that these specific embodiments and examples are intended to illustrate the present invention, rather than limiting it.

(4) Throughout the specification, terms used herein should be understood as generally used in the art, unless otherwise indicated. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one skilled in the art to which this invention belongs. In case of conflict, the present specification shall control.

(5) Unless otherwise specifically noted, the various starting materials, reagents, instruments, equipment, and the like used in the present invention are either commercially available or may be prepared by known methods.

(6) The overall idea of the present invention is as follows:

(7) According to an exemplary embodiment of the present invention, provided is a barium slag-modified aluminate quick-hardening special cementing material, comprising, in parts by weight, the following raw materials for the preparation of the barium slag-modified aluminate quick-hardening special cementing material:

(8) 10-12 parts of aluminate cement clinker, 2-3 parts of barium slag powder, 1.5-2 parts of sulfate material, and 0-1.5 parts of early-setting agent.

(9) The present invention provides a barium slag-modified aluminate quick-hardening special cementing material, in which each component cooperates: (1) Ba.sup.2+ in the barium slag and SO.sub.4.sup.2?+PO.sub.4.sup.3? in the sulfate generate framework materials barium sulfate and barium phosphate in the early stage, to which sulfate component is added, reacted with C.sub.3AH.sub.6 component produced in aluminate cement clinker which is unfavorable to the strength in the early stage, and form an ettringite which is favorable to the early strength, so that the barium slag-modified aluminate quick-hardening special cementing material has a very high strength at day 3 (the 3d compressive strength is above 60 MPa; the 14d compressive strength is above 6 5 MPa), and the neat strength is about 1.5-2 times of that of a single aluminate cement clinker. The reaction equations involved include:
Ba.sup.2++SO.sub.4.sup.2??BaSO.sub.4
Ba.sup.2++PO.sub.4.sup.3??Ba.sub.3(PO.sub.4).sub.2
SO.sub.4.sup.2?+Ca.sup.2++2H.sub.2O?CaSO.sub.4.Math.2H.sub.2O
3C.sub.3AH.sub.6+3(CaSO.sub.4.Math.2H.sub.2O)+8H.sub.2O=3CaO.Math.Al.sub.2O.sub.3.Math.3CaSO.sub.4.Math.32H.sub.2O; (2) Barium sulfate is generated from barium slag powder and sulfate materials in the early stage, which inhibits the conversion of the hydration products CAH.sub.10 and C.sub.2AH.sub.8 with higher strength to the material C.sub.3AH.sub.6 with lower strength. As the hydration reaction proceeds, carbonate ions provided by barium slag react with free calcium ions in the system to form calcium carbonate, which will react with C.sub.3AH.sub.6 to form CO.sub.3-AFM. At the same time, in an overbased system, the active calcium silicate component in the barium slag is excited and reacts with water and active aluminum in the cementing material to form CSH and C-A-SH. Further, the early generated barium sulfate is reacted with the calcium sulfate generated in the system to form tricalcium aluminate to generate a barium calcium sulphoaluminate mineral, providing later strength. The reaction equations involved include:
Ca.sup.2++CO.sub.3.sup.2??CaCO.sub.3
CaCO.sub.3+C.sub.3AH.sub.6+6H.sub.2O?CO.sub.3-AFM
C.sub.3S+nH+AH=C-(A)-SH+mCH;

(10) If too little barium slag powder is added, it will have a significant adverse effect on the strength regression in the later stage; If too much barium slag powder is added, it will have an adverse effect on the material's high fluidity; If too little sulfate material is added, it will have adverse effects on high barium ion leaching; If too much sulfate material is added, it will have an adverse effect on the material's high expansion;

(11) The sulfate material includes at least one of sodium sulfate, calcium sulfate, aluminum sulfate, potassium sulfate, phosphogypsum, gypsum, anhydrite, and celestite; preferably phosphogypsum.

(12) The early-setting agent includes at least one of calcium hydroxide, sodium hydroxide, sodium carbonate, sodium sulfate, lime, quicklime, carbide slag, and mirabilite; preferably the carbide slag.

(13) The mass proportion of tricalcium aluminate in the aluminate cement clinker is 20-40 wt %.

(14) The ratio of the molar mass of Ba.sup.2+ in the barium slag powder to the molar mass of SO.sub.4.sup.2?+PO.sub.4.sup.3? ions in the sulfate material is 1:1. The reason why the molar mass ratio is 1:1 is that Ba.sup.2+ forms a poorly soluble precipitate, controlling the leaching of Ba.sup.2+.

(15) The preparation method of the barium slag powder includes: obtaining a black barium slag powder satisfying that, according to GB 5085.3-2007 test, the leaching concentration of Ba.sup.2+ from black barium slag powder in an acidic solution with a liquid-solid ratio of 10:1 is 1500-2300 mg/L; and subjecting the black barium slag powder to calcining at 800-1200? C., ball milling, and passing through a 200-mesh sieve to obtain the barium slag powder.

(16) If the Ba.sup.2+ leaching concentration is less than 1500 mg/L, it cannot suppress the adverse effects of material strength degradation in the later stage, and if it is greater than 2300 mg/L, it has adverse effects such as high material fluidity and high environmental harm.

(17) The reason for passing through the 200-mesh sieve after ball milling is to sufficiently excite the properties of the cementing material.

(18) According to a typical embodiment of the present invention, provided is a method for preparing the barium slag-modified aluminate quick-hardening special cementing material, comprising: mixing, in parts by weight, 10-12 parts of aluminate cement clinker, 2-3 parts of barium slag powder, 1.5-2 parts of sulfate material, and 0-1.5 parts of early-setting agent, and then adding water and stirring until uniform to obtain the barium slag-modified aluminate quick-hardening special cementing material.

(19) The weight of the added water is 0.3-0.5 of the mass of solids, most preferably the optimal water cement ratio of the cementing material.

(20) The following will provide a detailed explanation of a barium slag-modified aluminate quick-hardening special cementing material and its preparation method in this application, combined with embodiments and experimental data.

Example 1

(21) This example provides a barium slag-modified aluminate quick-hardening special cementing material prepared from raw materials including: 10 parts of aluminate cement clinker, 2 parts of barium slag powder, 2 parts of phosphogypsum powder, and 0 parts of early-setting agent. Wherein the content of tricalcium aluminate in the aluminate cement clinker was 25%; the barium slag powder was black barium slag powder; the particle size of the barium slag powder after ball milling was controlled by passing through a 200-mesh sieve; the leaching concentration of the Ba.sup.2+ in an acidic solution with a liquid-solid ratio of 10:1 was 1980 mg/L.

(22) All the components were mixed with water and stirred to obtain the slag modified aluminate quick-hardening special cementing material.

Example 2

(23) This example provides a barium slag-modified aluminate quick-hardening special cementing material prepared from raw materials including, in parts by weight: 10 parts of aluminate cement clinker, 2 parts of barium slag powder, 1.5 parts of gypsum powder, and 1 part of carbide slag. Wherein the content of tricalcium aluminate in the aluminate cement clinker was 25%; the barium slag powder was black barium slag powder; the particle size of the barium slag powder after ball milling was controlled by passing through a 200-mesh sieve.

(24) All the components were mixed with water and stirred to obtain the slag modified aluminate quick-hardening special cementing material.

Example 3

(25) This example provides a barium slag-modified aluminate quick-hardening special cementing material prepared from raw materials including, in parts by weight: 12 parts of aluminate cement clinker, 3 parts of barium slag powder, 2 parts of gypsum powder, and 0.5 part of carbide slag. Wherein the content of tricalcium aluminate in the aluminate cement clinker was 25%; the barium slag powder was black barium slag powder; the particle size of the barium slag powder after ball milling was controlled by passing through a 200-mesh sieve; the leaching concentration of the Ba.sup.2+ in an acidic solution with a liquid-solid ratio of 10:1 was 1980 mg/L.

(26) All the components were mixed with water and stirred to obtain the slag modified aluminate quick-hardening special cementing material.

Example 4

(27) This example provides a barium slag-modified aluminate quick-hardening special cementing material prepared from raw materials comprising, in parts by weight:

(28) 10-12 parts of aluminate cement clinker, 4-5 parts of mixture powder, and 1 part of early-setting agent; the method for preparing the mixture powder included: thoroughly mixing a wet barium slag with wet phosphogypsum (the ratio of the molar mass of Ba.sup.2+ in the non-barium sulfate in the wet barium slag to the molar mass of SO.sub.4.sup.2?+PO.sub.4.sup.3? ions in the wet phosphogypsum being 1:1) to obtain a mixture material; subjecting the mixture material to stirring, standing, drying and grinding to obtain the mixture powder;

(29) The stirring time was 12 h. The particle size of the mixture powder was controlled by passing through a 200-mesh sieve. The standing time was 5 d. The molar mass ratio of Ba.sup.2+ in the wet barium slag to SO.sub.4.sup.2?+PO.sub.4.sup.3? ions in the wet phosphogypsum was 1:1.

Comp. Ex. 1

(30) This comparative example was 100% aluminate cement clinker.

Comp. Ex. 2

(31) The comparative example included 10 parts of aluminate cement clinker and 2 parts of phosphogypsum powder.

Experimental Example 1

(32) The setting times of the barium slag-modified aluminate quick-hardening special cementing material of Examples 1-4 (water cement ratio of 0.42) and the 100% aluminate cement clinker of Comp. Ex. 1 were tested. The setting time test was performed according to the specification of GBT 1346-2011, and the initial and final setting times are shown in Table 1 below.

(33) TABLE-US-00001 TABLE 1 The initial and final setting time of each material, h Group Initial setting time (h) Final setting time (h) Ex. 1 15 19 Ex. 2 6 8 Ex. 3 11 14 Ex. 4 6 8 Comp. Ex. 1 5 6 Comp. Ex. 2 6 8

(34) It can be seen from the data in Table 1 that:

(35) After adding modifiers such as the barium slag and sulfate, the final initial setting time of the aluminate cement clinker can be extended, making it difficult for barium slag-modified aluminate quick-hardening special cementing materials to quickly obtain early strength. However, after adding the early-setting agent calcium carbide slag, the initial and final setting times of barium slag-modified aluminate quick-hardening special cementing materials are close to the original initial and final setting times. An appropriate amount of early-setting agent can be added according to actual needs.

Experimental Example 2

(36) The compressive strength of the barium slag-modified aluminate quick-hardening special cementing material of Ex. 1-4 (water cement ratio of 0.42) and the 100% aluminate cement clinker of Com. Ex. 1-2 was tested, specifically including: preparing the cement mortar sample according to GB/T201-2015, demolding after 24 h at room temperature, and putting it into a curing box at 20? C. for curing. The compressive strengths are shown in Table 2 below.

(37) TABLE-US-00002 TABLE 2 Compressive strength at different ages of each material, MPa Group 3 d 7 d 14 d 28 d 60 d 90 d Ex. 1 64.2 68.2 69.5 71.4 72.2 72.9 Ex. 2 68.1 70.2 71.5 73.4 74.3 74.6 Ex. 3 69.3 70.5 72.1 74.2 75.5 76.2 Ex. 4 69.5 70.4 71.3 74.2 75.6 76.3 Comp. Ex. 1 50.3 60.5 62.3 65.4 63.8 59.7 Comp. Ex. 2 51 62 64 65 64 62

(38) As can be seen from the data in Table 2,

(39) Compared with Comp. Ex. 1 and Comp. Ex. 2, the barium slag-modified aluminate quick-hardening special cementing materials of Ex. 1-4 of the present invention have a very high strength at day 3. The 3d compressive strength was above 60 MPa; and the 14d compressive strength was above 65 MPa. The neat strength was about 1.5-2 times of that of a single aluminate cement clinker.

(40) In Comp. Ex. 1 and Comp. Ex. 2, a significant strength reduction was observed after 90 days due to the absence of barium slag modifier, and in Ex. 1-4 of the present invention, the strength still increased at 60-90 days due to the addition of modifier, indicating that the barium slag-modified aluminate quick-hardening special cementing material has long-term stable strength characteristics.

(41) Finally, it should be noted that the terms include, comprise, or any other variation thereof are intended to cover non exclusive inclusion, so that a process, method, item, or device that includes a series of elements not only includes those elements, but also other elements that are not explicitly listed, or also include elements inherent in such a process, method, item, or device.

(42) While preferred embodiments of the present invention have been described, additional variations and modifications to these embodiments will occur to those skilled in the art once the basic inventive concept is known. Therefore, it is intended that the appended claims be interpreted as including the preferred embodiments and all alterations and modifications that fall within the scope of the present invention.

(43) It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. Thus, provided that these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, they are also intended to be included.