Composition for preparing unburned bricks, unburned bricks and preparation method thereof

Abstract

The present invention relates to the technical field of solid waste resource utilization, and discloses a composition for preparing unburned bricks, unburned bricks and preparation method thereof. The composition for preparing unburned bricks contains the following components: oil-based rock debris residue, sand and gravel, cement, fiber, modifier, and hydrophobic agent; based on the total mass of the composition, the content of the oil-based rock debris residue is 40-70wt%, the content of the sand and gravel is 20-30wt%, the content of the cement is 10-20wt%, the content of the fiber is 0.1-0.5wt%, the content of the modifier is 0.05-0.2wt%, and the content of the hydrophobic agent is 2-5wt%; the composition for preparing unburned bricks provided by the present invention can directly utilize oil-based rock debris residue with an oil content of <2wt%, and the unburned bricks prepared have better hydrophobic effect and antifreeze effect while maintaining higher compressive strength.

Description

Technical Field

[0001] The present invention relates to the technical field of solid waste resource utilization, and in particular to a composition for preparing unburned bricks, unburned bricks and a preparation method thereof. Background Art

[0002] Oil-based cuttings are drilling cuttings with oil attached. They are produced during the drilling process using oil-based drilling fluids prepared with white oil or mineral oils such as diesel as the continuous phase. They are included in the "National List of Hazardous Wastes".

[0003] Thermal desorption is a physical treatment method for treating oil-based cuttings. It separates oil from cuttings by distilling oil at 600°C. It can not only recover the residual oil in the oil-based cuttings, but also render them harmless. It is a technology encouraged by the national "Guidelines for the Environmental Management of Hazardous Wastes in Onshore Oil and Natural Gas Production". However, the average solid content of oil-based cuttings is greater than 70%, or even higher. After thermal desorption treatment, a large amount of residue is still produced, which needs further resource utilization. The preparation of unburned bricks is one of the best ways to turn waste into treasure. However, the physical and chemical properties of thermal desorption residues themselves lead to many problems in the preparation of unburned bricks, such as:

[0004] (1) The residue on the 20-mesh sieve is less than 10%, and the median average particle size of the sieved part is less than 100 μm. The particle size is small and dusty. The conventional method for preparing unburned bricks has a small mixing amount, difficulty in bonding, and difficulty in meeting the flexural strength and water absorption standards or the standards are low, which restricts its application range;

[0005] (2) It has hydrophobic and oleophilic surface characteristics. Since a large amount of emulsifiers, wetting agents, organic soil and other oleophilic colloids are added to the oil-based drilling fluid, they adhere to or impregnate the surface and interior of the oil-based rock cuttings, reversing the surface wettability to oleophilicity. After thermal desorption, the residue decreases with the reduction of oil and oleophilic colloids, but still exists. When preparing unfired bricks by conventional methods, cement, coarse aggregate and water are all hydrophilic materials, which reduces the bonding performance of other materials with the thermal desorption residue of oil-based rock cuttings, thereby affecting the key properties of unfired bricks such as compressive strength.

[0006] CN101805161A discloses a binder for making unburned bricks from drilling solid waste, which is composed of 3.3%-8% polyaluminium chloride, 6%-25% phosphogypsum, 10%-26% quicklime, 20%-60% fly ash, and 4.4%-12% ferrous sulfate. 10-22 parts of the binder, 30-55 parts of drilling solid waste, and 35-45 parts of coarse aggregate are mixed uniformly, and the mixture is extruded and formed using an unburned brick making machine to make unburned bricks. This proposal publicly teaches the use of binders in the preparation of unfired bricks, but this method is not suitable for the preparation of unfired bricks from oil-based rock cuttings residues, because the calcium oxide in quicklime can easily cause the unfired bricks to crack. The main function of polyaluminum chloride, ferrous sulfate, etc. is to change the state of water in drilling solid waste, and change a large amount of adsorbed water and bound water in the colloids in the drilling solid waste into free water, which plays a destabilizing role. Fly ash mainly has a water-absorbing effect. This formula is only suitable for water-based drilling solid waste with a higher water content.

[0007] CN105967595A discloses unburned bricks prepared from oil-based drill cuttings residue, which are characterized by: cement, aggregate, oil-based drill cuttings residue and fly ash are mixed and stirred to obtain a solid phase mixture, water is added to the solid phase mixture and mixed and stirred to obtain a semi-dry mixture, the semi-dry mixture is sent to an unburned brick machine for mold filling, pressing and demolding, and the demolded bricks are naturally cured; the weight percentages of the components are: cement 5-8%, aggregate 19-76%, oil-based drill cuttings residue 10-60%, fly ash 2-6%, and water 3-11%. This scheme does not consider the influence of the lipophilic properties of the surface of oil-based drill cuttings residues on the bonding strength and water absorption of unfired bricks, nor does it consider the water absorption and service life of unfired bricks, especially the impact on the microstructure of unfired bricks when rainwater and snow water enter the gaps of unfired bricks and the ambient temperature is below 0°C and the water phase changes to ice; and the oil-based drill cuttings residues used in this scheme need to control the oil content below 0.3%, which has high requirements for the oil content control of the previous oil-based rock cuttings disposal procedure. The current general requirement is that the oil content is less than 2%. If it is to be reduced to 0.3%, it is necessary to reduce the disposal volume per unit time or improve the disposal conditions (temperature, or amount of reagents added), thereby limiting the energy consumption and process conditions of the front-end oil-based rock cuttings disposal.

[0008] CN114349535A discloses a hydrophobic, environmentally friendly, coal gangue unfired brick, characterized by using an organosilicon nanomaterial to hydrophobically treat the unfired brick. The unfired brick is made of the following raw materials by mass: 40%-70% coal gangue, 12%-42% natural sand, 5.14% fly ash, and 12.86% cement. After the unfired brick is formed, the surface is sprayed with the organosilicon nanomaterial to perform a hydrophobic treatment. Although this proposal discloses the research idea of hydrophobic modification of unfired bricks using hydrophobic materials, this method mainly involves surface modification of the unfired bricks through a coating method. The coating of the unfired brick is easily damaged during transportation and use, losing or partially losing its hydrophobic protective ability, thereby affecting the water absorption performance of the unfired brick. Summary of the Invention

[0009] The purpose of the present invention is to solve the problems of low frost resistance and high water absorption in the prior art of preparing unburned bricks using oil-based rock debris residues.

[0010] In order to achieve the above object, one aspect of the present invention provides a composition for preparing unburned bricks, wherein the composition contains the following components stored separately or in combination:

[0011] Oil-based rock debris, sand and gravel, cement, fiber, modifier, hydrophobic agent;

[0012] Based on the total mass of the composition, the content of the oil-based rock debris residue is 40-70wt%, the content of the sand and gravel is 20-30wt%, the content of the cement is 10-20wt%, the content of the fiber is 0.1-0.5wt%, the content of the modifier is 0.05-0.2wt%, and the content of the hydrophobic agent is 2-5wt%;

[0013] The oil content of the oil-based rock debris residue is less than 2 wt % and the median particle size is 1-100 μm;

[0014] The modifier is selected from at least one of sodium dodecylbenzenesulfonate, sodium lauryl sulfate, and dodecyltrimethylammonium chloride;

[0015] The hydrophobic agent is selected from at least one of perfluorooctyltriethoxysilane, trimethylsilane, trichloromethylsiloxane, hexadecyltrimethylsilane, and tetrafluorosilane.

[0016] The second aspect of the present invention provides a method for preparing unburned bricks, which is carried out using the composition described in the first aspect, comprising:

[0017] (1) first mixing the fiber, the oil-based rock debris residue, and the modifier to obtain a mixture I;

[0018] (2) performing a second mixing of sand, gravel, cement, a hydrophobic agent, and the mixture I to obtain a mixture II;

[0019] (3) molding the mixture II to obtain the unburned brick.

[0020] The third aspect of the present invention provides unfired bricks prepared by the method described in the second aspect.

[0021] The unburned bricks prepared using the composition provided by the present invention have at least the following advantages:

[0022] (1) The present invention uses specific types of hydrophobic agents and modifiers in specific ratios, and compounding specific amounts of oil-based rock debris residue, sand and gravel, cement and fiber. The unburned bricks prepared have better hydrophobic and antifreeze effects while maintaining high compressive strength.

[0023] (2) The composition for preparing unfired bricks provided by the present invention can directly utilize oil-based rock cuttings residues with an oil content of less than 2wt%. Compared with the oil-based drill cuttings residues used in the prior art, which need to control the oil content to below 0.3wt%, the present invention can achieve efficient resource utilization of solid waste and reduce the energy consumption of front-end oil-based rock cuttings disposal.

[0024] (3) The present invention achieves the purpose of preparing high-performance, durable, cold-resistant resource products by consuming a large amount of oil-based rock cuttings thermal desorption residues, and has good practical value and application prospects. DETAILED DESCRIPTION

[0025] The endpoints of the ranges and any values disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0026] As mentioned above, the first aspect of the present invention provides a composition for preparing unburned bricks, wherein the composition contains the following components stored separately or in combination:

[0027] Oil-based rock debris, sand and gravel, cement, fiber, modifier, hydrophobic agent;

[0028] Based on the total mass of the composition, the content of the oil-based rock debris residue is 40-70wt%, the content of the sand and gravel is 20-30wt%, the content of the cement is 10-20wt%, the content of the fiber is 0.1-0.5wt%, the content of the modifier is 0.05-0.2wt%, and the content of the hydrophobic agent is 2-5wt%;

[0029] The oil content of the oil-based rock debris residue is less than 2 wt % and the median particle size is 1-100 μm;

[0030] The modifier is selected from at least one of sodium dodecylbenzenesulfonate, sodium lauryl sulfate, and dodecyltrimethylammonium chloride;

[0031] The hydrophobic agent is selected from at least one of perfluorooctyltriethoxysilane, trimethylsilane, trichloromethylsiloxane, hexadecyltrimethylsilane, and tetrafluorosilane.

[0032] Preferably, the oil-based rock debris residue comprises: 30-44 wt% SiO2, 1-4.5 wt% CaO, 11.2-20 wt% Al2O3; the loss on ignition is 4%-7%; the radioactive nuclide content thereof complies with the nuclide content index of GB6566-2010 building main material, i.e., I Ra ≤1.0Bq / Kg, I γ ≤1.0Bq / Kg.

[0033] Preferably, based on the total mass of the composition, the oil-based rock debris residue comprises 45-59wt%, the sand and gravel comprises 29-30wt%, the cement comprises 10-20wt%, the fiber comprises 0.3-0.5wt%, the modifier comprises 0.05-0.1wt%, and the hydrophobic agent comprises 2-5wt%. The inventors have found that under this preferred embodiment, the unburned bricks obtained by the present invention have better compressive strength and frost resistance.

[0034] Preferably, the hydrophobic agent is selected from at least one of perfluorooctyltriethoxysilane and trimethylsilane.

[0035] More preferably, the hydrophobic agent is a combination of perfluorooctyltriethoxysilane and trimethylsilane in a mass ratio of 1:2-4. The inventors have found that under this preferred embodiment, the unfired bricks obtained by the present invention have lower water absorption.

[0036] Preferably, the perfluorooctyltriethoxysilane is a 20-40 wt% aqueous solution of perfluorooctyltriethoxysilane, and the trimethylsilane is a 70-80 wt% aqueous solution of trimethylsilane. The inventors have found that under this preferred embodiment, the unfired bricks obtained by the present invention have lower water absorption.

[0037] Preferably, the modifier is a sodium dodecylbenzenesulfonate aqueous solution with a concentration of 2-5 wt%. The inventors have found that under this preferred embodiment, the unfired bricks obtained by the present invention have better compressive strength and frost resistance and lower water absorption.

[0038] Preferably, the average length of the fibers is 3-15 mm.

[0039] More preferably, the fiber is at least one of polypropylene fiber, polyacrylonitrile fiber, nylon fiber, polyester fiber, and asbestos.

[0040] Preferably, the sand and gravel has a mud content of less than 5wt%, and an average particle diameter of 0.85-15mm.

[0041] As mentioned above, the second aspect of the present invention provides a method for preparing unburned bricks, which is carried out using the composition described in the first aspect, comprising:

[0042] (1) first mixing the fiber, the oil-based rock debris residue, and the modifier to obtain a mixture I;

[0043] (2) performing a second mixing of sand, gravel, cement, a hydrophobic agent, and the mixture I to obtain a mixture II;

[0044] (3) molding the mixture II to obtain the unburned brick.

[0045] In order to reduce the loss of hydrophobic agent and modifier during the brick making extrusion process, which affects the effective content and application effect of the hydrophobic agent and modifier, preferably, the moisture content of the mixture I in the initial system for the second mixing is less than 30wt%.

[0046] In the present invention, the moisture content of the mixture I in the initial system for the second mixing is less than 30 wt %, which can be controlled by conventional technical means in the field. For example, the mixture I can be placed with a controlled thickness of no more than 0.5 m and dried naturally by multiple flipping and tossing. The present invention will not go into details here, and it should not be understood as a limitation to the present invention.

[0047] Preferably, the molding process conditions include: a pressure of 5-20 MPa and a time of 30-60 s.

[0048] Preferably, the conditions for the first mixing and the second mixing independently include: a stirring speed of 30-60 rpm, a time of 1 h-2 h, and a temperature of 10-40°C.

[0049] In the present invention, the method for preparing unburned bricks also includes conventional post-processing methods in the art. For example, the prepared unburned bricks are cured under the following conditions: a temperature of 10-20° C., a relative humidity of not less than 30%, and a curing time of 14-28 days. The present invention will not be further described herein, and should not be construed as limiting the present invention.

[0050] As mentioned above, the third aspect of the present invention provides unfired bricks prepared by the method described in the second aspect.

[0051] The present invention will be described in detail below through examples.

[0052] In the following examples, unless otherwise specified, the experimental instruments, reagents, and raw materials involved are all commercially available, and the reagents are all analytically pure products.

[0053] In the following examples, unless otherwise specified, each wt% represents 10 g.

[0054] raw material

[0055] Oil-based rock chip residue I: oil content is 1.65 wt%, median particle size is 73.2 μm, containing 35.5 wt% SiO2, 4.5 wt% CaO, and 17.5 wt% Al2O3;

[0056] Oil-based rock debris residue II: oil content 0.25wt%, median particle size 37.5μm, containing 43wt% SiO2, 3.1wt% CaO, 11.2wt% Al2O3;

[0057] Sand and gravel: Gobi desert natural sand and gravel, taken from a Gobi material field in the northwest edge of the Junggar Basin, washed with clean water three times, sieved, and selected the particle size range of 0.85mm-15mm;

[0058] Cement: brand: Pusi 42.5, purchased from Xinjiang Tianshan Cement Company;

[0059] Fiber I: polypropylene fiber, average length 4 mm, purchased from Karamay Jinxin Technology Co., Ltd.

[0060] Fiber II: asbestos, average length 3 mm, purchased from Karamay Jinxin Technology Co., Ltd.

[0061] Modifier I: 4 wt% aqueous solution of sodium dodecylbenzenesulfonate;

[0062] Modifier II: 1 wt% aqueous solution of sodium dodecylbenzenesulfonate;

[0063] Modifier III: 4 wt% OP-10 aqueous solution;

[0064] Hydrophobic agent I: a 30 wt % aqueous solution of perfluorooctyltriethoxysilane and a 75 wt % aqueous solution of trimethylsilane in a mass ratio of 1:3;

[0065] Hydrophobic agent II: Hydrophobic agent I: a 10 wt% aqueous solution of perfluorooctyltriethoxysilane and a 90 wt% aqueous solution of trimethylsilane in a mass ratio of 1:3;

[0066] Hydrophobic agent III: a 30 wt % aqueous solution of perfluorooctyltriethoxysilane and a 75 wt % aqueous solution of trimethylsilane in a mass ratio of 1:8;

[0067] Hydrophobic agent IV: tetrafluorosilane;

[0068] Hydrophobic agent V: methylsilicic acid.

[0069] Example 1

[0070] This example is used to illustrate that the unburned bricks of the present invention are prepared according to the formula and process parameters in Table 1 and the method described below.

[0071] The method for preparing the unburned brick comprises:

[0072] (1) performing a first mixing of fibers, oil-based rock debris residue, and a modifier to obtain a mixture I; the first mixing conditions are: a stirring speed of 35 rpm, a temperature of 25° C., and a time of 2 h;

[0073] (2) performing a second mixing of sand, cement, hydrophobic agent and the mixture I to obtain a mixture II; the second mixing conditions are: a stirring speed of 35 rpm, a temperature of 25° C., and a time of 1 h;

[0074] (3) molding the mixture II to obtain the unburned brick; the molding conditions include: a pressure of 10 MPa and a time of 50 s.

[0075] Unless otherwise specified, the remaining examples were carried out using a process similar to that of Example 1, except that the formulations and process parameters used in each example were different. For details, see Table 1 (Note: the parameters not listed in Table 1 are the same as the corresponding parameters in Example 1).

[0076] Table 1

[0077]

[0078]

[0079] Example 8

[0080] This embodiment is carried out using a process similar to that of embodiment 1, except that, in this embodiment, in step (2), the water content of mixture I in the initial system for the second mixing is 40%.

[0081] The rest are the same as in Example 1.

[0082] The unfired brick S8 was prepared.

[0083] Comparative Example 1

[0084] This comparative example was carried out using a process similar to that of Example 1, except that in this comparative example, the modifier III of the same mass was used to replace the modifier I in Example 1.

[0085] The rest are the same as in Example 1.

[0086] The unfired brick DS1 was prepared.

[0087] Comparative Example 2

[0088] This comparative example was carried out using a process similar to that of Example 1, except that, in this comparative example, the hydrophobic agent V of the same mass was used to replace the hydrophobic agent I in Example 1.

[0089] The rest are the same as in Example 1.

[0090] The unfired brick DS2 was prepared.

[0091] Comparative Example 3

[0092] This comparative example was carried out using a method similar to that of Example 1, except that, based on the total mass of the composition for preparing unburned bricks, in this comparative example, the amount of hydrophobic agent I was 9 wt %, and the amount of oil-based rock debris residue I was 40.65 wt %.

[0093] The rest are the same as in Example 1.

[0094] The unfired brick DS3 was prepared.

[0095] Comparative Example 4

[0096] This comparative example was prepared using a method similar to that of Example 1, except that, based on the total mass of the composition for preparing unburned bricks, in this comparative example, the amount of cement was 8 wt % and the amount of oil-based rock debris residue I was 58.65 wt %.

[0097] The rest are the same as in Example 1.

[0098] The unfired brick DS4 was prepared.

[0099] Test Example 1

[0100] The unburned bricks prepared in the above examples and comparative examples were tested for compressive strength, water absorption, and frost resistance according to the "Test Methods for Concrete Blocks and Bricks" GB / T4111-2013, and compared with the "Ordinary Concrete Small Blocks" standard GB / T 8239-2014. The test results are shown in Table 2, and the GB / T 8239-2014 standard is shown in Table 3.

[0101] Table 2

[0102]

[0103]

[0104] Table 3

[0105]

[0106] Test Example 2

[0107] The present invention exemplarily provides unburned bricks prepared in Example 1 and Example 2. The environmental impact indicators related to the leachate are measured according to the method required by DB65 / T3997-2017. The results are shown in Table 4.

[0108] Table 4

[0109] Test items Standard value Example 1 Example 2 pH 2-12.5 11.63 11.25 Hexavalent chromium (mg / kg) ≤13 2 2 Copper (mg / kg) ≤600 23.9 25.6 Zinc (mg / kg) ≤1500 57.9 59.3 Nickel (mg / kg) ≤150 19.4 15.9 Lead (mg / kg) ≤600 16.7 26.8 Cadmium (mg / kg) ≤20 0.3 0.3 Arsenic (mg / kg) ≤80 14.7 18.1 Benzo[α]pyrene (mg / kg) ≤0.7 Not detected Not detected Oil content (%) ≤2 0.16 0.05 COD (mg / L) ≤150 70 85

[0110] It can be seen from the results in Table 2 and Table 4 that the unburned bricks prepared by using the composition provided by the present invention have better hydrophobic effect and antifreeze effect while maintaining high compressive strength, and the leachate meets the relevant environmental impact indicators.

[0111] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A composition for preparing unburned bricks, characterized in that: The composition contains the following components which are stored separately or mixed together: Oil-based rock debris, sand and gravel, cement, fiber, modifier, hydrophobic agent; Based on the total mass of the composition, the content of the oil-based rock debris residue is 40-70wt%, the content of the sand and gravel is 20-30wt%, the content of the cement is 10-20wt%, the content of the fiber is 0.1-0.5wt%, the content of the modifier is 0.05-0.2wt%, and the content of the hydrophobic agent is 2-5wt%; The oil content of the oil-based rock debris residue is less than 2 wt % and the median particle size is 1-100 μm; The modifier is selected from at least one of sodium dodecylbenzenesulfonate, sodium lauryl sulfate, and dodecyltrimethylammonium chloride; The hydrophobic agent is selected from at least one of perfluorooctyltriethoxysilane, trimethylsilane, trichloromethylsiloxane, hexadecyltrimethylsilane, and tetrafluorosilane.

2. The composition according to claim 1, characterized in that Based on the total mass of the composition, the content of the oil-based rock debris residue is 45-59wt%, the content of the sand and gravel is 29-30wt%, the content of the cement is 10-20wt%, the content of the fiber is 0.3-0.5wt%, the content of the modifier is 0.05-0.1wt%, and the content of the hydrophobic agent is 2-5wt%.

3. The composition according to claim 1 or 2, characterized in that The hydrophobic agent is selected from at least one of perfluorooctyltriethoxysilane and trimethylsilane.

4. The composition according to claim 3, characterized in that The hydrophobic agent is a combination of perfluorooctyltriethoxysilane and trimethylsilane in a mass ratio of 1:2-4.

5. The composition according to claim 4, characterized in that The perfluorooctyltriethoxysilane is a perfluorooctyltriethoxysilane aqueous solution with a concentration of 20-40 wt %; the trimethylsilane is a trimethylsilane aqueous solution with a concentration of 70-80 wt %.

6. The composition according to claim 1 or 2, characterized in that The modifier is a sodium dodecylbenzenesulfonate aqueous solution with a concentration of 2-5 wt%.

7. The composition according to claim 1 or 2, characterized in that The average length of the fibers is 3-15 mm; And / or, the sand and gravel has a mud content of less than 5wt%, and an average particle diameter of 0.85-15mm.

8. The composition according to claim 7, characterized in that The fiber is at least one of polypropylene fiber, polyacrylonitrile fiber, nylon fiber, polyester fiber, and asbestos.

9. A method for preparing unburned bricks, characterized in that: The method is carried out using the composition according to any one of claims 1 to 8, comprising: (1) first mixing the fiber, the oil-based rock debris residue, and the modifier to obtain a mixture I; (2) performing a second mixing of sand, gravel, cement, a hydrophobic agent, and the mixture I to obtain a mixture II; (3) molding the mixture II to obtain the unburned brick.

10. The method according to claim 9, characterized in that In step (2), the water content of the mixture I in the initial system for the second mixing is less than 30 wt%.

11. The method according to claim 9 or 10, characterized in that The molding process conditions include: a pressure of 5-20 MPa and a time of 30-60 seconds.

12. Unfired bricks prepared by the method according to any one of claims 9 to 11.

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