A high-temperature and high-pressure synthesis method for black silicon crystal

Abstract

The present invention provides a high-temperature and high-pressure synthesis method of black silicon crystal, comprising: ball milling construction waste, clay, feldspar, bluestone and colorant to obtain a mixed material, pre-sintering the mixed material to obtain a high-temperature material, spraying the high-temperature material with cooling water, completing water quenching and rapid cooling to obtain a pre-treated material; mixing the pre-treated material, composite crystal nucleation agent, foaming agent and flux to obtain a dry material, putting the dry material, deionized water and abrasive balls into a ball mill for wet ball milling to obtain a precursor material, placing the precursor material in a constant temperature and humidity environment for aging and homogenization to obtain a mud material; extruding the mud material, then cutting it to obtain a blank, and drying and sintering the blank in sequence to obtain black silicon crystal. The high-temperature and high-pressure synthesis method provided by the present invention has a simple process flow, the construction waste used is waste, and the obtained black silicon crystal product has high value, realizing the harmless treatment and high added value of construction waste.

Description

Technical Field

[0001] The invention belongs to the technical field of silicon crystal preparation and relates to a high-temperature and high-pressure synthesis method of black silicon crystal. Background Art

[0002] Black silica spar is made of shale, coal gangue, fly ash, construction waste, river and lake silt, sludge, etc. as the main raw materials, and is made by extrusion molding, drying and roasting. It has high-quality properties such as light weight and high strength, thermal insulation, waterproof and moisture-proof, sound insulation and noise reduction, fire resistance and durability, freeze-thaw resistance, and easy cutting and processing. In the context of prefabricated buildings, it can be widely used in the construction of prefabricated wall projects. It is a new type of environmentally friendly green high-end building material.

[0003] With the rapid development of the construction industry, the total production of construction waste is also growing. Construction waste mainly includes construction debris, waste bricks and stones, etc., but the current treatment methods for construction waste generated by the construction industry are still immature. A small number of them are used to produce low-end building materials such as permeable bricks, while most of the construction waste is directly piled up or landfilled in the open air in the suburbs without any treatment. Not only is the treatment cost high, but also the dust pollution and other problems generated during the transportation and stacking process have caused serious environmental pollution. In addition, the process technology for using construction waste as roadbed filling material is not mature enough and the utilization rate is not high. Therefore, the efficient recycling of construction waste in the production of black silicon crystal not only greatly reduces the production cost of black silicon crystal, but also effectively solves the damage of construction waste to the urban environment. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a high-temperature and high-pressure synthesis method of black silicon crystal. The high-temperature and high-pressure synthesis method of black silicon crystal provided by the present invention has a simple process flow, the construction debris used is waste, and the obtained black silicon crystal product has high value, thereby realizing the harmless treatment of construction debris and high added value.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] The present invention provides a high-temperature and high-pressure synthesis method of black silicon crystal stone, and the high-temperature and high-pressure synthesis method comprises:

[0007] (I) mixing and ball-milling construction waste, clay, feldspar, bluestone and a colorant to obtain a mixed material, pre-sintering the mixed material to obtain a high-temperature material, spraying the high-temperature material with cooling water, and performing water quenching and rapid cooling to obtain a pre-treated material;

[0008] (II) mixing the pretreated material, a composite crystal nucleating agent, a foaming agent and a flux to obtain a dry material, wherein the composite crystal nucleating agent is composed of Cr2O3, CaF2, ZrO2 and B2O3; placing the dry material, deionized water and abrasive balls in a ball mill for wet ball milling to obtain a precursor material, placing the precursor material in a constant temperature and humidity environment for aging and homogenization to obtain a mud material;

[0009] (III) Extruding the clay material into a shape, and then cutting it to obtain a green body, and then drying and sintering the green body in sequence to obtain the black silicon crystal stone.

[0010] The present invention adopts a two-step production process to prepare black silicon crystal with excellent performance. First, building debris, clay, feldspar and bluestone are mixed in proportion according to the required crystal phase and glass phase components, and after high-temperature melting and water quenching treatment, a metastable high-temperature material is obtained. The high-temperature material is sprayed with cooling water to achieve water quenching and rapid cooling, thereby maintaining the activation energy of the high-temperature material, and crystals can be quickly precipitated in the subsequent sintering process.

[0011] Subsequently, the pretreated material, composite nucleus agent, foaming agent and flux are mixed and wet ball-milled and aged to obtain mud. By adding foaming agent to the pretreated material, gas can be generated under heating conditions to ensure the formation of the expected spatial structure during the sintering process. By adding composite nucleus agent to the pretreated material, the crystallization process can be controlled to a certain extent, so that the residual grain system in the pretreated material is uniform. Under the induced crystallization conditions, the crystal structure of the material is effectively controlled to obtain the expected grain size and crystal space overlap structure, meeting the production cost and performance requirements of the prefabricated building market for black silicon crystal stone materials.

[0012] The high-temperature and high-pressure synthesis method of black silicon spar provided by the present invention has a simple process flow, the used construction debris is waste, the obtained black silicon spar product has high value, and the harmless treatment and high added value of the construction debris are achieved.

[0013] As a preferred technical solution of the present invention, in step (I), the construction waste consists of Fe2O3, Al2O3, SiO2, TiO2, Na2O, CaO, MgO and K2O.

[0014] In some optional examples, the clay consists of Fe2O3, Al2O3, SiO2, TiO2, Na2O, CaO, MgO, K2O and MnO.

[0015] In some optional instances, the feldspar is composed of Fe2O3, Al2O3, SiO2, TiO2, Na2O, CaO, MgO, K2O and MnO.

[0016] In some optional instances, the bluestone is composed of Fe2O3, Al2O3, SiO2, TiO2, Na2O, CaO, MgO, K2O and MnO.

[0017] In some optional examples, the colorant includes any one of cobalt oxide, nickel oxide, manganese oxide or copper oxide, or a combination of at least two thereof.

[0018] As a preferred technical solution of the present invention, the mass fractions of the components in the construction waste are as follows:

[0019]

[0020] The mass fraction of Fe2O3 can be 0.4wt%, 0.41wt%, 0.42wt%, 0.43wt%, 0.44wt%, 0.45wt%, 0.46wt%, 0.47wt%, 0.48wt%, 0.49wt% or 0.5wt%; the mass fraction of Al2O3 can be 13wt%, 13.2wt%, 13.4wt%, 13.6wt%, 13.8wt%, 14wt%, 14.2wt%, 14.4wt%, 14.6wt%, 14.8wt% or 15wt %; the mass fraction of SiO2 can be 60wt%, 61wt%, 62wt%, 63wt%, 64wt%, 65wt%, 66wt%, 67wt%, 68wt%, 69wt% or 70wt%; the mass fraction of TiO2 can be 0.05wt%, 0.055wt%, 0.06wt%, 0.065wt%, 0.07wt%, 0.075wt%, 0.08wt%, 0.085wt%, 0.09wt%, 0.095wt% or 0.1wt%; the mass fraction of Na2O can be The mass fraction of CaO can be 0.3wt%, 0.32wt%, 0.34wt%, 0.36wt%, 0.38wt%, 0.4wt%, 0.42wt%, 0.44wt%, 0.46wt%, 0.48wt% or 0.5wt%; the mass fraction of MgO can be 0.3wt%, 0.3 % , 5.2wt%, 5.3wt%, 5.4wt%, 5.5wt%, 5.6wt%, 5.7wt%, 5.8wt%, 5.9wt% or 6.0wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0021] In some optional examples, the mass fractions of the components in the clay are as follows:

[0022]

[0023]

[0024] Wherein, the mass fraction of Fe2O3 can be 2.0wt%, 2.1wt%, 2.2wt%, 2.3wt%, 2.4wt%, 2.5wt%, 2.6wt%, 2.7wt%, 2.8wt%, 2.9wt% or 3.0wt%; the mass fraction of Al2O3 can be 16wt%, 16.2wt%, 16.4wt%, 16.6wt%, 16.8wt%, 17wt%, 17.2wt%, 17.4wt%, 17.6wt%, 17.8wt% or 18wt%; the mass fraction of SiO2 can be 70wt%, 70.5wt%, 71wt%, 72wt%, 73wt%, 74wt%, 75wt% or 76wt%. 1.5wt%, 72wt%, 72.5wt%, 73wt%, 73.5wt%, 74wt%, 74.5wt% or 75wt%; the mass fraction of TiO2 can be 0.4wt%, 0.41wt%, 0.42wt%, 0.43wt%, 0.44wt%, 0.45wt%, 0.46wt%, 0.47wt%, 0.48wt%, 0.49wt% or 0.5wt%; the mass fraction of Na2O can be 0.1wt%, 0.11wt%, 0.12wt%, 0.13wt%, 0.14wt%, 0.15wt%, 0.16wt%, 0. The mass fraction of CaO can be 0.6wt%, 0.62wt%, 0.64wt%, 0.66wt%, 0.68wt%, 0.7wt%, 0.72wt%, 0.74wt%, 0.76wt%, 0.78wt% or 0.8wt%; the mass fraction of MgO can be 0.3wt%, 0.32wt%, 0.34wt%, 0.36wt%, 0.38wt%, 0.4wt%, 0.42wt%, 0.44wt%, 0.46wt%, 0.48wt% or 0.5wt%; The mass fraction of 2O can be 1.0wt%, 1.1wt%, 1.2wt%, 1.3wt%, 1.4wt%, 1.5wt%, 1.6wt%, 1.7wt%, 1.8wt%, 1.9wt% or 2.0wt%; the mass fraction of MnO can be 0.05wt%, 0.055wt%, 0.06wt%, 0.065wt%, 0.07wt%, 0.075wt%, 0.08wt%, 0.085wt%, 0.09wt%, 0.095wt% or 0.1wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable.

[0025] In some optional examples, the mass fractions of the components in the feldspar are as follows:

[0026]

[0027]

[0028] The mass fraction of Fe2O3 can be 2.0wt%, 2.1wt%, 2.2wt%, 2.3wt%, 2.4wt%, 2.5wt%, 2.6wt%, 2.7wt%, 2.8wt%, 2.9wt% or 3.0wt%; the mass fraction of Al2O3 can be 10wt%, 10.2wt%, 10.4wt%, 10.6wt%, 10.8wt%, 11wt%, 11.2wt%, 11.4wt%, 11.6wt%, 11.8wt% or 12wt%; the mass fraction of SiO2 can be 38wt%, 38.2wt%, 38.4wt%, 38 .6wt%, 38.8wt%, 39wt%, 39.2wt%, 39.4wt%, 39.6wt%, 39.8wt% or 40wt%; the mass fraction of TiO2 can be 0.3wt%, 0.32wt%, 0.34wt%, 0.36wt%, 0.38wt%, 0.4wt%, 0.42wt%, 0.44wt%, 0.46wt%, 0.48wt% or 0.5wt%; the mass fraction of Na2O can be 1.0wt%, 1.02wt%, 1.04wt%, 1.06wt%, 1.08wt%, 1.1wt%, 1.12wt%, 1.14 wt%, 1.16wt%, 1.18wt% or 1.2wt%; the mass fraction of CaO can be 1.3wt%, 1.32wt%, 1.34wt%, 1.36wt%, 1.38wt%, 1.4wt%, 1.42wt%, 1.44wt%, 1.46wt%, 1.48wt% or 1.5wt%; the mass fraction of MgO can be 1.3wt%, 1.32wt%, 1.34wt%, 1.36wt%, 1.38wt%, 1.4wt%, 1.42wt%, 1.44wt%, 1.46wt%, 1.48wt% or 1.5wt%; the mass fraction of K2O can be 1. The fraction may be 1.3wt%, 1.32wt%, 1.34wt%, 1.36wt%, 1.38wt%, 1.4wt%, 1.42wt%, 1.44wt%, 1.46wt%, 1.48wt% or 1.5wt%; the mass fraction of MnO may be 0.05wt%, 0.055wt%, 0.06wt%, 0.065wt%, 0.07wt%, 0.075wt%, 0.08wt%, 0.085wt%, 0.09wt%, 0.095wt% or 0.1wt%, but is not limited to the listed values, and other values ​​not listed within the numerical range are equally applicable.

[0029] In some optional examples, the mass fractions of the components in the bluestone are as follows:

[0030]

[0031]

[0032] Wherein, the mass fraction of Fe2O3 can be 3.0wt%, 3.1wt%, 3.2wt%, 3.3wt%, 3.4wt%, 3.5wt%, 3.6wt%, 3.7wt%, 3.8wt%, 3.9wt% or 4.0wt%; the mass fraction of Al2O3 can be 13wt%, 13.2wt%, 13.4wt%, 13.6wt%, 13.8wt%, 14wt%, 14.2wt%, 14.4wt%, 14.6wt%, 14.8wt% or 15wt%; the mass fraction of SiO2 can be 70wt%, 70.2wt%, 70.4wt% t%, 70.6wt%, 70.8wt%, 71wt%, 71.2wt%, 71.4wt%, 71.6wt%, 71.8wt% or 72wt%; the mass fraction of TiO2 can be 0.4wt%, 0.42wt%, 0.44wt%, 0.46wt%, 0.48wt%, 0.5wt%, 0.52wt%, 0.54wt%, 0.56wt%, 0.58wt% or 0.6wt%; the mass fraction of Na2O can be 3.0wt%, 3.1wt%, 3.2wt%, 3.3wt%, 3.4wt%, 3.5wt%, 3.6wt% %, 3.7wt%, 3.8wt%, 3.9wt% or 4.0wt%; the mass fraction of CaO can be 1.5wt%, 1.51wt%, 1.52wt%, 1.53wt%, 1.54wt%, 1.55wt%, 1.56wt%, 1.57wt%, 1.58wt%, 1.59wt% or 1.6wt%; the mass fraction of MgO can be 1.4wt%, 1.41wt%, 1.42wt%, 1.43wt%, 1.44wt%, 1.45wt%, 1.46wt%, 1.47wt%, 1.48wt%, 1.49wt% or 1.5w t%; the mass fraction of K2O can be 2.0wt%, 2.1wt%, 2.2wt%, 2.3wt%, 2.4wt%, 2.5wt%, 2.6wt%, 2.7wt%, 2.8wt%, 2.9wt% or 3.0wt%; the mass fraction of MnO can be 0.1wt%, 0.11wt%, 0.12wt%, 0.13wt%, 0.14wt%, 0.15wt%, 0.16wt%, 0.17wt%, 0.18wt%, 0.19wt% or 0.2wt%, but is not limited to the listed values, and other values ​​not listed within the numerical range are equally applicable.

[0033] As a preferred technical solution of the present invention, in step (I), the mass ratio of the construction waste, clay, feldspar, bluestone and colorant is (14-15):1:1:1:1, for example, it can be 14:1:1:1:1, 14.1:1:1:1, 14.2:1:1:1:1, 14.3:1:1:1:1, 14.4:1:1:1:1, 14.5:1:1:1:1, 14.6:1:1:1:1, 14.7:1:1:1:1, 14.8:1:1:1:1, 14.9:1:1:1:1 or 15:1:1:1:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable.

[0034] In some optional examples, the construction waste includes a first construction waste and a second construction waste with different particle sizes, wherein the particle size of the first construction waste is 60-80 mesh, for example, it can be 60 mesh, 62 mesh, 64 mesh, 66 mesh, 68 mesh, 70 mesh, 72 mesh, 74 mesh, 76 mesh, 78 mesh or 80 mesh; the particle size of the second construction waste is 100-120 mesh, for example, it can be 100 mesh, 102 mesh, 104 mesh, 106 mesh, 108 mesh, 110 mesh, 112 mesh, 114 mesh, 116 mesh, 118 mesh or 120 mesh, but it is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0035] In some optional instances, the mass ratio of the first construction waste to the second construction waste is 1:(2-3), for example, it can be 1:2.0, 1:2.1, 1:2.2, 1:2.3, 1:2.4, 1:2.5, 1:2.6, 1:2.7, 1:2.8, 1:2.9 or 1:3.0, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0036] In order to effectively improve the various properties of black silicon crystal and reduce the risk of explosion of black silicon crystal after sintering, the present invention uses construction waste with different particle size gradations as the main raw material, introduces appropriate amounts of clay, feldspar, bluestone and other inorganic raw materials, and adopts extrusion molding, high-temperature sintering and other processes to prepare lightweight and high-strength black silicon crystal.

[0037] The present invention particularly limits the mass ratio of the first construction waste to the second construction waste to 1: (2-3). With the increase of the amount of the second construction waste added, the bulk density of the prepared black silicon crystal gradually increases, and the water absorption rate gradually decreases and tends to be stable. This is because the fine-grained second construction waste has a large specific surface area and high sintering activity, and is fully melted and softened during sintering. The more the second construction waste, the more liquid phase is produced, and the denser the green body becomes, so that the density of the prepared black silicon crystal is improved, the bulk density is increased, the porosity is reduced, and water molecules are not easy to enter the interior of the green body. When the produced liquid phase reaches saturation, the water absorption rate of the black silicon crystal no longer decreases and tends to be stable. However, the addition amount of the second construction debris should not be too high. When it exceeds the upper limit of the range specified in the present invention, the compressive strength of the prepared black silica spar shows a downward trend. This is because the more fine-grained the second construction debris is, the more it can promote the formation of sintering liquid phase, but too much liquid phase will cause the clay, feldspar and bluestone in the formula to lose their function, thereby reducing the compressive strength of the black silica spar finally prepared.

[0038] In some optional examples, the ball milling speed of the mixed ball mill is 200-300 r / min, for example, it can be 200 r / min, 210 r / min, 220 r / min, 230 r / min, 240 r / min, 250 r / min, 260 r / min, 270 r / min, 280 r / min, 290 r / min or 300 r / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0039] In some optional examples, the ball milling time of the mixed ball milling is 10 to 12 hours, for example, it can be 10 hours, 10.2 hours, 10.4 hours, 10.6 hours, 10.8 hours, 11 hours, 11.2 hours, 11.4 hours, 11.6 hours, 11.8 hours or 12 hours, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0040] As a preferred technical solution of the present invention, in step (Ⅰ), the heating rate of the pre-sintering is 10-12°C / min, for example, it can be 10°C / min, 10.2°C / min, 10.4°C / min, 10.6°C / min, 10.8°C / min, 11°C / min, 11.2°C / min, 11.4°C / min, 11.6°C / min, 11.8°C / min or 12°C / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0041] In some optional examples, the sintering temperature of the pre-sintering is 1000-1200°C, for example, it can be 1000°C, 1020°C, 1040°C, 1060°C, 1080°C, 1100°C, 1120°C, 1140°C, 1160°C, 1180°C or 1200°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0042] In some optional examples, the pre-sintering holding time is 40 to 60 min, for example, it can be 40 min, 42 min, 44 min, 46 min, 48 min, 50 min, 52 min, 54 min, 56 min, 58 min or 60 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0043] In some optional examples, the temperature of the cooling water is 15-25°C, for example, it can be 15°C, 16°C, 17°C, 18°C, 19°C, 20°C, 21°C, 22°C, 23°C, 24°C or 25°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0044] In some optional embodiments, the spraying volume of the cooling water is 3000-4000m 3 / h, for example, 3000m 3 / h、3100m 3 / h、3200m 3 / h、3300m 3 / h、3400m 3 / h、3500m 3 / h、3600m 3 / h、3700m 3 / h、3800m 3 / h、3900m 3 / h or 4000m 3 / h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0045] In some optional examples, the spray pressure of the cooling water is 0.2-0.3 MPa, for example, it can be 0.2 MPa, 0.21 MPa, 0.22 MPa, 0.23 MPa, 0.24 MPa, 0.25 MPa, 0.26 MPa, 0.27 MPa, 0.28 MPa, 0.29 MPa or 0.3 MPa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0046] In some optional examples, the cooling rate of the high-temperature material surface is 30-40°C / s, for example, it can be 30°C / s, 31°C / s, 32°C / s, 33°C / s, 34°C / s, 35°C / s, 36°C / s, 37°C / s, 38°C / s, 39°C / s or 40°C / s, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0047] As a preferred technical solution of the present invention, in step (II), based on the mass fraction of the composite nucleating agent being 100wt%, the mass fractions of the components are as follows:

[0048]

[0049]

[0050] Wherein, the mass fraction of Cr2O3 can be 40wt%, 40.5wt%, 41wt%, 41.5wt%, 42wt%, 42.5wt%, 43wt%, 43.5wt%, 44wt%, 44.5wt% or 45wt%; the mass fraction of CaF2 can be 25wt%, 25.5wt%, 26wt%, 26.5wt%, 27wt%, 27.5wt%, 28wt%, 28.5wt%, 29wt%, 29.5wt% or 30wt%; the mass fraction of ZrO2 can be 15wt% %, 15.5wt%, 16wt%, 16.5wt%, 17wt%, 17.5wt%, 18wt%, 18.5wt%, 19wt%, 19.5wt% or 20wt%; the mass fraction of B2O3 can be 10wt%, 10.2wt%, 10.4wt%, 10.6wt%, 10.8wt%, 11wt%, 11.2wt%, 11.4wt%, 11.6wt%, 11.8wt% or 12wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable.

[0051] Cr 3+ It is a high field strength transition cation. In the calcium-rich phase, Cr 3+ With Ca 2+The enrichment together can attract non-bridging oxygen, order the surrounding cations, and precipitate the chromium-rich phase in the form of a compound to become a non-uniform nucleation center, inducing crystal precipitation. The present invention specifically limits the mass fraction of Cr2O3 in the composite nucleating agent to 40-45wt%. When the addition amount of Cr2O3 is within the numerical range specified by the present invention, the viscosity of the mud melt is significantly improved. This is because, on the one hand, the solubility of Cr2O3 in the mud melt is low, and on the other hand, a high content of Cr2O3 will form a spinel solid solution phase, which significantly increases the viscosity of the mud melt. As the addition amount of Cr2O3 increases, the crystallization kinetic activation energy shows a downward trend, and the grains are gradually refined. The structure of the black silicon crystal finally prepared is denser and the compressive strength is significantly improved. When the addition amount of Cr2O3 exceeds the upper limit of the range specified by the present invention, an irregular block-shaped magnesium-iron-chromium spinel second phase is formed in the prepared black silicon crystal, which causes the surrounding grains to grow abnormally, resulting in a decrease in the compressive strength of the black silicon crystal.

[0052] The present invention adds CaF2 to the composite nucleus agent, which can simultaneously exert the dual effects of the nucleus agent and the flux, and can reduce the melting point of the clay and increase the fluidity of the clay during the melting process. This is because CaF2 can play a diluting role in the clay melt and does not affect the relative distribution of the structural units in the clay melt; at the same time, the addition of CaF2 causes the complex structural units in the clay melt to depolymerize, thereby reducing the degree of polymerization of the clay melt; in addition, the addition of CaF2 causes part of the non-bridging oxygen in the structure of the clay melt to be replaced by fluoride ions, resulting in relaxation of the clay structure.

[0053] The present invention specifically limits the mass fraction of CaF2 in the composite nucleating agent to 25-30wt%. As the amount of CaF2 added increases, the viscosity, glass transition temperature and crystallization temperature of the clay melt gradually decrease. This is because F - Replace O2 - The effect is to increase the amount of free oxygen provided to the molten mud, resulting in a decrease in the degree of polymerization of the crystal structure, a decrease in viscosity, a decrease in the migration resistance of ions, and an easier adjustment of the crystal structure, which is beneficial to the formation of crystal nuclei and the growth of crystals. When the amount of CaF2 added is lower than the lower limit of the range defined by the present invention, the crystallization rate is too slow, and only surface crystallization can be caused. The final black silica crystal still has a lot of glass phase inside, resulting in low compressive strength of the black silica crystal and easy deformation. When the amount of CaF2 added exceeds the upper limit of the range defined by the present invention, excess F will precipitate in the form of crystalline phase fluorite, which ultimately affects the compressive strength of the black silica crystal.

[0054] As a preferred technical solution of the present invention, in step (II), the mass ratio of the pretreatment material, the composite nucleus agent, the foaming agent and the flux is (70-80):(5-7):(1-2):(4-6), for example, it can be 70:5:1:4, 71:5.2:1.1:4.2, 72:5.4:1.2:4.4, 73:5.6:1.3:4.6, 74:5.8:1.4:4.8, 75:6:1.5:5, 76:6.2:1.6:5.2, 77:6.4:1.7:5.4, 78:6.6:1.8:5.6, 79:6.8:1.9:5.8 or 80:7:2:6, but is not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable.

[0055] In some optional examples, the foaming agent includes any one of sodium carbonate, potassium carbonate, sodium bicarbonate, or a combination of at least two of them.

[0056] The present invention preferably uses sodium carbonate as a foaming agent, because sodium carbonate can not only be used as a foaming agent, but also can play the role of a crystal nucleating agent. Its working principle is: the radius of sodium ions is smaller than the length of the silicon-oxygen bond. During the sintering process, sodium ions can enter the silicon-oxygen tetrahedral structure to destroy the silicon-oxygen connection, thereby reducing the melting temperature of the mud material and promoting crystal nucleation and crystallization; at the same time, sodium ions can also reduce the structural stress between crystals, making the crystal structure more tightly connected, which is beneficial to improving the compressive strength of black silicon crystal stone.

[0057] In some optional examples, the flux includes any one of aluminum oxide and sodium metasilicate, or a combination of at least two of them.

[0058] In some optional examples, the mass ratio of the dry material, deionized water and abrasive balls is 1:(0.8-1.2):(3-5), for example, it can be 1:0.8:3, 1:0.85:3.2, 1:0.9:3.4, 1:0.95:3.6, 1:1:3.8, 1:1.05:4, 1:1.1:4.2, 1:1.15:4.4, 1:1.2:4.6, 1:1.1:4.8 or 1:1.2:5, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0059] In some optional examples, the particle size of the abrasive balls is 10 to 15 mm, for example, 10 mm, 10.5 mm, 11 mm, 11.5 mm, 12 mm, 12.5 mm, 13 mm, 13.5 mm, 14 mm, 14.5 mm or 15 mm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0060] In some optional examples, the ball milling speed of the wet ball milling is 200-300 r / min, for example, it can be 200 r / min, 210 r / min, 220 r / min, 230 r / min, 240 r / min, 250 r / min, 260 r / min, 270 r / min, 280 r / min, 290 r / min or 300 r / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0061] In some optional examples, the wet ball milling time is 10 to 12 hours, for example, 10 hours, 10.2 hours, 10.4 hours, 10.6 hours, 10.8 hours, 11 hours, 11.2 hours, 11.4 hours, 11.6 hours, 11.8 hours or 12 hours, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0062] In some optional examples, the aging and homogenization temperature is 20-30°C, for example, it can be 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C or 30°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0063] In some optional examples, the humidity of the aging and homogenization is 40-50%, for example, it can be 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49% or 50%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0064] In some optional examples, the standing time for aging and homogenization is 36 to 48 hours, for example, it can be 36 hours, 37 hours, 38 hours, 39 hours, 40 hours, 41 hours, 42 hours, 43 hours, 44 hours, 45 hours, 46 hours, 47 hours or 48 hours, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0065] As a preferred technical solution of the present invention, in step (III), the extrusion molding extrusion pressure is 2 to 3 MPa, for example, it can be 2.0 MPa, 2.1 MPa, 2.2 MPa, 2.3 MPa, 2.4 MPa, 2.5 MPa, 2.6 MPa, 2.7 MPa, 2.8 MPa, 2.9 MPa or 3.0 MPa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0066] In some optional examples, the drying temperature of the blank is 120-150°C, for example, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C or 150°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0067] In some optional examples, the drying time of the blank is 12 to 24 hours, for example, it can be 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, 21 hours, 22 hours, 23 hours or 24 hours, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0068] As a preferred technical solution of the present invention, in step (III), the sintering process includes:

[0069] The dried green body is heated to a first sintering temperature T1 at a first heating rate V1, then continuously heated to a second sintering temperature T2 at a second heating rate V2, then continuously heated to a third sintering temperature T3 at a third heating rate V3, then continuously heated to a fourth sintering temperature T4 at a fourth heating rate V4, then continuously heated to a fifth sintering temperature T5 at a fifth heating rate V5, and kept at the fifth sintering temperature T5;

[0070] After the insulation is completed, the temperature is lowered to the first cooling temperature T6 at the first cooling rate V6, and then lowered to room temperature at the second cooling rate V7 to complete the sintering.

[0071] The first heating rate V1, the second heating rate V2, the third heating rate V3, the fourth heating rate V4 and the fifth heating rate V5 satisfy the following relationship:

[0072] V1>V2>V3>V4>V5.

[0073] The first sintering temperature T1, the first sintering temperature T2, the first sintering temperature T3, the first sintering temperature T4 and the first sintering temperature T5 satisfy the following relationship:

[0074] T1<T2<T3<T4<T5.

[0075] The first cooling rate V6 and the second cooling rate V7 satisfy the following relationship:

[0076] V6>V7.

[0077] As a preferred technical solution of the present invention, the first heating rate V1 is 10-12°C / min, for example, it can be 10°C / min, 10.2°C / min, 10.4°C / min, 10.6°C / min, 10.8°C / min, 11°C / min, 11.2°C / min, 11.4°C / min, 11.6°C / min, 11.8°C / min or 12°C / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0078] In some optional examples, the first sintering temperature T1 is 150-200°C, for example, it can be 150°C, 155°C, 160°C, 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C or 200°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0079] In some optional instances, the second heating rate V2 is 6 to 8°C / min, for example, it can be 6.0°C / min, 6.2°C / min, 6.4°C / min, 6.6°C / min, 6.8°C / min, 7.0°C / min, 7.2°C / min, 7.4°C / min, 7.6°C / min, 7.8°C / min or 8.0°C / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0080] In some optional examples, the second sintering temperature T2 is 500-600°C, for example, it can be 500°C, 510°C, 520°C, 530°C, 540°C, 550°C, 560°C, 570°C, 580°C, 590°C or 600°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0081] In some optional instances, the third heating rate V3 is 4 to 6°C / min, for example, it can be 4.0°C / min, 4.2°C / min, 4.4°C / min, 4.6°C / min, 4.8°C / min, 5.0°C / min, 5.2°C / min, 5.4°C / min, 5.6°C / min, 5.8°C / min or 6.0°C / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0082] In some optional examples, the third sintering temperature T3 is 700-800°C, for example, it can be 700°C, 710°C, 720°C, 730°C, 740°C, 750°C, 760°C, 770°C, 780°C, 790°C or 800°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0083] In some optional instances, the fourth heating rate V4 is 3 to 5°C / min, for example, it can be 3.0°C / min, 3.2°C / min, 3.4°C / min, 3.6°C / min, 3.8°C / min, 4.0°C / min, 4.2°C / min, 4.4°C / min, 4.6°C / min, 4.8°C / min or 5.0°C / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0084] In some optional instances, the fourth sintering temperature T4 is 900-1000°C, for example, it can be 900°C, 910°C, 920°C, 930°C, 940°C, 950°C, 960°C, 970°C, 980°C, 990°C or 1000°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0085] In some optional instances, the fifth heating rate V5 is 2 to 3°C / min, for example, it can be 2.0°C / min, 2.1°C / min, 2.2°C / min, 2.3°C / min, 2.4°C / min, 2.5°C / min, 2.6°C / min, 2.7°C / min, 2.8°C / min, 2.9°C / min or 3.0°C / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0086] In some optional instances, the fifth sintering temperature T5 is 1100-1200°C, for example, it can be 1100°C, 1110°C, 1120°C, 1130°C, 1140°C, 1150°C, 1160°C, 1170°C, 1180°C, 1190°C or 1200°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0087] In some optional examples, the holding time at the fifth sintering temperature T5 is 2 to 4 hours, for example, it can be 2.0h, 2.2h, 2.4h, 2.6h, 2.8h, 3.0h, 3.2h, 3.4h, 3.6h, 3.8h or 4.0h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0088] In some optional instances, the first cooling rate V6 is 10-12°C / min, for example, it can be 10°C / min, 10.2°C / min, 10.4°C / min, 10.6°C / min, 10.8°C / min, 11°C / min, 11.2°C / min, 11.4°C / min, 11.6°C / min, 11.8°C / min or 12°C / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0089] In some optional examples, the first cooling temperature T6 is 130-150°C, for example, it can be 130°C, 132°C, 134°C, 136°C, 138°C, 140°C, 142°C, 144°C, 146°C, 148°C or 150°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0090] In some optional instances, the second cooling rate V7 is 6 to 8°C / min, for example, it can be 6.0°C / min, 6.2°C / min, 6.4°C / min, 6.6°C / min, 6.8°C / min, 7.0°C / min, 7.2°C / min, 7.4°C / min, 7.6°C / min, 7.8°C / min or 8.0°C / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0091] Compared with the prior art, the present invention has the following beneficial effects:

[0092] The present invention adopts a two-step production process to prepare black silicon crystal with excellent performance. First, building debris, clay, feldspar and bluestone are mixed in proportion according to the required crystal phase and glass phase components, and after high-temperature melting and water quenching treatment, a metastable high-temperature material is obtained. The high-temperature material is sprayed with cooling water to achieve water quenching and rapid cooling, thereby maintaining the activation energy of the high-temperature material, and crystals can be quickly precipitated in the subsequent sintering process.

[0093] Subsequently, the pretreated material, composite nucleus agent, foaming agent and flux are mixed and wet ball-milled and aged to obtain mud. By adding foaming agent to the pretreated material, gas can be generated under heating conditions to ensure the formation of the expected spatial structure during the sintering process. By adding composite nucleus agent to the pretreated material, the crystallization process can be controlled to a certain extent, so that the residual grain system in the pretreated material is uniform. Under the induced crystallization conditions, the crystal structure of the material is effectively controlled to obtain the expected grain size and crystal space overlap structure, meeting the production cost and performance requirements of the prefabricated building market for black silicon crystal stone materials.

[0094] The high-temperature and high-pressure synthesis method of black silicon spar provided by the present invention has a simple process flow, the used construction debris is waste, the obtained black silicon spar product has high value, and the harmless treatment and high added value of the construction debris are achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0095] Figure 1 A flow chart of a high temperature and high pressure synthesis method of black silicon spar provided in Examples 1-5 of the present invention;

[0096] Figure 2 This is a scanning electron microscope image of the interior of the black silicon crystal prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0097] The technical solution of the present invention is described in detail below in conjunction with specific embodiments and their accompanying drawings. The embodiments recorded herein are specific embodiments of the present invention, which are used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary and should not be construed as limitations on the embodiments of the present invention and the scope of protection of the present invention. In addition to the embodiments recorded herein, those skilled in the art can also adopt other obvious technical solutions based on the contents disclosed in the claims of this application and its specification, including technical solutions that adopt any obvious replacements and modifications to the embodiments recorded herein.

[0098] Example 1

[0099] This embodiment provides a high temperature and high pressure synthesis method of black silicon crystal stone. Figure 1 As shown, the high temperature and high pressure synthesis method comprises:

[0100] (1) mixing construction waste soil, clay, feldspar, bluestone and a coloring agent, cobalt oxide, in a mass ratio of 14:1:1:1:1, wherein the construction waste soil includes a first construction waste soil and a second construction waste soil in a mass ratio of 1:2, wherein the particle size D90 of the first construction waste soil is 60 mesh, and the particle size D90 of the second construction waste soil is 100 mesh, and after mixing, dry ball milling is performed at a rotation speed of 200 r / min for 12 hours to obtain a mixed material;

[0101] The contents of each component in construction waste, clay, feldspar and bluestone are shown in Table 1.

[0102] Table 1: Composition of construction waste, clay, feldspar and bluestone

[0103]

[0104] The mixed material is heated to 1000℃ at a heating rate of 10℃ / min and kept at this temperature for 60min to complete pre-sintering and obtain high-temperature material; the high-temperature material is sprayed with cooling water at 15℃ until the high-temperature material cools to room temperature, and the spraying amount of cooling water is 4000m 3 / h, the spraying pressure is 0.2MPa, the cooling rate of the high-temperature material surface is 40℃ / s, and the pretreated material is obtained after the water quenching and rapid cooling;

[0105] (2) mixing the pretreated material, the composite nucleation agent, sodium carbonate and alumina in a mass ratio of 70:5:1:4 to obtain a dry material, wherein the composite nucleation agent consists of 40wt% of Cr2O3, 30wt% of CaF2, 20wt% of ZrO2 and 10wt% of B2O3;

[0106] The dry material, deionized water and abrasive balls were put into a ball mill in a mass ratio of 1:0.8:3 for wet ball milling. The particle size of the abrasive balls was 10 mm, the ball milling speed was 200 r / min, and the ball milling time was 12 h. After the ball milling, a precursor material was obtained. The precursor material was placed in a constant temperature and humidity environment with a temperature of 20° C. and a humidity of 50% for aging and homogenization for 36 h to obtain a mud material;

[0107] (3) The slurry is extruded and formed at a pressure of 2 MPa, and then a green body is obtained after cutting. The green body is placed at 120°C for drying for 24 hours, and then the dried green body is heated to 150°C at a heating rate of 10°C / min, and then the temperature is further increased to 500°C at a heating rate of 6°C / min, and then the temperature is further increased to 700°C at a heating rate of 4°C / min, and then the temperature is further increased to 900°C at a heating rate of 3°C / min, and then the temperature is further increased to 1100°C at a heating rate of 2°C / min, and kept at 1100°C for 4 hours; after the insulation is completed, the temperature is reduced to 130°C at a cooling rate of 10°C / min, and then the temperature is reduced to room temperature at a cooling rate of 6°C / min to complete sintering and obtain the black silicon crystal stone.

[0108] Figure 2 This is a scanning electron microscope image of the black silicon crystal prepared in this example. It can be seen from the image that there are a number of pores evenly distributed inside the matrix of the black silicon crystal, with an average pore diameter of about 60μm. This structure makes the black silicon crystal have the characteristics of light weight and high strength.

[0109] Example 2

[0110] This embodiment provides a high temperature and high pressure synthesis method of black silicon crystal stone. Figure 1 As shown, the high temperature and high pressure synthesis method comprises:

[0111] (1) mixing construction waste, clay, feldspar, bluestone and nickel oxide, a coloring agent, in a mass ratio of 14.2:1:1:1:1, wherein the construction waste includes a first construction waste and a second construction waste in a mass ratio of 1:2.2, wherein the particle size D90 of the first construction waste is 65 mesh, and the particle size D90 of the second construction waste is 105 mesh, and after mixing, dry ball milling is performed at a rotation speed of 220 r / min for 11.5 hours to obtain a mixed material;

[0112] The contents of each component in construction waste, clay, feldspar and bluestone are shown in Table 2.

[0113] Table 2: Composition of construction waste, clay, feldspar and bluestone

[0114]

[0115] The mixed material was heated to 1050℃ at a heating rate of 10.5℃ / min and kept at this temperature for 55min to complete pre-sintering and obtain high-temperature material; the high-temperature material was sprayed with cooling water at 18℃ until the high-temperature material cooled to room temperature, and the spraying volume of cooling water was 3800m 3 / h, the spraying pressure is 0.22MPa, the cooling rate of the high-temperature material surface is 38℃ / s, and the pretreated material is obtained after the water quenching and rapid cooling;

[0116] (2) mixing the pretreated material, the composite nucleation agent, potassium carbonate and alumina in a mass ratio of 72:5.5:1.2:4.5 to obtain a dry material, wherein the composite nucleation agent consists of 41wt% of Cr2O3, 30wt% of CaF2, 18wt% of ZrO2 and 11wt% of B2O3;

[0117] The dry material, deionized water and abrasive balls were put into a ball mill in a mass ratio of 1:0.9:3.5 for wet ball milling. The particle size of the abrasive balls was 11 mm, the ball milling speed was 220 r / min, and the ball milling time was 11.5 h. After the ball milling, a precursor material was obtained. The precursor material was placed in a constant temperature and humidity environment with a temperature of 22° C. and a humidity of 48% for aging and homogenization for 38 h to obtain a mud material;

[0118] (3) The slurry is extruded and formed at a pressure of 2.2 MPa, and then a green body is obtained after cutting. The green body is placed at 130°C for drying for 21 hours, and then the dried green body is heated to 160°C at a heating rate of 10.5°C / min, and then the temperature is further increased to 520°C at a heating rate of 6.5°C / min, and then the temperature is further increased to 720°C at a heating rate of 4.5°C / min, and then the temperature is further increased to 920°C at a heating rate of 3.5°C / min, and then the temperature is further increased to 1120°C at a heating rate of 2.2°C / min, and kept at 1120°C for 3.5 hours; after the insulation is completed, the temperature is cooled to 135°C at a cooling rate of 10.5°C / min, and then the temperature is cooled to room temperature at a cooling rate of 6.5°C / min to complete sintering and obtain the black silicon crystal stone.

[0119] Example 3

[0120] This embodiment provides a high temperature and high pressure synthesis method of black silicon crystal stone. Figure 1 As shown, the high temperature and high pressure synthesis method comprises:

[0121] (1) mixing construction waste, clay, feldspar, bluestone and colorant manganese oxide in a mass ratio of 14.5:1:1:1:1, wherein the construction waste includes a first construction waste and a second construction waste in a mass ratio of 1:2.5, wherein the particle size D90 of the first construction waste is 70 meshes, and the particle size D90 of the second construction waste is 110 meshes, and after mixing, dry ball milling is performed at a rotation speed of 250 r / min for 11 hours to obtain a mixed material;

[0122] The contents of each component in construction waste, clay, feldspar and bluestone are shown in Table 3.

[0123] Table 3: Composition of construction waste, clay, feldspar and bluestone

[0124]

[0125]

[0126] The mixed material is heated to 1100℃ at a heating rate of 11℃ / min and kept at this temperature for 50min to complete pre-sintering and obtain high-temperature material; the high-temperature material is sprayed with cooling water at 20℃ until the high-temperature material cools to room temperature, and the spraying amount of cooling water is 3500m 3 / h, the spraying pressure is 0.25MPa, the cooling rate of the high-temperature material surface is 35℃ / s, and the pretreated material is obtained after the water quenching and rapid cooling;

[0127] (2) mixing the pretreated material, the composite nucleus agent, sodium bicarbonate and sodium metasilicate in a mass ratio of 75:6:1.5:5 to obtain a dry material, wherein the composite nucleus agent consists of 42wt% of Cr2O3, 28wt% of CaF2, 18wt% of ZrO2 and 12wt% of B2O3;

[0128] The dry material, deionized water and abrasive balls were put into a ball mill in a mass ratio of 1:1:4 for wet ball milling. The particle size of the abrasive balls was 12 mm, the ball milling speed was 250 r / min, and the ball milling time was 11 h. After the ball milling, a precursor material was obtained. The precursor material was placed in a constant temperature and humidity environment with a temperature of 25° C. and a humidity of 45% for aging and homogenization for 40 h to obtain a mud material;

[0129] (3) The slurry is extruded and formed at a pressure of 2.5 MPa, and then a green body is obtained after cutting. The green body is placed at 140°C for drying for 18 hours, and then the dried green body is heated to 170°C at a heating rate of 11°C / min, and then the temperature is further increased to 550°C at a heating rate of 7°C / min, and then the temperature is further increased to 750°C at a heating rate of 5°C / min, and then the temperature is further increased to 950°C at a heating rate of 4°C / min, and then the temperature is further increased to 1150°C at a heating rate of 2.5°C / min, and kept at 1150°C for 3 hours; after the insulation is completed, the temperature is cooled to 140°C at a cooling rate of 11°C / min, and then cooled to room temperature at a cooling rate of 7°C / min to complete sintering and obtain the black silicon crystal stone.

[0130] Example 4

[0131] This embodiment provides a high temperature and high pressure synthesis method of black silicon crystal stone. Figure 1 As shown, the high temperature and high pressure synthesis method comprises:

[0132] (1) mixing construction waste, clay, feldspar, bluestone and copper oxide, a coloring agent, in a mass ratio of 14.8:1:1:1:1, wherein the construction waste includes a first construction waste and a second construction waste in a mass ratio of 1:2.8, wherein the particle size D90 of the first construction waste is 75 mesh, and the particle size D90 of the second construction waste is 115 mesh, and after mixing, dry ball milling is performed at a rotation speed of 280 r / min for 10.5 h to obtain a mixed material;

[0133] The contents of each component in construction waste, clay, feldspar and bluestone are shown in Table 4.

[0134] Table 4: Composition of construction waste, clay, feldspar and bluestone

[0135]

[0136] The mixed material was heated to 1150℃ at a heating rate of 11.5℃ / min and kept at this temperature for 45min to complete pre-sintering and obtain high-temperature material; the high-temperature material was sprayed with cooling water at 22℃ until the high-temperature material cooled to room temperature. The spraying amount of cooling water was 3200m 3 / h, the spraying pressure is 0.28MPa, the cooling rate of the high-temperature material surface is 32℃ / s, and the pretreated material is obtained after the water quenching and rapid cooling;

[0137] (2) mixing the pretreated material, the composite nucleation agent, sodium carbonate and alumina in a mass ratio of 78:6.5:1.8:5.5 to obtain a dry material, wherein the composite nucleation agent consists of 43wt% of Cr2O3, 25wt% of CaF2, 20wt% of ZrO2 and 12wt% of B2O3;

[0138] The dry material, deionized water and abrasive balls were put into a ball mill in a mass ratio of 1:1.1:4.5 for wet ball milling. The particle size of the abrasive balls was 13 mm, the ball milling speed was 280 r / min, and the ball milling time was 10.5 h. After the ball milling, a precursor material was obtained. The precursor material was placed in a constant temperature and humidity environment with a temperature of 28° C. and a humidity of 42% for aging and homogenization for 44 h to obtain a mud material;

[0139] (3) The slurry is extruded and formed at a pressure of 2.8 MPa, and then a green body is obtained after cutting. The green body is placed at 140°C for drying for 15 hours, and then the dried green body is heated to 180°C at a heating rate of 11.5°C / min, and then the temperature is further increased to 580°C at a heating rate of 7.5°C / min, and then the temperature is further increased to 780°C at a heating rate of 5.5°C / min, and then the temperature is further increased to 980°C at a heating rate of 4.5°C / min, and then the temperature is further increased to 1180°C at a heating rate of 2.8°C / min, and kept at 1180°C for 2.5 hours; after the insulation is completed, the temperature is reduced to 145°C at a cooling rate of 11.5°C / min, and then the temperature is reduced to room temperature at a cooling rate of 7.5°C / min to complete sintering and obtain the black silicon crystal stone.

[0140] Example 5

[0141] This embodiment provides a high temperature and high pressure synthesis method of black silicon crystal stone. Figure 1 As shown, the high temperature and high pressure synthesis method comprises:

[0142] (1) mixing construction waste, clay, feldspar, bluestone and a coloring agent, cobalt oxide, in a mass ratio of 15:1:1:1:1, wherein the construction waste includes a first construction waste and a second construction waste in a mass ratio of 1:3, wherein the particle size D90 of the first construction waste is 80 meshes, and the particle size D90 of the second construction waste is 120 meshes, and after mixing, dry ball milling is performed at a rotation speed of 300 r / min for 10 hours to obtain a mixed material;

[0143] The contents of each component in construction waste, clay, feldspar and bluestone are shown in Table 5.

[0144] Table 5: Composition of construction waste, clay, feldspar and bluestone

[0145]

[0146] The mixed material is heated to 1200℃ at a heating rate of 12℃ / min and kept at this temperature for 40min to complete pre-sintering and obtain high-temperature material; the high-temperature material is sprayed with cooling water at 25℃ until the high-temperature material cools to room temperature, and the spraying amount of cooling water is 3000m 3 / h, the spraying pressure is 0.3MPa, the cooling rate of the high-temperature material surface is 30℃ / s, and the pretreated material is obtained after the water quenching and rapid cooling;

[0147] (2) mixing the pretreated material, the composite nucleation agent, sodium carbonate and alumina in a mass ratio of 80:7:2:6 to obtain a dry material, wherein the composite nucleation agent consists of 45wt% of Cr2O3, 30wt% of CaF2, 15wt% of ZrO2 and 10wt% of B2O3;

[0148] The dry material, deionized water and abrasive balls are put into a ball mill in a mass ratio of 1:1.2:5 for wet ball milling. The particle size of the abrasive balls is 15 mm, the ball milling speed is 300 r / min, and the ball milling time is 10 h. After the ball milling, a precursor material is obtained. The precursor material is placed in a constant temperature and humidity environment with a temperature of 30° C. and a humidity of 40% for aging and homogenization for 48 h to obtain a mud material;

[0149] (3) The slurry is extruded and formed at a pressure of 3 MPa, and then a green body is obtained after cutting. The green body is placed at 150°C for drying for 12 hours, and then the dried green body is heated to 200°C at a heating rate of 12°C / min, and then the temperature is further increased to 600°C at a heating rate of 8°C / min, and then the temperature is further increased to 800°C at a heating rate of 6°C / min, and then the temperature is further increased to 1000°C at a heating rate of 5°C / min, and then the temperature is further increased to 1200°C at a heating rate of 3°C / min, and kept at 1200°C for 2 hours; after the insulation is completed, the temperature is reduced to 150°C at a cooling rate of 12°C / min, and then the temperature is reduced to room temperature at a cooling rate of 8°C / min to complete sintering and obtain the black silicon crystal stone.

[0150] Comparative Example 1

[0151] This comparative example provides a high-temperature and high-pressure synthesis method of black silica spar, which differs from Example 1 in that the mass ratio of the first construction waste soil to the second construction waste soil is adjusted to 1:1, and the other process parameters and operating steps are exactly the same as those in Example 1.

[0152] Comparative Example 2

[0153] This comparative example provides a high-temperature and high-pressure synthesis method of black silica spar, which differs from Example 1 in that the mass ratio of the first construction waste soil to the second construction waste soil is adjusted to 1:4, and other process parameters and operating steps are exactly the same as those in Example 1.

[0154] Comparative Example 3

[0155] This comparative example provides a high-temperature and high-pressure synthesis method of black silicon spar. The difference from Example 1 is that the mass fraction of Cr2O3 in the composite nucleating agent is adjusted to 35wt%, and the other components are enlarged in proportion, as follows:

[0156]

[0157]

[0158] Other process parameters and operation steps are exactly the same as those in Example 1.

[0159] Comparative Example 4

[0160] This comparative example provides a high temperature and high pressure synthesis method of black silicon spar, which is different from Example 1 in that the mass fraction of Cr2O3 in the composite nucleating agent is adjusted to 50wt%, and the other components are reduced in proportion, as follows:

[0161]

[0162] Other process parameters and operation steps are exactly the same as those in Example 1.

[0163] Comparative Example 5

[0164] This comparative example provides a high temperature and high pressure synthesis method of black silicon spar, which is different from Example 1 in that the mass fraction of CaF2 in the composite nucleating agent is adjusted to 20wt%, and the other components are enlarged in proportion, as follows:

[0165]

[0166] Other process parameters and operation steps are exactly the same as those in Example 1.

[0167] Comparative Example 6

[0168] This comparative example provides a high temperature and high pressure synthesis method of black silicon spar, which is different from Example 1 in that the mass fraction of CaF2 in the composite nucleating agent is adjusted to 35wt%, and the other components are reduced in proportion, as follows:

[0169]

[0170] Other process parameters and operation steps are exactly the same as those in Example 1.

[0171] The bulk density, water absorption rate and compressive strength of the black silicon spar prepared in Examples 1-5 and Comparative Examples 1-6 were tested, and the specific test steps are as follows:

[0172] (1) Bulk density

[0173] The higher the bulk density (density) of black silica spar, the greater the strength. At the same time, as a building material, the weight will also increase under the same volume. Therefore, minimizing the bulk density while meeting the strength requirements is the ideal goal.

[0174] The present invention adopts the test method provided in GB / T5486-2008 "Test Methods for Inorganic Hard Insulation Products" to test the bulk density of black silicon spar. First, the black silicon spar is cut into square test blocks with a side length of 100 mm, and the test blocks are placed in a drying oven and dried at 100°C to a constant weight, then cooled to room temperature, and the mass G of the test blocks is weighed. The size of the test blocks is determined according to the standard method, and the volume V is calculated. The bulk density of the test blocks is calculated according to the following formula:

[0175]

[0176] Where: ρ is the bulk density of the sample (g / cm 3 ), G is the mass of the sample block (g), V is the volume of the sample block (cm 3 ).

[0177] For each embodiment (comparative example), 5 groups of test pieces were tested and the average value was taken.

[0178] (2) Water absorption

[0179] Water absorption is an important indicator for testing the eligibility of building materials. The higher the water absorption, the higher the surface porosity of the black silicon spar and the lower the service life. Conversely, the lower the service life, the higher the water absorption. The present invention adopts the test method provided in GB / T5486-2008 "Test Methods for Inorganic Hard Insulation Products" to test the water absorption of black silicon spar. First, the black silicon spar is cut into square sample blocks with a side length of 100 mm, and the sample blocks are placed in a drying oven and dried at 100°C to a constant weight, then cooled to room temperature, and the mass G0 of the sample blocks is weighed. Then, the sample blocks are placed in boiling distilled water for 3 hours, during which the sample blocks are kept 10 mm below the water surface. After 3 hours, the surface water stains of the sample blocks are wiped off with a cloth that has been saturated with water, and the mass G1 of the sample blocks is weighed. The water absorption rate (ω) of the sample blocks is calculated as follows:

[0180]

[0181] For each embodiment (comparative example), 5 groups of test pieces were tested and the average value was taken.

[0182] (3) Compressive strength

[0183] The measurement of compressive strength is an important indicator to characterize the bearing capacity of black silicon spar. The present invention adopts the test method provided in GB / T5486-2008 "Test Methods for Inorganic Hard Insulation Products" to test the water absorption rate of black silicon spar. First, the black silicon spar is cut into square test blocks with a side length of 100 mm, and the test blocks are placed in a drying oven and dried at 100°C to a constant weight, then cooled to room temperature, and the surface is filled with emulsified asphalt to fill the compressed surface, and dried to a constant weight. The compressive strength (ω) of the test block is calculated as follows:

[0184]

[0185] Where: σ is the compressive strength of the specimen (MPa), P is the pressure (N), S is the pressure area (m 2 ).

[0186] For each embodiment (comparative example), 5 groups of test pieces were tested and the average value was taken.

[0187] The test results are shown in Table 6.

[0188] Table 6 Test results of black silicon crystal prepared by Examples 1-5 and Comparative Examples 1-6

[0189]

[0190]

[0191] It can be seen from the data in Table 6 that the bulk density and compressive strength of the black silicon crystal prepared in Examples 1-5 of the present invention are higher than those in Comparative Examples 1-6, while the water absorption rate is lower than that in Comparative Examples 1-6. This indicates that the high-temperature and high-pressure synthesis method provided by the present invention can be used to prepare lightweight and high-strength black silicon crystal, thereby achieving efficient recycling of construction waste.

[0192] It can be seen from the test data of Example 1, Comparative Example 1 and Comparative Example 2 that the bulk density and compressive strength of the black silicon crystal prepared in Comparative Example 1 and Comparative Example 2 are lower than those in Example 1, while the water absorption rate is higher than that in Example 1. This indicates that the mass ratio of the first construction waste to the second construction waste will directly affect the bulk density, water absorption rate and compressive strength of the black silicon crystal. Only when the mass ratio of the first construction waste to the second construction waste is within the range of 1:(2 to 3) can lightweight and high-strength black silicon crystal be obtained.

[0193] It can be seen from the test data of Example 1, Comparative Example 3 and Comparative Example 4 that the bulk density and compressive strength of the black silicon crystal prepared in Comparative Example 3 and Comparative Example 4 are lower than those in Example 1, while the water absorption is higher than that in Example 1, which indicates that the mass fraction of Cr2O3 in the composite nucleation agent will directly affect the bulk density, water absorption and compressive strength of the black silicon crystal. Only when the mass fraction of Cr2O3 in the composite nucleation agent is in the range of 40 to 45wt%, can lightweight and high-strength black silicon crystal be obtained.

[0194] It can be seen from the test data of Example 1, Comparative Example 5 and Comparative Example 6 that the bulk density and compressive strength of the black silicon crystal prepared in Comparative Example 5 and Comparative Example 6 are lower than those in Example 1, while the water absorption rate is higher than that in Example 1, which indicates that the mass fraction of CaF2 in the composite nucleation agent will directly affect the bulk density, water absorption rate and compressive strength of the black silicon crystal. Only when the mass fraction of CaF2 in the composite nucleation agent is in the range of 25 to 30wt%, can lightweight and high-strength black silicon crystal be obtained.

[0195] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A high temperature and high pressure synthesis method of black silicon spar, characterized in that: The high temperature and high pressure synthesis method comprises: (I) mixing and ball-milling construction waste, clay, feldspar, bluestone and a colorant to obtain a mixed material, pre-sintering the mixed material to obtain a high-temperature material, spraying the high-temperature material with cooling water to complete water quenching and rapid cooling to obtain a pretreated material; (II) mixing the pretreated material, a composite crystal nucleating agent, a foaming agent and a flux to obtain a dry material, wherein the composite crystal nucleating agent is composed of Cr2O3, CaF2, ZrO2 and B2O3; placing the dry material, deionized water and abrasive balls in a ball mill for wet ball milling to obtain a precursor material, placing the precursor material in a constant temperature and humidity environment for aging and homogenization to obtain a mud material; (III) extruding the clay material into a shape, and then cutting the shape into a green body, and drying and sintering the green body in sequence to obtain the black silicon crystal stone; In step (I), the mass ratio of the construction waste, clay, feldspar, bluestone and colorant is (14-15):1:1:1:1; the mass fraction of each component in the construction waste is as follows: Fe2O3 0.4~0.5wt%; Al2O3 13~15wt%; SiO2 60~70wt%; TiO2 0.05~0.1wt%; Na2O 2~3wt%; CaO 0.3~0.5wt%; MgO 0.3~0.5wt%; K2O 5~6wt%; Others are unavoidable impurities; The construction waste soil includes first construction waste soil and second construction waste soil with different particle sizes, wherein the particle size of the first construction waste soil is 60-80 meshes, and the particle size of the second construction waste soil is 100-120 meshes; The mass ratio of the first construction waste to the second construction waste is 1:(2-3); In step (II), based on the mass fraction of the composite crystal nucleating agent being 100wt%, the mass fractions of the components are as follows: Cr2O3 40~45wt%; CaF2 25~30wt%; ZrO2 15~20wt%; B2O3 10~12wt%.

2. The high temperature and high pressure synthesis method according to claim 1, characterized in that: In step (I), the colorant includes any one of cobalt oxide, nickel oxide, manganese oxide or copper oxide, or a combination of at least two of them.

3. The high temperature and high pressure synthesis method according to claim 1, characterized in that: The mass fractions of the components in the clay are as follows: Fe2O3 2~3wt%; Al2O3 16~18wt%; SiO2 70~75wt%; TiO2 0.4~0.5wt%; Na2O 0.1~0.2wt%; CaO 0.6~0.8wt%; MgO 0.3~0.5wt%; K2O 1~2wt%; MnO 0.05~0.1wt%; Others are unavoidable impurities; The mass fractions of the various components in the feldspar are as follows: Fe2O3 2~3wt%; Al2O3 10~12wt%; SiO2 38~40wt%; TiO2 0.3~0.5wt%; Na2O 1~1.2wt%; CaO 1.3~1.5wt%; MgO 1.3~1.5wt%; K2O 1.3~1.5wt%; MnO 0.05~0.1wt%; Others are unavoidable impurities; The mass fractions of the components in the bluestone are as follows: Fe2O3 3~4wt%; Al2O3 13~15wt%; SiO2 70~72wt%; TiO2 0.4~0.6wt%; Na2O 3~4wt%; CaO 1.5~1.6wt%; MgO 1.4~1.5wt%; K2O 2~3wt%; MnO 0.1~0.2wt%; Others are inevitable impurities.

4. The high temperature and high pressure synthesis method according to claim 1, characterized in that: The ball milling speed of the mixed ball mill is 200-300 r / min; The ball milling time of the mixed ball milling is 10 to 12 hours.

5. The high temperature and high pressure synthesis method according to claim 1, characterized in that: In step (I), the heating rate of the pre-sintering is 10-12°C / min; The sintering temperature of the pre-sintering is 1000-1200°C; The pre-sintering holding time is 40 to 60 minutes; The temperature of the cooling water is 15-25°C; The spray volume of the cooling water is 3000~4000m 3 / h; The spray pressure of the cooling water is 0.2~0.3MPa; The cooling rate of the high-temperature material surface is 30-40°C / s.

6. The high temperature and high pressure synthesis method according to claim 1, characterized in that: In step (II), the mass ratio of the pre-treated material, the composite nucleating agent, the foaming agent and the flux is (70-80):(5-7):(1-2):(4-6); The foaming agent includes any one of sodium carbonate, potassium carbonate, sodium bicarbonate or a combination of at least two thereof; The flux comprises any one of aluminum oxide and sodium metasilicate or a combination of at least two thereof; The mass ratio of the dry material, deionized water and abrasive balls is 1:(0.8-1.2):(3-5); The particle size of the abrasive balls is 10-15 mm; The ball milling speed of the wet ball milling is 200-300 r / min; The wet ball milling time is 10 to 12 hours; The temperature of the aging and homogenization is 20-30°C; The humidity of the stale homogenization is 40-50%; The standing time of the aging and homogenization is 36 to 48 hours.

7. The high temperature and high pressure synthesis method according to claim 1, characterized in that: In step (III), the extrusion pressure of the extrusion molding is 2-3 MPa; The drying temperature of the green body is 120-150°C; The drying time of the green body is 12 to 24 hours.

8. The high temperature and high pressure synthesis method according to claim 1, characterized in that: In step (III), the sintering process comprises: The dried green body is heated to a first sintering temperature T1 at a first heating rate V1, then continuously heated to a second sintering temperature T2 at a second heating rate V2, then continuously heated to a third sintering temperature T3 at a third heating rate V3, then continuously heated to a fourth sintering temperature T4 at a fourth heating rate V4, then continuously heated to a fifth sintering temperature T5 at a fifth heating rate V5, and kept at the fifth sintering temperature T5; After the heat preservation is completed, the temperature is lowered to the first cooling temperature T6 at the first cooling rate V6, and then lowered to room temperature at the second cooling rate V7 to complete the sintering; The first heating rate V1, the second heating rate V2, the third heating rate V3, the fourth heating rate V4 and the fifth heating rate V5 satisfy the following relationship: V1>V2>V3>V4>V5; The first sintering temperature T1, the first sintering temperature T2, the first sintering temperature T3, the first sintering temperature T4 and the first sintering temperature T5 satisfy the following relationship: T1<T2<T3<T4<T5; The first cooling rate V6 and the second cooling rate V7 satisfy the following relationship: V6>V7.

9. The high temperature and high pressure synthesis method according to claim 8, characterized in that: The first heating rate V1 is 10-12°C / min; The first sintering temperature T1 is 150-200°C; The second heating rate V2 is 6-8°C / min; The second sintering temperature T2 is 500-600°C; The third heating rate V3 is 4-6°C / min; The third sintering temperature T3 is 700-800°C; The fourth heating rate V4 is 3-5°C / min; The fourth sintering temperature T4 is 900-1000° C.; The fifth heating rate V5 is 2-3°C / min; The fifth sintering temperature T5 is 1100-1200° C. The holding time at the fifth sintering temperature T5 is 2 to 4 hours; The first cooling rate V6 is 10-12°C / min; The first cooling temperature T6 is 130-150°C; The second cooling rate V7 is 6-8°C / min.

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