Artificial stone plate sand as well as preparation method and application thereof

Abstract

The invention relates to the technical field of building materials, and discloses artificial stone plate sand as well as a preparation method and application thereof. According to the preparation method of the artificial stone plate sand provided by the invention, the black talc is calcined, so that the black talc is subjected to phase transformation, and the artificial stone plate sand with zero crystalline silicon is generated. Compared with a traditional method, on one hand, the method is safer, the risk of silicosis is basically eliminated due to the characteristic of zero crystalline silicon, and the health guarantee of operators is greatly improved; on the other hand, the method is more economical, the comprehensive cost is reduced by about 24.6%, and raw material supply is stable; and on the other hand, the method is more environment-friendly, pollutants such as acid wastewater and crystalline silicon dust can be reduced, and the method conforms to the sustainable development trend of the artificial stone industry.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, specifically to an artificial stone slab sand, its preparation method, and its application. Background Technology

[0002] Artificial stone, a more economical alternative to natural stone, has been widely used in homes, restaurants, hotels, and offices. However, in recent years, an incurable lung disease has been reported to be linked to artificial stone used on common kitchen or bathroom countertops.

[0003] Traditional artificial stone is made from natural quartz sand. Large blocks of raw quartz stone mined from natural quartz mines are processed through peeling, sorting, acid washing, crushing, filtration, drying, color sorting, and magnetic separation to become quartz sand, which is then used as aggregate or filler in artificial stone.

[0004] However, natural silica sand contains a large amount of crystalline silicon (α-quartz), which easily generates inhalable dust during processing. This significantly increases the risk of silicosis during product processing and use. Therefore, it is necessary to develop new environmentally friendly materials to replace natural silica sand in the production of artificial stone slabs. Summary of the Invention

[0005] In view of this, the present invention provides artificial stone slab sand, its preparation method, and its application to solve the problem of high crystalline silicon content in natural quartz sand used for making artificial stone slabs. The present invention relates to an innovative method for producing artificial stone slab sand, which obtains artificial stone slab sand containing zero crystalline silicon by calcining a specific proportion of black talc raw materials. This method can significantly reduce the risk of silicosis caused by crystalline silicon dust in traditional artificial stone slab sand during product processing, while also meeting the stringent requirements for raw materials in high-end artificial quartz stone slabs and complying with environmental protection material requirements.

[0006] In a first aspect, the present invention provides a method for preparing artificial stone slab sand, comprising the following steps:

[0007] The raw material mixture is subjected to wet ball milling, pressure filtration and mud refining in sequence to obtain mud material; wherein, the raw material mixture includes black talc;

[0008] The clay material is extruded and dried to obtain dried clay blocks;

[0009] The dried mud blocks are calcined and crushed.

[0010] In one alternative embodiment, the raw material mixture further includes feldspar and kaolin;

[0011] Based on the total weight of the raw material mixture, the weight percentage of black talc is 60-85%, the weight percentage of feldspar is 5-20%, and the weight percentage of kaolin is 5-20%.

[0012] In one optional embodiment, the calcination conditions include:

[0013] The calcination temperature is 1200–1350℃, and the calcination time is 10–32 h.

[0014] In one optional embodiment, the conditions for the wet ball milling include:

[0015] The ball milling time is 20-60 hours, and the residue on a 325-mesh sieve is less than 0.3%.

[0016] In one optional embodiment, the pressure filtration includes:

[0017] The ball milling slurry obtained from wet ball milling is subjected to pressure filtration to reduce the moisture content of the slurry to 20-26%.

[0018] In one optional embodiment, the mud refining is vacuum mud refining, with a vacuum degree of -1 to 0 MPa and a time of 20 to 70 minutes.

[0019] In one alternative implementation, the drying conditions include:

[0020] The drying temperature shall not exceed 300℃, and the moisture content shall not exceed 3%.

[0021] Secondly, the present invention provides artificial stone slab sand prepared by the above-described preparation method.

[0022] Thirdly, the present invention provides the application of the above-mentioned artificial stone slab sand in the manufacture of artificial stone slabs.

[0023] Fourthly, the present invention provides an artificial stone slab, wherein the raw material of the artificial stone slab includes the aforementioned artificial stone slab sand.

[0024] Based on the above technical solutions, the present invention has at least the following beneficial effects:

[0025] 1. The method for preparing artificial stone slab sand provided by this invention involves calcining black talc to induce a phase transformation, generating artificial stone slab sand with zero crystalline silicon. Compared to traditional methods, this method is safer, as the zero-crystalline silicon characteristic essentially eliminates the risk of silicosis, significantly improving the health protection of operators. Furthermore, this method is more economical, reducing overall costs by approximately 24.6% and ensuring a stable supply of raw materials. Finally, this method is more environmentally friendly, reducing pollutants such as acidic wastewater and crystalline silicon dust, aligning with the sustainable development trend of the artificial stone industry. Details are as follows:

[0026] (1) Significantly reduces the risk of silicosis

[0027] Traditional process: High-purity crystalline silicon (α-quartz) is used, which generates a large amount of inhalable SiO2 dust (particle size ≤5μm) during processing. Long-term exposure can lead to fast-progressing silicosis (the disease can develop after 5 to 15 years of exposure).

[0028] The process of this invention: the zero-crystallization silicon generated by calcining black talc significantly reduces the pathogenicity of dust;

[0029] Crystalline silicon content: reduced from 60%–80% in traditional processes to ≤1% (compliant with OSHA / EU occupational exposure limits);

[0030] Dust-induced illness rate: Third-party testing (GBZ / T 192-2019) showed that under the same exposure conditions, the incidence of silicosis among operators decreased from 23% to <0.1%.

[0031] (2) Improve occupational health environment

[0032] Processing dust control: The surface passivation of zero-crystallization silicon particles after calcination can significantly reduce dust emissions (the measured PM2.5 concentration is 90% lower than that of traditional processes);

[0033] Long-term health effects: It eliminates the risk of progressive pulmonary fibrosis in traditional quartz sand processing, and can especially protect the health and safety of high-risk workers such as quartz grinders and sandblasters.

[0034] 2. The artificial stone slab sand provided by this invention has significantly improved physical and chemical properties such as flexural strength, whiteness, and acid resistance compared to traditional quartz sand. It can be directly used to replace traditional quartz sand and can be used directly in the manufacture of artificial stone slabs without adjusting existing production lines (resin curing time, pressing parameters, etc.), thus having good process compatibility.

[0035] 3. The artificial stone slab sand and its preparation method provided by this invention have lower raw material costs and lower environmental treatment costs, resulting in higher economic benefits. Furthermore, high-purity quartz sand faces resource depletion, while black talc has abundant reserves and offers resource sustainability.

[0036] 4. The artificial stone slab sand and its preparation method provided by this invention, compared with the processing technology of quartz sand, eliminates the acid washing / water washing process of quartz sand, reduces the overall carbon footprint by about 30%, and produces no hydrofluoric acid wastewater (an inevitable pollutant of traditional quartz sand acid washing process) and no heavy metal residue (natural quartz sand often contains impurities such as iron and manganese), thus having strong environmental friendliness. Attached Figure Description

[0037] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0038] Figure 1 This is the X-ray diffraction detection result in Test Example 1 of this invention. Detailed Implementation

[0039] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0040] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0041] This invention provides a method for preparing artificial stone slab sand, the production process of which is as follows:

[0042] Raw material weighing - ball milling into slurry in ball mill according to proportion - slurry pressing and filtering into mud - vacuum mud kneading and shaping - drying in kiln - finished product firing - crushing - sieving according to particle size requirements - packaging and warehousing.

[0043] The core technical points of this invention are as follows:

[0044] (1) Technological Innovation. The core of this process lies in processing black talc raw materials through a precisely controlled calcination process, achieving the following technological breakthroughs:

[0045] Specific formulation ratio: Optimize the proportion of black talc raw materials to ensure stable product performance after calcination;

[0046] Temperature control: Precisely control the calcination temperature profile to achieve zero-crystallization silicon;

[0047] Reaction conditions: Create a chemical reaction environment that is conducive to the release of silicon.

[0048] (2) Product performance advantages. The artificial stone slab sand produced using the technical solution of this invention has the following significant advantages:

[0049] Zero-crystallinity silicon: Meets the zero-crystallinity silicon standard (crystallinity <1%, SiO2 <60%), and complies with environmental protection requirements;

[0050] Whiteness control: can meet the whiteness requirements of products of different grades from 85 to 95 degrees;

[0051] Particle uniformity: Particle size distribution is precisely controllable, adapting to different mesh size requirements.

[0052] The present invention will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed by the present invention.

[0053] Example 1

[0054] Artificial stone slab sand is prepared according to the following method:

[0055] (1) Weigh black talc, feldspar and kaolin in proportion and mix them to obtain a raw material mixture; wherein, the amount of black talc is 60wt%, the amount of feldspar is 20wt%, and the amount of kaolin is 20wt%.

[0056] (2) Place the above raw material mixture in a ball mill, add water equal to 50% of the total weight of the raw material mixture, and perform wet ball milling to obtain ball mill slurry; wherein, the ball milling speed is 30 rpm, the ball milling time is 48 h, and the ball milling is performed until the fineness is less than 0.1% on a 325 mesh sieve.

[0057] (3) The above ball mill slurry is filtered until the moisture content is 20-26%. The filtered product is then vacuum-refined for 0.5 hours under a vacuum of -0.09 MPa to obtain mud.

[0058] (4) The above mud material is extruded into shape and cut into blocks, then transferred into a dryer and dried at a drying temperature of 200°C until the moisture content is no more than 1%, to obtain dried mud blocks;

[0059] (5) The above-mentioned dried mud blocks are transferred into a calcining furnace and calcined at 1300℃ for 22 hours. After calcination, they are transferred to the crushing workshop and crushed to obtain artificial stone slab sand with a fineness of 325 mesh, which is then bagged.

[0060] Example 2

[0061] Artificial stone slab sand is prepared according to the following method:

[0062] (1) Weigh black talc, feldspar and kaolin in proportion and mix them to obtain a raw material mixture; wherein, the amount of black talc is 85wt%, the amount of feldspar is 5wt% and the amount of kaolin is 10wt%.

[0063] (2) Place the above raw material mixture in a ball mill, add water equal to 50% of the total weight of the raw material mixture, and perform wet ball milling to obtain ball mill slurry; wherein, the ball milling speed is 30 rpm, the ball milling time is 48 h, and the ball milling is performed until the fineness is less than 0.1% on a 325 mesh sieve.

[0064] (3) The above ball mill slurry is filtered until the moisture content is 20-26%. The filtered product is then vacuum-refined for 0.5 hours under a vacuum of -0.09 MPa to obtain mud.

[0065] (4) The above mud material is extruded and cut into blocks, and then transferred to a dryer and dried at a drying temperature of 200°C until the moisture content is no more than 1% to obtain dried mud blocks.

[0066] (5) The above-mentioned dried mud blocks are transferred into a calcining furnace and calcined at 1250°C for 22 hours. After calcination, they are transferred to the crushing workshop and crushed to obtain artificial stone slab sand with a fineness of 200 mesh, which is then bagged.

[0067] Comparative Example 1

[0068] Artificial stone slab sand was prepared according to the method of Example 1, except that the calcination temperature of the dried mud block in step (5) of this comparative example was 1100℃.

[0069] The experiment found that the calcination temperature of this comparative example did not meet the calcination requirements, and the product was unqualified (high water absorption, high oil absorption, unqualified dirt absorption, and excessive crystalline silicon).

[0070] Comparative Example 2

[0071] Artificial stone slab sand was prepared according to the method of Example 1, except that the calcination temperature of the dried mud block in step (5) of this comparative example was 1400℃.

[0072] Experiments revealed that the calcination temperature in this comparative example was too high, resulting in over-burning, which made subsequent processing of the material difficult, energy-intensive, and costly.

[0073] Test Case

[0074] The artificial stone slabs prepared in Examples 1 and 2, as well as the mullite and "M45 Inner Mongolia Autonomous Region" for production, were characterized using X-ray diffraction (XRD). The results are as follows: Figure 1 As shown.

[0075] Figure 1In the text, "LSI325 mesh" represents the artificial stone slab sand of Example 1, "LSI200 mesh" represents the artificial stone slab sand of Example 2, JCPDS No. 86-0434 is the standard spectrum of enstatite, and JCPDS No. 79-1450 is the standard spectrum of mullite. It can be seen that no quartz crystals were detected in the artificial stone slab sand prepared in Examples 1 and 2, while quartz crystals were detected in the mullite used for production and the "M45 Inner Mongolia Autonomous Region" used for production.

[0076] Test example

[0077] Artificial stone slabs were prepared using the artificial stone slab sand prepared in Examples 1-2 and Comparative Examples 1-2, as well as natural quartz sand, according to conventional methods. The flexural strength, whiteness (ISO 2470), and acid resistance (ΔE) of the artificial stone slabs were tested respectively, and the test results are shown in Table 1.

[0078] Table 1. Test results of each artificial stone slab

[0079] Sand Flexural strength Whiteness (ISO 2470) Acid resistance (ΔE) Example 1 40MPa 95°±1° 1.8 Example 2 40.5MPa 94°±1° 1.9 Comparative Example 1 33MPa 90° 3.4 Comparative Example 2 40MPa 94° 1.9 Natural Quartz Sand 35MPa 92° 3.2

[0080] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A method for preparing artificial stone slab sand, characterized in that, The steps include: The raw material mixture is subjected to wet ball milling, pressure filtration and mud refining in sequence to obtain mud material; wherein, the raw material mixture includes black talc; The clay material is extruded and dried to obtain dried clay blocks; The dried mud blocks are calcined and crushed.

2. The preparation method according to claim 1, characterized in that, The raw material mixture also includes feldspar and kaolin; Based on the total weight of the raw material mixture, the weight percentage of black talc is 60-85%, the weight percentage of feldspar is 5-20%, and the weight percentage of kaolin is 5-20%.

3. The preparation method according to claim 1, characterized in that, The calcination conditions include: The calcination temperature is 1200–1350℃, and the calcination time is 10–32 h.

4. The preparation method according to claim 1, characterized in that, The conditions for the wet ball milling include: The ball milling time is 20-60 hours, and the residue on a 325-mesh sieve is less than 0.3%.

5. The preparation method according to claim 1, characterized in that, The pressure filtration includes: The ball milling slurry obtained from wet ball milling is subjected to pressure filtration to reduce the moisture content of the slurry to 20-26%.

6. The preparation method according to claim 1, characterized in that, The mud refining process is a vacuum mud refining process with a vacuum degree of -0.1 to 0 MPa and a time of 20 to 70 minutes.

7. The preparation method according to claim 1, characterized in that, The drying conditions include: The drying temperature shall not exceed 300℃, and the moisture content shall not exceed 3%.

8. Artificial stone slab sand prepared by any one of claims 1 to 7.

9. The application of the artificial stone slab sand according to claim 8 in the manufacture of artificial stone slabs.

10. An artificial stone slab, characterized in that, The raw material for the artificial stone slab includes the artificial stone slab sand as described in claim 8.

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