Method for producing thermally blended material of amorphous silica-crystalline silica, method for producing artificial stones from material by compression vibration in vacuum environment, and artificial stone product obtained by method

Abstract

The present invention relates to a process for the production of a thermally blended material of amorphous silica-crystalline silica (thermally blended silica-PheniSilicTM) from silica-containing materials (e.g. Sand, cristobalite, cullet, waste rock powder / burrs from a process for producing artificial stones, waste products and by-products from mining and processing of natural quartzite). The invention also relates to an artificial stone product produced by using a base resin such as an unsaturated polyester, an epoxy resin, an acrylic acid or a combination thereof, and the reinforcement is a thermally blended material of amorphous silica-crystalline silica wherein the artificial stone has a bending strength of > = 40 N / mm2, a water absorption of < = 0.05%, an impact resistance of > = 3 J, and a tensile strength of > = 10 N / mm2. And a method for producing such an artificial stone.

Description

Field of the Invention

[0001] The present invention relates to a method for producing a thermal blend material (thermal blend silica - PheniSilic TM ) of amorphous silica - crystalline silica from silica - containing materials such as sand, cristobalite, cullet, waste rock powder / burrs from the method of producing artificial stone, waste products and by - products from the mining and processing of natural quartz stone. The present invention also relates to artificial stone products produced by using a base resin such as unsaturated polyester, epoxy resin, acrylics or a combination thereof and a reinforcement which is a thermal blend material of amorphous silica - crystalline silica, wherein the artificial stone has a flexural strength of ≥40 N / mm 2 , a water absorption rate of ≤0.05%, an impact resistance of ≥3 J, and a method for producing such artificial stone. Background of the Invention

[0003] In some recent studies, the use of materials such as quartz / silica sand during industrial production generally generates crystalline form silica dust. This dust, when released into the air, can have harmful effects on human health through the respiratory tract, causing a lung disease called silicosis. Therefore, there is a need for materials that have properties equivalent to quartz / silica sand but do not generate crystalline form silica dust or have limited and controlled emission levels during industrial production.

[0004] Amorphous silica is a form of silica material with an amorphous structure, different from quartz / silica sand in its crystalline form. Therefore, during industrial production, crystalline silica dust is not emitted. However, in the production of artificial stone, amorphous silicon materials are only used as a minor type because they have SiO 2 in the range of 50 to 70% by weight (ordinary glass), which does not ensure the properties of artificial stone products and they are not commonly and widely used. Summary of the Invention

[0005] The object of the present invention is to provide a method for producing a thermal blend material (thermal blend silica - PheniSilic TM ) of amorphous silica - crystalline silica from silica - containing materials such as sand, cristobalite, cullet, waste rock powder / burrs from the method of producing artificial stone, waste products and by - products from the mining and processing of natural quartz stone, and thereafter this material is used as a reinforcement for producing artificial stone products by the vibration - pressing method in a vacuum environment.

[0006] For achieving the above-mentioned objectives, according to one aspect, the present invention provides a method for producing a thermal blend material (thermal blend silica - PheniSilic) of amorphous silica - crystalline silica from silica-containing materials such as sand, cristobalite, cullet, waste rock powder / burr from the method of producing artificial stone, waste products and by-products from the mining and processing of natural quartz stone, etc., the method comprising the following steps: TM ) which includes the following steps:

[0007] i) Heating a mixture of sand, cullet and solid waste from quartz stone production in an amount of 60 - 90% by weight together with additional materials and processing aids at a temperature between 1000 °C and 1600 °C to obtain a molten amorphous silica component (Component A) having an amorphous silica content in the range of 50 - 90% by weight, the additional materials being soda / feldspar (Na 2 O) in an amount of 1 - 10% by weight, alumina / feldspar powder (Al 2 O 3 ) in an amount of 1 - 10% by weight, limestone / dolomite (CaCO 3 / MgCO 3 ) in an amount of 5 - 10% by weight;

[0008] ii) Preparing crystalline silica (Component B) by mixing calcined impurity-removed sand (Component B1) with crystalline silica in the form of cristobalite (Component B2), wherein the crystalline silica (Component B) is prepared as follows:

[0009] Calcining sand in the range of temperature from 1000 to 1600 °C for removing impurities to obtain calcined impurity-removed sand (Component B1);

[0010] Calcining the obtained sand with additives such as alkaline salts or alkaline hydroxides at a temperature in the range of 1000 to 1600 °C to obtain crystalline silica in the form of cristobalite (Component B2);

[0011] iii) Mixing molten amorphous silica (Component A) with crystalline silica (Component B), wherein the proportion of Component A is in the range of 50 - 99% by weight and the proportion of Component B is in the range of 1 - 50% by weight, and the total silica content of the obtained product ranges from about 70% - 95% by weight;

[0012] iv) Rapidly cooling the mixture of Component A and Component B to form large particulate matter; and

[0013] v) Grinding the large particulate matter from step (iv) through a mill system to obtain a thermal blend material of amorphous silica-crystalline silica (thermal blend silica-PheniSilic) with a desired size. TM )

[0014] In one embodiment of the invention, in step (i), heating is carried out at 1300 °C for 2 hours to form molten glass.

[0015] In one embodiment of the invention, in step (ii), calcination is carried out at 1300 °C for 2 hours to obtain calcined sand with impurities removed, and calcination is carried out at 1500 °C for 2 hours to obtain crystalline silica in the form of cristobalite.

[0016] In one aspect, the invention relates to a thermal blend material of amorphous silica-crystalline silica (thermal blend silica-PheniSilic) obtained by the method of the invention, TM ), wherein the material consists of the following chemical composition:

[0017] 70% < SiO 2 < 95% by weight, wherein amorphous SiO 2 is in the range of 50 - 90% by weight; crystalline SiO 2 is in the range of 1 - 50% by weight;

[0018] 1.0% < Na 2 O < 10% by weight;

[0019] 1.5% < CaO / MgO < 10% by weight;

[0020] 1.0% < Al 2 O 3 < 10% by weight;

[0021] and other additives such as Fe 2 O 3 < 0.1% by weight, TiO 2 < 0.1% by weight.

[0022] The blend material of amorphous silica-crystalline silica (thermal blend silica-PheniSilic) of the invention TM ) has properties equivalent to quartz / silica sand, and in particular has the advantage of not generating crystalline form silica dust or controlled emissions during the production and processing of artificial stone products, thereby reducing the harmful effects on human health through the respiratory tract due to the use of materials such as quartz / silica sand.

[0023] In one aspect, the present invention provides a method for producing artificial stone, wherein the method comprises the following steps:

[0024] i) Heating a mixture of sand, crushed glass, and solid waste from quartz stone production in an amount of 60 - 90% by weight together with additional materials and processing aids at a temperature between 1000 °C and 1600 °C to obtain a molten amorphous silica component (Component A) having an amorphous silica content in the range of 50 - 90% by weight. The additional materials are soda / feldspar (Na 2 O) in an amount of 1 - 10% by weight, alumina / feldspar powder (Al 2 O 3 ) in an amount of 1 - 10% by weight, and limestone / dolomite (CaCO 3 / MgCO 3 ) in an amount of 5 - 10% by weight;

[0025] ii) Preparing crystalline silica (Component B) by mixing calcined impurity - removed sand (Component B1) with crystalline silica in the cristobalite form (Component B2), wherein the crystalline silica (Component B) is prepared as follows:

[0026] Calcining sand in the range of 1000 to 1600 °C to remove impurities to obtain calcined impurity - removed sand (Component B1);

[0027] Calcining the obtained sand with additives such as alkaline salts or alkaline hydroxides at a temperature in the range of 1000 to 1600 °C to obtain crystalline silica in the cristobalite form (Component B2);

[0028] iii) Mixing molten amorphous silica (Component A) with crystalline silica (Component B), wherein the proportion of Component A is in the range of 50 - 99% by weight and the proportion of Component B is in the range of 1 - 50% by weight, and the total silica content of the obtained product ranges from about 70% - 95% by weight;

[0029] iv) Rapidly cooling the mixture of Component A and Component B to form large - particle material; and

[0030] v) Grinding the large - particle material from step (iv) through a mill system to obtain a thermally blended material of amorphous silica - crystalline silica (thermally blended silica - PheniSilic TM );

[0031] (vi) Producing artificial stone products by the pressure vibration method in a vacuum environment using the amorphous silica - crystalline silica blend material obtained in step (v) and a base resin such as unsaturated polyester, epoxy resin, acrylic, or a combination thereof, wherein the ratio of the base resin used is in the range of 6 - 15% by weight, and the ratio of the amorphous silica - crystalline silica blend material obtained in step (v) is in the range of 85 - 94% by weight.

[0032] In one aspect, the present invention provides an artificial stone product obtained from the method of the present invention, wherein the artificial stone product comprises a base resin such as unsaturated polyester, epoxy resin, acrylic, in a ratio in the range of 6 - 15% by weight, and the reinforcing agent is a thermal blend material of amorphous silica - crystalline silica (thermal blend silica - PheniSilic TM ), in a ratio in the range of 85 - 94% by weight, wherein the total ratio of silica is in the range of 70% - 95% by weight, and the artificial stone product has a flexural strength of ≥40 N / mm 2 , a water absorption rate of ≤0.05%, and an impact resistance of ≥3 J.

[0033] BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a diagram of an apparatus for a heating process and for producing a thermal blend material of amorphous silica - crystalline silica (thermal blend silica - PheniSilic TM ) according to an embodiment of the present invention.

[0035] Figure 2 is the morphology of the obtained thermal blend material of amorphous silica - crystalline silica (thermal blend silica - PheniSilic TM ).

[0036] Figure 3 is an artificial stone product using a material of a thermal blend material of amorphous silica - crystalline silica (thermal blend silica - PheniSilic TM ) or a material mixture of thermal blend silica - PheniSilic TM and quartz, sand, cristobalite.

[0037] Figure 4 is an image of a sample of the thermal blend material of amorphous silica - crystalline silica (thermal blend silica - PheniSilic TM ) before and after being ground into pellet - like strips under a microscope.

[0038] Figure 5Showing X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) of samples of a thermal blend material of amorphous silica - crystalline silica (thermal blend silica - PheniSilic TM ). Detailed Description of the Invention

[0039] Hereinafter, preferred embodiments of the method according to the present invention will be described in more detail. However, it is noted that the scope of the invention is not limited to the preferred embodiments described below as illustrative examples of the invention, and it should be understood that the scope of the invention includes all their modifications and other equivalent changes.

[0040] Blending Components

[0041] Sand

[0042] The sand used according to the present invention is white sand, which has an iron oxide content lower than the allowable level of sand used in glass production and does not require enrichment, has a moisture content lower than 4.5% and no caking phenomenon.

[0043] Crushed Glass

[0044] The crushed glass used according to the present invention is glass beads of various sizes (such as 0.3÷0.6 mm, 1.2÷2.5 mm, 3.0÷5.0 mm, etc.) purchased from a glass bead supplier from a recycling source.

[0045] Solid Waste from Quartz Stone Production

[0046] Waste rock powder / burrs from the production of artificial stone have a particle size in the range of 0.1 to 10 nm, waste products and by-products from the mining and processing of natural quartz stone.

[0047] In a first aspect, as Figure 1 shown, the present invention provides a method for producing a thermal blend material of amorphous silica - crystalline silica (thermal blend silica - PheniSilic TM ) from a material containing silica (such as sand, cristobalite, crushed glass, waste rock powder / burrs from the production of artificial stone, waste products and by-products from the mining and processing of natural quartz stone), the method comprising the following steps:

[0048] i) Heating a mixture of sand, crushed glass and solid waste from quartz stone production in an amount of 60 - 90% by weight together with additional materials and processing aids at a temperature between 1000 °C and 1600 °C to obtain a molten amorphous silica component (Component A) having an amorphous silica content in the range of 50 - 90% by weight, the additional materials being soda / feldspar (Na 2O), alumina / feldspar powder in an amount of 1-10% by weight (Al 2 O 3 ), limestone / dolomite (CaCO 3 / MgCO 3 ) in an amount of 5-10% by weight;

[0049] ii) Crystalline silica (Component B) is prepared by mixing calcined impurity-removed sand (Component B1) with crystalline silica in the form of cristobalite (Component B2), wherein the crystalline silica (Component B) is prepared as follows:

[0050] The sand is calcined at a temperature in the range of 1000 to 1600 °C to remove impurities to obtain calcined impurity-removed sand (Component B1);

[0051] The obtained sand is calcined at a temperature in the range of 1000 to 1600 °C with an additive such as an alkaline salt or an alkaline hydroxide to obtain crystalline silica in the form of cristobalite (Component B2);

[0052] iii) Molten amorphous silica (Component A) is mixed with crystalline silica (Component B), wherein the proportion of Component A is in the range of 50-99% by weight and the proportion of Component B is in the range of 1-50% by weight, and the total silica content of the obtained product ranges from about 70% to 95% by weight;

[0053] iv) The mixture of Component A and Component B is rapidly cooled to form large particle material; and

[0054] v) The large particle material from step (iv) is ground by a mill system to obtain a thermal blend material of amorphous silica-crystalline silica (thermal blend silica-PheniSilic TM ).

[0055] In some embodiments, step (i) is carried out by thoroughly mixing the main components and additional components with or without additives, including one or more types of main components in an amount of 60-90% by weight, such as natural sand, cristobalite, glass / cullet, waste rock powder / burr from the method of producing artificial stone, waste products and by-products from the mining and processing of natural quartz stone, wherein the content of soda / feldspar (Na 2 CO 3 ) is in an amount of 1-10% by weight, alumina / feldspar powder (Al 2 O 3 ) is in an amount of 1-10% by weight, limestone / dolomite (CaCO 3 / MgCO 3)In an amount of 5 - 10% by weight and their additives are in the range of 0 - 10% by weight, preferably in the range of 0 - 1% by weight in order to prepare the mixture.

[0056] Here, the molten mixture is heated to a temperature in the range of 1000 to 1600 °C in the following stages:

[0057] Stage 1 (heating period): The temperature is gradually increased from room temperature to the melting temperature within 2 hours (heating rate ~ 10 ÷ 20 °C / min) to produce the molten mixture;

[0058] Stage 2 (maintaining period): Maintain at the sintering temperature for 1 to 3 hours.

[0059] In some preferred embodiments, in this step, some additives can be used to adjust the processing aids, such as to improve the physical and mechanical durability, such as SiO 2 、Al 2 O 3 、ZrO 2 ; lower the firing temperature, such as K 2 O、Na 2 O、CaO、MgO, and improve the chemical durability, such as CaO、MgO, or color additives from metals or metal oxides, such as manganese, selenium, tin oxide.

[0060] In a preferred embodiment, in step (i), heating is carried out at a temperature of 1300 °C for 2 hours to form the molten glass.

[0061] In some embodiments, in step (ii), crystalline silica (component B) is prepared from calcined sand with impurities removed (component B1) and crystalline silica in the form of cristobalite (component B2), where the calcined sand with impurities removed (component B1) is prepared by heating the sand in a converter 2, thereby removing impurities at a temperature in the range of 1000 to 1600 °C, and the heating process includes the following stages:

[0062] Stage 1 (heating period): The temperature is gradually increased from room temperature to the melting temperature within 2 hours (heating rate ~ 10 ÷ 20 °C / min) to produce the molten mixture;

[0063] Stage 2 (maintaining period): Maintain at the firing temperature for 1 to 3 hours.

[0064] In some embodiments, crystalline silica in the form of cristobalite (component B2) is prepared from calcined sand and additives such as alkaline salts or alkaline hydroxides at a temperature in the range of 1000 to 1600 °C, and the heating process includes the following two stages:

[0065] Stage 1 (Heating period): Gradually increase the temperature from room temperature to the melting temperature within 2 hours (heating rate ~10÷20 °C / min) to produce a molten mixture;

[0066] Stage 2 (Maintenance period): Maintain at the firing temperature for 1 to 3 hours.

[0067] In one embodiment of the invention, in step (ii), calcination is carried out at 1300 °C for 2 hours to obtain calcined sand with impurities removed, and calcination is carried out at 1500 °C for 2 hours to obtain crystalline silica in the form of cristobalite.

[0068] In some preferred embodiments, step (iii) is carried out by mixing molten amorphous silica (component A) with crystalline silica (component B), where the proportion of component A is in the range of 50 - 99% by weight and the proportion of component B is in the range of 1 - 50% by weight, and the total silica content of the obtained product ranges from about 70% - 95% by weight.

[0069] In one aspect, the present invention relates to a thermal blend material of amorphous silica - crystalline silica (thermal blend silica - PheniSilic TM ) obtained by the method of the present invention, wherein the material consists of the following chemical composition:

[0070] 70% < SiO 2 < 95% by weight, wherein amorphous SiO 2 is in the range of 50 - 90% by weight; crystalline SiO 2 is in the range of 1 - 50% by weight;

[0071] 1.0% < Na 2 O < 10% by weight;

[0072] 1.5% < CaO / MgO < 10% by weight;

[0073] 1.0% < Al 2 O 3 < 10% by weight;

[0074] and other additives such as Fe 2 O 3 < 0.1% by weight, TiO 2 < 0.1% by weight.

[0075] Obtain a thermal blend material of amorphous silica - crystalline silica (thermal blend silica - PheniSilic TM ) in solid state. Compared with natural quartz stone (which has crystalline SiO 2The content is >99% by weight), different from the thermally blended silica - PheniSilic TM The material has a total silica content in the range of about 70% - 95% by weight, where the main components are amorphous silica in the range of 50 - 99% by weight and crystalline silica in the range of 1 - 50% by weight, and a very small portion of other impurities are metal oxides from additives added during the synthesis process, such as iron oxide, alumina, titanium oxide, etc. Additionally, in step (iii), the molten amorphous silica (component A) is mixed with crystalline silica (component B) so as to cover the crystalline silica component with amorphous silica, thereby reducing the ability to disperse crystalline silica during the production and processing of current quartz-based artificial stone products (where the silica content is >90% by weight, which affects the formation and development of silicosis). The uniform mixing of molten glass (component A - molten amorphous silica) and calcined sand or cristobalite (component B - crystalline silica) is carried out in a uniform converter, where the molten glass (component A) and the calcined sand or cristobalite (component B) are injected into the uniform converter 3 from converters 1 and 2 at a weight ratio of component A / component B = (50÷99% by weight) / (1÷50% by weight), thus helping to produce a blended material of amorphous silica and crystalline silica in the desired ratio, where the total content of silica is in the range of 70% to 95% by weight.

[0076] In some embodiments of the invention, in step iv), the rapid cooling of the mixture of component A and component B is carried out at as low as 90÷110 °C for a short time of 30 to 60 minutes to form large particulate matter. Then, the mixture is naturally cooled to room temperature.

[0077] In some embodiments of the invention, in step (v), the grinding of the particulate matter formed in step (iv) is carried out as follows to obtain a thermally blended material of amorphous silica - crystalline silica (thermally blended silica - PheniSilic TM ) : After cooling to room temperature, the particulate matter formed in step (iv) has a large size, and then it is put into a grinding device to be ground into particles with the desired size, such as a particle size of 0.1 - 0.4 mm, a particle size of 0.3 - 0.6 mm, etc.

[0078] The material particles obtained after grinding are composed of particles of amorphous silica and particles of crystalline silica that are completely or partially encapsulated by amorphous silica, where according to the initial mixing ratio, the proportion of component A is in the range of 50 - 99% by weight and the proportion of component B is in the range of 1 - 50% by weight.

[0079] In one aspect, the present invention provides a method for producing artificial stone, wherein the method comprises the following steps:

[0080] i) Heating a mixture of sand, crushed glass, and solid waste from quartz stone production in an amount of 60 - 90% by weight together with additional materials and processing aids at a temperature between 1000°C and 1600°C to obtain a molten amorphous silica component (Component A) having an amorphous silica content in the range of 50 - 90% by weight. The additional materials are soda / feldspar (Na 2 O) in an amount of 1 - 10% by weight, alumina / feldspar powder (Al 2 O 3 ) in an amount of 1 - 10% by weight, and limestone / dolomite (CaCO 3 / MgCO 3 ) in an amount of 5 - 10% by weight;

[0081] ii) Preparing crystalline silica (Component B) by mixing calcined impurity - removed sand (Component B1) with crystalline silica in the form of cristobalite (Component B2), wherein the crystalline silica (Component B) is prepared as follows:

[0082] Calcining sand in the temperature range of 1000 to 1600°C to remove impurities to obtain calcined impurity - removed sand (Component B1);

[0083] Calcining the obtained sand with additives such as alkaline salts or alkaline hydroxides in the temperature range of 1000 to 1600°C to obtain crystalline silica in the form of cristobalite (Component B2);

[0084] iii) Mixing molten amorphous silica (Component A) with crystalline silica (Component B), wherein the proportion of Component A is in the range of 50 - 99% by weight and the proportion of Component B is in the range of 1 - 50% by weight, and the total silica content of the obtained product ranges from about 70% - 95% by weight;

[0085] iv) Rapidly cooling the mixture of Component A and Component B to form large - particle material; and

[0086] v) Grinding the large - particle material from step (iv) through a mill system to obtain a thermally - blended material of amorphous silica - crystalline silica (thermally - blended silica - PheniSilic TM ) having a desired size;

[0087] (vi) By using the amorphous silica-crystalline silica blend material obtained in step (v) and a base resin such as unsaturated polyester, epoxy resin, acrylic, or a combination thereof, an artificial stone product is produced by the vibration pressing method in a vacuum environment, wherein the ratio of the base resin used is in the range of 6-15% by weight, and the ratio of the amorphous silica-crystalline silica blend material obtained in step (v) is in the range of 85-94% by weight.

[0088] In one aspect, the present invention provides an artificial stone product obtained from the method of the present invention, wherein the artificial stone product comprises a base resin such as unsaturated polyester, epoxy resin, acrylic, in a ratio in the range of 6-15% by weight, and the reinforcing agent is a thermal blend material of amorphous silica-crystalline silica (thermal blend silica - PheniSilic TM ), in a ratio in the range of 85-94% by weight, wherein the total ratio of silica is in the range of 70%-95% by weight, and the artificial stone product has a flexural strength of ≥40 N / mm 2 and a water absorption rate of ≤0.05% and an impact resistance of ≥3 J.

[0089] In some embodiments of the invention, in a vacuum environment, by the vibration pressing method, a base phase of a synthetic resin and a material of thermal blend silica - PheniSilic TM or a material of thermal blend silica - PheniSilic TM and a reinforcing agent of a mixture of quartz, cristobalite, sand, etc. are used in step vi) for producing the artificial stone product.

[0090] In some embodiments of the invention, in step (vi), the artificial stone product uses a base phase of a synthetic resin having a ratio in the range of 6-15% by weight and a material of thermal blend silica - PheniSilic TM or a material of thermal blend silica - PheniSilic TM and a reinforcing agent of a mixture of quartz, cristobalite, sand, etc.

[0091] In some embodiments, in step (vi), the binder for forming the sheet is selected from the following: epoxy resin, unsaturated polyester resin, etc., or any suitable combination thereof. However, the present invention is not limited to those resins. The binder resin for forming the sheet can be colorless and transparent or can be colored as needed by adding inorganic pigments. The binder resin for forming the sheet can have a type for indoor applications or an ultraviolet (UV)-resistant type for use in outdoor applications.

[0092] In some embodiments, the material mixture is vibrated under pressure in a mold under a vacuum pressure condition of 10 to 25 mbar (1000 to 2500 Pa) to effectively remove a certain amount of air present in the resin mass, thereby maximizing the formation of solid stone chips.

[0093] To achieve this effect, it is preferred to carry out the vibration under pressure method under vacuum conditions in two or more stages, each stage lasting 1 - 10 minutes, and using a vibration frequency in the range of 500 - 3000 rpm.

[0094] In some embodiments, after vibration under pressure under vacuum conditions, depending on the type of binder resin used, the mixture in the mold is solidified under cold - setting or heat - setting conditions. The solidification ends when the binder resin is cured and completely dried.

[0095] In some embodiments of the invention, artificial stone products using an enhancer of a material of thermally blended silica - PheniSilic TM have properties as shown in Table 1:

[0096] Table 1

[0097] Physical and mechanical properties Test methods Value Water absorption, % BS EN 14617-1:2013 ≤0.05 <![CDATA[Flexural strength, N / mm 2 > BS EN 14617-2:2016 ≥40.0 Impact resistance, J BS EN 14617-9:2005 ≥3.0 Scratch hardness of surface, Mohs EN 101:1991 ≤8.0

[0098] The blend material of amorphous silica - crystalline silica of the present invention (thermally blended silica - PheniSilic TM ) has properties equivalent to quartz / silica sand, and in particular has the advantage of not generating crystalline form silica dust or controlled emissions during the production and processing of artificial stone products, thereby reducing the harmful effects on human health through the respiratory tract due to the use of materials such as quartz / silica sand.

[0099] Examples

[0100] The present invention is illustrated by the following examples, but these examples should not be construed as limiting the scope of the present invention in any way.

[0101] Example 1: A method for producing a thermally blended material of amorphous silica - crystalline silica (thermally blended silica - PheniSilic TM ) from silica - containing materials such as sand, cristobalite, crushed glass, waste rock powder / burrs from the method of producing artificial stone, waste products and by - products from the mining and processing of natural quartz stone

[0102] Preparation of molten glass (Component A - molten amorphous silica)

[0103] 500 kg of natural sand in a dry state with an average particle size of 0.5 mm, 500 kg of broken glass from damaged glass (which is waste from a glass factory crushed into pieces with a size of < 10 mm), 600 kg of by - products from artificial stone production, and 260 kg of Na with a weight percentage > 99% 2 CO 3 , 90 kg of alumina powder, and 120 kg of limestone are mixed together to obtain a mixture.

[0104] This mixture is placed in a furnace and heated from ambient temperature to 1300 °C for 2 hours (heating rate ~ 12.3 °C / min), with a holding time of 2 hours. The resulting product is molten glass (Component A).

[0105] Tin oxide, antimony, and zinc oxide are added to produce an opaque white molten amorphous silica.

[0106] Crystalline silica (Component B) is prepared

[0107] 450 kg of sand is heated in a converter 2. The heating process is carried out from ambient temperature to 1300 °C for 2 hours (heating rate ~ 10.6 °C / min), with a holding time of 2 hours. The resulting product is calcined sand with impurities removed (Component B1).

[0108] A mixture of 445 kg of sand and 5 kg of Na 2 CO 3 (ensuring an additive ratio of 1% by weight) is placed in converter 2. The heating process is carried out from ambient temperature to 1500 °C for 2 hours (heating rate ~ 12.3 °C / min), with a holding time of 2 hours. The resulting product is cristobalite (Component B2).

[0109] The products obtained from the above steps (which are Component A, and a mixture of Component B1 and Component B2) are added to a homogeneous converter, then mixed for 30 min, and then the mixture is poured into a tank for rapid cooling to a temperature in the range of 90 °C - 110 °C for 45 min, and then cooled to ambient temperature for 1 hour.

[0110] After cooling, the large - particle material is fed into a grinding system and ground to the desired particle size shown in Table 2:

[0111] Table 2

[0112]

[0113] The technical characteristics of the thermally - blended silica - PheniSilic TM obtained according to the present invention when compared with broken glass and commercially available silica samples are shown in Table 3 below, and the crystalline SiO 2, proportion of amorphous SiO 2 Result of analysis (by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR)):

[0114] Table 3: Chemical composition of thermally blended silica - PheniSilic TM , cullet, and commercially available silica

[0115]

[0116]

[0117] *MKN: Weight loss after heating

[0118] In addition, in other embodiments, when adjusting the desired ratio of amorphous silica, results such as those shown in Table 4 etc. will be given:

[0119] Table 4: Thermally blended silica - PheniSilic obtained from the present invention TM products

[0120]

[0121] Color

[0122] The color of the silica samples was measured on a colorimeter Xrite C17800 (Xrite, USA). The color measurement method is based on the reflection principle using the CIE Lab color space L*, a*, b*, ΔE* according to ASTM E313 - 10:2010. The results are shown in Table 5.

[0123] Where:

[0124] L*: white / black (L = 100: white; L = 0: black)

[0125] a*: magenta / green (a* = 0÷100: magenta; a* = 0÷ - 100: green)

[0126] b*: yellow / blue (b* = 0÷100: yellow; a* = 0÷ - 100: blue).

[0127] Table 5: L*, a*, b* parameters of samples of thermally blended silica - PheniSilic TM materials and commercially available silica in the present invention

[0128] Sample <![CDATA[L * > a* b* <![CDATA[PheniSilic TM 01]]> 95.50 -0.45 0.71 <![CDATA[PheniSilic TM 02]]> 95.41 -0.41 0.77 <![CDATA[PheniSilic TM 05]]> 94.98 -0.34 0.95 <![CDATA[PheniSilic TM 10]]> 94.52 -0.12 1.15 <![CDATA[PheniSilic TM 20]]> 94.12 -0.01 1.34 <![CDATA[PheniSilic TM 30]]> 93.84 0.06 2.15 <![CDATA[PheniSilic TM 40]]> 93.05 0.15 2.61 Commercially available silica 92.41 0.24 2.89

[0129] Example 2: Influence of the PheniSilic TM material obtained in Example 1 on the workability, physical, and mechanical properties of artificial stone products

[0130] Using the PheniSilic of Example 1 with different particle size ranges and different blending ratios optimized according to the calculation TM materials to produce artificial stone samples in the laboratory and compare them with the artificial stone samples using the fully crystalline SiO 2 materials with the same optimization method and formula.

[0131] The artificial stone samples using unsaturated polyester resin were prepared by the pressure vibration method in a vacuum environment and cured by the heating method at 130 °C for 40 minutes and had dimensions of 300x300x20 mm. The total weight of the raw materials for making the stone samples was 5000 g. In particular, the mixing components for preparing the artificial stone samples included 580 g of unsaturated polyester resin (11.6% of the total weight of the raw materials), and the resin included additives for the curing process. The PheniSilic TM material or crushed glass included 1165 g in the form of powder with a size ≤ 0.1 mm (23.3% of the total material weight) and 3255 g in the form of powder with a size of 0.1÷0.4 mm (65.1% of the total material weight).

[0132] The workability and physical and mechanical properties of the artificial stone products with the above mixing formula are shown in Table 6 below.

[0133] Table 6: Comparison of the workability of artificial stone product samples using PheniGlass TM materials, crushed glass and commercially available silica

[0134]

[0135] Using PheniSilic TM and ordinary silica materials, the artificial stone products have similar curing times, flexible materials after pressure vibration, polishing and no scratches on the surface (Table 6). At the same time, the artificial stone products using crushed glass are difficult to process, less flexible after pressure vibration, have bubbles, dents and are difficult to wear, have scratches on the surface, and are not polished.

[0136] Table 7: Influence of materials on the physical and mechanical properties of artificial stone products

[0137]

[0138] It can be seen from Table 7 that the artificial stone products using PheniSilic TM materials have physical and mechanical properties equivalent to those of artificial stone products using commercially available silica and have excellent properties compared with natural granite samples. Using thermally blended silica-PheniSilic TMThe artificial stone of the material has good flexural strength and impact resistance, which results in easy processing without causing chipping or cracking.

[0139] Thermally blended silica - PheniSilic TM The material has properties equivalent to quartz / silica sand and, in particular, has the advantage of not generating crystalline form silica dust or controlled emissions during the production and processing of artificial stone products, thereby reducing the harmful effects on human health through the respiratory tract due to the use of materials such as quartz / silica sand.

[0140] Advantages of the invention

[0141] Different from the use of commercially available silica (>99% crystalline silica) in artificial stone production, the method of the present invention produces thermally blended silica - PheniSilic from materials containing silica such as sand, cristobalite, cullet, waste rock powder / burrs from the method of producing artificial stone, waste products and by - products from the mining and processing of natural quartz stone TM The material, wherein the material has an amorphous silica content in the range of 50 - 99% by weight and a crystalline silica content in the range of 1 - 50% by weight, and a total silica content in the range of about 70% - 95% by weight, which is used for producing artificial stone. Therefore, the material can be processed more easily than natural granite and ensures that the possibility of silicon dust generation is lower than the permissible level similar to natural granite. The method of the present invention combines molten amorphous silica (molten glass) and crystalline silica (calcined sand and cristobalite with impurities removed) to produce thermally blended silica - PheniSilic with a total silica content of about 70% to 95% by weight having properties similar to commercially available silica TM of a new material type.

[0142] The method of the present invention utilizes solid waste from quartz stone production (waste rock powder / burrs with a particle size range of 0.1 - 10 mm from the method of producing artificial stone), waste, by - products from the mining and processing of natural quartz stone, and due to an appropriate mixing method and a thermal profile for heating the raw material mixture to produce molten glass during the heating step, it helps to minimize solid emissions into the environment. In addition, uniform mixing helps to control the ratio of amorphous silica and crystalline silica to obtain thermally blended silica - PheniSilic TM with a desired content and composition of amorphous silica.

[0143] The thermally blended silica - PheniSilic of the present invention TMThe material has properties similar to quartz / silica sand and in particular has the advantage of not generating crystalline silica dust or controlled emissions during the production and processing of artificial stone products, thereby reducing the harmful effects on human health through the respiratory tract due to the use of materials such as quartz / silica sand.

[0144] The present invention provides an artificial stone product using a reinforcing agent which is a thermally blended silica - PheniSilic TM material or a thermally blended silica - PheniGlass TM material and a mixture of quartz, cristobalite, and sand. The artificial stone product of the present invention has a flexural strength of ≥40 N / mm 2 , a water absorption rate of ≤0.05%, and an impact resistance of ≥3 J.

Claims

1. For producing amorphous silica-crystalline silica thermally blended materials (thermal blended silica-PheniGlass) from silica-containing materials such as sand, cristobalite, crushed glass, waste rock powder / burrs from processes for producing artificial stone, waste products and by-products from mining and processing of natural quartz stone TM ), the method comprising the following steps: i) A mixture of sand, cullet, and solid waste from quartz stone production in an amount of 60 - 90% by weight is heated together with additional materials and processing aids at a temperature between 1000°C and 1600°C to obtain a molten amorphous silica component (Component A) having an amorphous silica content in the range of 50 - 90% by weight. The additional materials are soda / feldspar (Na2O) in an amount of 1 - 10% by weight, alumina / feldspar powder (Al2O3) in an amount of 1 - 10% by weight, and limestone / dolomite (CaCO3 / MgCO3) in an amount of 5 - 10% by weight; ii) Crystalline silica (Component B) is prepared by mixing calcined impurity - removed sand (Component B1) with crystalline silica in the cristobalite form (Component B2), wherein the crystalline silica (Component B) is prepared as follows: The sand is calcined at a temperature in the range of 1000 to 1600°C to remove impurities to obtain calcined impurity - removed sand (Component B1); The obtained sand is calcined at a temperature in the range of 1000 to 1600°C with additives such as alkaline salts or alkaline hydroxides to obtain crystalline silica in the cristobalite form (Component B2); iii) The molten amorphous silica (Component A) is mixed with the crystalline silica (Component B), wherein the proportion of Component A is in the range of 50 - 99% by weight and the proportion of Component B is in the range of 1 - 50% by weight, and the total silica content of the obtained product ranges from about 70% - 95% by weight; iv) The mixture of Component A and Component B is rapidly cooled to form large - grained material; and v) grinding the large particle material from step (iv) by a mill system to obtain a thermally blended material of amorphous silica-crystalline silica (thermal blended silica-PheniSilic) having a desired size; TM ).

2. The method according to claim 1, wherein in step (i), heating is carried out at 1300°C for 2 hours to form molten glass.

3. The method according to claim 1, wherein in step (ii), the sand is calcined at 1300°C for 2 hours to obtain calcined impurity - removed sand, and is calcined at 1500°C for 2 hours to obtain crystalline silica in the cristobalite form.

4. The material obtained from the method according to claim 1, wherein the material consists of the following chemical composition: 70% < SiO2 < 95% by weight, wherein amorphous SiO2 is in the range of 50 - 90% by weight; crystalline SiO2 is in the range of 1 - 50% by weight; 1.0% < Na2O < 10% by weight; 1.5% < CaO / MgO < 10% by weight; 1.0% < Al2O3 < 10% by weight; and other additives such as Fe2O3 < 0.1% by weight, TiO2 < 0.1% by weight.

5. A method for producing artificial stone, wherein the method comprises the following steps: i) heating a mixture of sand, cullet and solid waste from quartz production in an amount of 60-90% by weight together with additional materials and processing aids at a temperature between 1000° C. and 1600° C. to obtain a fused amorphous silica component (component A) having an amorphous silica content in the range of 50-90% by weight, the additional materials being soda / feldspar (Na2O) in an amount of 1-10% by weight, alumina / feldspar powder (Al2O3) in an amount of 1-10% by weight, limestone / dolomite (CaCO3 / MgCO3) in an amount of 5-10% by weight; ii) preparing crystalline silicon dioxide (component B) by mixing calcined sand (component B1) from which impurities have been removed and crystalline silicon dioxide (component B2) in the form of cristobalite, wherein the crystalline silicon dioxide (component B) is prepared as follows: calcining the sand at a temperature in the range of 1000 to 1600° C. for removing impurities to obtain calcined decontaminated sand (component B1); calcining the obtained sand with additives such as alkaline salts or alkaline hydroxides at a temperature in the range of 1000 to 1600° C. to obtain crystalline silicon dioxide in the form of cristobalite (component B2); iii) mixing molten amorphous silicon dioxide (component A) with crystalline silicon dioxide (component B), wherein the proportion of component A is in the range of 50-99% by weight and the proportion of component B is in the range of 1-50% by weight, wherein the total silicon dioxide content of the obtained product is in the range of about 70%-95% by weight; iv) rapidly cooling the mixture of component A and component B to form a large particle mass; and v) grinding the large particle material from step (iv) by a mill system to obtain a thermally blended material of amorphous silica-crystalline silica (thermal blended silica-PheniSilic) having a desired size; TM ); (vi) producing an artificial stone product by a pressure vibration method in a vacuum environment by using the amorphous silica-crystalline silica blend material obtained in step (v) and a base resin such as unsaturated polyester, epoxy resin, acrylic or a combination thereof, wherein the ratio of the base resin used is in the range of 6-15% by weight, and the ratio of the amorphous silica-crystalline silica blend material obtained in step (v) is in the range of 85-94% by weight.

6. The artificial stone product obtained from the method according to claim 5, wherein the artificial stone product comprises a base resin such as unsaturated polyester, epoxy resin, acrylic, in a ratio in the range of 6-15% by weight, and the reinforcement is a thermally blended material of amorphous silica-crystalline silica (thermal blended silica-PheniSilic TM ), the ratio is in the range of 85-94% by weight, wherein the total ratio of silicon dioxide is in the range of 70%-95% by weight, and the artificial stone product has ≥40N / mm 2 Flexural strength, water absorption ≤0.05%, impact resistance ≥3J.

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