Low crystalline silica stone slabs, systems, and methods

Abstract

Stone slabs, and systems and methods of forming slabs, are described. Some example slabs include a pattern defined by a particulate mineral mix having a low crystalline silica content.

Description

Low Crystalline Silica Stone Slabs, Systems, andMethodsCROSS-REFERENCE TO RELATED APPLICATION

[0001] This present application claims benefit of U.S. Provisional Application No. 63 / 540,323 filed September 25, 2023, which is hereby incorporated herein in its entirety by reference.TECHNICAL FIELD

[0002] This document describes stone slab products, systems, and processes for stone slab products, for example, stone slabs suitable for use in living or working spaces (e.g., along a countertop, table, floor, or the like) and having silica-based components that provide a low crystalline silica content.BACKGROUND

[0003] Stone slabs are a commonly used building material. Granite, marble, soapstone, and other quarried stones are often selected for use as countertops due to their aesthetic properties. Stone slabs may also be formed from a combination natural and other materials that can provide improved stain resistant or heat resistant properties, aesthetic characteristics, reproducibility, etc. Some stone slabs have been made from a combination of particulate mineral material and binder, such as a polymer resin or cement, and have a colored pattern.SUMMARY

[0004] Some embodiments described herein include stone slabs having low crystalline silica content suitable for use in living or working, and systems and processes for forming such stone slabs. In some embodiments, slabs can bemanufactured by forming a cured and hardened slab that includes a low crystalline silica material. For example, slabs can be manufactured by at least partially filing a slab mold with one or more particulate mineral mixes, including a particulate mineral mix made up partially, predominantly, or completely of low crystalline silica material, binder, and / or one or more pigments, and then curing and / or hardening the contents of the slab mold to form a slab. In some embodiments, a stone slab includes multiple regions of different particulate mineral mixes that have different characteristics, such as different low crystalline silica material content, chemical composition, sheen, hardness, thickness, roughness, gloss, etc.

[0005] In general, an aspect disclosed herein is a processed slab formed from a plurality of particulate mineral mixes, including a slab width that is at least 2 feet, a slab length that extends perpendicular to the slab width and that is at least 6 feet, and a slab thickness extending perpendicular to the slab width and the slab length, the slab length greater than the slab width, the slab width greater than the first slab thickness; the processed slab having a crystalline silica content that is less than 50% by weight (wt %).

[0006] Examples may include one or more of the following features. The processed slab where the crystalline silica content can be less than or equal to 1 wt %. The first particulate mineral mix can include greater than 50 % of a low crystalline silica material selected from the group may include of fused quartz, soda-lime glass, nepheline syenite, feldspar, wollastonite, albite, and amorphous silica. The processed slab may include quartz at an overall slab wt % that can be less than or equal to an overall slab wt % of the low crystalline material. The tow crystalline silica material may include more than 30 wt % fused quartz. The low crystalline silica material may include more than 30 wt % soda-lime glass. The low crystalline silicamaterial may include more than 30 wt % nepheline syenite. The low crystalline silica material may include more than 30 wt % of feldspar. The low crystalline silica material may include more than 30 wt % of amorphous silica. The low crystalline silica material can have an abrasion resistance in a range from 80 to 90 on the taber index. The processed slab may include quartz at a wt % that can be less than the low crystalline silica material wt %. The processed slab where the processed slab may include a low crystalline silica material and a binder. The processed slab may include a pigment at a pigment wt %. The low crystalline silica material can have a b’ value that can be less than 0 in a hunter color space. The processed slab can have a different pigment wt % that can be less than the pigment wt % when the low crystalline silica material can have the b greater than or equal to 0 in a hunter color space.

[0007] In general, an aspect disclosed herein is a process of forming a processed slab from a plurality of different particulate mineral mixes, the process including dispensing a first low crystalline silica mineral mix to a first set of regions of a slab mold; dispensing a second low crystalline silica mineral mix to a second set of regions of the slab mold; contemporaneously vibrating and compacting the first particulate mineral mix and the second particulate mlnerai mix arranged in the slab mold so as to form a processed, molded slab that is generally rectangular and has a slab thickness and a major surface having a slab width of at least 2 feet and a slab length of at least 6 feet; and curing the processed molded slab into a cured slab.

[0008] Examples may include one or more of the following features. The process where the first low crystalline silica mineral mix can include a predominate mineral material selected from the group may include of fused quartz, soda-lime glass, nepheline syenite, feldspar, wollastonite, albite, amorphous silica. The secondlow crystalline silica mineral mix can include a predominate mineral material selected from the group may include ef fused quartz, soda-lime glass, nepheline syenite, feldspar, wollastonite, albite, amorphous silica. The first low crystalline silica mineral mix and the second low crystalline silica mineral mix may include a binder. The process may include abrading a major surface of the cured slab.

[0009] The systems and techniques described here may provide one or more of the following advantages. First, some embodiments described herein include stone slabs having a low crystalline silica content. The particulate mineral mix can be arranged in a pattern, and / or can define some or all of a top major surface of the finished slab.

[0010] Second, some embodiments described herein provide an aesthetic appearance that accentuates and / or exaggerates various characteristics of quarried stone slabs. For example, some stone slabs described herein provide a pattern having geometric characteristics suggestive of patterns of quarried stone slabs.

[0011] Third, some embodiments described herein can provide stone slab products that have a tactile and / or visible texture. For example, in some embodiments, one or more surfaces of the slab includes regions of different tactile and / or visible characteristics, for example different tactile and / or visible characteristics associated with the low crystalline silica composition of the stone slab.

[0012] Fourth, some embodiments described herein can provide stone slab products that have a texture that resembles that of quarried stone.

[0013] Fifth, some embodiments described herein can provide stone slab products that have an aesthetic appeal similar to that of quarried stone and with improved performance benefits such as heat and stain resistance and reproducibility,but without the cost and / or perceived environmental impact associated with stone quarrying.

[0014] The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the description and drawings, and from the claims.DESCRIPTION OF DRAWINGS

[0015] FIG. 1 is a perspective view of an example processed slab., in accordance with some embodiments.

[0016] FIG. 2 is a d iagram of an example system for forming a processed slab product, in accordance with some embodiments.

[0017] FIG. 3 is a diagram of an example system for applying a surface treatment to texturize a processed slab product, in accordance with some embodiments.

[0018] FIGS. 4 and 5 are diagrams of example systems for applying a surface treatment to texturize a processed slab product, in accordance with some embodiments.

[0019] FIG. 6 is a flow diagram of an example process for producing a processed slab product, in accordance with some embodiments.DETAILED DESCRIPTION

[0020] In general, this document describes stone slabs, systems and methods that provide a slab having low crystallized silica materials. The most common form of crystalline silica is quartz. Other examples include cristobalite and tridymite. For example, some embodiments provide stone slabs that include a pattern, such as apattern defined by a particulate mineral mix having a relatively low crystallized silica content.

[0021] Additionally, this document describes systems and techniques in which processed stone slabs having textured faces can be manufactured by abrading a cured (e.g., hardened) slab having exposed regions of different component materials that abrade or erode differently (e.g., at different rates when subjected to a common treatment), and / or otherwise reveal different textures due to the abrasion. For example, hardened materials are worn down in different manners to produce one or more different surface characteristics based on the component materials (e.g., and in an example embodiment does not include imparting a pattern into soft, uncured materials and then allowing the pattern to harden). In some embodiments, an example stone slab includes varying texture that caricatures natural erosion and fissuring and / or provides different characteristics that create a predetermined aesthetic and tactile characteristics.

[0022] As used herein, the term “about will be understood by persons of ordinary skill in the art and will vary to some extent on the context in which it is used. As used herein when referring to a measurable value such as an amount, a temporal duration, and the like, the term “about" is meant to encompass variations of ±20% or ±10%, including ±5%, ±1%, and ±0.1% from the specified value, as such variations are appropriate to perform the disclosed methods.

[0023] Referring now to FIG. 1, an example slab 50 can be formed from a combination of different particulate mineral mixes that are poured into different, designated regions of a respective mold (while the mold Is horizontally oriented, for example). These designated regions are repeated for each mold in a series of molds (described in more detail below) due to, for example, a set of stencil structures thatcan be positioned over each mold and that provide a predefined complementary and repeatable dispensation pattern for the particulate mineral mixes in each mold. In some embodiments described herein, the predefined complementary and repeatable dispensation pattern for the particulate mineral mixes provides the selected striations and veining patterns that are generally repeatable for each separately molded slab.

[0024] Depending upon the predefined dispensation pattern of the complementary partial stencils, the dispensation process can provide an aesthetic effect that emulates or accentuates a veined appearance of natural quarried stone slabs such as granite or marble, including an example region 51 and another example region 52 that extend partly or fully across a complete length L of the hardened slab 50.

[0025] The regions 51 and 52 have thicknesses that extend entirely through the thickness T of the slab 50, for example. Such thicknesses can provide an appearance in which the pattern defined by the particulate mineral mixes are visible through the entire thickness T of slab 50 along periphery edges, such as when slab 50 is cut for installation.

[0026] The finished slab 50 has a major surface 60 having various aesthetic and tactile features and characteristics such as color, sparkle, roughness, height, depth, sheen, and / or other characteristics. In some embodiments, the characteristics differ between regions in the finished slab 50. In an example embodiment, regions 51 and 52 have aesthetic appearances and / or tactile characteristics that differ from the other of regions 51 or 52. Alternatively or additionally, the entire major surface 60 has a consistent texture (e.g., consistent smooth, glossy surface) that differs in aesthetic characteristics between regions 51 and 52. such as different color, tonality, visible particle size / shape, etc.

[0027] In some embodiments, the slab 50 is at least 3 feet wide by at least 6 feet long, e.g., between about 3 feet and 6 feet wide and between about 6 feet and 12 feet long, between about 4.5 feet and 5.5 feet wide and between about 10 feet and 11 feet long, and preferably a size selected from one of about 4.5 feet wide by about 10 feet long or about 5.5 feet wide by about 11 feet long. Not only can such regions51 and 52 extend across the full length of the slab product, but such regions 51 and52 can also extend through the thickness of the slab 50 (thereby providing a natural vein appearance even when the slab is cut and edged to specific shapes in living or working spaces (e.g., along a countertop, table, floor, or the like). Because each slab 50 in the set of separately molded slabs can include the layers of different particulate mineral mixes dispensed into the mold according to the predefined and repeatable dispensation patterns of complementary stencils, multiple slabs 50 in the set of separately molded slabs can have substantially the same appearance to one another.

[0028] In examples in which the slab 50 has more than one region, the slab 50 comprises two different particulate mineral mixes that are separately dispensed into the mold through two complementary stencils (e.g., a first stencil that is essentially a negative of a second stencil). However, in some embodiments, three or more stencils may be used to repeatably pattern the distribution of three or more different particulate mineral mixes that are separately dispensed into the mold. The different mixes dispensed into each mold according to the repeatable pattern can be compaction molded and cured in the mold so as to provide the hardened slab 50.

[0029] One or more of the mixes that are used to form the composite stone material include an inorganic component. The inorganic component includes a low crystalline silica material. The low crystalline silica material includes a highpercentage by weight ef non-crystalline silica, such as amorphous silica, and a Sow percentage by weight of crystalline silica (e.g., quartz). Some examples of the low crystalline silica material include no crystalline silica (e.g., 0 wt %). The low crystalline silica material facilitates production of a slab having a low overall crystalline silica content, such as less than or equal to 50 wt %, less than or equal to 40 wt %, less than or equal to 30 wt %, less than or equal to 20 wt %, less than or equal to 10 wt %, less than or equal to 5 wt %, less than or equal to 2 wt %, less than or equal to 1 wt %, or about or equal to 0 wt % overall crystalline silica content of the slab.

[0030] The low crystalline silica material includes a variety of low crystalline silica materials, such as, for example, but not limited to: fused quartz, soda-lime glass, nepheline syenite, feldspar, wollastonite, albite, amorphous silica, and the like, or any combination thereof. In some embodiments, all of the different particulate mineral mixes (e.g., that define respective veins or regions of the slab pattern) each comprise a low crystalline silica material as a predominant component.

[0031] In some embodiments, the tow crystalline silica material is provided as a blend of low crystalline silica grit, and low crystalline silica powder. For example, blends of the low crystalline silica material include a range from about 80 wt % grit to about 60 % grit, to a range from about 40 wt % powder to about 20 wt % powder (e.g., a range from about 75 wt % grit to about 65 % grit, to a range from about 35 wt % powder to about 25 wt % powder, or a range from about 72 wt % grit to about 68 % grit, to a range from about 32 wt % powder to about 28 wt % powder).

[0032] The low crystalline silica grit has a particle size meeting a mesh value threshold. Mesh is a measurement of particle size used in determining the particlesize distribution of a granular material. The size distribution of the low crystallinesilica grit can be defined by a fraction having different mesh sizes. For example, the low crystalline silica grit can have 50+ Mesh (M) size fraction (e.g., larger than 50 M), a 50 M fraction, a 70 M fraction, a 100 M fraction, a 140 M fraction, or a 140- M fraction (e.g., smaller than 140 M). In general, the fractions listed sum to about 100, e.g., 100 % of the grit sizes. The low crystalline silica grit has a +50 Mesh (M) size fraction in a range from about 0 to about 3 (e.g., in a range from about 0.01 to about 5, In a range from about 0.1 to about 8), a 50 M size fraction in a range from about 1 to about 50 (e.g., in a range from about 1 to about 40, in a range from about 1 to about 30), a 70 M size fraction in a range from about 10 to about 50 (e.g., in a range from about 10 to about 40, in a range from about 10 to about 30), a 100 M size fraction in a range from about 15 to about 50 (e.g., in a range from about 15 to about 40, in a range from about 15 to about 30), a 140 M size fraction in a range from about 1 to about 15 (e.g., in a range from about 1 to about 12, in a range from about 1 to about 10), a -140 M size fraction in a range from about 0 to about 70 (e.g., in a range from about 0 to about 60, in a range from about 0 to about 12, in a range from about 0 to about 5).

[0033] The low crystalline silica powder has a particle size distribution such that the majority of the particles have a diameter of less than 1300 μm, e.g., less than 800 μm, less than 500 μm, less than 200 μm, less than 100 μm, or less than 50 μm). The particle size distribution can be defined using values for D90, D50, and / or D10. As used herein, the length unit of D90 represents 90% of particles, D50 represents 50% of particles, and D10 represents 10% of particles in the powders being smaller than this size.

[0034] The low crystalline silica powder has a particle size distribution such that the D90 is less than 100 μm, e.g., less than 80 μm, less than 50 μm; the D50 is lessthan 30 μm, e.g., less than 20 μm, less than 18 μm; and / or the D10 is less than 5 μm, e.g., less than 3 μm, less than 2 μm.

[0035] In some examples, the particulate mineral mixes that define regions 51 and 52 predominately include the low crystalline silica material, such as at least 30 wt %, at least 50 wt %, at least 70 wt %, or more of a low crystalline silica material. Alternatively, some of the particulate mineral mixes include a relatively low content of quartz by weight compared to the other components of the mixture (e.g., less than the low crystalline silica material by weight). Some examples of the mineral mixes do not include quartz. In one example, the particulate mineral mixes of regions 51 include quartz, and the particulate mineral mix of region 52 does not include quartz. In general, the particulate mineral mixes can include quartz equal to or less than the low crystalline silica material by weight.

[0036] In some embodiments, the low crystalline silica material includes fused quartz. The fused quartz can provide the low crystalline silica material in a processed slab in a range from 5 wt % to 90 wt % of the processed slab (e.g., from 10 wt % to 90 wt %, from 25 wt % to 90 wt %, from 40 wt % to 90 wt %, from 50 wt % to 90 wt %, from 80 wt % to 90 wt %, from 50 wt % to 85 wt %, from 60 wt % to 85 wt %, or from 75 wt % to 85 wt %).

[0037] In some embodiments, the low crystalline silica material includes sodalime glass. The soda-lime glass can provide the low crystalline silica material in a processed slab in a range from 5 wt % to 90 wt % of the processed slab (e.g., from 10 wt % to 90 wt %, from 25 wt % to 90 wt %, from 40 wt % to 90 wt %, from 50 wt % to 90 wt %, from 80 wt % to 90 wt %, from 50 wt % to 85 wt %, from 60 wt % to 85 wt %, or from 75 wt % to 85 wt %).

[0038] In some embodiments, the low crystalline silica material includes nepheline syenite. The nepheline syenite can provide the low crystalline silica material in a processed slab in a range from 5 wt % to 90 wt % of the processed slab (e.g., from 10 wt % to 90 wt %, from 25 wt % to 90 wt %, from 40 wt % to 90 wt %, from 50 wt % to 90 wt %, from 80 wt % to 90 wt %, from 50 wt % to 85 wt %, from 60 wt % to 85 wt %, or from 75 wt % to 85 wt %).

[0039] In some embodiments, the low crystalline silica material includes feldspar. The feldspar can provide the low crystalline silica material in a processed slab in a range from 5 wt % to 90 wt % of the processed slab (e.g., from 10 wt % to 90 wt %, from 25 wt % to 90 wt %, from 40 wt % to 90 wt %, from 50 wt % to 90 wt %, from 80 wt % to 90 wt %, from 50 wt % to 85 wt %, from 60 wt % to 85 wt %, or from 75 wt % to 85 wt %).

[0040] In some embodiments, the low crystalline silica material includes amorphous silica. The amorphous silica can provide the low crystalline silica material in a processed slab in a range from 5 wt % to 90 wt % of the processed slab (e.g., from 10 wt % to 90 wt %, from 25 wt % to 90 wt %, from 40 wt % to 90 wt %, from 50 wt % to 90 wt %. from 80 wt % to 90 wt %, from 50 wt % to 85 wt %, from 60 wt % to 85 wt %, or from 75 wt % to 85 wt %).

[0041] In some embodiments, the particulate mineral mixes that define regions 51 and 52 include low crystalline silica material by weight as an alternative to a ‘high' crystallized silica particulate mineral mix, e.g., a particulate mineral mix having a substantial quantity by weight of quartz. One example of a particulate mineral mix can include about 60 wt % quartz grit, about 30 wt % quartz powder, e.g.. in a range from about 50 to 70 % quartz grit, and about 40 wt % to about 20 wt % quartz powder.

[0042] Replacing some or all of the quartz grit and / or powder with a low crystalline silica material reduces the overall content by weight of crystalline silica in a slab produced using such materials. The low crystalline silica mineral mixes defined herein include SO wt % low crystalline silica grit, about 30 wt % low crystalline silica powder, e.g., in a range from about 50 to 70 % low crystalline silica grit, and about 40 wt % to about 20 wt % low crystalline silica powder.

[0043] Low crystalline silica material can facilitate a finished stone slab having a desirable aesthetic appearance. Some low crystalline silica materials described herein facilitate production of a stone slab 50 having a particular color, such as a relatively blue color, and / or the color can be achieved while using relatively iess or no pigment due to the characteristics of the low crystalline silica material. For example, a low crystalline silica material described herein, such as soda-lime glass, nepheline syenite, feldspar, wollastonite, albite, amorphous silica, can facilitate a finished slab having a blue color (e.g., 'b:values equal to or less than 0 in the Hunter color space) while including less than or equal to 2 wt % pigment, less than or equal to 1 wt % pigment, less than or equal to 0.5 wt % pigment, less than 0.2 wt % pigment. In various embodiments, the color of a low crystalline silica material can be described as having L, a, b values in a Hunter color space of: L in a range from 80.6 - 85.4, ‘a’ in a range from -2 to 5, and *b’ in a range from 0-9. In such examples, the color of the low crystalline silica material can alter the amount of pigment in a processed slab to achieve desired color values. For example, in instances in which the low crystalline silica material has a blue color, the quantity of pigment to achieve a desired color value for the slab may be reduced compared to slabs which include no low crystalline silica materials, or substantially transparent low crystalline silica materials. In such examples, the low' crystalline silica slabs may have less than orequal to 2 wt % pigment, less than or equal to 1 wt % pigment, less than or equal to 0.5 wt % pigment, less than 0.2 wt % pigment, or about 0 wt % pigment.

[0044] In some embodiments, the particulate mineral mixes that define regions 51 and 52 include low crystalline silica material by weight in addition to a standard particulate mineral mix. Blending the quartz grit and / or powder with a low crystalline silica material reduces the overall content by weight of crystalline silica in a slab produced using such materials. In such embodiments, the particulate mineral mixes include about 30 wt % quartz grit, about 30 wt % low crystalline silica grit, about 12 wt % low crystalline silica powder, and about 12 wt % quartz powder, in general, the particular mineral mixes can include quartz grit to low crystalline silica grit in a ratio from about 1 : 1 wt:wt. about 1 :2 wt:wt, about 1 :4 wt:wt, about T.5 wt:wt, or about 1 :10 wt:wt In some examples, the particulate mineral mixes includes quartz grit in a range from about 1 wt % to about 40 wt % (e.g., in a range from about 5 wt % to about 30 wt % in a range from about 10 wt % to about 20 wt % in a range from about 10 wt % to about 15 wt %). In some examples, the particulate mineral mixes includes quartz powder in a range from about 1 wt % to about 30 wt % (e.g., in a range from about 5 wt % to about 20 wt % in a range from about 8 wt % to about 15 wt % in a range from about 10 wt % to about 12 wt %). In some embodiments, such values of quartz and low crystalline silica material can complement one another and provide desirable visual, tactile, and / or structural characteristics in a finished stone slab. For example, such percentages of quartz can facilitate a bright white appearance, while maintaining a low overall crystalline silica content of the finished slab 50.[004S] In the slab 50, the inorganic materials can be linked using a binder, which may include for example, monofunctional or multifunctional silane molecules, dendrimeric molecules, and the like, that may have the ability to bind the inorganiccomponents of the composite stone mix. The binders may further include a mixture of various components, such as initiators, hardeners, catalysators, binding molecules and bridges, or any combination thereof. Some or all of the mixes dispensed in the mold may include components that are combined in a mixing apparatus (not shown) prior to being conveyed to the mold. The mixing apparatus can be used to blend raw material (such as the low crystalline silica material, organic polymers, unsaturated polymers, and the like) at various ratios to provide different particulate mineral mixes (e.g., different hardness, different resistance to abrasion, different pigments, different compositions, different additives) according to predefined and repeatable dispensation pattern into the mold until filled.

[0046] For example, some or all of the mixes dispensed in the mold may include about 80-95% low crystalline silica materials to about 5-15% binders (e.g., such as about 12% binder). An example of a binder is a polymer resin material. In addition, various additives, may be added to the raw materials in the mixing apparatus. Such additives may include, for example, metallic pieces (e.g., copper flecks or the like), colorants, dyes, pigments, chemical reagents, antimicrobial substances, fungicidal agents, and the like, or any combination thereof.

[0047] Alternatively or additionally, the particulate mineral mix includes one or more additional components, such as between 3 wt % and 30 wt % binder (e.g.. silicon), between 4 wt % and 25 wt % binder, between 4 wt % and 15 wt %, between 4 wt % and 8 wt % binder, or about 15 wt % binder, and / or a range from about 0.1 wt % to 5 wt % pigment (e.g., a range from about 0.2 wt % to 3 wt % pigment, or a range from about 0.5 wt % to 2 wt % pigment).

[0048] Some examples of the particulate mineral mixes include one or more pigments that can impact the aesthetic appearance of regions 51 or 52, including thecolor, tonality, etc. For example, the pigment of the particulate mineral mixes includes T1O2 pigment. Such a pigment can brighten or lighten the appearance of the regions 51 or 52. in some embodiments, the addition of a TiOs pigment (e.g., within the wt % described above) can facilitate an aesthetic appearance that is similar or complementary to the appearance of stainless steel fixtures or appliances commonly found in kitchens and living spaces.

[0049] One example of the low crystalline silica mix includes about 61 wt % low crystalline silica grit, about 27 wt % low crystalline silica powder, about 11 wt % binder, about 1 wt % pigment. Another example of the low crystalline silica mix includes about 61.5 wt % low crystalline silica grit, about 27 wt % low crystalline silica powder, about 11 wt % binder, about 0,5 wt % pigment. Another example of the low crystalline silica mix includes about 30 wt % low crystalline silica grit, about 30 wt % quartz grit, about 13 wt % low crystalline silica powder, about 13 wt % quartz powder, about 11 wt % binder, about 1.5 wt % pigment. Another example of the low crystalline silica mix includes about 60 wt % quartz grit, about 27 wt % low crystalline silica powder, about 11 wt % binder, about 1,5 wt % pigment.

[0050] Some examples of the first or second particulate mineral mix include metal materials that provides a metal appearance on a surface of the finished slab 50, e.g., the appearance of a metallic pattern having one or more metallic widthwise and / or lengthwise veins. Such an appearance can emphasize or exaggerate patterns that may be found in quarried stone slabs, and / or create a unique veined or patterned appearance that simulates, but is not found in, quarried slabs. In various example embodiments, one or more regions having a relatively high content of metal materials, and one or more regions having a relatively high content of another lowcrystalline silica content facilitates a finished slab having an overall low crystalline silica content.

[0051] The inorganic particulate component may include one or more metals, such as stainless steel, carbon steel, brass, copper, bronze, aluminum, zinc, titanium, gold, silver, iron, magnesium, tungsten, nickel, tin, platinum, cobalt, chromium, vanadium, molybdenum, beryllium, bismuth, gallium, indium, palladium etc., one or more of silicon, basalt, glass, diamond, rocks, pebbles, shells, a variety of quartz containing materials, such as, for example, crushed quartz, sand, quartz particles, and the like, and / or any combination thereof.

[0052] In some embodiments, such as slabs having a textured finish, a gloss meter (e.g., “BYKmac i” meter, available from BYKGARDNER) can be used to measure graininess (SG), sparkle index (Si), and sparkle amount (Sa). In various example embodiments, textured alloy veins and textured non-alloy veins exhibit graininess (SG), sparkle index (Si), and sparkle amount (Sa) that are meaningfully different. Example alloy veins exhibit a sum of SG, Si, and Sa (“sparkle sum"), measured in some embodiments at a 15° angle. In various example embodiments, the sparkle sum ranges from about 40 to about 200, about 40 to about 160, or about 50 to about 150 (e.g., at regions 51 and / or 52). In some embodiments, the sum of SG, Sj, and Sa, measured at a 15“ angle, is greater than 40. Some examples of the veins exhibit sparkle sums ranging from about zero to about 35. in some embodiments, the sum of SG, Si, and Sa. measured at a 15“ angle, is less than 40.

[0053] Such sparkle values can be associated with predetermined aesthetic surface characteristics that provide a unique and desirable stone slab suitable for work surfaces and / or other building applications.

[0054] The surface characteristics and aesthetics are, alternatively or additionally, measurable and quantifiable as a transparency which can promote appealing visual characteristics. For example, the transmittance through a thickness of finished stone slab (e.g., having a thickness of 1 cm), is relatively high in some embodiments, providing an appearance having depth.

[0055] The surface characteristics and aesthetics are, alternatively or additionally, measurable and quantifiable as a diffusiveness which can be useful in promoting a bright white appearance.

[0056] The surface characteristics and aesthetics are, alternatively or additionally, measurable and quantifiable as an abrasion resistance which can be useful in reducing damage to major surfaces of the slab during handling, Installation, and use. In some embodiments, the slab has an abrasion resistance as measured on the Taber Index in a range from 50 to 250 (e.g., from 60 to 200, from 70 to 150, from 75 to 100, from 80 to 90, or about 85).

[0057] The surface characteristics and aesthetics are, alternatively or additionally, measurable and quantifiable as a vein height, a vein roughness, and background roughness. The vein height is a distance the region 51 and / or 52 extends above or below the thickness of the major surface 60, for example. The region roughness is measured by a surface roughness tester, such as a “Mitutoyo SJ210” available from MITUTOYO, or “MarSurf PS 10" roughness meter available from MAHR GROUP. The roughness of the primary fill is measured by a roughness tester similar or the same to the roughness tester used for the region.

[0058] Some examples of the average region roughness ranges from between 10 μm and 180 μm, between 20 μm and 130 μm, between 30 μm and 90 μm, between 40 μm and 60 μm, between 50 μm and 60 μm, and about 55 μm. The averagebackground roughness (e.g., the roughness of the primary fill region 51) ranges from between 0 μm and 30 μm, between 1 μm and 20 μm, between 2 μm and 18 μm, between 3 μm and 15 μm, between 5 μm and 15 μm, or about 10 μm. In some example embodiments, region 51 includes a roughness between about 0 μm and 6 μm, 1 μm and 4 μm, or about 1 μm and 2 μm, such as for a region 51 that has been subjected to a polishing operation and / or exhibits a relatively high gloss.

[0059] In some example embodiments, region 51 includes a roughness between about 1 μm and 10 μm, 2 μm and 8 μm, or about 4 μm and 6 μm, such as for a region 51 that has a relatively matte finish. Such roughness values can be associated with a predetermined tactile and aesthetic surface characteristics that provide a unique and desirable stone slab suitable for work surfaces and / or other building applications. In some embodiments, such roughness values can be associated with a noticeable contrast between different regions, including regions 51 and / or 52 with relatively higher roughness and region 51 with relatively tower roughness.[006G] For example, a roughness of regions 51 or 52 may be between 2 and 200 times greater, 2 and 175 times greater, 2 and 150 times greater, 5 and 100 times greater, 10 and 150 times greater, or about 25 times greater than a roughness of the other region. As described herein, the roughness values can be predictably obtained based on the particulate mineral mixes that define regions 51 and 52, respectively (e.g., including the particle size, shape, distribution, hardness, composition, etc.), and / or surface abrasion, polishing, or other treatments after the slab has been hardened and at least partially cured.

[0061] In some implementations, roughness (e.g., region roughness, background roughness), sparkle (e.g., graininess, sparkle index, sparkle amount, sparkle sum).gloss and / or reflectance haze measurements can be performed as a test of finished product. For example, after a slab is cured and finished , a quality control operation is performed that includes measurement of roughness (e.g., region roughness, background roughness), sparkle (e.g., graininess, sparkle index, sparkle amount, sparkle sum), reflectance haze and / or gloss of the slab. The quality control operation can be performed to determine if the slab is within predetermined ranges (e.g., of roughness (e.g., region roughness, background roughness), sparkle (e.g., graininess, sparkle index, sparkle amount, sparkle sum), gloss, reflectance, haze, and / or other characteristics.

[0062] The quality control operation can be used to qualify a product for sale (e.g., that it is within the predetermined specification for a conforming slab), and / or for categorization purposes (e.g., to group the slabs with other similar slabs have similar roughness, sparkle, gloss / reflectance haze values, to label the slab for sale as a high gloss / reflectance version of the product or to label the slab for sale as a low gloss / reflectance version of the product, etc.).

[0063] In an example embodiment, multiple measurements are obtained at various locations of the slab, such as at predetermined locations of alloy and nonalloy material, according to a predetermined pattern for the example slab. Measurements obtained for the alloy material locations are compared to specified acceptable alloy ranges, and / or measurements obtained for the nonalloy material locations are compared to specified acceptable nonalloy ranges. In some embodiments, a pass / fail determination is made to determine whether the slab conforms to the specified ranges. Alternatively or additionally, measured values are stored and associated with an identifier specifically associated with the measured slab. The measured values are used in one or more subsequent operations, such asio match the measured slab with another slab having similar or complementary values.

[0064] Various slabs described herein provide robust strength suitable for installation in living / working spaces in a variety of configurations. Structural strength of slabs can be characterized using a three point flexural test. For example, structural strength can be characterized based on a modulus of rupture (MOR) (e.g., determined according to ATSM International C99 / C99M - 18 “Standard Test Method for Modulus of Rupture of Dimension Stone” (2018).

[0065] In an example embodiment, 12” x 12" x 2 cm finished low crystalline silica slab portions having a straight line across the center thereby divided into five equally sized specimens at the expected modulus of rupture (MOR) breaking point (e.g., the center of a 3 point bending span). All five specimens are tested in accordance with the ATSM International C99 / C99M ~ 18 “Standard Test Method for Modulus of Rupture of Dimension Stone”.

[0066] In an example embodiment, one or more regions 51 and 52 can be characterized by reflectivity. Reflectivity is measured under defined conditions to identify direct reflection, diffuse reflection, and total reflection values. For example, a surface location of the slab is illuminated by a predefined light source at a predefined angle of incidence, such as 15 degrees, 30 degrees, 45 degrees, etc. The reflected light is measured and quantified, including direct, diffuse, and total reflectance, for example. The resulting values provide an indicator of the magnitude of the reflected light, as well as whether light is reflected evenly in many directions, intensely focused in certain directions (e.g., providing a quantifiable “sparkle” effect), etc.

[0067] In an example embodiment, region 51 and / or 52 exhibits a relatively high direct reflectivity and / or diffuse reflectively (e.g., while also having a textured / non-smooth surface). The relatively high reflectivity (e.g., relatively high diffuse reflectivity) can represent a relatively high sheen, luster, and / or intensity.

[0068] In some embodiments, the reflection values provide a numeric indicator of relative similarity / difference. For example, reflectivity (e.g., direct, diffuse, and / or total) differ between regions 51 and 52 based on the surface texture and characteristics of the materials that define these regions. A smooth, glossy surface can exhibit a relatively higher direct reflection and / or relatively lower diffuse reflection. A textured surface can exhibit a relatively higher diffuse reflection.

[0069] Alternatively or additionally, reflectivity (e.g., direct, diffuse, and / or total) provides a metric to qualify a set of slabs having the same characteristics. For example, the systems, materials, and processes described herein facilitate manufacturing of a set of slabs having a predefined pattern and appearance.Reflectivity of one or more of regions 51 and 52, of slabs of a same type having the same predefined pattern have reflectivity values (e.g., at a same location on the slab / within a same region 51 and 52) that are consistent (e.g., without 15 %, within 10 %, within 5 %, within 2 %, etc.) of one another.

[0070] Referring now to FIG. 2, a diagram of an example system 200 for forming a low crystalline silica processed slab product is shown. In some embodiments, the system 200 for forming a set of processed slab products (e.g., slab 50) Is configured to dispense particulate mineral mixes (e.g., that are differently resistant to abrasion when formed into th® cured slab) into the slab mold 230. The slab mold 230 are then advanced to a subsequent compression molding operation (e.g., vibro-compaction molding, curing, etc.). The system 200 includes a conveyor 210. A collection of slab mold 230 are transported on the conveyor 210. The slab mold 230 provide a form forprocessed molded slab products that are at least three feet wide and at least six feet long, and about 4.5 feet wide by about 10 feet long, for example.

[0071] The conveyor 210 transports the slab mold 230 to a dispenser 260 (e,g., a mineral aggregate distributor). In the illustrated example, the dispenser 260 is configured to release different particulate mineral mixes (e.g., different cured resistances to abrasion, different textures, different pigments, different mineral compositions, different additives, or a combination thereof). In some embodiments, multiple dispensers 260 may be used (e.g., each dispenser configured to dispense different particulate mineral mix or combination of mixes).

[0072] The slab mold 230 receives the different mineral mixes (comprising mostly a quartz material as described above) from the dispenser(s) 260. For example, the dispenser 260 can be configured with a shutter or valve apparatus that is controllable to regulate the flow of particulate mineral mix from the dispenser 260 for input to the slab mold 230. In some embodiments, the dispensing heads (or other inputs for distributing the particulate mineral mixes to the slab mold 230) can be controlled according to a predetermined control algorithm so as to define successive layers or regions of the different particulate mineral mixes for dispensation into the slab mold 230. In the illustrated example, the slab mold 230 is filled with a primary fill region 291 and two other different types of particulate mineral mixes to create two different types of patterns such as a region 292 and a region 293.

[0073] In some examples, multiple dispensers 260 can be used to dispense different particulate mixes into different regions of the slab. The slab may be formed from a number of different particulate mineral mixes, such as between 2 and 20 different particulate mineral mixes (e.g., and the system includes a corresponding number of dispensers 260 or a single dispenser 260). In some examples, thenumber of dispensers 260 can correspond equally to the number of differently pigmented particulate mineral mixes used to create the slab product.

[0074] The filled molds 280 are then moved to one or more subsequent stations in the system 200 for forming the hardened slab. For example, each of the filled molds 280 can continue to a subsequent station in which a top mold attachment 294 is positioned over the filled mold 280 so as to encase the layers of particulate mineral mixes between the slab mold 230 and a top cover mold piece. From there, the filled mold 280 (e.g., including the top cover mold piece) advances to a subsequent station in which a vibrocompaction press 295 applies compaction pressure, vibration, and / or vacuum to the contents inside the filled mold 280, converting the particulate mixes into a rigid slab. The filled mold is subjected to a curing station 296 in which the material used to form the slab (including any binder material) are cured via a heating process or other curing process, strengthening the slab inside the filled mold 280. In an example embodiment, the contents of the filled molds are initially uncured. For example, each of the plurality of particulate mineral mixes within the filled molds include uncured binder. The particulate mineral mixes are contemporaneously subjected to pressure, vibration, vacuum, and / or heat in order to contemporaneously harden / cure each of the particulate mineral mixes to form the finished slab. For example, the filled mold does not include some portions of previously hardened / cured particulate mineral mixes and a region pattern defined by an unhardened / un hardened particulate mineral mix.

[0075] After the slab is fully cured (and, optionally, after the slab is cooled), the slab mold 230 and the top mold cover piece are removed from the hardened and cured slab at a mold removal station 297. The slab mold 230 is then returned to the conveyor 210. The hardened and cured slab Is moved to a surface treatment station298, in which a major surface of the slab is abraded, to reveal a complex abraded surface having a predetermined texture and pattern. In some embodiments of the system 200, the abraded or otherwise exposed major surface of each of the processed molded slabs can provide an outer appearance that is substantially repeatable for the other slabs (from the other filled molds 280 in FIG. 8).

[0076] FIG . 3 is a d iagram of an example system 300 for applying a surface treatment to texturize a low crystalline silica processed slab product (e.g., a face treatment apparatus), in accordance with some embodiments. In some embodiments, the system 300 is included in the example surface treatment station 298 of FIG. 2. The system 300 is configured to modify at least a portion of at least one face of a cured and hardened processed stone slab by abrading the slab to reveal visible and / or tactile differences in the depth and / or roughness of different materials exposed at the processed face(s).

[0077] A collection of hardened and cured slabs 330 (e,g., the hardened and cured slabs removed at the example mold removal station 897) are transported on a conveyor 310 to a surface treatment station 340. The hardened and cured slabs 330 include a primary fill region 391 (e.g. the primary fill region 51 of the example slab 50, the primary fiil 891 after it has been cured and hardened, etc.), and / or one or more regions 392 and 393. In an example embodiment, the primary fill region 391 is made of a first particulate mineral mix that differs in one or more characteristics as compared to second and third particulate mineral mix region 392, 393. For example, the hardness, brittleness, resistance to abrasion, and / or other characteristics differs between the first particulate mineral mix compared to the second and / or third particulate mineral mix,

[0078] The surface treatment station 340 modifies a major surface 332 of the hardened and cured slabs 330. For example, the surface treatment station 340 includes one or more abrasive brushes 342 configured to contact the major surface 332 vertically and rotate about a rotational axis arranged substantially perpendicular to the major surface 332. The one or more abrasive brushes 342 rotate in contact with the major surface 332 as they are drawn across the major surface to provide substantially the same amount (e.g., duration) of abrasion to all areas of the major surface 332. In an example embodiment, the movement of the one or more brushes 342 across the major surface 332 is independent of the region of the slab (e.g., independent of whether the brush is in contact with 391 , 392, 393). One or more abrasive fluid compound applicators 344 can be used to apply abrasion promoters and / or water to the areas being treated to modify the action of the abrasive brushes 342, to control the temperature of the process, and / or to reduce the production of dust. The selection of brush type, vertical pressure, rotational speed, lateral direction, lateral pattern, abrasive grit, water flow, and slab advancement speed can all be controlled to further control the abrasion process. In some implementations, the abrasion process may be applied evenly to provide a uniform level of abrasion, or it may be applied unevenly across the major surface 332 to provide an intentionally nonuniform level of abrasion. In various example embodiments, the one or more abrasive brushes include silicon carbine, diamond, or other abrasive brushes such as diamond abrasive brushes available from Tenax USA of Charlotte, NC. in some embodiments, a series of brushes having differing abrasive grit ratings are used in sequence. In some embodiments, abrasive brush application pressures are between 0.5 bar to above 8.0 bar, between 0.8 bar to 4 bar. In some examples, the abrasive brushes 342 can be spun at speeds ranging from 200 RPM to 1500RPM, 300 RPM to 1200 RPM, ar between 400 RPM to 550 RPM. to some implementations, water is applied to the abrasion site at flow rates ranging from zero to 4 gallons per minute or more. In some embodiments, the abrasive brushes 342 are advanced across the major surface 610 at speeds ranging from below 3000 to above 18000.

[0079] As the abrasive brushes 342 abrade the major surface 332, small amounts of the major surface 332 are removed to provide a processed major surface 352 of a processed stone slab product 350. The particulate mineral mixes in regions 391 , 392, 393, abrade at different rates and / or in different manners (e.g., based on different hardness, particle size, resistance to abrasion, etc.).

[0080] to some example embodiments, the primary fill region 391 is harder and / or more abrasion resistant than the regions 392, 393 such that the areas of the regions 392, 393 exposed at the major surface 332 (e.g., face areas) recede beiow a piane generally defined by the primary fill region 391. The resulting processed slab has a slab thickness that varies (e.g,, between regions 391 , 392, 393), with the average thickness of the primary fill region 391 generally thicker than the average thickness of the regions 392, 393). In some embodiments, the exposed surface can resemble the appearance of a topographical or relief map of a plain with valleys running through it.

[0081] In some example embodiments, the primary fill region 391 is softer or less abrasion resistant than the regions 392, 393, the areas of the major surface 332 exposed at the major surface 332 may recede below bumps and mounds made up of the regions 392, 393. For example, the exposed surface can resemble the appearance of a topographical or relief map of a plain with hills or mountain rangesrising from it. Examples of materials which can cause the regions 391 , 392, or 393 to be softer include naturai / synthetic micas, talc, calcite, and limestone.

[0082] In some example embodiments, the region 392 is softer than the primary fill region 391, and the region 393 is harder than the primary fill region 391. The resulting texture of the major surface has features that are both raised (e.g., region 393) and recessed (e.g., region 393) relative to the average thickness. The processed major surface 352 has a texture that can be seen and / or felt due to the differences in average slab thicknesses in regions of the primary' fill region 391 , the region 392, and the region 393.

[0083] In some embodiments, the processed stone slab product 350 produced by the example system 300 can be the example processed slab 50. In some implementations, the processed stone slab product 350 may be further processed. For example, the major surface 352 may be polished to round or blunt sharp peaks, or the peaks may be polished or flattened to define flattened raised regions resembling plateaus.

[0084] In some example embodiments, the system 300 includes a calibration station arranged before or after the surface treatment station 340. For example, the major surfaces 332 of the cured slabs 330 can polished, planed, smoothed, and / or otherwise provided with a substantially even surface across the entire major surface 332 prior to being abraded. In another example, the processed major surfaces 352 of the cured slabs 330 can be partly polished, planed, smoothed, or otherwise modified to have a collection of plateaus that define a substantially common plane across the processed major surface 352. In some example embodiments, such steps may be omitted (e.g., the abrasion is performed on the major surface 332 in the form that exists after mold removal 397 without subjecting the slab to an intermediate planningor calibration operation). In an exampie embodiment, the major surfaces 332 of the cured slabs 330 are calibrated to provide a substantially even surface across the entire major surface 332 prior to being abraded. The slab is then finished (e.g. , for use in subsequent fabrication and installation operations) without polishing the major surfaces 332 of the cured slabs 330. Such a sequence can facilitate a desired textured surface (e.g., including regions of differing thickness, such as a raised or recessed region pattern), while having a relatively low gloss regions and / or surface smoothness). In some embodiments, the major surfaces 332 of the cured slabs 330 are subjected to a polishing operation in addition to both calibration and abrading operations. Such a sequence can facilitate a desired textured surface (e.g., including regions of differing thickness, such as a raised or recessed region pattern), while having relatively high gloss regions and / or surface smoothness). In some embodiments, the polishing operation can facilitate roughness and / or sparkle measurements within predetermined ranges (e.g., such as predetermined roughness and sparkle measurements).

[0085] FIGS. 4-5 are diagrams of example systems 400 and 500 for applying a surface treatment to texturize a processed slab product. In some embodiments, the systems 400 and 500 are included in the example surface treatment station 298 (FIG, 2). In some example embodiments, the systems 400 and 500 include one or more features of the example system 300 described with reference to FIG. 3.

[0086] Referring to FIG. 4, the system 400 includes a surface treatment station 440. The surface treatment station 440 includes one or more cylindrical abrasion tools 442. In some embodiments, the tool 442 is an abrasive brush that contacts the surface being processed and rotates substantially perpendicular to the surface about an axis that is substantially parallel to the surface. In some embodiments, the tool442 can resemble a planning head configured to grind against the surface. The different materials in different areas of the surface abrade differently from each other due to the differences in their respective particulate mineral mixes, leaving behind a processed surface with a tactile and / or visual texture. In an example embodiment, the movement of the tool 442 across the major surface of the slab is independent of the region of the slab (e.g., independent of whether the brush is in contact with a particulate mineral mix), such that the tool 442 is consistently applied across the entire major surface of the slab.

[0087] Referring to FIG. 5, the system 500 includes a surface treatment station 540. The surface treatment station 540 has a nozzle 542 configured to perform abrasive blasting (e.g., sandblasting). In the illustrated example, a stream of abrasive material is forcibly propelled against the surface. The different materials in different areas of the surface abrade differently from each other due to the differences in their respective particulate mineral mixes, leaving behind a processed surface with a tactile and / or visual texture. In an example embodiment, application of the abrasive blasting across the major surface of the slab is independent of the region of the slab, such that the abrasive blasting is consistently applied across the entire major surface of the slab.

[0088] In some embodiments, the example systems 400, 500 may also use an abrasion promoter, such as an abrasive liquid or paste. In some embodiments, surface treatment stations may use a substantially nonabrasive brush or pad in combination with a paste, powder, or liquid that provides the abrasive properties. In some embodiments, surface treatment stations may use chemical etching, such as an acid or solvent for which the different materials in the slab react differently, to chemically etch the major surfaces of hardened and cured slabs. In someembodiments, surface treatment stations may use any appropriate combinations of the described tools, or any other appropriate tool or substance that can be used to abrade or erode the surface of a hardened and cured processed stone slab.

[0089] In some embodiments, the example systems 400, 500 may be configured with one or multiple stages of abrasion using one or multiple different types of abrasives, abrasion tools, abrasion patterns (e.g., the abrasion tool can be draw across the surface in predetermined straight lines, curves, circles), application pressures, grits, speeds, directions across the major surfaces, speeds across the major surfaces, any combination of these and / or other appropriate variables that can affect the abrasion of processed stone slabs.

[0090] FIG. 6 is a flow diagram of an example process 600 for producing a processed slab product from a plurality of different particulate mineral mixes. In some embodiments, the process 600 is performed by parts or all of the example systems 200500 described with reference to FIGS. 25.

[0091] At 610 a first particulate mineral mix is dispensed into a first set of regions of a slab mold. For example, a first particulate mineral mix is deposited into the slab mold to become one or more regions.

[0092] At 620, a second particulate mineral mix is dispensed into a second set of regions of the slab mold. For example, the dispenser dispenses primary fill into the slab mold.

[0093] At 630, th® first particulate mineral mix and the second particulate mineral mix arranged in the slab mold are contemporaneously vibrated and compacted so as to form a molded slab that is generally rectangular and has a slab thickness and a major surface having a width of at least 2 feet and a length of at least 6 feet. For example, a vibro-compaction press applies compaction pressure, vibration, and / orvacuum to the contents inside the filled mold, thereby canverting the particulate mixes into a rigid slab.

[0094] At 640, the compacted first particulate mineral mix and the compacted second particulate mineral mix are cured into a cured slab. For example, the curing station heats or otherwise cures the compacted slabs to further strengthen the slabs inside the filled molds.

[0095] In some implementation, the first particuiate mineral mix can include one or more first component materials having a first hardness, particle size, particle shape, composition, resistance to abrasion, etc. For example, the primary fill may be made up of a particulate mineral mix that includes a binder and a component having a particular hardness, particle size, particle shape, composition that cures relatively hard and / or with a high abrasion resistance, whereas the regions may be made up of a particulate mineral rnix and a binder that includes a component having a particular hardness, particle size, particle shape, composition that cures somewhat softer and / or with a lower abrasion resistance (e.g., allowing the binder to erode away to expose more hard particuiate, possibly resulting in a surface like sandstone or fine sandpaper). In some embodiments, the particulate mineral mix composition results in particulates (e.g., observable in a region or other region of a finished slab) with rounded facets and a microscopically bumpy surface, spherical shapes, round shapes, ovular shapes, ovoid shapes, rounded disc shapes, sharp edges, irregular shapes, and combinations thereof.

[0096] At 650, the major surface of the cured slab is abraded at locations of the first particulate mineral mix and the second particulate mineral mix with an abrading head to partly remove portions of the major surface such that the first particulate mineral mix in the first set of regions define a first thickness perpendicular to the slabwidth and the slab length, and the second particulate mineral mix in the second set of regions define a second thickness perpendicular to the slab width and the slab length. For example, the surface treatment stations 240, 240, and / or 540 can be used to abrade the major surface, and due to the differences (e.g., hardness, particle size, particle shape, composition, abrasion resistance) among regions of the primary fill and the regions, the various regions abrade or erode to different depths resulting in the primary fill and the regions having different thicknesses across the major surface 232.

[0097] In some embodiments, example process 600 optionally includes a material recovery operation 660. Abraded material removed from the slab is recovered and treated. For example, abraded material is subjected to a separation process that separates material particles based on density, specific gravity, and / or other characteristics. The abraded material is passed through one or more centrifuge processes until the abraded material is segregated into individual material compositions or types. In some embodiments, the segregated material is recycled for reuse in a particulate mineral mix to be used in forming a finished slab. For example, metal particulate (e.g., stainless steel, brass, etc.) recovered from the abraded material is incorporated into a particulate mineral mix for subsequent formation of a different slab (e.g., incorporated into a particulate mineral mix that defines region 51 and 52, etc., described above). In this way, a finished slab can include one or more regions defined partly or entirely of material recovered / recycled from a previous molded slab.

[0098] In some embodiments, abrading a portion of the major surface of the cured slab includes removing an amount of the major surface in the first set of regions to an average first thickness perpendicular to the slab width and the slablength that is at least partly different from a second average thickness removed from the second set of regions, wherein the first texture is based on the first average thickness and the second texture is based on the second average thickness.

[0099] In some embodiments, one of the first set of regions and the second set of regions can define a majority of the major surface, and the other of the first set of regions and the second set of regions can define a region extending at least partly across the major surface. For example, the primary fill occupies a first set of regions within the slab 350, and other particulate mineral mixes form the one or more regions, which extend partly or entirely across the surfaces and edges of the slab.

[0100] In some implementations, abrading the major surface of the cured slab includes abrading substantially the entire major surface. For example, the system 200 can be configured to apply the same type of abrasion across the entire major surface 232 (e.g., causing substantially ail of the primary fill region 291 exposed at the major surface 232 to erode to substantially the same average depth, and causing the regions 292 and 293 to each erode to their own respective average depths across the entire major surface 232).

[0101] In some implementations, abrading the major surface of the cured slab can include abrading by at least one of an abrasive brush and mechanical application of an abrasive fluid compound. For example, the example abrasive brushes 242 can be used to apply a fluid compound containing abrasive material to the major surface 232.

[0102] In some implementations, the first set of regions can have a first texture and the second set of regions can have a second texture different from the first texture. For example, the primary fill may have a smooth, glossy texture, while the region may have a relatively rougher, matte texture. In some embodiments, theroughness of the primary' fill and / or the region may be quantified by Ra, Rq, and Rz values. Alternatively or additionally, roughness of the primary fill and / or the region may be characterized based on roughness meter measurements.

[0103] Although a few implementations have been described in detail above, other modifications are possible. For example, the logic flows depicted in the figures do not require the particular order shown, or sequential order, to achieve desirable results. In addition, other steps may be provided, or steps may be eliminated, from the described flows, and other components may be added to, or removed from, the described systems. Accordingly, other implementations are within the scope of the following claims.EXAMPLES

[0104] Various examples of the low crystalline silica material were used to produce one or more test slabs. Each of the different low crystalline silica materials can have one or more characteristic effects (e.g., a color, compression, transparency, clarity, and / or texture effect) on the finished slab. For example, fused quartz is a pure form of amorphous silica and generally does not impart color, e.g. , blue color, in the slab. The following examples include recipes by which test slabs were produced using low crystalline silica material in grit (%grit) and powder (%powder) form, a binder (%binder), and a pigment (%pigment), unless indicated otherwise.

[0105] As used herein, the values of ‘L,' ‘a,’ and ‘b’ refer to values in the Hunter color space. The values express color as *L’ for perceptual lightness, and 'a' and ‘b’values which, when combined, determine values for the four unique colors of human vision: red, green, blue and yellow.Example - Formulation 1

[0106] One example of a standard ‘high’ crystalline silica material, e.g... quartz grit and powder, was used to produce test slabs. Formulation 1 test slabs were used as a comparator against other test slabs.

[0107] Test slabs were produced using the following ratios:

[0108] Test Slabs Group 1Example - Formulation 2

[0109] One example of a low crystalline silica materials was used to produce test slabs. The example low crystalline silica material, e.g., Formulation 2, was determined to be 100 wt % amorphous silica and both grit and powder forms were used in the slab productions as described above.

[0110] Slabs produced using Formulation 2 grit and / or powder can have a high binder demand which may be due to the particle size distribution. Formulation 2 hasa blue color In the powder / grit raw material. The blue undertone may be advantageous in specific designs or mixes. In general, the test slabs produced using Formulation 2 have an overall more glassy look, and smooth texture. Some examples made with Formulation 2 had a silky texture and a spongy feeling compared to Formulation 1 which may be related to poor compaction.

[0111] Grits grains of Formulation 2 appear clear and clean, e.g., low to no contamination, compared to Formulation 1. Formulation 2 powder has a white color and an opacity similar to other Formulation 1 and has a blue color. Formulation 2 has a Mohs hardness of greater than or equal to 5.

[0112] Formulation 2 was tested to have the following composition: SiOs: 58-59% CaO: 14-15%; AI2O3: 20-21%; K2O: 3.5-4.5%; MgO: 12%; Na2O: <1%; Fe2O3: <1%; TiO2: 0%; ZnO: <0.1%; ZrO2: <0.1%; Cl: <0.1%; P2O5: <0.1 %; SrO: <0.1%; SO3: <0.1%; NiO: <0.01%; and Pb: 0%.

[0113] Formulation 1 was tested to have an abrasion resistance on the Taber Index of 88.8.

[0114] The Formulation 2 powder has a lower b value than Formulation 1 (e.g., less yellow / more blue) and a lower a value as well (e.g., less red / more green) contributing to a blue-green appearance.

[0115] Test slabs were produced using the following ratios:Test Slabs Group 2Material %Grit %Powder %Sinder %PigmentFormulation 2 61.5 26,81 11.9 1.5PowdersMateria! D10 (p.m) D50 (pm) D90 (μm) L a bFormulation 2 1.72 13.10 47.50 84.54 -0.39 0.25

[0116] Examples of slabs produced using Formulation 2 resulted in a polymeric aesthetic with blue color undertones. Some examples of the slabs had a more glassy finish compared to Formulation 1 . Some examples had lower transparency than Formulation 1 with similar pigment dose. A yellow pigment may be used to alter the blue undertone, which in some cases may increase the opacity of produced slabs.

[0117] When some pigment (e.g., TiOa) is added to the test slabs to enhance a white color of the slab, then the aesthetic increases in opacity. Formulation 2 grit used with cristobalite powder makes a slab having a semiwhite color with some transparency depending on TiOz dose compared to Formulation 1. Increasing the Formulation 2 powder particle size may reduce binder demand and compaction in some cases.

[0118] Some examples had reduced compaction compared to Formulation 1 , while having up to 5% more binder. Some examples had a brown color compared toFormulation 1 .Example - Feldspar

[0119] Another example of a low crystalline silica material including feldspar was used to produce test slabs. Two examples of feldspar were used to produce the test slabs. The following slab recipes were used to produce two groups of test slabs. The feldspar #1 has a more white color than the feldspar #2. Feldspar #2 has a pink color. Both feldspar powders are smaller in size than the Formulation 1 powder, withthe feldspar #1 powder being the smallest particle size observed. The feldspar #1 powder has color closest to the Formulation 1 powder.Test S / abs Group 3

[0120] Test Slab Group 3 was produced using quartz grit (%Quartz Grit) and low crystalline silica material (%Powder). The compression of the test slab group 1 was similar to Formulation 1 . The color was dissimilar to test slabs produced using Formulation 1. An increased pigment dose may be used to reduce the color difference.Test Slabs Group 4

[0121] The grit and powder had a pink color compared to Formulation 1. This resulted in test tiles having a peach / tan color.Example - Nepheline Syenite

[0122] Another example of a low crystalline silica material Including nepheline syenite was used to produce test slabs. The following slab recipes was used to produce the test slabs. The particle size of the nepheline syenite powder is closest to the Formulation 1 powder.Test Slabs Group 5

[0123] Black specs were observed in Test Slabs Group 3. In some examples, 50+ mesh particles were screened out thereby improving the visual aesthetic. The material was blended 50 / 50 wt / wt with quartz, facilitating maintained color.Example - Soda-Lime Glass

[0124] Another example of a low crystalline silica material including soda-lime glass was used to produce test slabs. The following slab recipes was used to produce the test slabs.

[0125] The soda lime glass was tested to have an abrasion resistance on the Taber Index of 83.8.

[0128] The soda-lime glass powder has a lower b value than Formulation 1 (e.g., less yellow / more blue) and a lower a value as well (e.g., less red / more green) contributing to a blue-green appearance. The particle size of the soda lime glass grit is smaller than the Formulation 1 grit material.Test Slabs Group 6

[0127] Some test slabs had increased grey color and similar transparency to test slabs produced using Formulation 2 as the low crystalline silica materials. Other test slabs had a white color with similar transparency to test slabs produced using Formulation 2. Some test slabs had a white / blue color with similar transparency to test slabs produced using Formulation 2. Other test slabs had a brown color and similar transparency to test slabs produced using Formulation 2.

Claims

WHAT IS CLAIMED IS:

1. A processed slab formed from a plurality of particulate mineral mixes, comprising: a slab width that is at least 2 feet, a slab length that extends perpendicular to the slab width and that is at least 6 feet, and a slab thickness extending perpendicular to the slab width and the slab length, the slab length greater than the slab width, the slab width greater than the first slab thickness; wherein the plurality of particulate mineral mixes comprises a first particulate mineral mix, the first particulate mineral mix having greater than 50% of a low crystalline silica material, wherein the processed slab has a crystalline silica content that is less than 50% by weight (wt %).

2. The processed slab of claim 1 , wherein the crystalline silica content is less than or equal to 1 wt %.

3. The processed slab of claim 1 , wherein the first particulate mineral mix includes is selected from the group consisting of fused quartz, soda-lime glass, nepheline syenite, feldspar, wollastonite, albite, and amorphous silica.

4. The processed slab of claim 3, wherein the first particulate mineral mix comprises less than 5 wt % quartz, less than 0.5 wt % pigment, and L, a, b color values in which the ‘U value is in a range from 80.6 - 85.4, the ‘a’ value is in a range from -2 to5. and the!b!value is in a range from 0-9.

5. The processed slab of claim 3, further comprising a primary region and a secondary region, wherein the primary region comprises the first particulate mineral mix, and the secondary region comprises a second particulate mineral mix having greater than 50% of a low crystalline silica material.

6. The processed slab of claim 3, wherein the processed slab comprises quartz at an overall slab wt % that is less than or equal to an overall slab wt % of the low crystalline material.

7. The processed slab of claim 3, wherein the low crystalline silica material comprises more than 30 wt % fused quartz.

8. The processed slab of claim 3, wherein the low crystalline silica material comprises more than 30 wt % soda-lime glass.

9. The processed slab of claim 3, wherein the low crystalline silica material comprises more than 30 wt % nepheline syenite.

10. The processed slab of claim 3, wherein the low crystalline silica material comprises more than 30 wt % of feldspar.

11. The processed slab of claim 3, wherein the low crystalline silica material comprises more than 30 wt % of amorphous silica.

12. The processed slab of claim 5, wherein the processed slab comprises a pigment at a pigment wt %.

13. The processed slab of claim 12, wherein the low crystalline silica material has a 'b' value that is less than 0 in a Hunter color space.

14. The processed slab of claim 13, wherein the processed slab has a different pigment wt % that is less than the pigment wt % when the low crystalline silica material has the b greater than or equal to 0 in a Hunter color space.

15. The processed slab of claim 1 , wherein the low crystalline silica material has an abrasion resistance in a range from 80 to 90 on the Taber Index.

16. The processed slab of ciaim 1 „ wherein the processed slab comprises quartz at a wt % that is less than the low crystalline silica material wt %.

17. A process of forming a processed slab from a plurality of different particulate mineral mixes, comprising: dispensing a first low crystalline silica mineral mix to a first set of regions of a siab mold, the first iow crystalline silica mineral mix having greater than 50% of a first low crystalline silica material: dispensing a second iow crystalline silica mineral mix to a second set of regions of the slab mold; contemporaneously vibrating and compacting the first particulate mineral mix and the second particulate mineral mix arranged in the slab mold so as to form a processed molded siab that is generally rectangular and has a slab thickness and a major surface having a slab width of at least 2 feet and a slab length of at least 6 feet; and curing the processed molded slab into a cured slab.

18. The process of claim 17, wherein the first low crystalline silica mineral mix includes a predominate mineral material selected from the group consisting of fused quartz, soda-lime glass, nepheline syenite, feldspar, wollastonite, albite, amorphous silica.

19. The process of claim 17, wherein the second low crystalline silica mineral mix includes a predominate mineral material selected from the group consisting of fused quartz, soda-lime glass, nepheline syenite, feldspar, wollastonite, albite, amorphous silica.

20. The process of claim 17, wherein the second iow crystalline silica mineral mix having greater than 50% of a first low crystalline silica material21. A processed slab formed from a plurality of particulate mineral mixes, comprising: a slab width that is at least 2 feet, a slab length that extends perpendicular to the slab width and that is at least 6 feet, and a slab thickness extending perpendicular to the slab width and the slab length, the slab length greater than the slab width, the slab width greater than the first slab thickness; a first set of regions comprising a first mineral mix having greater than 50% of a first low crystalline silica material; a second set of regions comprising a second mineral mix having greater than 50% of a second low crystalline silica material, wherein the processed slab has a crystalline silica content that is less than 50% by weight (wt %).

22. The processed slab of claim 21 , wherein the first mineral mix has a first low crystalline silica material of 50 wt % to 90 wt %, from 80 wt % to 90 wt %, from 50 wt % to 85 wt %, from 60 wt % to 85 wt %, or from 75 wt % to 85 wt %.

23. The processed slab of claim 21 , wherein the second mineral mix has a second low crystalline silica material of 50 wt % to 90 wt %, from 80 wt % to 90 wt %, from 50 wt % to 85 wt %, from 60 wt % to 85 wt %, or from 75 wt % to 85 wt %.

24. The processed slab of claim 21 , wherein the processed slab has a crystalline silica content less than or equal to 40 wt %, less than or equal to 30 wt %, less than or equal to 20 wt %, less than or equal to 10 wt %, less than or equal to 5 wt %, less than or equal to 2 wt %, less than or equal to 1 wt %, or about or equal to 0 wt %.

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