Engineered stone

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Engineered stone is a composite material made of crushed stone bound together by an adhesive to create a solid surface. The adhesive is most commonly polymer resin, with some newer versions using cement mix. This category includes engineered quartz (SiO2), polymer concrete and engineered marble stone. [1] The application of these products depends on the original stone used. For engineered marbles the most common application is indoor flooring and walls, while the quartz based product is used primarily for kitchen countertops [2] as an alternative to laminate or granite. [3] Related materials include geopolymers and cast stone. Unlike terrazzo, the material is factory made in either blocks or slabs, cut and polished by fabricators, and assembled at the worksite.

Contents

Engineered stone kitchen countertops with undermount sink and cooktop installed. Tops are cut and polished at the fabricator's shop. Engineered stone countertop.jpg
Engineered stone kitchen countertops with undermount sink and cooktop installed. Tops are cut and polished at the fabricator's shop.

Engineered stone is also commonly referred to as agglomerate or agglomerated stone, the last term being that recognised by European Standards (EN 14618), although to add to the terminological confusion, this standard also includes materials manufactured with a cementitious binder.[ citation needed ] The quartz version (which end consumers are much more likely to directly deal with) is commonly known as 'quartz surface' or just 'quartz'. [4]

Manufacturing equipment

Breton S.P.A., a privately held company of Treviso, Italy, that developed the large-scale Breton method in 1960s, [1] is the dominant supplier of equipment for making engineered stone.[ citation needed ] Although Breton was the original manufacturer of moulding equipment and still holds multiple international patents on the process, there are now several other companies producing similar machinery.

Composition

99.9% pure silica in grits and powder form constitutes 90–93% of the body by weight dispersed in a matrix of unsaturated polyester resin (7–10%)  mixed with peroxide catalyst and cobalt accelerator which facilitates the curing of the thermoset at ambient temperature. The cured material is normally kept for 24–48 hours before polishing and finishing absorbers are also dosed into the chemical mix to inhibit the discoloration as a result of reaction of unsaturated polyester resin with UV light. Engineered quartz stones manufactured by using unsaturated polyester resins are characterized by low water absorption, superior chemical durability, high hardness, flexural strength and good thermal shock resistance compared to granite and marble. [5]

Process

Compaction by vibrocompression vacuum process uses elastomeric molds in which a crushed stone/resin mix is cast on a moving belt. The mixture of approximately 93% stone aggregates and 7% polyester resin by weight (66% quartz and 34% resin by volume) is heated and compressed under vacuum in a large press. The vibration helps compact the mixture and results in an isotropic slab with virtually no porosity. [1] Engineered stone is then processed in basically the same manner as its natural counterpart.

Some companies import boulders themselves to crush into agglomerates (stone powders) of various grain size for their products, others simply buy already-crushed stone powders.

Properties

Engineered stone is typically worked in the same way as natural stone using a water jet cutter or a diamond blade. This is in contrast with solid surface materials which can be cut with regular saws. [6]

The material can be produced in either 12 mm, 20 mm or 30 mm thicknesses. The most common slab format is 3040 mm x 1440 mm for Quartz and 3050 mm x 1240 mm for Breton-based marbles, but other sizes like 3040 mm x 1650 mm are produced according to market demand.

Engineered stone is non porous, [7] more flexible, and harder than many types of natural stone. Since it has a uniform internal structure, it does not have hidden cracks or flaws that may exist in natural stone and also has a color/pattern consistency from slab to slab. [8] Polyester resin binding agents allow some flexibility, preventing cracking under flexural pressure. But, the binding agents often continue to harden, leading to a loss of flexural strength over time. The polyester resins are not completely UV stable and engineered stone should not be used in outdoor applications. [9] Continuous exposure to UV can cause discoloration of the stone, and breakdown of the resin binder.

The material is sometimes damaged by direct application of heat. Quartz engineered stone is less heat resistant than other stone surfaces including most granite, marble and limestone; but is not affected by temperatures lower than 150 °C (300 °F). Quartz engineered stone can be damaged by sudden temperature changes. Manufacturers recommend that hot pots and pans never be placed directly on the surface, and that a hot pad or trivet is used under portable cooking units.

When used as floor tiles, care is required in ensuring compatibility with the adhesive used. Reaction resin adhesives and rapid drying cementitious adhesives are generally successful, but bond failure or discoloration can occur with other cementitious adhesives. Additionally, agglomerate stone tiles are more sensitive to both thermal expansion and contraction and to dampness from underlying screeds, necessitating the inclusion of movement joints at a higher frequency than for stone or ceramic floor tiles (see for example British Standard BS 5385-5: 2011) and verification by testing of the dryness of underlying layers.

Difference between marble and quartz

Although both the marble- and quartz-based engineered stones are created through a similar process, and multiple companies produce both at the same time, there are distinct differences in their properties and applications.

Marble is a relatively soft material which is prone to scratching, but simple to maintain. Typically it can be repeatedly polished until it becomes too thin. Marble is much more common and accessible around the world, and comes in a wider variety, which gives its engineered counterpart a significant edge in pricing, and more variety in pattern and colors. Engineered marble is typically used as flooring materials for large commercial projects such as hotels, shopping centers, business lobbies, where it combines the attractive appearance of marble with budget-friendly cost and reliable delivery time.

Quartz is a much harder material. The Mohs scale hardness of marble is roughly 3, whereas that of quartz is around 7. This makes it much more resistant to scratching, however it also makes re-polishing and general processing a more difficult task, which is why it is most commonly used for kitchen counter tops, where the value added through processing can offset its considerably higher cost.

There is also a difference between quartz and quartzite, which may be confused because of the similarities in the name. Quartz countertops are man-made even though quartz is a natural material. Quartzite countertops on the other hand are natural and they are considered to be a high end countertop material. [7]

Market development

Italy was the most dominant country in the supply of engineered stone products from the 1980s until the early 2000s, especially in engineered marble. The growth of the Chinese economy has changed the market drastically as China now has the most producers and largest overall quantity produced. There are estimated to be more than 100 engineered stone suppliers in China alone. India also has roughly 40 slab producing units as of December 2012. The original companies that operate Breton machines such as the Italian companies, Quarella, Santa Margherita and the Taiwanese company Romastone remain the most recognizable brands for marble. The private Spanish company Cosentino brand Silestone and the public Israeli company Caesarstone are the most recognizable brands for quartz, as well as Totem Quartz, an Iranian company which has a huge market in the middle east and Central Asia. Gulfstone, an Oman-based company, is the only producer of engineered quartz stone in the GCC. China is now probably the largest market for engineered marble due to new construction projects, while engineered quartz is primarily sold in North America and Europe as high end residential kitchen counter tops. [ citation needed ]

Health issues

As with any silica-containing stone, silicosis can result from breathing dust produced when cutting or processing engineered stone made with quartz. The risk of inhaling quartz dust can be mitigated by taking appropriate safety precautions. [10] [11] Risk of silicosis is high when little or no safety precautions or protective equipment are used. This may occur in small shops or in countries where the industry is not regulated or monitored. [12] [13]

In Australia, a National Dust Diseases Taskforce was established in July 2019. [14] In Western Australia, legislation was introduced to support the early detection of silicosis caused by engineered stone. [15] Medical practitioners in Western Australia are advised to follow strict guidelines for the health surveillance of at risk workers. [16] In February 2023 Australian trade unions called for banning the importation of engineered stone into Australia. [17] In December of the same year, Australia became the first country to ban engineered stone in response to workers developing silicosis. [18]

In California, 77 workers at quartz countertop fabrication shops have been diagnosed with silicosis as of July, 2023. Inspections by safety officials in 2019 and 2020 showed that 72% of these shops were out of compliance with federal silica dust exposure standards. The state's Occupational Safety & Health Standards Board approved emergency regulations in December, 2023. [19]

See also

Related Research Articles

<span class="mw-page-title-main">Marble</span> Type of metamorphic rock

Marble is a metamorphic rock consisting of carbonate minerals (most commonly calcite (CaCO3) or dolomite (CaMg(CO3)2)) that have recrystallized under the influence of heat and pressure. It has a crystalline texture, and is typically not foliated (layered), although there are exceptions.

<span class="mw-page-title-main">Silicon dioxide</span> Oxide of silicon

Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula SiO2, commonly found in nature as quartz. In many parts of the world, silica is the major constituent of sand. Silica is abundant as it comprises several minerals and synthetic products. All forms are white or colorless, although impure samples can be colored.

<span class="mw-page-title-main">Soapstone</span> Talc-bearing metamorphic rock

Soapstone is a talc-schist, which is a type of metamorphic rock. It is composed largely of the magnesium rich mineral talc. It is produced by dynamothermal metamorphism and metasomatism, which occur in the zones where tectonic plates are subducted, changing rocks by heat and pressure, with influx of fluids, but without melting. It has been a medium for carving for thousands of years.

<span class="mw-page-title-main">Terrazzo</span> Cementitious composite material, usually used in flooring

Terrazzo is a composite material, poured in place or precast, which is used for floor and wall treatments. It consists of chips of marble, quartz, granite, glass, or other suitable material, poured with a cementitious binder, polymeric, or a combination of both. Metal strips often divide sections, or changes in color or material in a pattern. Additional chips may be sprinkled atop the mix before it sets. After it is cured it is ground and polished smooth or otherwise finished to produce a uniformly textured surface. "Terrazzo" is also often used to describe any pattern similar to the original terrazzo floors.

<span class="mw-page-title-main">Quartzite</span> Hard, non-foliated metamorphic rock

Quartzite is a hard, non-foliated metamorphic rock which was originally pure quartz sandstone. Sandstone is converted into quartzite through heating and pressure usually related to tectonic compression within orogenic belts. Pure quartzite is usually white to grey, though quartzites often occur in various shades of pink and red due to varying amounts of hematite. Other colors, such as yellow, green, blue and orange, are due to other minerals.

<span class="mw-page-title-main">Silicosis</span> Pneumoconiosis caused by inhalation of silica, quartz or slate particles

Silicosis is a form of occupational lung disease caused by inhalation of crystalline silica dust. It is marked by inflammation and scarring in the form of nodular lesions in the upper lobes of the lungs. It is a type of pneumoconiosis. Silicosis, particularly the acute form, is characterized by shortness of breath, cough, fever, and cyanosis. It may often be misdiagnosed as pulmonary edema, pneumonia, or tuberculosis. Using workplace controls, silicosis is almost always a preventable disease.

<span class="mw-page-title-main">Fiber cement siding</span> Building material used to cover the exterior of a building

Fiber cement siding is a building material used to cover the exterior of a building in both commercial and domestic applications. Fiber cement is a composite material made of cement reinforced with cellulose fibers. Originally, asbestos was used as the reinforcing material but, due to safety concerns, that was replaced by cellulose in the 1980s. Fiber cement board may come pre-painted or pre-stained or can be done so after its installation.

<span class="mw-page-title-main">Dimension stone</span> Natural stone that has been finished to specific sizes and shapes

Dimension stone is natural stone or rock that has been selected and finished to specific sizes or shapes. Color, texture and pattern, and surface finish of the stone are also normal requirements. Another important selection criterion is durability: the time measure of the ability of dimension stone to endure and to maintain its essential and distinctive characteristics of strength, resistance to decay, and appearance.

<span class="mw-page-title-main">Countertop</span> Horizontal work surface

A countertop, also counter top, counter, benchtop, worktop or kitchen bench, bunker is a raised, firm, flat, and horizontal surface. They are built for work in kitchens or other food preparation areas, bathrooms or lavatories, and workrooms in general. The surface is frequently installed upon and supported by cabinets, positioned at an ergonomic height for the user and the particular task for which it is designed. A countertop may be constructed of various materials with different attributes of functionality, durability and aesthetics, and may have built-in appliances, or accessory items relative to the intended application.

<span class="mw-page-title-main">Fumed silica</span> Silicon dioxide with branched chains on micro scale

Fumed silica, also known as pyrogenic silica because it is produced in a flame, consists of microscopic droplets of amorphous silica fused into branched, chainlike, three-dimensional secondary particles which then agglomerate into tertiary particles. The resulting powder has an extremely low bulk density and high surface area. Its three-dimensional structure results in viscosity-increasing, thixotropic behavior when used as a thickener or reinforcing filler.

<span class="mw-page-title-main">Artificial stone</span>

Artificial stone is a name for various synthetic stone products produced from the 18th century onward. Uses include statuary, architectural details, fencing and rails, building construction, civil engineering work, and industrial applications such as grindstones.

<span class="mw-page-title-main">Sandblasting</span> Method of marking or cleaning a surface

Sandblasting, sometimes known as abrasive blasting, is the operation of forcibly propelling a stream of abrasive material against a surface under high pressure to smooth a rough surface, roughen a smooth surface, shape a surface or remove surface contaminants. A pressurised fluid, typically compressed air, or a centrifugal wheel is used to propel the blasting material. The first abrasive blasting process was patented by Benjamin Chew Tilghman on 18 October 1870.

<span class="mw-page-title-main">Concrete grinder</span> Machine for polishing or grinding hardened concrete

A concrete grinder is an abrasive machine for polishing or grinding hardened concrete. Concrete grinders can come in many configurations, the most common being a hand-held general purpose angle grinder, but it may be a specialized tool for countertops or floors. Angle grinders are small and mobile, and allow one to work on harder to reach areas and perform more precise work.

<span class="mw-page-title-main">Solid surface</span> Artificial material used for countertops

Solid surface is a man-made material usually composed of a combination of alumina trihydrate (ATH), acrylic, epoxy or polyester resins and pigments. It is most frequently used for seamless countertop installations.

<span class="mw-page-title-main">Flexible stone veneer</span>

Flexible stone veneer is a veneer with a layer of stone 1 to 5 mm thick. Flexible stone veneers should not be confused with traditional stone veneers. It is used for both interior and exterior and especially where bending to a curved surface is required. Flexible stone veneers are made from various types of slate, schist, or marble.

Caesarstone Ltd., or Caesarstone, is a publicly traded company that engages in the production and marketing of quartz surfaces used for kitchen countertops, vanity tops, flooring, wall cladding and general interior design. The company was founded in 1987 and is traded on the NASDAQ in New York (CSTE). Headquarters are located in Kibbutz Sdot Yam in Israel. Production facilities are in Israel, the United States and India with third party manufactured product sourced from China. Its products are sold in approximately 50 countries around the world through a network of 6 subsidiaries and numerous distributors.

<span class="mw-page-title-main">Conservation and restoration of ceramic objects</span> Preservation of heritage collections

Conservation and restoration of ceramic objects is a process dedicated to the preservation and protection of objects of historical and personal value made from ceramic. Typically, this activity of conservation-restoration is undertaken by a conservator-restorer, especially when dealing with an object of cultural heritage. Ceramics are created from a production of coatings of inorganic, nonmetallic materials using heating and cooling to create a glaze. These coatings are often permanent and sustainable for utilitarian and decorative purposes. The cleaning, handling, storage, and in general treatment of ceramics is consistent with that of glass because they are made of similar oxygen-rich components, such as silicates. In conservation ceramics are broken down into three groups: unfired clay, earthenware or terracotta, and stoneware and porcelain.

<span class="mw-page-title-main">Bretonstone</span>

Bretonstone, also known as vibro-compression under vacuum, is a formerly-patented technology invented in the early-1970s by Breton S.p.A.

Sand composites, most commonly sand reinforced polyester composites (SPCs), involve a building material with sand acting as reinforcement in the composite. Pioneers in using sand reinforced composites include German business men Gerhard Dust and Gunther Plötner, who made sand reinforced composite bricks with polyester resin and hardener to provide emergency relief housing for those affected by the 2010 earthquake in Haiti. Sand was used in the composites because of its abundance and ease in obtaining.

Akemi GmbH is a company in the chemical industry which is active worldwide. Its headquarters are in Nuremberg in Germany and its core competence is the manufacturing of two-component adhesive systems. The chemical-technical specialist factory manufactures adhesives, fillers as well as cleaning and care products for the natural stone sector. In addition, it produces fillers and repair materials, sealants, protective coatings, varnishes as well as cleaning and car care products for the automotive branch.

References

  1. 1 2 3 Sara Black (August 1, 2013). "Cast polymer categories". compositesworld.com. Retrieved July 9, 2018.
  2. ↑ "Q&A: Which countertop material is toughest?". Consumer Reports. July 9, 2007. Retrieved July 9, 2018.
  3. ↑ Jon Coile (May 27, 2017). "Open floor plans and parking among buyers' biggest desires". The Washington Post . Archived from the original on 10 July 2018. Retrieved July 9, 2018– via PressReader.
  4. ↑ Deborah K. Dietsch (January 21, 2017). "Quartz supplants granite as people's choice for countertops". The Washington Post . Archived from the original on 10 July 2018. Retrieved July 9, 2018– via PressReader.
  5. ↑ Santos, G. G.; Crovace, M. C.; Zanotto, E. D. (15 June 2019). "New engineered stones: Development and characterization of mineral-glass composites". Composites Part B: Engineering. 167: 556–565. doi:10.1016/j.compositesb.2019.03.010. S2CID   115151206.
  6. ↑ Spielman, Patrick (2002). The New Scroll Saw Handbook. Sterling Publishing Company, Inc. p. 298. ISBN   0-8069-7877-5.
  7. 1 2 Daniel DiClerico (April 9, 2016). "What Is the Difference Between Quartz and Quartzite?". Consumer Reports . Retrieved July 9, 2018.
  8. ↑ Jason Kamery (January 1, 2017). "One-on-One with Sophie Lubin". stoneworld.com. Retrieved July 8, 2018.
  9. ↑ Alexia (June 9, 2018). "Pros and Cons of Quartz Countertops - Engineered Quartz Countertops". renowaze.com. Archived from the original on June 28, 2018. Retrieved July 9, 2018.
  10. ↑ "Hazard Alert Worker Exposure to Silica during Countertop Manufacturing, Finishing and Installation" (PDF). osha.gov. Occupational Safety and Health Administration . Retrieved April 2, 2016.
  11. ↑ Atkin, Michael (16 September 2019). "Silicosis surge prompts more calls for a ban on engineered stone products". ABC News. Australian Broadcasting Corporation. Retrieved 7 December 2019. There are now 260 cases across Australia, with 166 in Queensland, 61 in Victoria, 23 in NSW, 5 in Tasmania, 3 in WA, and 1 each in the ACT and SA. In SA there are also 66 cases where workers need specialist follow-up.
  12. ↑ Barry Meier (April 1, 2016). "Popular Quartz Countertops Pose a Risk to Workers". The New York Times . Retrieved April 2, 2016.
  13. ↑ Rose, Cecile; Heinzerling, Amy; Patel, Ketki; Sack, Coralynn; Wolff, Jenna; Zell-Baran, Lauren; Weissman, David; Hall, Emily; Sooriash, Robbie; McCarthy, Ronda B.; Bojes, Heidi; Korotzer, Brian; Flattery, Jennifer; Weinberg, Justine Lew; Potocko, Joshua; Jones, Kirk D.; Reeb-Whitaker, Carolyn K.; Reul, Nicholas K.; LaSee, Claire R.; Materna, Barbara L.; Raghu, Ganesh; Harrison, Robert (27 September 2019). "Severe Silicosis in Engineered Stone Fabrication Workers — California, Colorado, Texas, and Washington, 2017–2019". MMWR. Morbidity and Mortality Weekly Report. 68 (38): 813–818. doi:10.15585/mmwr.mm6838a1. PMC   6762184 . PMID   31557149.
  14. ↑ Ageing, Australian Government Department of Health and, National Dust Disease Taskforce, Australian Government Department of Health and Ageing, retrieved 2021-11-19
  15. ↑ "Media Statements - Health surveillance requirements for silica strengthened". Archived from the original on 2021-05-24. Retrieved 2021-05-24.
  16. ↑ "Silica Dust (respirable crystalline) – Health Surveillance – Guide for medical practitioners". Department of Mines, Industry Regulation and Safety Western Australia. 2019-10-01. Archived from the original on 2021-10-16. Retrieved 2021-11-19.
  17. ↑ "Jo didn't know her admin job could be dangerous, but after five years she was diagnosed with silicosis". ABC News. 2023-02-20. Retrieved 2023-10-11. https://www.australianunions.org.au/2023/10/24/unions-vote-to-ban-engineered-stone/
  18. ↑ Thorne, Leonie; Atkin, Michael (13 December 2023). "Australia makes world-first decision to ban engineered stone following surge in silicosis cases". ABC News. Retrieved 13 December 2023.
  19. ↑ Emily Alpert Reyes (December 14, 2023). "California embraces emergency rules to protect countertop workers from incurable silicosis". Los Angeles times.
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