$8.21
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--> For other related pozzolan concrete materials: <--
https://www.etsy.com/shop/NorthernWestStuff?ref=hdr_shop_menu&search_query=pozzolan
--> For other related cement materials: <--
https://www.etsy.com/shop/NorthernWestStuff?ref=hdr_shop_menu&search_query=cement
Not all sizes are pictured.
This has several uses, one as a ceramic raw material:
The online ceramics resource, DigitalFire, has meta kaolin under "Calcined Kaolin". It is used as a glaze suspension modifier and drying and shrinkage modifier for engobes, for example (whatever you're adding meta kaolin to will shrink less):
https://digitalfire.com/4sight/material/calcined_kaolin_167.html :
"...once raw kaolin percentages pass 20% in a [glaze] recipe shrinkages can be to high (causing crawling). In these cases substituting part of the raw kaolin for calcined material solves the problem, maintaining the chemistry of the glaze but reducing the shrinkage and cracking. In other words, by substituting some of the raw kaolin for calcined the physical properties of the glaze slurry can be controlled without impacting the chemistry of the fired melt. Of course, mixing the raw and calcined materials must take into account the LOI of the raw material...
Calcined kaolins are also useful in tuning the shrinkage and plasticity of slips (engobes) which are applied to wet, leather hard or dry ware. Engobes contain higher clay percentages than glazes and it is more important to control their drying shrinkage. As with glazes, they can be substituted for part of the regular kaolin to tune drying while maintaining fired properties...
Calcined kaolin has many other uses in ceramics. The key property it has is as a refractory material. It softens at about cone 35 and it thus useful in refractory castables and furniture, thermal insulation bodies, low expansion bodies, permeable ceramic compositions, and investment casting (see molochite)."
This particular metakaolin's manufacturer makes it specifically for pozzolan concrete, so it's more effective that brand "X" metakaolin. It's basically a pure clay that's been altered by heating, (called 'calcining') to remove the water content. Kaolins are the primary ingredient in porcelains and other ceramics. They tend to be pure and white, derived from the mineral kaolinite. They also find use as pozzolanic materials, partly because of their very small particle size and their chemical composition as aluminosilicates (aluminum disilicates). In basic terms a pozzolan makes a concrete flowable so it doesn't need compaction, making it less porous, densifying, strengthening, and reducing its cost.
Because many other pozzolans are dark colored (silica fume and fly ash are prime examples, they range from dark gray to brown), there exists a need for a pozzolan that is white or at least a light color. Calcined kaolins are one spectrum of materials that can fill that requirement. With advanced development there now exist many pozzolans that are a light color. There are also degrees of pozzolanic reactivity within the metakaolins.
Here is the Wiki article on metakaolin (which includes it's use as a pozzolan):
https://en.wikipedia.org/wiki/Metakaolin
Here is the website of a company that processes and sells both metakaolins and silica fume:
http://www.metakaolin.com/metakaolin/metakaolin-description
Heres a direct link to a pdf on metakalins:
http://www.metakaolin.com/metakaolin/metakaolin-description
There are several very informative pdfs on both metakaolin and silica fume. It's a good site for browsing.
Here are some additional links to pozzolans in general (and that list specific pozzolans):
1) https://gharpedia.com/blog/metakaolin-in-concrete-advantages-and-disadvantages-and-properties/
2) http://ferrocement.net/ferro/files/pozzolans-uwe.html
3) https://en.wikipedia.org/wiki/Pozzolan (the Wikipedia article on pozzolans)
How much to use in your concrete?
The manufacturer says (paraphrased):
Metakaolin should be used in terms of total cement weight at 5-15% loading rate.
Tests have shown that for optimum pozzolanic reactivity an 8% replacement is efficient. For prevention of ASR (Alkali-Silica Reaction) or efflorescence, as well as for enhanced durability in GFRC (Glass Fiber Reinforced Concrete), higher loading rates, up to 15% by weight of cement may prove to be most effective. In terms of concrete works, as always, good production and construction practices must be observed. Most importantly the water/cement ratio must be controlled.
That means however much portland cement (by weight) is in your mix, use 8% less portland cement, and replace that amount of omitted portland cement with metakaolin.
This is one of a series of listings I'm making for materials that can be used to enhance concrete and other cementitious mixes. I decided I wanted to migrate away from using polymers like epoxy, urethane, polyester, and other 'resins' for making castings. One reason was the high cost of resins and another was nuisance/safety factor of using them and inevitably the organic solvents you have to use to clean up drips and spills.
Over the years I'd already used gypsum cements as casting materials, but their physical properties (when cured) weren't always to my liking. Their surfaces are kind of 'dead' unless you add a coating, and they are brittle (low tensile strength). I'd also tried using concrete/mortar mixtures and was even more unhappy with their cured properties.
The property I wanted from a casting material was high hardness and tensile strength (above any existing cement), whiteness (so I could add pigment to make it any color I wanted), and a degree of translucency (about like marble). I started researching and discovered some things that led me to believe I could formulate my own casting material. Here are some of those things:
New gypsum cements that I wasn't familiar with, refractory cements I'd forgotten about, a casting system already formulated that was close to what I wanted: Forton MG, the fact that you can use elements of Forton outside the Forton MG system, new concrete types I wasn't familiar with, new concrete additives I wasn't familiar with, the concrete countertop industry, pozzolanic materials I wasn't familiar with.
I was aiming for a very specific results (some translucency, etc) and because the ingredients chosen for the particular results you're after can be very different from mine, it's impractical to go into any more detail because the interactions between ingredients are just too complex. If what you're trying to do varies by even a little from what I was trying to do, it's too difficult to predict what will work and what won't. I have listed links above for information on pozzolan materials, so you'll have a handy means starting research into whichever material you're interested in. And there is a wealth of sources about these materials on the internet above and beyond what I'm citing. (Please note that I have other materials in my shop which could fit into this 'cementitious mixes' category. To locate them do a shop search on "Colloidal", "Thixo", "Cab-o-sil", "Cement", "Kaolin", and "Calcium": Calcium Chloride is a cement accelerator and Calcium Sulfate Dihydrate (raw gypsum) is a pozzolan).-
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Nov 22, 2024
Well Packaged and Came as described.
Gustavo
Jul 3, 2024
Very happy to find this source for metakaolin since there are no pottery supply places in my area. Really appreciate the reasonable s&h and the speed of delivery!
Lillian Hopkins
Jun 3, 2024
Great product and communication. Fast shipping. Will definitely buy again.
Mariana
Mar 1, 2023
Well packaged, works great with my Concrete recipe, arrived very fast, seller very courteous, acknowledges my order almost immediately. Will continue to purchase this Metakaolin for my design projects.
Robin Parker
Feb 17, 2023
Well packaged, arrived on time, responded and shipped quickly. Ordered a second bag.
Robin Parker
