FreeShip- Coal Slag Repurposed, Coal Glass, Black and Green/Gold, 20/40 mesh- (Rebate on orders 3 or more FreeShip items!)

DESCRIPTION-> Click "Learn more about this item" for article & instructions!
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30/60 mesh is the finest coal slag we carry, this 20/40 is one notch coarser than that. The coarser the coal slag the better it fits the "Black Beauty" brand name, being a deeper black with less green-gold particles and having more reflectivity.
As we find real uses for byproducts of both our industrial and post industrial civilization, such as creating all the uses we've found for crumb rubber made from the millions of rubber tires we make and wear out, we are attempting to do the same with byproducts of coal burning: finding uses for the slag that's a byproduct of burning coal at very high temperatures (~2500 F) in power plants:
Coal slag can be used as clinker in the manufacturing of portland cement which is used to make concrete in staggering amounts world wide. It is also used as a replacement aggregate in concrete masonry products. Two other large uses are as the grit that is used with asphalt in roofing materials and as a "sand blasting" grit.

Using a byproduct of coal burning in the arts can be a statement of recycling a tainted material (coal) that is turned into a safe material ("coal glass") and in a way is the ultimate form of recycling because at this time in human civilization, coal is a necessary "evil" if we are to have electricity. Hopefully someday we will have efficient enough solar panels, wind farms, or even cold fusion to generate the electricity we all use (the higher income among us need it to charge the batteries for that snazzy electric car!). Coal could be called an "organic rock". Almost all other rocks and minerals are inorganic. Transforming an organic rock into an inorganic one (see the ingredients below), is unique and makes it a material interesting to be used in art.
Coal Slag (aka "Boiler Slag", and "Clinker") are byproducts of electricity generating plants which use coal as a fuel to heat water into super high pressures to turn the blades of generators which produce electricity. Coal slag is one of two major recyclable byproducts from burning coal; Fly Ash and Coal Slag. An advantage of using these materials for whatever real purposes they can serve is that the end raw material does not have to be mined, it's there for the taking, both Coal Slag and Fly Ash.

Pulverized coal is a fine mesh coal powder which is blown into a boiler that works at very high temperatures (2,500 F). Coal can melt at that temperature and produce a byproduct (coal slag). The hot slag is subjected to quick cooling which turns it into a granulated glass. The glass is ground to various size particles and sold for some of the products mentioned above. A trade name for this graded coal slag when marketed as an abrasive blasting medium is "Black Beauty". It makes sharp, angular, glass-like particles. The constituents of it are (https://www.blackbeautyabrasives.com/application/files/5516/2981/9710/SPEC_BB_PRODUCT-original_2013.pdf }:
"Silicon Dioxide 48.78%
Aluminum Oxide 20.97%
Ferric Oxide 19.08%
Calcium Oxide 6.02%
Potassium Oxide 1.67%
Titanium Dioxide 0.94%
Magnesium Oxide 0.90%
Sodium Oxide 0.62%"
Some of its qualities for blasting are:
It has less than 0.1% microcrystalline silica, its hard (7 moh's), angular, has a consistent density, and has low dusting and friability (breaking). It is chemically inert, non-flammable, and it passes many safety specifications and regulations. It is relatively inexpensive, it's hardness is similar to quartz. More that 85% of total recycled coal slag is used in abrasive blasting and roofing granules.

How far have we come to the goal of making coal burning a zero emission fuel? Coal cleaning by 'washing' has been standard practice in developed countries for some time. It reduces emissions of ash and sulfur dioxide when the coal is burned. Electrostatic precipitators and fabric filters can remove 99% of the fly ash from the flue gases – these technologies are in widespread use.
Here is a current summary of how burning coal affects our environment and where the effort to achieve "zero or near zero carbon emissions" when burning the enormous world supply of coal:
{ https://world-nuclear.org/information-library/energy-and-the-environment/clean-coal-technologies.aspx }:
"Some 27% of primary energy needs are met by coal and 38% of electricity is generated from coal. About 70% of world steel production depends on coal feedstock. Coal is the world's most abundant and widely distributed fossil fuel source. However, each year burning coal produces over 14 billion tonnes of carbon dioxide (CO2), which is released to the atmosphere, most of this being from power generation. Development of new 'clean coal' technologies is attempting to address this problem so that the world's enormous resources of coal can be utilised for future generations without contributing to global warming. Much of the challenge is in commercialising the technology so that coal use would remain economically competitive despite the cost of achieving low, and eventually 'near-zero', emissions. The technologies are both costly and energy-intensive. As many coal-fired power stations approach retirement, their replacement gives much scope for 'cleaner' electricity. Alongside nuclear power and harnessing renewable energy sources, one hope for this is via 'clean coal' technologies, such as carbon capture and sequestration, also called carbon capture and storage...
It involves the geological storage of CO2, typically 2-3 km deep, as a permanent solution. However in its Energy Technology Perspectives 2014 the International Energy Agency notes: “CCS is advancing slowly, due to high costs and lack of political and financial commitment.” For its low-carbon 2 °C Scenario, “the rate of capture and storage must increase by two orders of magnitude” by 2025. By 2020 about 40 million tonnes of CO2 per year was being captured and sequestered from all sources...
Consequently the term 'clean coal' is increasingly being used for supercritical and ultra-supercritical coal-fired plants without CCS, running at 42-48% thermal efficiency. These are also known as high-efficiency low-emission (HELE) plants. The capital cost of ultra-supercritical (USC) HELE technology is 20-30% greater than a subcritical unit, but the higher efficiency reduces emissions and fuel costs to about 75% of subcritical plants. A supercritical steam generator operates at very high temperature (about 600 °C) and pressures (above 22 MPa), where liquid and gas phases of water are no longer distinct. In Japan and South Korea about 70% of coal-fired power comes from supercritical and ultra-supercritical plants."