User:Claywitch/sandbox

Article Evaluation
Ceramic glaze


 * Appears to be missing several citations
 * Can add information about leaded glazes being stable so long as they are bound 1-1 with silica, and dangers about barium glazes
 * Overall very informative and neutral

4/27/2020:

Will be making an addition to the Environmental Impacts section for the IFS final regarding barium carbonate ("Egyptian blue") toxicity and the substitution of strontium carbonate in making a similar blue glaze.

Semler, Daniel. (11/17/2009). "Leaving Bariumville: Replacing Barium Carbonate in Cone 10 Glazes". https://ceramicartsnetwork.org/daily/ceramic-glaze-recipes/glaze-chemistry/leaving-bariumville-replacing-barium-carbonate-in-cone-10-glazes/ Ceramic Arts Daily.


 * Describes experiments in replacing barium based glazes with strontium carbonate instead of barium carbonate
 * Experiments successful in gloss type glazes, not so successful in matte type glazes
 * as a rule only 75% of the original barium carbonate needs to be converted to strontium carbonate, and requires only 51% of the suggested whiting.
 * Reduction of whiting is needed as the results tend to be runnier in the substitute glaze.

PubChem. "Barium carbonate". pubchem.ncbi.nlm.nih.gov. Retrieved 2020-04-28.


 * Determined to be a safety hazard by the US National Institutes of Health
 * Acute toxicity when ingested
 * Attacks the nervous and cardiovascular systems, causes vomiting, diarrhea, convulsions, paralysis, and death.

"ATSDR - Public Health Statement: Barium". www.atsdr.cdc.gov. Retrieved 2020-04-28.


 * Takes a long time to break down and can linger in the environment.
 * Barium carbonate is a form of barium that can remain in soil and water for long periods of time, sometimes even combining with soil particles.
 * Dissolves in acid, making it possible to leach from barium-based glazes into food (not food safe)

5/6/2020:

PubChem. "Strontium carbonate". pubchem.ncbi.nlm.nih.gov. Retrieved 2020-05-07.


 * Unlike Barium carbonate, is not considered a serious health hazard.

Hansen, Tony. "Barium in Materials and Fired Glazes (hazard)". digitalfire.com. Retrieved 2020-05-07.


 * Barium carbonate is safest in frit form
 * Must be properly balanced (bonded equally to silica) in order to reduce leaching
 * The question of using barium-unique effects and food safety becomes an ethical one.
 * Some substitutions (especially in matte glazes) cannot be replicated.
 * Known as barium or Egyptian blue

DRAFT:

Barium carbonate and Strontium carbonate
Barium carbonate (BaCO3) is used to create a unique color known as barium blue. However, the ethical nature of using Barium carbonate for glazes on food contact surfaces has come into question. Barium poisoning by ingestion can result in convulsions, paralysis, digestive discomfort, and death. It is also somewhat soluble in acid, and can contaminate water and soil for long periods of time. These concerns have led to attempts to substitute Strontium carbonate (SrCO3) in glazes that require barium carbonate. Unlike Barium carbonate, Strontium carbonate is not considered a safety hazard by the NIH. Experiments in strontium substitution tend to be successful in gloss type glazes, although there are some effects and colors produced in matte type glazes that can only be obtained through use of barium.

To reduce the likelihood of leaching, barium carbonate is used in frit form and bound to silica in a 1:1 ratio. It is also recommended that barium glazes not be used on food contact surfaces.