Category:Bronzes: Difference between revisions

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(Created page with "Bone black (also called bone char) is a granular substance composed primarily of calcium carbonate, calcium phosphate and some charcoal. It is dense, having a specific gravity near π. ==Uses== * It is used as a filtration agent similar to charcoal and activated carbon. Bone black is particularly good at removing fluorides and heavy metals (including copper and zinc). * Feedstock for phosphoric acid ==Production== ===General method=== Calcine c...")
 
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Bone black (also called bone char) is a granular substance composed primarily of [[calcium carbonate]], [[calcium phosphate]] and some [[charcoal]]. It is dense, having a specific gravity near π.
Bronzes are [[copper]] [[:Category:alloys|alloys]] generally containing 80-95% [[copper]] and the rest [[tin]] or other metals. Bronzes generally have a lower melting point (~950°C) than copper (1085°C), making them easier to cast. Compared to copper, bronze is a superior tool material because it is less prone to work hardening, corrosion, or oxidation.
==Uses==
* It is used as a filtration agent similar to charcoal and activated carbon. Bone black is particularly good at removing fluorides and heavy metals (including [[copper]] and [[zinc]]).
* Feedstock for [[phosphoric acid]]


==Production==
* The coefficient of thermal expansion of bronzes is (in general) between 17.5 and 18.
===General method===
==Compositions==
Calcine clean bone fragments at over 500°C in a reducing environment.
* "Modern" bronze is 88% [[copper]] and 12% [[tin]]
* "Classical" cast bronze is 90/10 Cu/Sn
* "Mild bronze" is 94/6, and was used for sheet stock
* "Bell metal" is 72/28
* "Phosphor bronze" is copper/tin/lead/phosphorus, and used to make springs.


===Charcoal reduction===
[[Category:Alloys]][[Category:Structural Materials]]
In this method additional charcoal is added to the environment to assure a reducing environment
====Tools and materials====
# one unit by volume clean dry animal bones
# one unit by volume [[water]]
# one tenth unit by volume of [[charcoal]]
# one lidded crucible
# one pot
# one [[:Category:Kiln |kiln]] capable of reaching 500°C
# [[:Category:Fuels|fuel]] for kiln
 
====Prep====
# Place water in pot
# Crush bones into thin slivers
# Place crushed bones in crucible
# Place charcoal in crucible
# Place lid on crucible
====Calcine====
# Place crucible in kiln
# Wait until entire mixture has reached 500°C
# Remove crucible from kiln
# Let stand until cool
====Separate====
# Place contents of crucible in pot with water
# Mix thoroughly
# Let stand
# Skim and discard all floating material (charcoal)
# Filter and discard solution (water)
# Dry powder
#:Check: resultant powder should be grey/brown. If it is black, it is under-fired. If it is grey/white, it is over-fired.
 
==See Also==
* [[apatite]]
[[Category:Crude Mixtures]]

Latest revision as of 20:22, 2 December 2024

Bronzes are copper alloys generally containing 80-95% copper and the rest tin or other metals. Bronzes generally have a lower melting point (~950°C) than copper (1085°C), making them easier to cast. Compared to copper, bronze is a superior tool material because it is less prone to work hardening, corrosion, or oxidation.

  • The coefficient of thermal expansion of bronzes is (in general) between 17.5 and 18.

Compositions

  • "Modern" bronze is 88% copper and 12% tin
  • "Classical" cast bronze is 90/10 Cu/Sn
  • "Mild bronze" is 94/6, and was used for sheet stock
  • "Bell metal" is 72/28
  • "Phosphor bronze" is copper/tin/lead/phosphorus, and used to make springs.

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