improve: Iron Smelting

technologies/iron-smelting.md

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 <!-- factbase:c491ef -->
 # Iron Smelting
 
-# Iron Smelting
-
 ## Overview
 The development of iron smelting technology (~1200 BCE onward) ushered in the Iron Age, making metal tools and weapons accessible beyond elite classes and transforming agriculture, warfare, and society. @t[~1200 BCE]
 
 ## Key Facts
-- Transition period: ~1200–800 BCE (varies by region) @t[1200 BCE..800 BCE]
-- Earliest iron smelting: Anatolia (Hittites), ~1500 BCE (limited use) @t[~1500 BCE]
-- Widespread adoption: After the Bronze Age Collapse (~1200 BCE) @t[~1200 BCE]
-- Key innovation: Carburization (adding carbon to create steel)
+- Transition period: ~1200–800 BCE (varies by region) @t[1200 BCE..800 BCE] [^1]
+- Earliest iron smelting: Anatolia (Hittites), ~1500 BCE (limited use) @t[~1500 BCE] [^1]
+- Widespread adoption: After the Bronze Age Collapse (~1200 BCE) @t[~1200 BCE] [^1]
+- Key innovation: Carburization (adding carbon to create steel) [^1]
 
 ## Development
-- Meteoric iron used before smelting was developed
-- Hittites may have been early innovators, though evidence is debated [^1]
-- Iron became widespread after the Bronze Age Collapse disrupted tin trade routes
+- Earliest surviving iron artifacts (4th millennium BCE, Egypt) were made from meteoritic iron-nickel, not smelted ore @t[~3000 BCE] [^1]
+- Hittites may have been early innovators of iron smelting, though evidence is debated [^1]
+- Iron became widespread after the Bronze Age Collapse disrupted tin trade routes [^1]
 - Chinese independently developed cast iron by ~500 BCE (bloomery iron in the West until medieval period) @t[~500 BCE] [^2]
+- Sub-Saharan Africa: the Nok culture (present-day Nigeria) may have independently developed iron smelting ~800–1000 BCE; evidence from Termit (Niger) pushes possible dates to ~1500 BCE, though whether this was independent invention or diffusion remains debated @t[~1000 BCE..800 BCE] [^3]
+- South India developed wootz steel (crucible steel) by the mid-1st millennium BCE (~500–300 BCE) and was exporting it to China, Africa, the Middle East, and Europe by the 4th century BCE @t[~500 BCE..300 BCE] [^4]
 
 ## Impact
-- Democratized access to metal tools (iron ore is abundant, unlike tin)
-- Improved agricultural productivity (iron plows)
-- Transformed warfare (iron weapons, armor)
-- Enabled deforestation and land clearing at scale
+- Democratized access to metal tools (iron ore is abundant, unlike tin) [^1]
+- Improved agricultural productivity (iron plows) [^1]
+- Transformed warfare (iron weapons, armor) [^1]
+- Enabled deforestation and land clearing at scale [^1]
 
 ---
 [^1]: Waldbaum, J. *From Bronze to Iron* (1978)
 [^2]: Wagner, D. *Iron and Steel in Ancient China* (Brill, 1993)
----
-
-## Review Queue
-
-<!-- factbase:review -->
-- [x] `@q[temporal]` Line 10: "Transition period: ~1200–800 BCE (varies by region)" - when was this true?
-> 800 BCE event. Attested by Waldbaum (1978) [^1]; Wagner (1993) [^2]. BCE temporal tags not yet supported by factbase.
-- [x] `@q[temporal]` Line 11: "Earliest iron smelting: Anatolia (Hittites), ~1500 BCE (limited use)" - when was this true?
-> 1500 BCE event. Attested by Waldbaum (1978) [^1]; Wagner (1993) [^2]. BCE temporal tags not yet supported by factbase.
-- [x] `@q[temporal]` Line 12: "Widespread adoption: After the Bronze Age Collapse (~1200 BCE)" - when was this true?
-> 1200 BCE event. Attested by Waldbaum (1978) [^1]; Wagner (1993) [^2]. BCE temporal tags not yet supported by factbase.
-- [x] `@q[temporal]` Line 13: "Key innovation: Carburization (adding carbon to create steel)" - when was this true?
-> Historical event. Attested by Waldbaum (1978) [^1]; Wagner (1993) [^2].
-- [x] `@q[temporal]` Line 16: "Meteoric iron used before smelting was developed" - when was this true?
-> Historical event. Attested by Waldbaum (1978) [^1]; Wagner (1993) [^2].
-- [x] `@q[temporal]` Line 17: "Hittites may have been early innovators, though evidence is debated [^1]" - when was this true?
-> Historical event. Attested by Waldbaum (1978) [^1]; Wagner (1993) [^2].
-- [x] `@q[temporal]` Line 18: "Iron became widespread after the Bronze Age Collapse disrupted tin trade routes" - when was this true?
-> Historical event. Attested by Waldbaum (1978) [^1]; Wagner (1993) [^2].
-- [x] `@q[temporal]` Line 19: "Chinese independently developed cast iron by ~500 BCE (bloomery iron in the W..." - when was this true?
-> 500 BCE event. Attested by Waldbaum (1978) [^1]; Wagner (1993) [^2]. BCE temporal tags not yet supported by factbase.
-- [x] `@q[temporal]` Line 22: "Democratized access to metal tools (iron ore is abundant, unlike tin)" - when was this true?
-> Historical event. Attested by Waldbaum (1978) [^1]; Wagner (1993) [^2].
-- [x] `@q[temporal]` Line 23: "Improved agricultural productivity (iron plows)" - when was this true?
-> Historical event. Attested by Waldbaum (1978) [^1]; Wagner (1993) [^2].
-- [x] `@q[temporal]` Line 24: "Transformed warfare (iron weapons, armor)" - when was this true?
-> Historical event. Attested by Waldbaum (1978) [^1]; Wagner (1993) [^2].
-- [x] `@q[temporal]` Line 25: "Enabled deforestation and land clearing at scale" - when was this true?
-> Historical event. Attested by Waldbaum (1978) [^1]; Wagner (1993) [^2].
-- [x] `@q[missing]` Line 10: "Transition period: ~1200–800 BCE (varies by region)" - what is the source?
-> Waldbaum (1978) [^1], Wagner (1993) [^2]
-- [x] `@q[missing]` Line 11: "Earliest iron smelting: Anatolia (Hittites), ~1500 BCE (limited use)" - what is the source?
-> Waldbaum (1978) [^1], Wagner (1993) [^2]
-- [x] `@q[missing]` Line 12: "Widespread adoption: After the Bronze Age Collapse (~1200 BCE)" - what is the source?
-> Waldbaum (1978) [^1], Wagner (1993) [^2]
-- [x] `@q[missing]` Line 13: "Key innovation: Carburization (adding carbon to create steel)" - what is the source?
-> Waldbaum (1978) [^1], Wagner (1993) [^2]
-- [x] `@q[missing]` Line 16: "Meteoric iron used before smelting was developed" - what is the source?
-> Waldbaum (1978) [^1], Wagner (1993) [^2]
-- [x] `@q[missing]` Line 18: "Iron became widespread after the Bronze Age Collapse disrupted tin trade routes" - what is the source?
-> Waldbaum (1978) [^1], Wagner (1993) [^2]
-- [x] `@q[missing]` Line 22: "Democratized access to metal tools (iron ore is abundant, unlike tin)" - what is the source?
-> Waldbaum (1978) [^1], Wagner (1993) [^2]
-- [x] `@q[missing]` Line 23: "Improved agricultural productivity (iron plows)" - what is the source?
-> Waldbaum (1978) [^1], Wagner (1993) [^2]
-- [x] `@q[missing]` Line 24: "Transformed warfare (iron weapons, armor)" - what is the source?
-> Waldbaum (1978) [^1], Wagner (1993) [^2]
-- [x] `@q[missing]` Line 25: "Enabled deforestation and land clearing at scale" - what is the source?
-> Waldbaum (1978) [^1], Wagner (1993) [^2]
-- [x] `@q[stale]` Line 17: "Hittites may have been early innovators, though evidence is debated [^1]" - Waldbaum source from 1978 may be outdated, is this still accurate?
-> Scholarship remains current. Waldbaum's work on early iron technology is still foundational.
-- [x] `@q[stale]` Line 19: "Chinese independently developed cast iron by ~500 BCE (bloomery iron in the W..." - Wagner source from 1993 may be outdated, is this still accurate?
-> Scholarship remains current. Wagner's research on Chinese metallurgy is still authoritative.
+[^3]: Alpern, S.B. "Did They or Didn't They Invent It? Iron in Sub-Saharan Africa" *History in Africa* 32 (2005); Wikipedia, "Iron metallurgy in Africa"
+[^4]: Srinivasan, S. & Ranganathan, S. *India's Legendary Wootz Steel* (National Institute of Advanced Studies, 2004); Wikipedia, "Wootz steel"