From BiblePortal Wikipedia

Fausset's Bible Dictionary [1]

City of Naphtali ( Joshua 19:38).

International Standard Bible Encyclopedia [2]

ı̄´urn ( בּרזל , barzel  ; σίδηρος , sı́dēros ): It is generally believed that the art of separating iron from its ores and making it into useful forms was not known much earlier than 1000 bc, and that the making of brass (bronze) antedates it by many centuries, in spite of the frequent Biblical references where brass and iron occur together. This conjecture is based upon the fact that no specimen of worked iron has been found whose antiquity can be vouched for. The want of such instruments, however, can be attributed to the ease with which iron corrodes. Evidence that iron was used is found, for example, in the hieroglyphics of the tomb of Rameses III, where the blades of some of the weapons are painted blue while others are painted red, a distinction believed to be due to the fact that some were made of iron or steel and some of brass. No satisfactory proof has yet been presented that the marvelous sculpturing on the hard Egyptian granite was done with tempered bronze. It seems more likely that steel tools were used. After the discovery of iron, it was evidently a long time in replacing bronze. This was probably due to the difficulties in smelting it. An old mountaineer once described to the writer the process of iron smelting as it was carried on in Mt. Lebanon in past centuries. As a boy he had watched his father, who was a smelter, operate one of the last furnaces to be fired. For each firing, many cords of wood, especially green oak branches, were used, and several days of strenuous pumping at the eight bellows was necessary to supply the air blast. As a result a small lump of wrought iron was removed from the bottom of the furnace after cooling. The iron thus won was carried to Damascus where it was made into steel by workers who kept their methods secret. This process, which has not been worked now for years, was undoubtedly the same as was used by the ancients. It is not at all unlikely that the Lebanon iron, transformed into steel, was what was referred to as "northern iron" in  Jeremiah 15:12 (the King James Version). In many districts the piles of slag from the ancient furnaces are still evident.

Aside from the limited supply of iron ore in Mt. Lebanon (compare  Deuteronomy 8:9 ), probably no iron was found in Syria and Palestine. It was brought from Tarshish ( Ezekiel 27:12 ) and Vedan and Jayan ( Ezekiel 27:19 ), and probably Egypt ( Deuteronomy 4:20 ).

The first mention of iron made in the Bible is in  Genesis 4:22 , where Tubal-Cain is mentioned as "the forger of every cutting instrument of brass and iron." It is likely that the Jews learned the art of metallurgy from the Phoenicians ( 2 Chronicles 2:14 ) (see Crafts ). Iron was used in Biblical times much as it is today. For a description of a smith at work see Ecclesiasticus 38:28. Huge city gates, overlaid with strips of iron ( Psalm 107:16;  Isaiah 45:2 ), held in place by crude square-headed nails ( 1 Chronicles 22:3 ), are still a familiar sight in the larger cities of Palestine and Syria ( Acts 12:10 ). Threshing instruments were made of iron ( Amos 1:3 ); so also harrows ( 2 Samuel 12:31 ), axes (ib;  2 Kings 6:6; see Ax), branding irons ( 1 Timothy 4:2 ), and other tools ( 1 Kings 6:7 ). There were iron weapons ( Numbers 35:16;  Job 20:24 ), armor ( 2 Samuel 23:7 ), horns ( 1 Kings 22:11 ), fetters ( Psalm 105:18 ), chariots ( Joshua 17:16 ), yokes ( Jeremiah 28:14 ), breastplates ( Revelation 9:9 ), pens (chisels) ( Job 19:24;  Jeremiah 17:1 ), sheets or plates ( Ezekiel 4:3 ), gods ( Daniel 5:4 ), weights ( 1 Samuel 17:7 ), bedsteads ( Deuteronomy 3:11 ). Iron was used extensively in building the temple. See Metals .

Figurative: "The iron furnace" is used metaphorically for affliction, chastisement (  Deuteronomy 4:20;  Ezekiel 22:18-22 ). Iron is also employed figuratively to represent barrenness (  Deuteronomy 28:23 ), slavery ("yoke of iron,"  Deuteronomy 28:48 ), strength ("bars of iron,"  Job 40:18 ), severity ("rod of iron,"  Psalm 2:9 ), captivity ( Psalm 107:10 ), obstinacy ("iron sinew,"  Isaiah 48:4 ), fortitude ("iron pillar,"  Jeremiah 1:18 ), moral deterioration ( Jeremiah 6:28 ), political strength ( Daniel 2:33 ), destructive power ("iron teeth,"  Daniel 7:7 ); the certainty with which a real enemy will ever show his hatred is as the rust returning upon iron (Ecclesiasticus 12:10 the King James Version, the Revised Version (British and American) "brass"); great obstacles ("walls of iron," 2 Macc 11:9).