Reduction blowing - Kangenbuki

…The ore used in copper smelting often contains chalcopyrite and pyrite. Currently, pyrite and gangue are separated by flotation to produce a concentrate, but until the beginning of the 20th century, this technology did not exist, and copper was low-grade, so ore with high iron and sulfur content had to be smelted. For this reason, the ore was roasted before being put into the blast furnace, and a large amount of coke or coal was used in the blast furnace to maintain the furnace temperature by burning this fuel, and reduction was carried out inside the furnace. There was also a method of smelting with as little fuel as possible, where the ore was not roasted, but iron and sulfur were oxidized in the blast furnace and used as a heat source. The latter method was called raw ore smelting, as the ore was put in raw. …

*Some of the terminology that refers to "reduction blowing" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…銅製錬に用いる鉱石には黄銅鉱や黄鉄鉱が含まれている場合が多く，現在では浮遊選鉱によって黄鉄鉱や脈石を分離して精鉱としてから製錬を行うが，20世紀初めころまではこの技術がなく，したがって銅の品位は低く，鉄，硫黄分の高い鉱石を製錬しなければならなかった。そのため，溶鉱炉に入れる前に鉱石をあらかじめ焙焼（ばいしよう）し，溶鉱炉では，コークスや石炭を多く用いて，この燃料の燃焼により炉温を維持し，炉内で還元を行わせた還元吹と，鉱石を焙焼することなく，溶鉱炉で鉄と硫黄を酸化してこれを熱源とし，なるべく燃料を使わないで溶錬する方法とがあった。後者は鉱石を生のまま入れるので生鉱吹といわれた。…

※「還元吹」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報