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The Sumihira Tatara A week in images at Manabe Sumihira's Zuku-oshi Tatara  Mr.Manabe uses akome-satetsu, a type of complex iron ore that
includes various types of oxides (Fe3O4, Fe2O3, FeO), a
considerable amount of silica oxide as well as other important
impurirites. Most iron ores available for industrial purposes are
closer to what is called masame-satetsu in Japan, composed mainly of the overly strong Fe3O4, difficult to reduce in a continuous process tatara. First,
the iron ore must be sifted and prepared into pellets to help the
reduction process and concentration of the liquified iron into heavier
lumps that flow more efficiently to accumulate at the bottom of the
furnace. This involves the preparation of very fine charcoal powder, a
very time consumming and dirty job  performed
by apprentices, or me in this case. I processed over 100kg of charcoal
in order to sort it through five different mesh sizes and isolate the
powder. I also had to produce some by crushing fine charcoal in
order to meet our required quantities. Meanwhile, the furnace is repaired and prepared for the next smelt. This involves patching with refractory cement, de-icing remaining slag and iron on the furnace walls, putting it together.  It is important to dry the furnace by pouring a good load of hot coals let to burn free for an entire night in order to make sure the furnace is free of any moisture... or it could explode!  Pellets are prepared ideally in advance to be allowed to dry, but M.Manabe has taken the habit of geting this done the same day without any negative effect he could notice.   
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