Mizusawa Kagaku Kogyo Kabushiki Kaisha

Tatuya Kondo

Hiroyuki Naito

Yujiro Sugahara

Kiyoshi Takai

A process for recovery of nitric acid comprising incorporating or absorbing waste nitric acid and/or a nitrate in an oil-absorbing inorganic carrier and forming a nitrate-carrier granule containing water in the form of a hydroxide, a hydrate or adsorption moisture in an amount sufficient to generate a vapor of nitric acid stably and being substantially non-sticky at a decomposition temperature of the nitrate; heating the formed granule while keeping the substantially non-sticky state in the granule to decompose the nitrate in the granule to a vapor of nitric acid; and recovering the generated vapor of nitric acid is disclosed. According to this process, nitric acid can be directly recovered from waste nitric acid or a nitrate in the form of a vapor of nitric acid without substantial generation of nitrogen oxide gases by using a cheap and easily available inorganic carrier.

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Tsuruoka, Japan

Tatuya Kondo