An aquatic environment in Japan is claimed to have been progressively improved on the whole, but as to the water pollution caused by oily wastes there remain severe problems yet.
Oily waste water is roughly distinguished into two types. The one is a waste water containing free oil droplets, which can be recovered with a relatively simple treatment and effected with the use of physical procedures. Another is a waste water containing emulsified oil, which is so minutely dispersed as to need chemical or physico-chemical treatments.
So far, many apparatuses have been developed to treat such oily waste waters, but few compact machines are found that can remove oily contaminants effectively.
So, we studied such machines in detail, and the experience in mineral processing has enables us to develop a flotative oil separator which has a aeration mechanism like a flotation machine. Afterwards, we have developed a variant fitted with a static mixer instead of an aeration impeller. By applying these machines to the treatment of an effluent from the gas station's waste water ponds, many favorable performance data have been obtained.

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In order to offer a basic information for energy saving in raw materials treatment of the ferrochromium factories, an investigation was performed in regard to the cold bonded chromite pellet which doesn't need the firing at the time of agglomeration.
The experimental results showed that the cold bonded chromite pellet with portland cement has the strength required for the burden material of large electric furnace.
Mention is also made of a trial concerned with energy saving in grinding operation, by an application of the cold bonded pellet process.

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The separation of (K, NH₄) Cl from (K, NH₄)H₂PO₄ which were obtained from NH₄H₂PO₄-KCl double decomposition, was studied in the saturated solution by flotation.
The results indicated that lauryl amine acetate was suitable as a collector, then (K, NH₄)Cl was collected with the froth and (K, NH₄)H₂PO₄ into the tailing. The presence of impurities causing from phosphate rock resulted a decrease of flotation efficiency. The combination of collectors was also studied to improve the above problem.
The flotation was superior in separating of (K, NH₄)Cl from (K, NH₄)H₂PO₄ without discarding a mother liquid to a usual method using different solubility between them.

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