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AssigneeMitsubishi Rayon Co., Ltd.
InventorsHideyasu Takezawa, Toru Kuroda, Seiichi Kawato, Masanori Nitta
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A molybdenum-based precipitate is prepared according to a process including the first step of forming a crude precipitate by pH adjustment to 6.5 or less in the presence of an alkali metal compound, and the second step of dissolving the crude precipitate in aqueous ammonia and forming a precipitate by pH adjustment to 6.5 or less. Then, the resulting molybdenum-based precipitate is washed with an acid aqueous solution having a pH of 6.5 or less and containing not less than 0.01 mole/L of ammonium root. Thus, a change in average particle diameter can be suppressed and good workability can be achieved, so that a molybdenum-based precipitate having a high purity and a desired average particle diameter can be obtained.
A process for the preparation of a precipitate containing at least molybdenum and an element A (in which A is at least one element of phosphorus and arsenic), the process including:
A process for the preparation of a precipitate which includes the step of washing a precipitate containing at least molybdenum and an element A (in which A is at least one element of phosphorus and arsenic) with an acid aqueous solution, wherein the acid aqueous solution has a pH of 6.5 or less and contains not less than 0.01 mole/L of ammonium root.
A process for the preparation of a molybdenum-based catalyst represented by the following general formula (1):
Dependencies are inferred from the claim text.