Abstract
Difficulty is frequently experienced in obtaining accurate result in the determination of molybdenum in metals and alloys by the method based on the separation of MoS3. According to the Author's experience, the chief source of error ought to be an errornious adjustment of the acidity of the solution, taken before it is precipitated as MoS3. For instance, in the case of the precipitation in an acidic solution, if the solution is too slightly acid, H2S treatment causes a deep red coloured colloidal state of MoS3 in it, on the other hand, when the solution is too acid, the partical precipitation is obtained together with a blue colouration of the filtrate.
There are many papers published already on the special acidity in the MoS3 precipitation, but to know the safty range of acidity in which the precipitation goes to completion is highly disirable.
In this paper, the result obtained about the range of acidity for the complete precipitation of Mo in the form of MoS3 from an acid, or alkaline solution followed by dilute acid, with or without increased pressure, are given.
