Mechanical Operations Questions

• All resistances during washing of cake
• Agglomeration of individual particles into clusters (flocs) is called flocculation. To prevent flocculation, the most commonly used dispersing agents are
• Temperature of the product during ultrafine grinding
• __________ mills are termed as impactors.
• Higher is the mesh number, smaller will be the aperture size of the screen. It means that the aperture size of a 200 mesh screen will be smaller than that of 20 mesh screen. This is valid for
• Size measurement of ultrafine particles can be best expressed in terms of
• Which is a secondary crusher for a hard & tough stone?
• Height of liquid in agitation tank is normally maintained equal to the tank diameter. However, if the tank is too tall and a large liquid hold up is desired, then two or more impellers mounted on the same shaft may be used. The clearance between the tank bottom and the bottom most impeller should be about (where, D = impeller diameter)
• A __________ mixer resembles a ball mill without balls.
• Tank filter (e.g., Nutsch filter) is
• Cyclones are used primarily for separating
• Molten ammonium nitrate is mixed with ground limestone in fertilizer plant in a
• In a ball mill, the volume occupied by the balls (when the mill is stopped) is about __________ percent of the volume of the mill.
• Reciprocating screens are normally inclined at an angle of 5° with the horizontal and employ gyratory motion at feed end & reciprocating motion at the discharge end. They are not suitable for the screening of the
• Pick out the wrong statement.
• As the product becomes finer, the energy required for grinding
• Ore concentration by jigging is based on the difference in the __________ of the particles.
• Reduction ratio of crushers is the
• Which of the following equations is Rittinger's crushing law? (where P = power required by the machine, m = feed rate, k = a constant = volume surface mean diameter of feed & product respectively.)
• General mechanism of size reduction in intermediate and fine grinder is by