Mechanical Operations Questions

• Tube mill versus standard ball mill: select the combination of characteristics that correctly differentiates a tube mill (long mill) from a conventional ball mill used in fine grinding service.
• Bulk solids handling: bucket elevators are least suitable for vertically conveying which class of materials in process plants? Choose the most problematic feed type for filling, carry-up, and discharge.
• Liquid–solid separation fundamentals: when the goal is to remove trace suspended solids to produce a clear overflow, which unit process is typically selected as the primary polishing step?
• Centrifugal filtration principle: in a rotating basket or disc centrifuge used for filtration, which physical quantity actually provides the driving force for liquid flow through the cake and medium?
• Filtration practice: when a filter aid (e.g., diatomite, perlite, cellulose) is mixed into a slurry prior to filtration, what is the primary effect on the developing filter cake structure?
• Name the revolving grinding mill that is internally divided by perforated partitions into multiple sections so that preliminary grinding occurs in the feed-end compartment and finishing grinding occurs at the discharge end.
• Coal preparation practice: the washability of coal, used to predict how effectively ash and impurities can be removed at different cut densities, is routinely determined using which separation test?
• Kick’s law in comminution: if specific energy is expressed as energy per unit mass, what are the appropriate units of Kick’s constant Ck in the relationship E/m = Ck * ln(d1/d2)?
• Sugar process equipment selection: to continuously separate sugar juice from settled mud after clarification, which filtration device is most commonly employed for large throughputs?
• Specific surface area (SSA) in particle technology is defined as the total surface area available per unit of what fundamental basis? Choose the definition that matches standard engineering usage for powders and porous solids.
• Trommel screening hardware: the cylindrical rotating screen surface (the trommel shell) is typically fabricated from which form of screening material for durability and open area control?
• Shaking table (tabling) operation: the deck is set at a small angle to the horizontal. What is the typical inclination range used to separate particles primarily by density differences?
• Ball milling efficiency with coarse feed: for maximum grinding efficiency at a given coarse feed size, which ball size selection principle most directly improves impact breakage?
• Rod mills: identify the correct set of characteristics that describe common rod mill geometry, handling capability, and media configuration in industrial grinding circuits.
• Terminology check in fine size reduction: which of the following terms is not typically used to denote the process of reducing materials to fine sizes or powders in comminution practice?
• Primary crushing of run-of-mine (ROM) coal for domestic oven sizes: which machine is typically used first to reduce ROM coal to manageable size before further handling?
• Power requirement of roll crushers: horsepower demand varies most directly with which operating parameters in continuous service?
• Powder mixing of very light, fine materials (e.g., insecticide formulations): which mixer type is best suited to disperse and blend such low-density, dusty powders efficiently?
• Breakage mechanisms by equipment: in which of the following machines does size reduction not predominantly occur by compression of particles?
• In filtration engineering, the specific cake resistance for compressible sludges varies primarily as a function of the pressure drop across which part of the filter assembly?