CAR Material Selection & Properties 4

Question 1

Capacitors in older appliance motor-start circuits may contain which hazardous substance requiring special handling?

Accepted Answer

Polychlorinated biphenyls (PCBs)

Answer

Elemental sulfur

Answer

Asbestos fibers

Answer

Chromium VI compounds

Question 2

What is the primary advantage of using HDPE (High-Density Polyethylene) in washer drain hoses over PVC?

Accepted Answer

HDPE does not require plasticizers and is generally considered safer for water contact

Answer

HDPE is more rigid and maintains shape under pressure better than PVC

Answer

HDPE is always less expensive than PVC at scrap value

Answer

HDPE can withstand higher temperatures than any other plastic

Question 3

Which appliance material is classified as 'white goods' scrap and typically commands the lowest per-ton value?

Accepted Answer

Mixed painted steel sheet metal

Answer

Copper motor windings

Answer

Aluminum fin coils

Answer

Stainless steel drums

Question 4

Porcelain enamel coatings on appliance surfaces are made by fusing which base material onto steel?

Accepted Answer

Inorganic glass frit

Answer

Acrylic polymer resin

Answer

Zinc oxide compound

Answer

Epoxy resin layer

Question 5

When recovering refrigerant from a system, the presence of non-condensable gases (NCGs) typically indicates:

Accepted Answer

Air or nitrogen has entered the system, reducing efficiency and complicating recovery

Answer

The refrigerant is pure and uncontaminated

Answer

The compressor oil needs immediate replacement

Answer

The refrigerant charge is at optimal level

Question 6

The RoHS directive's restriction on hexavalent chromium (Cr VI) in appliances is significant for recyclers because:

Accepted Answer

Cr VI is a carcinogen that can contaminate soil and groundwater if improperly disposed

Answer

Cr VI enhances the magnetic sorting of stainless steel

Answer

Cr VI increases the scrap value of steel components

Answer

Cr VI is required for proper functioning of refrigerant compressors

Question 7

Which type of compressor found in window air conditioners contains the most recoverable copper by weight?

Accepted Answer

Rotary compressor with hermetic shell

Answer

Reciprocating compressor with accessible valves

Answer

Scroll compressor with aluminum body

Answer

Linear compressor with plastic housing