This set of Casting, Forming and Welding Multiple Choice Questions & Answers (MCQs) focuses on “Sand Reclamation Techniques”.
1. Thermal systems can be sufficient for reclamation of chemically bonded sands.
a) True
b) False
View Answer
Explanation: Chemically bonded sand uses binders to form rigid moulds by the application of heat. Reclamation of sand can be done by thermal, mechanical or wet scrubbing processes. But, thermal systems alone are sufficient for the reclamation of sands. Most of the thermal systems used are gas fired, however electrically fired thermal systems are also used widely.
2. High degree of cleanliness can be achieved by the dry reclamation systems in reclaiming the sand.
a) True
b) False
View Answer
Explanation: Dry reclamation system uses the mechanical scrubbing principle to separate the clay and the organic coatings. They can be utilized with all general types of sand. However, it is not possible to achieve the degree of cleanliness by the dry reclamation systems as compared to the other types of reclamation systems.
3. The wet reclamation systems are eco-friendly and widely used for reclaiming the sand particles.
a) True
b) False
View Answer
Explanation: The wet reclamation system uses wet scrubbing action to reclaim the sand. This method is quite effective in cleaning, but the cost of maintenance is very high and water discharge creates many problems which are unpleasant to the environment. These considerations have restricted their use in reclaiming the sands.
4. Burning of organic binders can be possible in thermal reclamation systems for reclaiming the sand.
a) True
b) False
View Answer
Explanation: Thermal reclamation system provides heat to the sand and high temperature is achieved which is enough to burn the organic binders. These systems can be gas fired or electrically operated for the reclaiming of sand. Thermal systems are specifically suitable for organically bonded sands, but the higher temperature gas fired systems can also be utilized for the clay bonded sands.
5. Sand reclamation is defined for repeatedly using new sand for the making of moulds in production of castings.
a) True
b) False
View Answer
Explanation: Sand reclamation is a physical and chemical treatment of used foundry sands so that they can be reused in making of cores and moulds for the production of casting components. The true reclamation cleans each and every single grain within the sand, whereas reconditioning is defined for the partial cleaning and treating of sand mass.
6. After reclamation of sand, reclaimed sand should be dry at an acceptable temperature.
a) True
b) False
View Answer
Explanation: Proper reclamation includes many objectives like the reclaimed sand should be dry at an acceptable temperature. It should be bonded and must have moulding and core making sand properties same as that of the new sand. And the reclaimed sand should produce casting parts of good quality same to those produced by the new sand.
7. Reclamation may improve the casting quality, but does not affect the economic expenditure.
a) True
b) False
View Answer
Explanation: For the increasing cost of new sand and limited availability of high quality sand sources, reclamation is very important and necessary from the economic point of view. It reduces the cost involved in making of moulds and cores by keeping the quality equal to that produced by the new sand. Reclamation makes the processes economical and environmental friendly.
8. Thermal reclamation system removes the organic as well as the inorganic binders associated with the sand.
a) True
b) False
View Answer
Explanation: Thermal reclamation systems burn away and remove all the organic binders from the sand, but it does not remove the inorganic binders associated with the sand mass, which are generally fused with the sand grains. Thermal reclamation units can be either electrically operated or gas fired, depending on the degree of reclamation and convenience.
9. In the dry reclamation system, a strong metal plate is used on which used sand is blasted to get converted into fine powder.
a) True
b) False
View Answer
Explanation: Dry reclamation process crushes the sand lumps into grain size, and then the binders are removed from the sand grains by the use of mechanical abrasion. Released fines particles are separated and then dry sand is prepared by crushing the sand to the metal plate by blasting which removes all the metal particles and the resulting fines are taken to a dust collector.
10. A vigorous scrubbing action takes place in the method of wet reclamation of sand.
a) True
b) False
View Answer
Explanation: In wet reclamation, a scrubbing action takes place in water to dissolve binders from the sand mass. Loose clay gets suspended in the water and scrubbing action removes the clay coatings from the sand grains. Wet reclamation treats clay bonded sands very efficiently and the reclaimed sand mass is almost equal in quality and purity to new sand.
Sanfoundry Global Education & Learning Series – Casting, Forming and Welding.
To practice all areas of Casting, Forming and Welding, here is complete set of 1000+ Multiple Choice Questions and Answers.
If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]
- Practice Casting, Forming and Welding I MCQ
- Apply for Mechanical Engineering Internship
- Practice Mechanical Engineering MCQs
- Check Metallurgical Engineering Books
- Apply for Metallurgical Engineering Internship
