Question

Which of the following additives are added to the sand in Co2 moulding for the improvement in collapsibility of the sand?

(a) Copper oxide

(b) Wood flour

(c) Aluminium oxide

(d) Oil

I have been asked this question in an online quiz.

The question is from CO2 Process in section Special Casting Techniques of Casting-Forming-Welding I

Answer 1

The correct option is (c) Aluminium oxide

To elaborate: After the preparation of the sand mixture by adding sodium silicate to the sand, the next step is to add additive, in which mainly aluminium oxide is added and sometimes molasses are also added to impart the favorable properties and for the improvement in the collapsibility of the sand mix.