Can pulsating DC be used for induction heating?
Assuming that your "pulsating DC" is likely to be a square wave. OR, even if your DC were pulsing between two non-zero values.  The answer is yes. 

Applying any changing voltage (current) to your induction coil at any frequency can and will likely result in induction heating of a conductor inside of your induction coil. You don't even need a resonating capacitor to achieve induction heating.  

Things get a little more complicated when you try to make a Good induction heater. Your 12v source sounds good for a very small induction heater. For first step, search around on internet (i.e. youtube), for other amateurs who are doing similar things. Selecting a frequency (or repetition rate) and resonating capacitors is of course essential to obtaining higher efficiency so that your limited power source could actually demonstrate Visible heating.