I dont know if the person the recommended a hand truck ever lifted one of these sinks, but these things were unbearably heavy way back when I was young and very strong. They were also old and ugly back when I was young and very strong, and I am now 66. Where the heck did the time go?
I bet that sink is pushing 80 years old, and the date is probably stamped on the bottom
Hire a plumber, let him have his helper break up and remove that thing and put in a new sink with all new stuff. That one has paid its dues, and wants to go to the landfill. Plus Joe the plumber needs to eat too.
PS Please tell the plumber about the Drano, and don't ever use that stuff again.
at my previous house, I had a huge double cement sink. well, cement double sink, but it felt like double cement too. my son and I hand trucked it upstairs and out to the curb. it was funny to see the two garbage guys trying ( in vain) to lift it, they barely got it off the ground. they just dropped it and the next day a front end loader came by and picked it up and plopped it into a dump truck.