I pulled up maybe 50 square feet of floor tile on my basement floor.

The tile was glued down with this thick black tar-like goo.

I used a heat gun and sharpened puddy knife to scrape up the glue.

So now that the tile and glue are off, all that is left is this smooth black surface, that is tacky.

I've read that solvents will only cause the tar to soak into the concrete pores.

Is there a machine or something that can scrape a fraction of an inch of the concrete off
so I can get a nice clean surface back?

A sander would only clog up with the residual tar, so I think that is out.

Thanks,

Find a decent rental company and ask to rent an electric twin disc grinder.
They are made by Edco, and can be used for various applications. Yours is one of them.
Be sure to get the diamond scarifiers with it.
We rent ours @ $56/day, plus the diamond scarifiers @ $96/day.
If you were to rent it here, it would cost you exactly $167.06 for 24hrs with the machine. That includes tax and insurance.

www.edcoinc.com/index.html/screen/dual_disc_grinder/session_id/a03c27ecd0263300a173c98b329693a3

Quoted: Find a decent rental company and ask to rent an electric twin disc grinder. They are made by Edco, and can be used for various applications. Yours is one of them. Be sure to get the diamond scarifiers with it. www.edcoinc.com/index.html/screen/dual_disc_grinder/session_id/a03c27ecd0263300a173c98b329693a3 www.edcoinc.com/library/jpg/944_1138656593.jpg

Will this require a forklift to get it into my truck, and half of a biker gang to carry it downstairs?

Quoted: Quoted: Find a decent rental company and ask to rent an electric twin disc grinder. They are made by Edco, and can be used for various applications. Yours is one of them. Be sure to get the diamond scarifiers with it. www.edcoinc.com/index.html/screen/dual_disc_grinder/session_id/a03c27ecd0263300a173c98b329693a3 www.edcoinc.com/library/jpg/944_1138656593.jpg Will this require a forklift to get it into my truck, and half of a biker gang to carry it downstairs?

They ARE heavy, but what you want to do, requires a machine of this caliber.
A set of motorcycle ramps will work fine.

go the other way and pour another half inch on top?

Whoa!

You might want to find out what exactly it is and what leveling compound was used underneath.
A lot of the older stuff has asbestos in it.

Are you prepping the concrete for tile or flooring? If for tile, mastic or thinset will be just fine on it.
Are you trying to get the concrete surface to be as it was? Probably not realistic, but there are some very good epoxy adhesive paints that you could use to paint the concrete surface with little preparation.

To remove the tacky residue, you can use Kerosine or Diesel fuel, but that is going to be messy.

Removed before even posted for COC violation.

You should have the residue tested for asbestos before doing anything dry to it.
Cutback was the name for the older tile adhesives, and some of them did contain asbestos.
If you want a tile floor, put down concrete backer board to bury the stuff.
For a wood floor put down plywood (on sleepers if needed.