I want to mix old latex paint with ready concrete mix or cat litter to make pavers.
Honestly this seems like more of a "life hacks".SE question.  There are how-to guides "all over the web" about tinting concrete with latex paint (normal mix, except when adding water, replace 25% of the water with latex paint). While the intent is not yours and they are obviously running out and buying paint for this purpose, the effect is the same.  

Despite your eagerness to make the paint go away, I would not increase the ratio further unless you want the concrete to fail.  If you think it's a hassle to dispose of 3000 pounds of paint, try disposing of 50,000 pounds of concrete. 

You may want stronger tints.  You can up-tint paint: adding more tints than are already in the can. - more yellow, or if yellow, some green/blue to make it greener.   Don't try to overpower tints with contradictory tints (ones on the other side of the color wheel), as the combination will turn to mud.   You'd need to find a family hardware store small enough not to have "policy" against selling you tints compatible with your system.