I have a 220v 30a kitchen range circuit with aluminum 2-wire cable. No ground wire, no neutral wire. The current kitchen range is hard wired with the neutral lead left detached. The new range will need a 4-prong outlet. Can that be safely done and how to do it? Most of the existing circuit is embedded in masonry and would be nearly impossible to replace. Also a careless worker cut the 2-wire cable in its only accessible location. How can it be safely spliced?
"Nearly impossible" is not "impossible." The new cable (or conduit) does not need to physically replace the inadequate, dangerous, damaged previous cable, which can be abandoned in place, with all accessible parts removed, and the bits buried in masonry left there.
Just run a new cable or conduit by a new path and be done with it, safely.
Personally, I'd choose conduit, preferably metallic conduit - much safer from careless workers and rodents, both.
You're buying the wrong appliance
The problem is your original appliance was not a range. It was a cooktop, and it was designed to not require neutral. I can tell because it was only 30A.
Now you're trying to replace it with a range (with oven). The range/oven needs more power than that circuit is capable of (first problem).
Also, the range requires neutral because it needs neutral to power some onboard loads, notably the oven light. What happens when you refuse to supply neutral? Easy: It electrifies the chassis of the oven!
In fact, so many people were getting killed by correct pre-1996 installations where the neutral wire broke, that ground was made mandatory to ranges. Now you can get around that by using a GFCI breaker, but that doesn't solve your neutral problem.
Or your "new appliance takes too much power" problem - you can't just ignore that one!
Buy the proper neutral-free appliance, and use GFCI
That is the answer. Back to the store it goes, and you shop more carefully for appliances which do not need neutral. You may have to settle for a cooktop and forego the built-in oven. The government would have never given the house an occupancy permit without an oven, so I suspect there is a separate 20-30A circuit for a separate oven. No, they cannot be combined.
In that case, simply buy separate oven and cooktop.
Anything that doesn't have a dedicated ground, put a GFCI breaker on it. They're not cheap, but you claim they are cheaper than running a ground wire so I'll take your word on it. Should I?
You really ought to look into conduit, though
Because the way you're talking about this wire it really seems like you are really new to electrical wiring. Someone burying a cable in masonry seems really, really unlikely. I suspect you have conduit there, in which case there are easy answers. In fact the workman may have known that, and therefore wasn't worried about damaging the cable, realizing it was obsolete.
Given your skill level you may be better off hiring an electrician, who would know what they are looking at and know what to do about it. They may have an easy solution, especially if a lot of units are built like this. They'll have both skill and experience in units like yours.