The situation
A producer was paying to dispose of a waste stream that looked like it might be an input to something else. The question was whether a recovery route existed that was commercially real, not just chemically available.
The constraint
Circular economy proposals are easy to make attractive on a slide and hard to defend against a capital committee. The answer had to hold technically, economically, and under the waste regulation that governs what can be sold and as what.
What I decided
I assessed calcium aluminate cement as the valorisation pathway and ran it through technical, economic, and environmental criteria together rather than sequentially, because a route that passes any one of the three in isolation is the usual way these proposals fail later. Where the economics depended on a price assumption, I reported the range instead of the midpoint.
What shipped
A structured evaluation of the after-treatment options, with the calcium aluminate route analysed for material properties, application feasibility, and sustainability trade-offs.
What it produced
A position the company could take to a capital decision on a circular product line, with the conditions under which it works stated rather than implied.