Many institutions from the public and private sector are interested in the characterization of the research taking place in waste recycling (WR) science. Tech mining analysis can be applied to scientific databases with this purpose in mind, but difficulties do arise when designing the search strategy to effectively capture this multidisciplinary area. This paper introduces the process followed to build a query system that aims to solve this problem. This system has been applied to a selection of scientific databases, and the steps followed to download and clean the data are detailed. Initial results are explained, indicating the relevance of each database and quantifying the overlap among them. The main subjects behind the retrieved data have been identified, namely, chemistry, biology and environmental sciences. A precision test conducted by random sampling indicated that, with a confidence level of 95%, the proportion of WR articles is between 74.2 and 79.2% of the retrieved items, while recall is expected to be high, according to available classifications. These results are deemed to be satisfactory enough for basing forthcoming tech mining analyses on this query system.