Creating a critical snapshot of the bioleaching sector by using patent databank analysis.

Abstract

This work defines the profile of the bio-hydrometallurgy sector by presenting a statistical analysis of the patent databank that covers the bioleaching field. The use of prior technology to take a snapshot helped provide a good panorama of the major players in the extractive metallurgy operation. Using an international classification code, 1226 patent families were retrieved. This code was chosen for microorganisms used in extracting nonferrous metals from ores or concentrates via wet processes. After a careful analysis that excluded (i) patent families without applicant information, (ii) those belonging to applicants with just a few families, (ii) those with indexing misconceptions, or (iv) duplicated families, only 312 patent families presented real interest and provided valuable information to facilitate a full analysis. Of the four largest companies producing patents in this area, BHP Billiton led the bioleaching of sulfide ores, followed by Beijing Nonferrous Central South University, which led the strain cultivation methods and inoculum generation, and Nippon Steel which led the wastewater treatment operations. This work also revealed that a classification of technical areas, although very important in classifying some technologies, should be used very carefully, because some mistakes were detected during indexing, and false results were sometimes retrieved while searching the patent databases. The evolution of patent production is closely related to the fluctuations in global metal prices. It is also affected by the strategic decision of a company CEO, especially when the time required to study a specific technology and develop an operation is very long, expensive, and requires specialized and committed technicians. Some challenges which remains to be overcome are: (i) bioleaching of low-grade chalcopyrite ores (ii) improving bacterial tolerance to chloride; (iii) industrial bioleaching of nickel laterites and (iv) bioleaching of rare earths.