Community-Level Process-Design for the Extraction of Lac Resin and Dye

Lac cultivation is the primary source of income for more than a million tribal families living in different states of India. Traditional lac cultivation methods involve extensive use of water for extracting different products, and the scarcity of water in the summer matches the harvesting season hindering value addition to the lac. Also, exposure to high temperatures and fumes during lac-processing is a health hazard. A safer, less water-requiring resin extraction process will thus help utilize the full livelihood potential in lac-permissive regions. Here we report a relatively less water-dependent process wherein crude lac was subjected to a sodium carbonate-based cascaded hot-wash process that softens the resin for easy removal of impurities and simultaneous removal of dissolved lac dye. Next, while the washed lac-resin is further extruded through cloth-filter for further purification, the lac dye (dissolved in wash discharge rich in sodium carbonate) was stirred with oxalic acid to retrieve the lac dye (laccaic acid). The solubility and purity of the lac resin were tested in isopropyl alcohol (IPA) and the solubility of the lac dye in water. Finally, a preliminary prototype for extruder-assembly is explored for the extraction of lac resin.