Technoeconomic assessment of metal recovery from chloric-based spent pickling liquor in Indonesia: A case study on Java Island

The conventional treatment of spent pickling liquor (SPL) generated by the steel industry poses significant environmental risks while overlooking valuable resource recovery opportunities. This study assesses the technoeconomic feasibility of metal recovery from SPL in Java Island, Indonesia. Findings indicate that conventional practices—neutralization and landfill disposal—remain widespread, despite their substantial environmental impact and lack of economic benefit. In contrast, this study identifies an integrated hybrid recovery approach, Scenario C, which combines selective precipitation with electrowinning, as the most effective option. A comprehensive process flow was developed and evaluated against conventional disposal in terms of recovery efficiency, operational costs, and contextual suitability. Treating 1,000 cubic meters of SPL annually can yield approximately 340,000 kg of iron, 24,000 kg of zinc, 4,500 kg of copper, and 1,500 kg of nickel, generating an estimated annual revenue of USD 171,300 and a net profit of USD 118,800 after accounting for annual energy and fuel costs of USD 52,500. Levelized cost analysis and sensitivity assessments further confirm the financial viability and resilience of Scenario C under varying market and operating conditions. The results demonstrate that implementing Scenario C for SPL management aligns with circular economy principles and delivers substantial financial and environmental benefits. This approach represents a sustainable and economically advantageous alternative to conventional SPL disposal methods in Indonesia, particularly for high-output regions such as Java Island.