Industrial waste repurposing reveals systemic gaps in carbon sequestration: slag’s potential exposes reliance on linear extractive models over circular solutions

Indigenous communities have long treated mining residues as part of ecological cycles, using slag in construction, soil amendment, and ceremonial practices. These systems operate on principles of reciprocity and regeneration, contrasting sharply with the extractive logic of modern mining. However, Western scientific frameworks often dismiss such knowledge as anecdotal, reinforcing epistemic violence. The study’s focus on mineral carbonation ignores the cultural and spiritual dimensions of waste in Indigenous worldviews.

The history of mining waste spans millennia, from Roman slag heaps to 19th-century industrial pollution that created today’s Superfund sites. Each era’s waste management reflects its economic priorities, from medieval silver mining to modern lithium extraction for green tech. The current focus on carbon sequestration mirrors past 'end-of-pipe' solutions that delayed systemic reform. Historical precedents show how techno-fixes often serve as stopgaps rather than transitions to circular economies.

In Japan, traditional *satoyama* systems integrate industrial byproducts into local ecologies, demonstrating how waste can be metabolized without extraction. African metallurgical traditions, such as those in Mali, have used slag in art and architecture for over a thousand years, embedding it in cultural identity. These examples highlight how cross-cultural repurposing often prioritizes community well-being over profit. The Western framing of slag as a 'problem' to be solved reflects a narrow, utilitarian worldview.

The study’s focus on water-dependent mineral carbonation aligns with established geochemical pathways but overlooks alternative sequestration methods like biochar or alkaline activation. Peer-reviewed research shows that slag’s carbon storage capacity varies widely based on composition and processing, yet the study’s conditions may not reflect real-world variability. The scientific community’s emphasis on lab-scale solutions often neglects field-scale implementation challenges. Further, the lack of lifecycle assessment in the study obscures potential trade-offs, such as energy use in processing.

Artists like Agnes Denes have long explored slag heaps as symbols of industrial hubris, transforming waste into commentary on human-nature relationships. In many cultures, slag is imbued with spiritual significance, seen as a bridge between earth and human labor. The repurposing of slag in art and ritual challenges the commodification of waste, offering a counter-narrative to its reductionist framing. However, these perspectives are rarely integrated into scientific or policy discussions.

Scenario modeling suggests that scaling slag-based carbon sequestration could offset 5-10% of industrial emissions by 2050, but only if paired with strict waste reduction policies. Without circular economy mandates, such solutions risk becoming another form of greenwashing, enabling continued extraction. Future systems must prioritize source reduction over end-of-life solutions to avoid lock-in to unsustainable practices. The study’s narrow focus on carbon storage ignores other environmental co-benefits, such as soil remediation or habitat restoration.

Frontline communities, particularly Indigenous groups and people of color, bear disproportionate burdens from mining waste yet are excluded from decision-making. Their knowledge of local ecologies and long-term impacts is systematically sidelined in favor of corporate-led research. The study’s lack of engagement with affected populations reflects a broader pattern of extractive research ethics. Amplifying these voices could reveal alternative pathways that prioritize justice over technological solutions.