The environmental cost of traditional craftsmanship
The precipitation method for producing white carbon black requires a large amount of water resources, with 50-100 tons of wastewater generated per ton of product, including pollutants such as sodium sulfate and sodium silicate. The gas-phase method requires expensive exhaust gas treatment systems due to the high-temperature cracking of SiCl ₄, which produces hydrogen chloride gas.



Green process innovation


Biomass silicon source substitution: Using rice husk ash and diatomaceous earth as raw materials, white carbon black is prepared by alkali dissolution acid precipitation method, which not only reduces the dependence on silica, but also realizes the resource utilization of agricultural waste. An Indian company uses rice husk ash to produce white carbon black, reducing costs by 20% and carbon emissions by 35%.
Closed loop production system: The gas-phase closed-loop process developed by Germany's Evonik recovers HCl from exhaust gas to produce hydrochloric acid, which is recycled for SiCl ₄ synthesis, achieving zero emissions. This technology reduces energy consumption per unit product by 18%.
Zero discharge technology for wastewater: Through membrane separation evaporation crystallization combination process, sodium sulfate in wastewater is recovered for glass manufacturing, sodium silicate is returned to the production process, and the water recycling rate reaches over 95%.
Policy driven and industry standards
China's "dual carbon" target promotes the transformation of the white carbon black industry towards green. The "Evaluation Index System for Clean Production in Industrial Silicon Industry" to be implemented in 2023 requires that the wastewater discharge per unit product of precipitated white carbon black should be ≤ 8 tons/ton, and the gas-phase method should be ≤ 15 tons/ton. Enterprises need to increase their investment in environmental protection, otherwise they face the risk of production restrictions.
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