Abstract:

Using industrial solid waste to calcinate non-water-soluble natural K-feldspar for CO₂ mineralization and potassium extraction is a multi-functional CO₂ capture, utilization and storage (CCUS) technology that can treat industrial solid waste, utilize potassium resource and reduce greenhouse-gas (GHG) emissions. Life cycle assessment (LCA) was adopted based on a functional unit of the produced potash fertilizer containing 1 ton of K₂O to compare two emerging technologies of simultaneous potash fertilizer production and CO₂ mineralization from K-feldspar and industrial solid waste (CaCl₂/phosphor-gypsum) with a traditional technology of potash fertilizer and white cement coproduction by smelting K-feldspar in blast furnace in terms of GHG-reduction potential and economic feasibility. The life-cycle (from raw material exploitation to transportation to production) GHG emissions and life-cycle cost of these technologies were accounted by using an improved allocation approach that considered the credit of avoided GHG emissions/cost from industrial solid waste treatment. The results showed that the two emerging technologies were preferred to the traditional technology in terms of both life-cycle GHG emissions and economic feasibility with GHG-reduction potential of about 81.16% and 20.48%, and cost savings of up to 34.75% and 45.11%, respectively.

Key words: life cycle assessment, K-feldspar, greenhouse gas, CO₂ capture, waste treatment

摘要：

利用工业固废活化非水溶性钾长石矿，矿化固定二氧化碳（CO₂）并提钾工艺，是同时处理工业固废、开发钾资源、减排CO₂等一举多得的CCUS路线。采用生命周期评价（LCA）方法，以生产含1 t K₂O的钾肥为功能单元，以传统的高炉冶炼钾长石制可溶性钾肥并联产白水泥工艺作为参照，对比评价了两种钾长石-工业固废体系矿化CO₂联产钾肥工艺过程的碳减排潜力和经济性。对工艺从原料开采、运输到产品生产的生命周期的温室气体排放量（简称“碳排放”）和成本进行了全流程的核算，研究了更全面的产品碳排放和成本分配方法。结果表明，无论是碳排放还是经济性，钾长石-工业固废体系矿化CO₂联产钾肥工艺均较传统工艺有很大提高，碳减排潜力分别可达81.16%和20.48%左右，成本可节约34.75%和45.11%左右。

关键词: 生命周期评价, 钾长石, 温室气体, 二氧化碳捕集, 废物处理