CO₂ Mineralization of Activated K-Feldspar + CaCl₂ Slag To Fix Carbon and Produce Soluble Potash Salt

Abstract

We report an alternative technology for the mineralization of CO 2 and production of soluble potash fertilizer via thermal activation of the insoluble K-feldspar with industrial waste of CaCl 2 with lower energy consumption since the activation temperature was about 800−900°C compared with the conventional temperature of 1300°C. A remarkable K-extraction and CO 2 mineralization ratio could be obtained at an appropriate activation temperature and content of additive CaCl 2 , which possessed the exchange of skeletal K + with dissociative Ca 2+ to form soluble K + species, the collapse of K-feldspar framework, and the formation of intermediates (e.g., anorthite, pseudowollastonite, and wollastonite) to react with CO 2 . Characterization results (e.g., XRD, EDS, and SEM) indicated that pseudowollastonite and wollastonite were the major species to fix CO 2 . Moreover, the reaction principles of the K-extraction and CO 2 mineralization were discussed, and a possible mechanism was proposed.

Extraction of potassium from K-feldspar via the CaCl2 calcination route

“…Han et al [33] regarded the high temperature reaction as a cation exchange reaction between potassium ions in the silica-alumina-oxygen network structure of K-feldspar and calcium ions in the calcium chloride melt. Recently, Xie et al [34] and Ye et al [35] proposed a novel approach for the simultaneous extraction of potassium via the calcination of A C C E P T E D M A N U S C R I P T…”

Sustainable Conversion of Carbon Dioxide: An Integrated Review of Catalysis and Life Cycle Assessment

“…The chemical utilization of the greenhouse gas CO 2 seems intuitively positive for the environment. ,,− However, environmental benefits from CO 2 conversion cannot be taken for granted: Transformation of the thermodynamically stable and kinetically inert CO 2 molecule usually requires some form of energy, and the generation of this energy will in turn also be associated with CO 2 emissions . There are CO 2 -based products which are thermodynamically more stable than CO 2 , such as inorganic carbonates obtained from mineralization. , In principle, these products could thus avoid the need for additional energy. These products are therefore currently studied for potential applications, e.g., in the building sector, , but they are beyond the scope of the present paper.…”

Can CO2 and Steam React in the Absence of Electrolysis at High Temperatures?

“…To date, numerous CaCl 2containing wastes are being generated from many industrial processes, such as the HCl-leaching of E-waste, [11] refinement of heavy oils, [12] and soda-ash production utilizing the Solvay process that generates more than 10 million tons of CaCl 2 -rich waste annually. [13] However, the recovery of HCl from CaCl 2 via pyrohydrolysis (Equation 3) is still unproven, which was believed to be thermodynamically infeasible in the operating temperature window of a commercial pyrohydrolyser (i. e., 600-1000°C). [14] CO 2ðaqÞ þ H 2 O ðaqÞ $ H 2 CO 3ðaqÞ $…”