Relationships Between Physicochemical Properties And Chemical Compositions Of Zeolite Ores

High grade clinoptilolite and mordenite from Muling, Heilongjing Province were taken as the research objects. Relationships between the chemical compositions and four fundamental physicochemical properties, including cation exchangeability, adsorption of acid gas and water vapor, thermal stability and acid resistance, were detailedly analyzed. With an emphasis on the combination of data, physicochemical principles, and result analysis, the consequent disciplines play a theoretical and instructional role in the exploration and application of zeolite ore deposits, thereby serve as the theoretical foundation and guarantee for the rapid prediction/assessment of the local zeolite mineral resources as well as the other localities nationwide. The thoughts and analyzing methodology also provide a wholly new reference and original resort for the resource evaluation research.The content of the mobile cations in zeolites determines the exchangeability and adsorption, while the Si/Al value influences the thermal stability and acid resistance. The following issues were addressed in the research, such as the characteristics of the chemical compositions of the types of zeolites, relationships between the cation content versus exchangeable content of K⁺ and NH4⁺, parameters of (MgO⁺CaO)/K2O and MgO/K2O versus adsorption of acid gases and water vapor, varied moisture absorption capacities after being heated by increasing temperatures versus zeolite types and Si/Al contents, varied rates of weight loss and crystallinities after acid dipping versus Si/Al, the negative factors that impede the physicochemical properties, as well as the geochemical indicator roles played by REE and trace elements.The target samples enrich in Na element, with a SiO₂/Al₂O₃ value higher than 8, or even high than 9 in most cases. Content of mobile cations in mordenite keeps a positive trend with the exchangeable content of K⁺ and NH4⁺, with which clinoptilolite shows a weak connection due to the cation blockage effect and the mixing of montmorillonite. Adsorption experiments using acid gases discovered that both types of zeolites specifically favor H2S and SO₂, but less CO₂. Parameters of (MgO⁺CaO)/K2O and MgO/K2O do not show evident relationship with acid gas adsorption, but link closely and positively with the adsorption of water vapor. Thermal stability and acid resistance depend on SiO₂/Al₂O₃ values. Mordenite shows superior stability to clinoptilolite in terms of moisture adsorption capacity after being heated. Clinoptilolite can stabilize up to 400°C, whereas mordenite can hold up to 800°C. Higher K and Na contents also contribute to the superior thermal stability of mordenite. To estimate the rate of weight loss and crystallinity after acid dipping also results in the discovery that mordenite is also superior to clinoptilolite in terms of acid resistance, for it keeps the crystal structure in 4M HCl solution without losing Al, and even increases its moisture adsorption capacity in the solution mentioned above. Both types of zeolites remain the crystallinity greater than 80% after being leached in 10M HCl solution, but mordenite holds higher crystallinity than clinoptilolite after 12M HCl solution leaching. The alkali and alkaline earth elements among trace elements (Rb, Cs, Sr, Ba) are good indicators of the cation contents in zeolite ores, while value of Th⁺U reveals the origin of parent rock. The research presented will definitely widen and deepen the insight on how zeolites perform their application advantages, and direct the development of the rapid assessment for application of zeolite mineral resources in the target area and all over the country.