Study On Carbon Sink Effect Caused By Feldspar Carbonation Based On Efficiency

In the study of carbon sink effect in desert areas,the estimation of desert inorganic carbon sink caused by feldspar weathering was slightly insufficient.In this thesis focuses on the study of potassium feldspar,sodium feldspar,and calcium feldspar as research objects,and carries out spraying and immersion experiments indoors.To provide a method and technical reference for accurately estimating the carbon sink of terrestrial ecosystems,in order to propose new directions for future research.The main research includes the following:（1）Feldspar triterminals with different particle sizes were sprayed under different p H carbonic acid solutions to determine the change of ion concentration in the solution after the dissolution reaction and determine the dissolution rate of feldspar.（2）The feldspar triterminal element and carbonic acid solution were immersed in experimental research,the reaction solution was collected in different time periods,the ion concentration change in the solution was measured,and the stability of feldspar under carbonic acid solution was compared and analyzed.（3）The carbon dioxide consumption of feldspar triterminal elements under carbonation was estimated to clarify the carbon sink effect caused by feldspar weathering.The experimental results show that:1.In the sprinkler experiment:（1）The solubility of feldspar under acidic conditions decreases with the increase of p H,and the slope is negative.Moreover,the amount of feldspar dissolution is greatly affected by the particle surface area.The smaller the feldspar particle size,the larger the total surface area,and the more obvious the carbonation effect.When the particle size is 0.075～0.25mm,the feldspar dissolution effect is the best.（2）As for the leaching law of calcium ions,the law followed by the stability of feldspar triterminal element under the action of carbonated solution is:potassium feldspar>sodium feldspar>calcium feldspar.As for the leaching law of silicon dioxide,the law followed by the stability of feldspar is:sodium feldspar>potassium feldspar>calcium feldspar.2.In the soaking experiment:（1）The feldspar dissolution process can be divided into three stages.Initial rapid reaction phase,dissolution rate mitigation phase,and stabilization phase.（2）The leaching concentration of silicon dioxide from the feldspar triterminal element increases with time.And feldspar has a higher dissolution intensity under carbonated solution than under neutral solution.（3）The amount of silicon dioxide dissolved changes over time,showing a"logarithmic function"relationship as a whole.Furthermore,the silicon dioxide dissolution rate has a high consistency.The stability law followed by the feldspar triterminal element under soaking is:potassium feldspar>sodium feldspar>calcium feldspar.3.Carbon sequestration effect:（1）In the sprinkler experiment,the carbon sequestration amount obtained from weathered calcium feldspar is higher than that of sodium feldspar and potassium feldspar.The amount of CO₂ consumed by weathered calcium feldspar is 8.58-13.03 times that of potassium feldspar and 9.38-13.9 times that of sodium feldspar.In this thesis,the optimal combination for feldspar weathering carbon sequestration is p H=5.0,particle size 0.075-0.25mm.At this time,the corresponding amount of CO₂ consumed by the feldspar triterminal element are:calcium feldspar1096.60871kg/km²,sodium feldspar 116.90305kg/km² and potassium feldspar127.85717kg/km².（2）After 30 days of soaking,the amount of CO₂consumed by weathered sodium feldspar is higher than that of weathered potassium feldspar,with an increase of 14%to 67.1%.（3）Feldspar weathering not only provides the main source of material and nutrient elements for the formation of soil,but also absorbs CO₂ in the atmosphere or soil and ultimately fixes it in the form of carbonates,achieving the effect of carbon sequestration.