Systematic Analysis Of Trace Elements In Carbonate Minerals By Acid Dissolution And New Method Initial Research

Extraction of geochemical information from carbonate rocks is a key task in palaeoenvironmental studies.For the extraction of rare earth elements of carbonate minerals in the original parent rock,researchers have proposed various partial dissolution methods,one of the most commonly used is the acid dissolution ICP-MS method,However,the specific operating procedures,such as sample particle size,acid concentration,and leaching time,are different,There is no systematic analysis of the content and the parameters of rare earth,this raises doubts about the accuracy of the determination of the content of rare earth elements in carbonate minerals by acid dissolution,the information about the oxidation or reduction of the ancient environment revealed by the corresponding measurement results needs to be further confirmed.This article combines predecessors and laboratory research groups have done research,choose 14 samples,divide each sample into 5 particle sizes and rinse with 6 acetic acid concentrations respectively,in order to obtain complete and systematic experimental data of the determination of the content of rare earth elements in carbonate by the acid dissolution method of acetic acid.Different from the previous analysis of experimental data to find the optimal acid concentration,in this experiment,the measured data is analyzed to determine the possible pollution sources through the distribution model of rare earth elements and the common parameters of rare earth elements at different acidities and different particle sizes,This has a crucial role in improving the acid dissolution method to reduce non-target components in a targeted manner;and the correlation analysis method of calcium and trace elements,aluminum and trace elements was established through the leaching concentration,and finally,from the trace elements measured,it is found that the method is feasible to certain elements.Analysis of the behavior of rare earth elements leached at different acetic acid concentrations revealed that water-soluble minerals and adsorbates may have dissolved at low acetic acid concentrations,the REE pattern may be altered e.g.lessening of negative Ce anomaly,altering of Eu anomaly,Y/Ho ratio and relative fractionation LREE,this phenomenon is particularly obvious at a concentration of 0.3% acetic acid.At higher acetic acid concentrations,non-carbonate mineral phases such as clay,iron-manganese oxide,and phosphate may be dissolved;The comparison of rare earth element distribution pattern maps with different acetic acid leaching found that the non-carbonate component rare earth element distribution pattern map may be similar to that of the original parent rock.The correlation analysis of calcium and aluminum shows that Ba?Zr?Tl?Mn?Sr?Ni etc.may be more present in carbonate minerals,which is easier to accurately determine in the acid dissolution test.All the rare earth elements are basically related to the dissolution law of aluminum element,which verify our previous conclusion,the dissolution of a small amount of non-carbonate minerals such as clay will greatly affect the measurement results.The elements Sc?V?In?Be?Ga?and Th have significant correlations with the leaching concentration of aluminum for many times,indicating that they are abundant in non-carbonate minerals.Based on the above research results,a new method-dynamic gradient column leaching method is proposed.Specifically,?water-ammonium sulfate-weak acid? with increasing dissolution strength in three stages dissolves and elutes water-soluble salts,ion exchanges elutes rare earth elements adsorbed on the clay surface,and dissolves and elutes carbonate minerals for testing.The feasibility of the simulation method through manual mixing of samples in the laboratory,and the optimization of the parameters of the clay adsorbent ammonium sulfate,laid the foundation for the subsequent smooth development of dynamic gradient column leaching experiments.