当前位置: X-MOL 学术Aquat. Geochem. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Incorporation of Rare Earths and Yttrium in Calcite: A Critical Re-evaluation
Aquatic Geochemistry ( IF 1.7 ) Pub Date : 2020-02-12 , DOI: 10.1007/s10498-020-09369-9
Peter Möller , Marco De Lucia

The reported partition coefficients of REE with calcite are reviewed and critically discussed. In some of the reported experimental sets, REE concentrations are found to be supersaturated with respect to individual REE2(CO3)3 but never to REE(OH)3. Although the solutions are unsaturated with respect to individual REY carbonates, REY including Y are incorporated in calcite surfaces, where they are overgrown by calcite. Charge balances may be obtained by building {REY–Na-(CO3)2}n or by exchange of 2Ca2+ against REY3+ + blank space calcite lattice. These surface compounds may either be homogeneously distributed or clustered. Both the size and frequency of clusters increase with [REY]/[Ca] or [ΣREY3+]/[Ca2+] in solution. If these surface precipitates are removed into solutions saturated with respect to ΣREE2(CO3)3, they start growing in the aqueous phase. In this case, the apparent DREY and kREY values decrease with increasing REY concentrations in solution. In previous studies, only the individual distribution coefficients are reported not considering that the entirety of REY determines their behavior in partitioning. Given enough time, these surface clusters equilibrate with the aqueous phase before being overgrown by calcite. In the double logarithmic plots of {REY}/{Ca} versus [REY]/[Ca] or [REY3+]/[Ca2+], two relationships evolve characterizing the REY distribution in marine calcite and experimental calcites grown in Mg2+-free solutions. The double logarithmic plots of partition coefficients of REY3+i in calcite grown from seawater show a slope exceeding unity, whereas those from fluids without Mg2+ depict slopes less than unity being both in contrast to the Henderson–Kracek rule.

中文翻译:

方解石中稀土和钇的掺入:关键性的重新评估

审查并严格讨论了报告的稀土与方解石的分配系数。在一些已报告的实验组中,发现REE浓度相对于单个REE 2(CO 33是过饱和的,但从未相对于REE(OH)3过饱和。尽管相对于单个的REY碳酸盐而言,溶液是不饱和的,但包括Y的REY掺入了方解石表面,在方解石表面过长。电荷余额可以通过建立{REY–Na-(CO 32 } n或通过将2Ca 2+与REY 3+交换而获得。 +空白方解石晶格。这些表面化合物可以均匀分布或成簇。溶液中簇的大小和频率都随[REY] / [Ca]或[ΣREY3 + ] / [Ca 2+ ]而增加。如果将这些表面沉淀物去除到相对于REE 2(CO 33饱和的溶液中,它们将开始在水相中生长。在这种情况下,视在D REYk REY值随着溶液中REY浓度的增加而降低。在以前的研究中,仅报告了单个分配系数,而不考虑REY的整体决定了它们在分区中的行为。给定足够的时间,这些表面团簇在被方解石过度生长之前与水相平衡。在{REY} / {Ca}与[REY] / [Ca]或[REY 3+ ] / [Ca 2+ ]的双对数图中,两个关系演变为表征海洋方解石和实验方解石在镁中的REY分布的特征2种以上免费解决方案。海水中方解石中REY 3+ i的分配系数的双对数图显示了超过1的斜率,而不含镁的流体中的斜率超过1。2+表示与Henderson-Kracek规则相反的小于1的斜率。
更新日期:2020-02-12
down
wechat
bug