公开(公告)号：US10246341B2

公开(公告)日：2019-04-02

申请号：US15789997

申请日：2017-10-21

Applicant: XIANGTAN UNIVERSITY

Inventor： Lixin Yang ,  Mi Fu ,  Yi Wang ,  Hongyu Qi ,  Yu Xu ,  Yali Liu ,  Yalin Gui ,  Jing He

IPC: C01D15/00 ,  C01D15/08 ,  B01D11/04 ,  B01D12/00 ,  C07F9/11 ,  C01F5/22 ,  C01F5/24 ,  C07B63/00

Abstract: The present invention discloses a method for producing lithium carbonate from a low-lithium brine by separating magnesium and enriching lithium. A salt-lake brine is used as a raw material and is converted into halide salts through dehydration by evaporation and separation by crystallization; the halide salts are directly extracted using trialkyl phosphate or a mixture of trialkyl phosphate and monohydric alcohol, and an organic extraction phase as well as remaining halide salts are obtained after solid-liquid separation; reverse extraction is performed on the organic extraction phase to obtain a lithium-rich solution with a low magnesium-to-lithium ratio, and lithium carbonate is obtained after concentration and removal of magnesium by alkalization. The used solid-liquid extraction method is simple with no co-extraction agent used, and a solute distribution driving force is strong, unaffected by phase equilibrium of the brine extraction agent. The mass ratio of magnesium-to-lithium significantly decreases in the extraction phase.

公开(公告)号：US20220135416A1

公开(公告)日：2022-05-05

申请号：US17577065

申请日：2022-01-17

Applicant: XIANGTAN UNIVERSITY

Inventor： Lixin Yang ,  Qinyao Zhou ,  Qianling Xie ,  Cong Li ,  Chang Liu ,  Haibo Li

IPC: C01D15/08 ,  C01B35/10 ,  C01D15/04 ,  C22B26/12 ,  C22B26/22 ,  C22B3/26 ,  C25B1/34

Abstract: The extraction system contains secondary amides and alkyl alcohols which are separately used as the extractants for extracting lithium and boron and consist of a single compound or a mixture of two or more compounds, and the total number of carbon atoms in their molecules are 12˜18 and 8˜20 respectively; the extraction system has a freezing point less than 0° C. With a volume ratio of an organic phase and a brine phase being 1˜10:1, at a brine density of 1.25˜1.38 g/cm3, at a brine pH value of 0˜7 and at a temperature of 0˜50° C., a single-stage or multi-stage countercurrent extraction and a stripping are conducted to obtain a water phase with a low magnesium-lithium ratio, which is subjected to concentration, impurity removal and preparation to get lithium chloride, lithium carbonate, lithium hydroxide and boric acid respectively. Water is used for stripping, greatly reducing the consumption of acid and base.