高硫高硬气田采出水提锂过程关键技术及应用

气田采出水既是含有高盐、高硫、高硬、石油类和复杂有机物的难处理废水，又是具有多种高值元素的矿产资源，其中锂元素作为能源金属备受关注。通过有效预处理和锂吸附法相结合，成功从复杂组分的气田采出水中提取了锂元素，制备成合格的碳酸锂产品，同时处理后出水达到回用水水质要求。实验结果表明，通过高效旋流气浮分离和吹脱塔脱硫处理后，实现油、悬浮物和硫化物去除率分别达到90.4%、92.9%和98.1%；通过高效吸附法实现锂回收率达到88.0%；富锂液通过纳滤膜净化、反渗透和电渗析膜耦合高倍浓缩后，最终制备得到的碳酸锂产品纯度可达到99.8%，产品符合GB/T 11075—2013《碳酸锂》Li₂CO₃-1级标准。

Key technology and application of lithium extraction from produced water in high sulfur and high hardness gas fields

The produced water of gas field is not only a refractory wastewater with high salt，high sulfur，high hardness，petroleum and complex organic matter，but also a mineral resource with a variety of high value elements，among which lithium is the most concerned.The combination of effective pretreatment process and lithium adsorption method was applied.Lithium element was successfully extracted from the complex composition of the gas field produced water，and qualified industrial grade lithium carbonate products were prepared.At the same time，the treated effluent met the water quality requirements of reuse water.The experimental results showed that the removal rates of oil，suspended solids and sulfide could reach 90.4%，92.9% and 98.1%，respectively.After the high efficiency cyclone floatation and stripping tower desulfurization treatment.The recovery rate of lithium could reach 88.0% with efficient adsorption.The lithium rich liquid was purified by nanofiltration membrane and concentrated by reverse osmosis and electrodialysis membrane.The purity of the final lithium carbonate product could reach 99.8%，and the product was in line with GB/T 11075—2013“Lithium Carbonate” Li₂CO₃-1 standard.