(中南大學(xué) 冶金與環(huán)境學(xué)院，長(zhǎng)沙 410083)
摘 要: 本文研究了富鋰液中鋰的選擇性提取工藝，通過(guò)磷酸鹽選擇性沉淀實(shí)現(xiàn)了富鋰液中雜質(zhì)的凈化和鋰的高效提取。通過(guò)磷酸鹽沉淀過(guò)程熱力學(xué)分析，考察了富鋰液磷酸鹽凈化除鎂的效果，詳細(xì)研究了富鋰液初始鋰濃度、反應(yīng)時(shí)間、磷酸鹽用量、反應(yīng)溫度對(duì)沉鋰過(guò)程的影響。針對(duì)低溫低鋰濃度下沉鋰效果不佳的問(wèn)題，提出了反溶劑沉淀法和晶種誘導(dǎo)法以強(qiáng)化沉淀效果。結(jié)果表明：在15 ℃下，采用磷酸鹽除鎂，鎂的去除率可達(dá)98.73%。沉鋰過(guò)程中鋰的沉淀率隨著鋰濃度、反應(yīng)時(shí)間、磷酸鹽用量、反應(yīng)溫度的增加而提升。通過(guò)磷酸鋰晶種誘導(dǎo)法可以有效地強(qiáng)化低溫沉鋰效果，在15 ℃下，晶種用量為理論用量的1.5倍時(shí)，鋰的沉淀率可達(dá)82.5%，母液殘余鋰濃度可降至0.35 g/L。
關(guān)鍵字: 鋰；磷酸鋰；沉淀；提取；反溶劑；晶種誘導(dǎo)
（School of Metallurgy and Environment, Central South University, Changsha 410083, China）
Abstract:In this paper, the selective extraction process of lithium in lithium-enriched solution was studied, and the purification of impurities in lithium-enrich solution and the efficient extraction of lithium were achieved by phosphate selective precipitation. The effect of phosphate removal of magnesium from lithium-enrich solution was investigated by thermodynamic analysis of phosphate precipitation process, and the effects of initial lithium concentration, reaction time, phosphate dosage and reaction temperature of lithium-enrich solution on lithium precipitation process were studied in detail. For the problem of poor lithium precipitation efficiency at low temperature and low lithium concentration, the anti-solvent precipitation method and seed-induced method were proposed to enhance the precipitation efficiency. The results show that the magnesium removal rate can reach 98.73% at 15 ℃ by phosphate precipitation. The precipitation rate of lithium in the lithium precipitation process is increased with the increase of lithium concentration, reaction time, phosphate dosage and reaction temperature. The low-temperature lithium precipitation efficiency can be effectively enhanced by the Li3PO4 seed induction method, and the lithium precipitation rate can reach 82.5% at 15 ℃ when the seed usage is 1.5 times of the theoretical precipitation amount, and the residual lithium concentration of the mother liquor can be reduced to 0.35 g/L.
Key words: lithium; lithium phosphate; precipitation; extraction; anti-solvent; seed-induced
