(1. 中南大學(xué) 冶金與環(huán)境學(xué)院，長沙 410083；
2. 青海省環(huán)境科學(xué)研究設(shè)計院，西寧 810000)
摘 要: 詳細(xì)研究氯化鉛在碳酸氫銨溶液中的物相轉(zhuǎn)化機(jī)理，對比分析同一條件下不同轉(zhuǎn)化劑的轉(zhuǎn)化脫氯效果，轉(zhuǎn)化脫氯效果由大到小依次為NH4HCO3、Na2CO3、(NH4)2CO3、K2CO3；得出NH4HCO3作為轉(zhuǎn)化劑時的最佳轉(zhuǎn)化條件：溶液初始pH=10.0、NH4HCO3濃度1.68 mol/L、反應(yīng)溫度50 ℃、反應(yīng)時間120 min；PbCl2在轉(zhuǎn)化過程中會經(jīng)歷PbCl2 Pb2Cl2(CO3) PbCO3的轉(zhuǎn)化過程，在最佳工藝條件下轉(zhuǎn)化率可達(dá)99%以上，轉(zhuǎn)化產(chǎn)物為純凈的PbCO3。通過不同轉(zhuǎn)化階段得到的產(chǎn)物的物相分析，確定PbCl2在NH4HCO3溶液中轉(zhuǎn)化為PbCO3的機(jī)理、途徑及影響機(jī)制。轉(zhuǎn)化體系的pH值是影響轉(zhuǎn)化率、轉(zhuǎn)化途徑及最終產(chǎn)物物相組成的最顯著因素，而轉(zhuǎn)化劑濃度、轉(zhuǎn)化時間和溫度，只會對PbCl2脫氯速率造成影響，并不會影響PbCl2的轉(zhuǎn)化途徑和最終產(chǎn)物組成。
關(guān)鍵字: 氯化鉛；碳酸氫銨；物相轉(zhuǎn)化機(jī)理；脫氯率；轉(zhuǎn)化產(chǎn)物
（1. School of Metallurgy and Environment, Central South University, Changsha 410083, China;
2. Qinghai Provincial Research and Design Academy of Environmental Sciences, Xining, 810000, China）
Abstract:The phase transformation mechanism of PbCl2 in ammonium bicarbonate solution was investigated. The dechlorination efficiencies of different conversion agent in the same condition were determined as follow from big to little: NH4HCO3, Na2CO3, (NH4)2CO3, K2CO3. The optimum transforming conditions of PbCl2 using NH4HCO3 as transforming agent were also detected and determined as follow: initial pH=10.0, cNH4HCO3=1.68 mol/L, reacting temperature 50 ℃, reaction time 120 min. 99% PbCl2 transforms into PbCO3 through PbCl2 Pb2Cl2(CO3) PbCO3 process. The final resultant is pure PbCO3. The phase analysis of conversion products at different conversion stages were carried out to investigate the transformation and influencing mechanism. The results indicate that pH value of the solution is the most significant influencing factor on PbCl2 conversion rate, transformation path and final resultant compositions. While, the NH4HCO3 concentration, reaction time and temperature only affect the dechlorination rate, and don’t affect the transformation path of PbCl2 and the compositions of the conversion products.
Key words: lead chloride; ammonium bicarbonate; phase transformation mechanism; dechlorination rate; transformation product
