磷酸三丁酯萃取脱硫废液中硫氰酸根的初步研究

焦炉煤气含污染物H_2S 5g/m~3-8gm~3、HCN1g/m~3-2.5g/m~(31]),目前主要用催化氧化-氨水吸收法(NH_3-OMC)工艺处理.由此产生的脱硫脱氰废液中主要含有NH_4SCN、(NH_4)_2S_2O_3等无机盐,其中,SCN~-及S_2O_3~(2-)浓度均影响脱硫催化剂的效率,规定其总浓度不得超过250g/L.

Preliminary study on TBP extraction of thiocyanate from waste solution for coke oven gas desulfurization

The extraction of thiocyanate(SCN~-)from potassium thiocyanate(KSCN)solution and waste solution for coke oven gas desulfurization using tributyl phosphate (TBP)and affect of several factors were investigated.IR analysis shows that TBP is able to extract SCN~-,but can not extract thiosulfate anion(S_2O_3~(2-)).For extaction from 6% KSCN solution with TBP,the single extraction rate of SCN~- is 10.95% and the partition coefficient is 0.1230.SCN~- is extracted by TBP via the formation of ccordination bond.The main impacting factors on extraction includes phase ratio,extraction time,and the presence of NH_4~+.For extracting SCN~- from diluted waste solution for coke oven gas desulfurization,the average single extraction rate is 15.39%,and the waste solution can be reused after desalting extraction.The single stripping rate is 61.73% using distilled water as strippant.The total stripping rate can reach 95.15%,after stripping for three times.For reuse of TBP that removed SCN~-,it must be undergone further purification.