盐酸法生产钛白废液制取高纯Fe2O3实验研究

对盐酸法生产钛白的含氯化亚铁废酸液制取高纯氧化铁产品和无害化排放应用进行了实验研究.实验结果表明,用质量分数为7.5%的氨水作中和沉淀剂,控制溶液pH值为4,反应温度50℃,除去钛硅等杂质;再用质量分数为0.21%的稀硝酸处理氧化铁,除去钙镁杂质,所得产品Fe2O3纯度可大于99.3%,符合原电子部工业标准SJ/T 10383-93要求.废液中硝酸的质量浓度低于0.4g/L,沉淀氧化铁后的滤液经蒸发结晶回收氯化铵,可实现废液无害化排放.     

Adsorptive Removal of Nitrate and Phosphate from Water by a Purolite Ion Exchange Resin and Hydrous Ferric Oxide Columns in Series

Elevated concentrations of nitrate and phosphate in surface and ground waters can lead to eutrophication, and nitrate can also cause health hazards to humans. The adsorption process is generally considered to be an efficient technique in removing these ions provided that the adsorbent is highly selective for these ions. Removal of nitrate and phosphate from a synthetic water (50 mg N/L as nitrate, 15 mg P/L as phosphate) and a wastewater (12.9 mg N/L as nitrate, 5.9 mg P/L as phosphate) using a Purolite A500P anion exchange resin and a hydrous ferric oxide (HFO) columns (60 cm height, 2 cm diameter, flow rate 1 m/h) in series containing 1–10% (w/w) of these adsorbents and the remainder anthracite (90–99%) were studied. Data from batch adsorption experiment at various concentrations of adsorbents satisfactorily fitted to Langmuir adsorption isotherm for nitrate and phosphate on Purolite with adsorption maxima of 64 mg N/g and 7 mg P/g and only for phosphate on HFO with adsorption maxima of 14 mg P/g. Both batch and column experiments showed that Purolite selectively removed nitrate and HFO selectively removed phosphate. The Purolite column BTC time was greater for nitrate than for phosphate. At the highest percentage by weight of Purolite almost all nitrate was removed in batch study and up to 1000 min in column study, but it was not able to remove a comparatively high percentage of phosphate. However, when the effluent from the Purolite column was passed through the HFO column almost all phosphate was removed. The two columns when set up in series also removed almost all nitrate and phosphate from the wastewater.     

Magnetic Carrier for Radionuclide Removal from Aqueous Wastes: Parameters Investigated in the Development of Nanoscale Magnetite Based Carbamoyl Methyl Phosphine Oxide

Abstract

A study on superparamagnetic magnetite polymer composite development was undertaken for application to magnetically assisted chemical separation. Tetramethyl ammonium hydroxide as an alternative to ammonia was used as a precipitation agent to obtain nanoscale magnetite particles. Investigation on stoichiometry control of Fe(III) and Fe(II) ions suggested a correlation between alkalinity and initial Fe(III): Fe(II) ratio for precipitation of magnetite. Studies on polymerization conditions suggested that polymers setting at ambient conditions enable retention of superparamagnetic property of substrate magnetite. Vaporization method for impregnation of solvent extractant CMPO, yielded product that had a high sorption capability for radionuclide europium as compared to wet impregnation method.