高硅尾渣固体氰溶解洗涤工艺

针对某公司氰化尾渣浮选后的高硅尾渣的特点,采用洗涤的方式对其中存在的固体氰化物进行实验研究。采用单因素实验方法对pH值、反应时间、投加药剂种类和投加量、淋洗液种类及淋洗次数等影响因素进行了优化。结果表明,投加螯合剂有利于高硅尾渣固体氰化物的洗涤溶出。最佳实验条件为pH值为13,投加3 g葡萄糖酸钠反应3 h,对滤饼用清水淋洗2次,处理后的高硅尾渣总氰化物浓度从653.65 mg/kg降至27.21 mg/kg,去除率达到95.84%。研究结果对高硅尾渣中固体氰化物的脱除有一定的借鉴意义。

氰化钠阴云何时散

氰化钠的检出给天津港“8·12”爆炸事故再添阴云。在此之前,人们仅仅知道氰化钠是剧毒危险品,只需0.1克即可让一个成年人丧命。实际上,我国已成为全球氰化钠第一生产大国,同时,氰化钠作为基础工业原料之一,广泛用于黄金提取、电镀等行业。为了满足日益增长的需求,有关氰化钠的大型项目频频上马,

Physico-chemical Characteristics of a Gold Mining Tailings Dam Wastewater

The study was conducted on the status of the quality of wastewater from the tailings dam of Central Africa Gold Limited in Bibiani, Ghana, to ascertain the level of contamination of the wastewater. The tailings dam stores process effluent from the gold extraction plant. Wastewater samples taken from the tailings dam were analyzed for physico-chemical characteristics. Arsenic, iron and cyanide were identified as the major pollutants in the tailings dam wastewater with average concentrations of 4.5, 25.2 and 11.1 mg.L1, respectively. Arsenic, iron and free CN （cyanide） concentrations in the process effluent exceeded the Ghana EPA discharge limits of 0.2, 2 and 0.2 mg.Ll, respectively. High conductivity, total dissolved solids, sulphate and ammonium were found in the wastewater studied. The tailings dam serves as a natural reservoir that removes most of the total suspended solids and the turbidity, resulting in the improvement in the aesthetic appeal of the wastewater. Nonetheless, arsenic, iron and cyanide concentrations were still high and hence the wastewater cannot be discharged into the environment without prior treatment.

2-羧乙基-3-氰基-5-甲基己酸乙酯的合成

以异戊醛和丙二酸二乙酯为原料,经克脑文盖尔缩合反应(knoevenagel缩合)、氰化加成两步反应合成了普瑞巴林中间体2-羧乙基-3-氰基-5-甲基己酸乙酯。通过对合成工艺中选用溶剂、反应温度、物料投料比例、后处理方式等条件进行优化,得到优化条件下中间体的收率为91.3%;2-羧乙基-3-氰基-5-甲基己酸乙酯的收率97.8%,总收率为89.3%。