氧化预处理联合微波焙烧技术回收锌冶炼酸泥中的硒汞工艺

Recovery of Selenium and Mercury from Acid Mud Produced in Zinc Smelting Process by Oxidation Pretreatment Combined with Microwave Roasting Technology

针对锌冶炼过程产生的含汞酸泥现有湿法工艺中汞硒浸出率低,常规焙烧工艺能耗高和造渣量大的现状,提出一种酸泥氧化预处理回收硒-微波焙烧回收汞的新工艺,以实现酸泥中汞硒的高效分离回收.对高锰酸钾氧化浸出硒汞的原理和工艺条件进行了研究,向浸硒液中加入氢氧化钠能得到氧化汞沉淀,将其与含汞浸出渣混合干燥后,进行微波焙烧处理回收汞单质.向含硒滤液中通入二氧化硫还原得到硒单质,最终实现了硒和汞高效分离回收的目的.结果表明:当浸出温度为80℃,浸出时间为5 h,液固比为10∶1,转速为550 r/min,高锰酸钾加入量为理论值的1.2倍(以硒化汞和硫化汞含量计),溶液中的硫酸浓度为100g/L时,硒的浸出率达到96%.当微波焙烧温度为500℃,焙烧时间为30 min时,汞回收率达到了98.5%.本工艺的硒浸出率和汞回收率高、能耗低,是一种具有应用前景和绿色高效的酸泥处理技术.

In view of the low leaching rate of mercury and selenium in the existing wet process, high energy consumption and large amount of slag formation in the conventional roasting process of mercury-containing acid mud produced in zinc smelting process, this paper proposes a new process of acid mud oxidation pretreatment to recover selenium and microwave roasting to recover mercury in order to achieve efficient separation and recovery of mercury and selenium in acid mud. The principle and process conditions of selenium leaching by oxidation of potassium permanganate were studied, and the addition of sodium hydroxide to the selenium leaching solution could obtain mercury oxide precipitation, which was mixed and dried with the mercury-containing leaching residue and then microwave roasted to recover mercury monomers, and the selenium-containing filtrate was reduced by passing sulfur dioxide to obtain selenium monomers, which finally realized the purpose of efficient separation and recovery of selenium and mercury. When the leaching temperature was 80 ℃, the leaching time was 5 hours, the liquid-solid ratio was 10∶1, the rotation speed was 550 r/min, the amount of potassium permanganate added was 1.2 times of the theoretical value(in terms of mercury selenide and mercury sulfide content), and the concentration of sulfuric acid in the solution was 100 g/L, the leaching rate of selenium reached 96%. When the microwave roasting temperature was 500 ℃ and the roasting time was 30 min, the recovery of mercury reached 98.5%. With high selenium leaching rate and mercury recovery rate, low energy consumption, this process is a promising, green and efficient treatment technology of acid mud.