微泡柱沉淀浮选法介尺度调控去除选矿废水金属污染物的基础研究

To realize the full cycling of beneficiation wastewater, it is very significant to exploit wastewater treatment and recycling technology based on water quality control, which will promote the green development of non-ferrous metal industry. Aimed at the universal scientific issues of the full cycling of beneficiation wastewater (including bauxite and copper-lead-zinc ore wastewater) and the separation process of minerals, the fundamental study on mesoscale controlling removal of metal pollutants using precipitation flotation process of micro-bubble column in recycling processes is carried out in this project. The key problem is the directional precipitation of metal ions and the mesoscale control of precipitate flotation. Baed on technical superiority of the existing reagents and equipment, the main contents are mainly included by the following: 1) the chemical constitution of beneficiation wastewater and the species distribution of metal pollutants; 2) the transforming behavior between metal ions and its precipitation, and the distribution characteristics of beneficiation reagents on these precipitation particles; 3) the stability and interface behavior of metal pollutant particles in the flow-transfer- separation process; 4) The precipitation flotation behavior of metal pollutants in micro-bubble floatation column, outfield intensify, and real-time regulation of the recycle water. This project will provide the supports for the development of precipitation flotation technology of micro-bubble column considering mesoscale structure, the realization of the selective purification and cyclic utilization of beneficiation wastewater, and the foundation of a theory and method for the control of full cycling of bulk beneficiation wastewater.

开发基于水质调控的废水净化与循环利用技术，实现选矿生产过程的废水全循环，对我国有色金属工业的绿色发展意义重大。针对（铝土矿、铜铅锌矿）选矿废水和难选物质分离过程共性科学问题，本项目开展微泡柱沉淀浮选法介尺度调控去除金属污染物的基础研究。微泡柱沉淀浮选能否成功的关键在于金属离子定向沉淀转化和沉淀颗粒浮选过程介尺度行为的调控程度。依托现有药剂与装备技术优势，研究内容包括：1）选矿废水溶液化学组成、金属污染物化学形态分布规律；2）金属离子-沉淀颗粒间定向转化行为及药剂在颗粒表面分维特征与作用机制；3）金属污染物沉淀颗粒流动-传递-分离过程的稳定性与表界面驱动行为；4）金属污染物微泡柱沉淀浮选行为、外场强化与净化废水循环动态调控。本项目将为开发基于介尺度行为调控的微泡柱沉淀浮选技术，实现有色金属选矿废水的选择性净化与循环利用，构建大宗废水全循环过程调控理论与方法提供支撑。

实现选矿生产过程废水的高效净化，对我国有色金属工业的绿色发展意义重大。本项目开展微泡柱沉淀浮选法介尺度调控去除金属污染物的基础研究。研究内容包括：选矿废水溶液化学组成、金属污染物化学形态分布规律；金属离子-沉淀颗粒间定向转化行为及药剂在颗粒表面分维特征与作用机制；污染物沉淀颗粒流动-传递-分离过程的稳定性与表界面驱动行为；污染物微泡柱沉淀浮选行为、外场强化与净化废水循环动态调控。结果表明，采用含Cu2+，Pb2+，Zn2+金属污染物模拟废水，药剂HA为螯合沉淀剂，Fe3+基调控剂为沉淀颗粒絮体调控药剂，CTAB作为浮选捕收剂。在螯合沉淀转化阶段，HA的-COOH和-OH与其螯合形成单齿配体HAM+和双齿配体HA2M等。Fe3+基调控剂显著增大MHA螯合反应的条件稳定常数logKs，更易于形成稳定螯合沉淀。浮选分离阶段中CTAB能够使沉淀絮体颗粒尺寸增加到30.0~40.0 μm，其机理在于CTAB与MHA-Fe沉淀絮体间的静电引力作用和吸附作用。在沉淀转化-絮体生长调控-浮选分离过程中沉淀颗粒絮体的尺度、结构强度及形貌特性变化反映了沉淀浮选分离的作用机制。得到金属污染物溶液的最佳螯合沉淀条件为溶液pH=6.0，HA用量为理论用量/实际用量摩尔比1.0，反应时间30 min，金属污染物沉淀转化率分别为99.95，99.98和99.58%；在Fe3+用量1.2 mmol/L，搅拌强度500 r/min，搅拌时间20 min，浮选溶液pH=6.1，CTAB用量100.8 mg/L，浮选充气流量0.5 L/min，浮选时间30 min条件下，沉淀絮体粒径为31.3~39.4μm，浮选脱除率为99.6~99.9%，残余的离子浓度满足排放标准。本项目将为开发微泡柱沉淀浮选技术，实现有色金属选矿废水的净化与循环利用，构建大宗废水全循环过程调控理论与方法提供支撑。