Classification and reuse technology of polymetallic ore dressing wastewater

In view of the many problems existing in the treatment and reuse of polymetallic ore beneficiation wastewater, this paper mainly designs the reuse plan of polymetallic beneficiation wastewater based on the input nodes of flotation reagents and the composition properties of wastewater in each loop.

Introduction of polymetallic ore flotation reagents

Flotation reagents are divided into three categories according to their uses: collectors, foaming agents, and regulators. The main function of the collector is to make the surface of the target mineral particles hydrophobic and increase their floatability. Commonly used collectors mainly include xanthate collectors, black medicine collectors, sulfur and nitrogen collectors, this urethane, mercaptan collectors, Baiyao, etc.

The foaming agent is a surface-active substance whose main function is to promote the formation of foam and ensure that the foam formed by the bubbles loaded with mineral particles on the surface of the pulp can be discharged smoothly. Commonly used foaming agents are pine oil, No. 2 oil, methyl amyl alcohol, ether alcohol oil, and butyl ether oil.

The main function of the modifier is to adjust the role of other agents and the surface of the mineral particles, adjust the properties of the pulp, and improve the selectivity of the flotation process.

A feasible scheme for the staged reuse of copper-lead-zinc polymetallic beneficiation wastewater

In a copper-lead-zinc concentrator, the products are zinc concentrate, lead concentrate, and copper concentrate. Process route of beneficiation: after the raw ore is crushed by the second stage and the first closed circuit, it is then subjected to a closed circuit grinding; the grinding qualified products are subjected to a copper-lead mixing selection, a copper-lead sweeping selection, and two copper-lead selections to obtain a copper-lead mixed concentrate. The copper-lead mixed concentrate enters the copper-lead separation process, and the floating copper and lead suppression process are adopted. Copper is subjected to one roughing, one copper beneficiation, and three sweeps to obtain copper concentrate and leads concentrate; copper and lead mixed tailings undergo one zinc roughing, four zinc beneficiation, and two zinc sweeps to obtain zinc concentrate. mine.

There are three places for adding chemicals in this process route, which are: copper and lead mixing site, zinc inhibitor (sodium sulfite, zinc sulfate), copper and lead collector (Xanthate B), foaming agent (No. 2 oil); In the copper-lead separation place, add adsorbents (activated carbon, mainly used to adsorb the chemicals added in the previous copper-lead mixing selection to reduce the adverse effects on the back-end copper-lead separation), lead inhibitors (water glass, carboxymethyl fiber) element), copper collector (Z-200); at the lead separation of tailings, add adjuster (lime), zinc activator (copper sulfate), zinc collector (butanexanthate), No. 2 oil (foaming) agent).

If the beneficiation wastewater in this process route is not reused in stages and is directly mixed and reused at the front-end classifier, it will affect the grades of the copper concentrate, lead concentrate, and zinc concentrate behind. The reasons are: the presence of the mixed water at the same time Inhibitors and activators of lead and zinc, and the mutual interference of various agents will reduce the flotation effect; different agents in the mixed liquid may undergo chemical reactions, reducing the flotation effect; due to the complexity of the agents in the mixed water, if they are reused from the front end, the subsequent The section can only increase the concentration of the corresponding agent, resulting in the continuous accumulation of the concentration of the agent.

In order to realize the graded reuse of wastewater and dry tailings discharge, the wastewater reuse scheme proposed in this paper is as follows:

Newly added thickener (copper and lead mixed separation, tailings before zinc separation). The filtered water can be reused in the ball mill + spiral classifier (if there is an excess backwater, the excess part should go to the spiral classifier. If the backwater is not enough, it may be necessary to add fresh water), the main agent is zinc inhibitor (sodium sulfite, Zinc sulfate), copper-lead collector (Xanthate B), foaming agent (No. 2 oil);

A plate and frame filter press are installed at the tail end of the tailings, and the filtered water can be reused for the front-end stirring tank of zinc selection. medicine), No. 2 oil (foaming agent), and a small amount of sodium sulfite, zinc sulfate, ethyl xanthate, etc. remain during the mixing of copper and lead. The water produced by the dehydration of the zinc concentrate can be combined with the tail pressure filtration water of the total exhaust and reused for the front-end stirring tank of the zinc selection.

The water produced by dehydration of copper concentrate and lead concentrate can be reused in copper concentrate, lead concentrate flotation tank, or front-end stirring tank for copper and lead separation. The main agents are adsorbent (activated carbon), lead inhibitor (water glass, carboxyl Methylcellulose), copper collector (Z200), and a small amount of sodium sulfite, zinc sulfate, ethyl xanthate, etc. remaining during the mixing of copper and lead.

Analysis of the effect of transformation

Costs increased in the transformation: a thickener, a plate and frame filter press for tailings dry discharge, a pipeline system for graded reuse water (three-way), a newly constructed reservoir for each section of graded reuse water, and operating costs.

The benefits brought about by the transformation: the amount of freshwater supplementation is greatly reduced; the amount of a single type of chemical added is reduced; the grades of copper concentrate, lead concentrate, and zinc concentrate are guaranteed.

The positive environmental benefits brought by dry tailings drainage: greatly reduce the land occupation and reduce the damage to the ecological environment; avoid the hidden dangers of accidents such as dam collapse; avoid the risk of pollution of the surrounding water environment due to damage to the bottom of the reservoir.

Conclusion

This design scheme is practical and feasible, and can fully realize the dry discharge of tailings and the reuse of all wastewater, greatly reduce the amount of freshwater taken and ensure product quality, bringing greater productivity and environmental benefits.

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