Can FeSO4 reduce ammonia-copper complex ions in the treatment of ammonia-copper wastewater?

Copper ions in complexing wastewater form a relatively stable complex with complexing agent, which is one of the more difficult circuit board wastewater to treat. Some circuit board enterprises mainly recycle it and convert copper into CuSO4, CuO, Cu, ammonium sulfate or ammonium chloride, and some enterprises discharge it into sewage treatment system for treatment. The treatment of complexation wastewater (EDTA, cuprammonium hydroxide) should first consider the destruction of complexation to free copper ions. At present, in actual operation, there are many methods to disconnect the network, which are summarized as follows (note: ★ indicates that this method is the most commonly used). Method 1: adjust the PH value to break the network (adjust the PH value of wastewater to about acidity 2 to break the network); Method 2: oxidation-reduction of oxidant (naclo); Method 3: breaking the net by ion exchange-electrolysis; ★ Method 4: Chemical agent replacement, collateral breaking (Na2S, FeCl3, special agent, etc. ); In the above four methods, acidic solution (HCl, H2SO4) is added to adjust the PH value of complex wastewater to 2-3, and Cu2+ is released from the complex, which has a good chromium breaking effect. However, because the raw water of complex wastewater is mostly alkaline, it consumes a lot of acid liquor when adjusting the acidic PH value to 2-3, and copper precipitates after the complex is broken, which consumes a lot of alkali liquor, so it is not widely used. The technological process is as follows: Methods Generally, the reduction method is used to break the net. Under acidic conditions, iron filings Fe and ferrous ion Fe2+ are reduced, and the reaction lasts for about 20-30 minutes. Fe2+ reduces Cu2+ in Cu2+EDTA complex to Cu+. Because Cu+ is not easy to combine with EDTA under alkaline conditions, Cu2O is generated and reacts with Fe (OH) under alkaline conditions. The scrap iron reactor broken by scrap iron polymerization method is easy to scale and agglomerate, which affects the normal operation of the equipment and the labor intensity of scrap iron renewal is high, which hinders the application of this method. Breaking the net with sodium hypochlorite is a side effect of cyanide-containing wastewater, which has a certain effect on breaking the net. This method has practical significance only if the sewage contains cyanide. In the third method, ion exchange electrolysis is rarely used because of the disadvantages of high concentration of heavy metals, easy pollution of complex or aging of exchange resin, large power consumption of electrolysis and single type of metal to be treated. The fourth method uses chemical agents such as Na2S, FeCl3 _ 3 and special agents, which are easily available, moderately priced, effective and easy to use. It has application and popularization value in circuit board wastewater, and is also a widely used method in circuit board wastewater treatment at present. FeCl3 _ 3 _ 3 has a good function of breaking collaterals, but it is highly corrosive and requires high transportation, storage and preparation, so it is rarely used. There are many kinds of collateral specific drugs, most of which are patented products. For example, ISX (insoluble cross-linked starch xanthate) is a water treatment agent developed in 1970s, which can precipitate most heavy metals with a wide PH range of 3- 1 1 and rapid precipitation. TMT (trimetazidine trisodium) is a new type of heavy metal precipitant recently developed in the United States. S946 is also a new treatment agent. Treating complex wastewater with Na2S is the choice of wastewater treatment in most circuit board enterprises. Na2S is not only used to treat complexed wastewater, but also used to treat non-complexed wastewater, which has good copper removal effect. Copper ions in S2 precipitation complex react to form CuS.