Copper Wastewater Treatment

Solution: 

Mainly in sulfuric acid wastewater containing copper and copper ion is given priority to, wastewater into IVECDEST low-temperature vacuum distillation system, finally extract more than 90% pure distilled liquid, the remaining 5% ~ 10% high mother liquor of salt, mother liquor VESALT scraper into the vacuum drying in low temperature crystallization system, eventually get dry solid crystal salt, solid crystal salt, moisture content of 15% or less. The water vapor in the wastewater condenses to form a distillate, which is collected into a clear water bucket. The water yield can reach more than 99%, the water quality is clear and transparent, and the distillate can be reused as middle water or meet the discharge standard.

Application：

Brief Introduction:

Copper containing wastewater is the wastewater produced by metallurgy, electronics and other industries, mainly including printed circuit board etching wastewater and electroplating wastewater. Copper content is high in copper containing wastewater. Direct emissions not only pollute the environment, but also waste resources. Therefore, it is necessary to treat copper containing wastewater, recover copper by technical means, and discharge it after water quality meets the standards.

1. Chemical industry, printing and dyeing, electroplating, non-ferrous smelting, non-ferrous metal mining, electronic material cleaning wastewater, dye production and other processes often produce wastewater containing a large number of copper ions. Depending on the valence of the copper ion, there are divalent and monovalent copper ions; According to the existing form, there are free copper (such as Cu2+) and complex copper (such as copper cyanide complex ion [Cu(CN)3]2-, copper ammonia complex [Cu(NH3)42+], etc.).

2. Copper ions often exist in the form of complexes in the wastewater containing copper in dyes, electroplating and other industries, such as copper cyanide complex ions [Cu(CN)2], [Cu(CN)3]2-, [Cu(CN)4]3-. It is generally believed that the copper cyanide complex ions in wastewater mainly exist in [Cu(CN)3]2-. The copper chloride complex ions decompose into Cu+ and Cl-, and the monovalent copper ions spontaneously dismutate in aqueous solution to form divalent copper ions. Taking acid copper plating wastewater as an example, the wastewater mainly contains cations such as Cu2+, H+, Fe2+, Fe3+ and anions such as SO42- and C1-. There are 300~450mg/L free cyanide ions and 400~550mg/L monovalent copper ions in the cyanide copper plating wastewater.

3. The life of the electrolytic copper foil foil and surface treatment, such as the main production process requires a lot of water to wash of copper foil surface, which include copper wastewater and wastewater containing chromium, nickel waste water, waste water containing zinc, such as washing wastewater. Because of electrolytic copper foil production wastewater with less impurity, the characteristic of the large amount of wastewater, the new copper foil factory has a large number of membrane process used to resource recycling of waste water, after obtaining a high concentration of copper, nickel, zinc, chromium concentrate at the same time, to make waste water to achieve closed-circuit circulation, near zero emissions, to achieve the purpose of saving resources and protecting the environment.

But from the operation of the wastewater containing copper resource reuse project case, in such aspects as technology, economy, management, there are many difficulties, resource recycling and truly "near zero emissions" is very difficult, some publicity and successful case is down.

The main problems are:

1. The concentration of BWRO and SWRO did not reach the designed target value

The membrane process was used to concentrate the wastewater under acidic operating conditions of pH 1 to 3, although ion crystallization on the concentrated water side of the membrane element was avoided. But as a result of reverse osmosis membrane at pH 7.5 ~ 7.8 desalting rate is highest, under the condition of low pH runtime of desalting rate is not high. In addition, due to the influence of concentration polarization and water temperature, only when the membrane pressure of BWRO and SWRO is greater than the osmotic pressure of the concentrated solution by 10bar, the ion concentration in BWRO and SWRO concentrates cannot reach the designed target value, so the number of NF cycles needs to be increased, which aggravates the operation load of NF.

2. The reduction efficiency of NF concentrate can not meet the design requirements

The relationship between the salt content of the NF input solution and the amount of liquid yield and concentrated solution is that under a certain working pressure, the higher the salt content of the stock solution, the smaller the amount of liquid yield and the greater the amount of concentrated solution. Therefore, when the concentration of the feed liquid changes, in order to ensure that the amount of NF concentrate meets the design requirements, it must be adjusted to a higher working pressure to meet the processing requirements. However, in some similar cases that have been operated, there is no excess in the pressure design of the NF liquid feed pump. When the NF operating conditions change, because the pressure of the NF liquid feed pump has reached the limit working pressure, the NF has been unable to concentrate effectively, and the concentrated liquid volume far exceeds the design target, and the production line cannot consume such a large amount of concentrated liquid.

3. Reverse osmosis and nanofiltration membrane element shorter service life

The diaphragm, water inlet separator, water production separator and adhesives of reverse osmosis and nanofiltration membrane elements are all made of chemical materials. Long-term operation under low pH conditions of pH value of 1 to 3 will cause irreversible changes in the fine structure or molecular structure of chemical materials, accelerate the decay of membrane performance, and reduce the service life of membrane elements. From the copper foil factory has run the similar case, membrane element change cycle is one year long, short, three months has to be replaced. Because of the price is higher, membrane element change frequency too frequently, causing system operation cost is higher.

4. System maintenance and management difficulties

Wastewater resource utilization adopts the whole membrane process. Compared with the traditional wastewater treatment process, the operation and maintenance personnel are required to have more professional and refined operation, maintenance and management level. Some enterprises in order to reduce investment cost, low degree of automation equipment, and there is no reliable on-line monitoring instrument, and a lack of offline detection methods, which leads to many projects can only maintain the project acceptance is difficult to solve the problem, not stable operation.

VESALT IVECDEST low temperature evaporator temperature drying crystallization system can perfect solution containing copper waste liquid processing. More than one hundred intellectual property rights and patents make this evaporator a technological pioneer in vacuum distillation systems.

In our zero wastewater production and Application center, we have been developing innovative technologies that significantly improve the quality of distilled water for many years. Our suggestion is very clear. For example, the IVECDEST low-temperature evaporator and VESALT scraping plate crystallization technology with special technology can meet the quality requirements through a set of ingenious system preparation, so as to obtain clear distilled water and dry solid crystals. This makes our cryogenic vacuum distillation systems unique in the global market.

Process Diagram：

Mainly in sulfuric acid wastewater containing copper and copper ion is given priority to, wastewater into IVECDEST low-temperature vacuum distillation system, finally extract more than 90% pure distilled liquid, the remaining 5% ~ 10% high mother liquor of salt, mother liquor VESALT scraper into the vacuum drying in low temperature crystallization system, eventually get dry solid crystal salt, solid crystal salt, moisture content of 15% or less. The water vapor in the wastewater condenses to form a distillate, which is collected into a clear water bucket. The water yield can reach more than 99%, the water quality is clear and transparent, and the distillate can be reused as middle water or meet the discharge standard.