Nickel acid cleaning water treatment and reuse system
We use this process more frequently in other customers. The process is very mature. The nickel sulfamate and nickel sulfate processes can basically achieve zero emissions, and the pollution reduction and emission reduction effects are very significant.
Step 1: The nickel sulfate cleaning water is collected through the pipeline and enters the collection pool. The nickel-containing wastewater is pumped into the first-stage T27 ion concentration for preliminary separation through the lifting pump. The fresh water after the first-stage T27 concentration separation is used as the raw water of the T40 ion concentration system, and the concentrated water of the first-stage T27 is used as the raw water of the third-stage T27 concentration system, Step 2: The fresh water of the second-stage concentration system T40 enters the RO system for further treatment, T45 concentrated water goes to the first-stage T27 raw water, Step 3: The concentrated water of the first-stage T27 enters the raw water tank of the fourth-stage concentration system T27 as the raw water of the fourth-stage circulation concentration, and the fresh water of the fourth-stage concentration returns to the raw water tank of the first-stage concentration system T27 as the raw water of the first-stage concentration system, the concentrated water enters the subsequent concentrated water tank as the raw water of the fifth-stage high-pressure concentration system T100, Step 5: The concentrated water of the fourth-stage concentration T27 enters the fifth-stage T100 through the pump The high-pressure concentration system is used for concentration, and the fresh water returns to the raw water tank of the three-stage concentration system T27. When the nickel concentration of the T100 concentrate reaches 30g/L, the concentrate is deglazed and nickel-plated in the tank.
Modified special membrane
In the selection of special membranes, the concentration part uses Yixuan Ni/CuT27, Ni/CuT45, and Ni/CuT100 modified concentration membranes. The concentration part uses
four-stage concentration, and the fresh water sewage station is used for deep treatment to meet the standards to ensure that the nickel content of the wastewater discharged by the system is stable and meets the standards.
Modified concentration membrane (YX-Ni/CuT27):
1) Yixuan modified concentration membrane is based on the original characteristics of RO membrane and nanofiltration membrane to modify the pore size and anti-pollution ability, Yixuan modified membrane has a molecular weight cutoff between reverse osmosis membrane and nanofiltration membrane, about 100-2000Da. Yixuan modified membrane is a composite membrane, and its surface separation layer is composed of polyelectrolytes, so it has a certain retention rate for inorganic salts. There are two main types of Yixuan modified membranes, Ni/CuT27 membrane and Ni/CuT40 membrane: ① The operating range of Ni/CuT40 membrane is between nanofiltration and reverse osmosis, with a retention rate of about 20% to 70% for monovalent ions and a retention capacity of 50% to 98% for divalent ions. The removal rate of soluble low-valent ions is lower than that of high-valent ions. Ni/CuT40 membrane is generally used for the recovery and concentration of industrial valuable metals, and partially removes dissolved salts. It is used for the concentration and recovery of valuable precious metals in electroplating and electronic circuit board wastewater production. The operating pressure of Ni/CuT40 membrane is generally 3.5-30bar. ②The operating range of Ni/CuT27 membrane is between ultrafiltration and nanofiltration, with a monovalent ion retention rate of ≤1% and a divalent ion retention capacity of 70%-90%. There is almost no removal rate for soluble low-valent ions. Ni/CuT40 membrane is generally used to remove organic matter and pigments in landfill leachate, industrial sewage, surface water, hardness in groundwater, separation and purification of monovalent ions and divalent ions, and partial removal of dissolved salts, and extraction and concentration of useful substances in food and pharmaceutical production. The operating pressure of N270 membrane is generally 3.0-30bar.
2) Currently, Ni/CuT45 membrane is mainly used for the concentration and metal recovery of double-glazed copper foil cleaning water, copper clad copper foil cleaning water, electroplated copper sulfate cleaning water, nickel sulfate cleaning water, trivalent chromium cleaning water, blue passivation cleaning water, and electronic circuit board primary copper and secondary copper cleaning water
3) Currently, Ni/CuT27 membrane is mainly used for the concentration of organic matter in pre-treatment cleaning wastewater, concentration of food wastewater, salt separation and purification of concentrated liquid, separation of organic matter and salt in the chemical industry, and separation of monovalent ions and divalent ions. The retention rate of Ni/CuT27 for organic matter is 70%, the retention rate for divalent ions is 98%, and the retention rate for monovalent ions is almost 0. The key to the concentration process is the membrane. The requirements for membrane materials are: good film-forming properties, thermal stability, chemical stability, high mechanical strength, resistance to acid, alkali and microbial erosion, resistance to chlorine and other oxidizing substances, high water flux and high salt retention rate, and resistance to colloid and suspended solids pollution. The membrane materials used for Ni/CuT45 membranes are mostly aromatic and polyacid hydrogen asymmetric composite membranes. Ni/CuT45 concentration membranes are composed of two parts: one part is a porous membrane that plays a supporting role, and its mechanism is screening, the other part is a thin layer of dense membrane that plays a separation role, and its separation mechanism can be explained by the dissolution diffusion theory. For composite membranes, the skin layer and the support layer that play a separation role can be optimized in terms of materials and structures, respectively, to obtain composite membranes with excellent performance. The forms of membrane components include hollow fiber, roll type, plate and frame type, and tube type. Among them, hollow fiber and spiral membrane components have high packing density, low cost, and good fluid mechanics conditions in the components, however, these two types of membrane components have high manufacturing technology requirements, difficult sealing, poor anti-pollution ability during use, and high requirements for pretreatment of feed liquid. Although plate-frame and tubular membrane components are easy to clean and resistant to pollution, they have low packing density and high cost. Therefore, hollow fiber or spiral membrane components are mostly used in nanofiltration systems.
Our company has developed three modified concentration membranes based on the types and characteristics of wastewater, while retaining the original characteristics of nanofiltration membranes and RO. These are special membrane products that have significant effects on separation of metal ions and anti-pollution for reclaimed water reuse.
For general reverse osmosis membranes, the desalination rate is an important indicator of membrane separation performance, but for modified concentration membranes, the desalination rate alone cannot explain their separation performance. Sometimes the retention rate of modified concentration membranes for substances with larger molecular weight is lower than that for substances with smaller molecular weight. The filtration mechanism of modified concentration membranes is very complex. Since the modified concentration membrane technology is an emerging technology, our research on the mechanism of modified concentration membrane is still in the initial exploration stage, and there are few relevant literatures. However, since the modified concentration membrane is a branch of reverse osmosis, many phenomena can be explained by the mechanism model of reverse osmosis.
The filtration performance of the modified concentration membrane is also related to the charge of the membrane, the process of membrane manufacturing, etc. Different modified concentration membranes have different selective permeabilities to solutes, such as Ni/CuT27 for the separation of monovalent ions and divalent ions, solution purification, organic matter and salt separation, organic matter purification, and pharmaceutical purification. The actual separation performance of the modified concentration membrane is also related to the operating pressure, solution concentration, temperature, pH value and other conditions of the concentration process. For example, the permeation flux increases with the increase of operating pressure, and the retention rate decreases with the increase of solution concentration.
