Shield the upper edge of the anode plate

The edge of the anode plate is not shielded, and the surface of the copper foil is prone to oxidation when the temperature is high.

The so-called shielding means that a strip of pure titanium or plastic Flat noodles with a width of about 60-80mm and a length equal to the horizontal length of the anode plate is vertically pasted on the anode plate. The shielding effect makes the cathode roll non-conductive at the moment when it enters the electrolyte, and the electrolyte is used to drain the gas adsorbed on the surface of the cathode roll.

Because an important characteristic of titanium is its ability to strongly absorb gases (oxygen, nitrogen, hydrogen, etc.), the electrolyte in the foil generator has the highest number of oxygen bubbles in the liquid when it is about to flow out of the electrode space. At this time, the bubbles that accumulate on the surface of the cathode roller may be the most. Therefore, when the cathode roller surface first enters the foil generator electrolyte, do not let it deposit copper. Let the electrolyte wash away the gas on the cathode roller first to avoid copper foil oxidation.

Before entering the electrolytic cell, the surface of the cathode roller may absorb a certain amount of gas, and the higher the temperature, the greater the suction. After entering the electrolyte, the surface of the cathode roller should present a pure titanium oxide film, and there should be no gas on the surface. This way, the raw foil is less prone to oxidation.

Cathode roller grinding roller polishing

The cathode roller has been used in the electrolytic cell for a long time, and the thickness of the organic and oxide films on the surface has increased. The copper foil is prone to oxidation, and even the copper foil has already oxidized when peeled off from the cathode roller. When the cathode roller has been produced in the electrolytic cell for a certain period of time, it must be polished and ground. If the cell is temporarily stopped for more than 4 hours, grinding or polishing must also be carried out when re slotting, otherwise the surface of the produced copper foil is prone to oxidation.

The thickness of the oxide film on the surface of the cathode roller may affect cathode polarization, causing the precipitation of hydrogen and monovalent copper, resulting in blackening of the copper foil surface and lack of metallic luster. From the actual production situation, it can be seen that if the production time of the cathode roller is too long and the copper foil oxidizes, whether the organic film on the surface of the cathode roller has a greater impact or the oxide film has a greater impact, further research and actual measurement are needed by later researchers to solve this mystery as soon as possible.

The low surface temperature of the cathode roller may affect cathode polarization and lead to hydrogen evolution at the cathode. This is not only due to the oxidation of the copper foil surface, but sometimes also causes pinholes in the copper foil.

This indicates that there must be hydrogen evolution phenomenon when the surface temperature of the cathode roller is low. Cathode hydrogen evolution forms a hydrogen potential, leading to a decrease in overpotential and the precipitation of monovalent copper, resulting in the formation of dark red copper powder on the smooth surface of the copper foil.

So, before the cathode roller is powered for production, the surface temperature must be raised to meet the process requirements before starting power production, so as to ensure that the copper foil surface does not oxidize or produce pinholes. Otherwise, the copper foil produced is waste, wasting energy and resources, and wasting effort.

The chloride ion content in the electrolyte is too high

When adding sulfur urea to the electrolyte, it is generally necessary to add chloride ions at the same time for equilibrium. If the amount of chloride ions added is too high, a cuprous chloride film will be formed on the cathode surface to hinder the adsorption of copper ions. The diffusion of adsorbed copper atoms on the cathode surface can lead to the formation of insoluble cuprous chloride and its inclusion in the grain boundaries, causing the copper foil to become rough.

Excessive chloride ion content affects anodic polarization, crystal orientation, and appearance of copper foil structure. In this case, copper foil not only oxidizes, but also becomes rough, with an increase in dendritic crystals and long copper spikes. The solution is to add organic additives appropriately.

Or stop production and add excessive thiourea to the electrolyte, stir vigorously, and when the temperature drops to 30 degrees, add hydrogen peroxide to the electrolyte and stir. Add granular activated carbon and filter it out to remove some chloride ions and most organic matter. After adding hydrogen peroxide, the electrolyte turns green, and when activated carbon is added and stirred, the electrolyte turns blue.

The surface of the squeezing roller is uneven

The squeezing roller and water squeezing roller have pits or significant differences in diameter, resulting in uneven contact with the copper foil surface on the cathode roller. Some areas have been in contact, while others have not, resulting in uneven liquid and water squeezing on the surface of the copper foil, leading to varying amounts of liquid remaining on different parts of the copper foil surface.

The amount of residual liquid on the surface of copper foil causes different corrosion strengths and colors on the copper foil surface. Areas with high residual liquid are prone to oxidation and discoloration of the copper foil. The surface roughness of copper foil varies, resulting in different extrusion effects and surface corrosion states, as well as different colors.

Places with high liquid volume have a longer corrosion time and are prone to oxidation, while places with low liquid volume have a shorter corrosion time and do not oxidize. The degree of oxidation on the copper foil surface varies in color. The squeezing roller has this problem and can easily cause gray and blue acid channels; The squeezing roller has this problem, which can easily cause black or dark gray water channels. If this problem occurs, only the squeezing roller and water squeezing roller can be finely ground to achieve a smooth surface and meet the technical requirements before use. This type of grinder and grinding wheel require extremely high precision and cannot be ground without special equipment and methods.

Splashing and dripping acid

If the surface of the copper foil is splashed or dripped with electrolyte or sulfuric acid solution, the rolled copper foil will have a circular blue mark printed on the smooth surface. If the liquid volume is high, the mark will be large, and if the liquid volume is low, the mark will be small. People call this type of mark "acid". If the marks formed by water splashing or dripping on the surface of copper foil are called water droplets, the color of water droplets on the copper foil surface varies depending on their position. The color is lighter at the center of the copper foil roll and darker at the edges, which may be related to the amount of air contact. The air in the copper foil workshop contains acid gas.

There is a large amount of liquid splashing and dripping on the copper foil, with a large area of etching, high acid concentration in the solution, dark color, and some turning purple red. It is difficult to remove on the surface treatment line. So, in production, we must pay attention to every detail and never be careless at any time. Carelessness can lead to loss of Jingzhou!

Article source: Internet