How to control electroplating pickling solution? What is the replacement standard?

Basically, it is decided according to the complexity of the product you process, if the appearance of the product is relatively smooth, basically without any water, it can be replaced once in 2-3 days, if it is a lot of blind holes, concave surfaces and other products with large amounts of water, it is basically replaced once a day, as for the amount of acid required, it depends on what kind of plating you are processing, according to its characteristics to decide what acid to use, and how much acid is there, etc., about 5-10% on it, not easy to be oxidized to take the lower limit, As for the functional pickling, such as the roughened pickling (HCL), it is replaced according to the color of the water, the micro-etching behind the acid copper cylinder, sulfuric acid + ammonium persulfate, because its purpose is not only to eliminate the oxide layer, but also to kill the residual dye (light agent) of the copper layer, basically depending on the color to replace.

To be precise, there are two aspects of control: first, the acidity value of the pickling solution, which can generally be added according to the acid-base titration analysis or empirical value.

2. The dissolved metal impurities in the pickling solution can also be analyzed or replaced according to experience.

1) hydrochloric acid is volatile, the initial preparation should not be too thin, if less than 1:1, it will soon lose its effectiveness, although by prolonging the pickling time, it can still be used, but the pickling is not easy to be thorough; If the concentration is too large, the smell is too large during operation, and it is inconvenient to operate. Generally, the ratio of water to hydrochloric acid is 1:

2. It is more appropriate.

2) The hydrochloric acid tank should be equipped with a lid and an exhaust device to reduce the volatilization of hydrochloric acid and improve the operating conditions.

3) If there are fine washing parts in the pickling parts, in order to prevent them from over-corrosion, it is advisable to add 2-3g l of urotropine (corrosion inhibitor), but the hidden hall should not add too much, because it is not economical in the first place, and it will also affect the speed of rust removal.

4) Hydrochloric acid is not suitable for heating, although the speed of rust removal can be accelerated when the temperature is high, the salt cavity acid will accelerate volatilization, and urotropine will also accelerate the decomposition of the stove, the utilization rate of the material will be reduced, and if the pickling time is not properly controlled, the workpiece may also be corroded.

5) It is forbidden to pickle copper workpieces in the hydrochloric acid pickling solution, such as the pickling parts should be tied with iron wire, not copper wire, and the hook should not be in direct contact with the acid, otherwise the copper layer will be replaced on the surface of the steel parts due to the presence of copper in the pickling solution, which will affect the bonding strength of the coating and the matrix.

6) Adding 1-2g lop emulsifier or, sodium lauryl sulfate to hydrochloric acid is conducive to improving the rust removal speed and rust removal effect.

In fact, the pickling time basically depends on the concentration of iron ions (iron salts) in hydrochloric acid and the temperature of the pickling solution. Relationship between pickling time and zinc application: There is a well-known fact in hot-dip galvanizing operations, that is, the use of galvanized workpieces to protect over-pickling will lead to more zinc application, that is, "over-pickling" will increase zinc consumption.

In general, soaking in the pickling tank for 1 hour is enough to completely remove the rust, and sometimes under the working conditions of the factory, the plated workpiece can be placed in the pickling tank overnight, that is, soaked for 10 15 hours. Such galvanized workpieces are coated with more zinc than pickling them at normal times. (See references)

Attention should be paid to the addition of corrosion inhibitors to prevent excessive corrosion.

When using galvanizing equipment for electroplating, the following problems should be paid attention to when pickling with hydrochloric acid. The concentration of hydrochloric acid should not be too low, otherwise the pickling rate will be very slow. Some enterprises do not add water to dilute when pickling with hydrochloric acid, and directly use galvanizing equipment for electroplating, which is also not advisable.

Because the high concentration of hydrochloric acid is seriously volatilized, it is easy to overcorrode the workpiece. The most suitable concentration ratio is two parts hydrochloric acid and one part water. It's best to add a little corrosion inhibitor.

The addition of corrosion inhibitors can prevent over-corrosion, especially for pickling in high-precision events. Corrosion inhibitors can use metropine. , the dosage is 2-3 g l.

Do not heat up. Because hydrochloric acid is too volatile. If hydrochloric acid is heated, it will lose a lot and pollute the working environment.

Hydrochloric acid pickling solution should not come into contact with copper products. Otherwise, the dissolved copper will be replaced with the iron, which will affect the quality of the plating.

The effect of electroplating on the workpiece is present.

First of all, there will be pre-treatment before electroplating, and there is a chemical polishing process in the pre-treatment that will make the size of the workpiece smaller, because the surface of the workpiece will be corroded partially, and the thickness of the corrosion is related to the treatment method, some are very few, and some are more obvious;

During plating, the size increases due to the coating layer on the surface of the workpiece, and this increased size is related to the thickness of the plating layer.

The usual coating thickness is in.

One or two microns, basically no effect, but if it is hard chrome plating, it can reach more than one millimeter, and the impact is greater.

The main problem to pay attention to when galvanizing using hydrochloric acid pickling is not to cause corrosion to the equipment, to grasp the amount of equipment pickling corrosion inhibitor, if the pickling is improper, it will cause fatal damage to the galvanizing equipment, and the galvanized oxide film is corroded thinly, it is not only a problem that the pickling project money cannot be recovered, but the owner will be compensated. Galvanized pipes are generally used in the first air conditioning system, and the error is the price of a first air conditioning system. Equipment pickling and passivation is a relatively professional project, which requires certain qualifications.

Ventilation to prevent hydrogen deflagration.

a. The waste Zhiye bright acid in the electroplating plant can improve the saline-alkali land, but it is not suitable because it contains heavy metal ions and is toxic

b. It is feasible to formulate a reasonable spine protection plan

c. It is strictly forbidden to build entertainment venues in the protected area, which is conducive to the protection of scenic spots d. Untreated wastewater is strictly forbidden to be discharged and relaxed

So choose A