Why metal corrosion inhibitors use nitrite instead of nitrate

Not necessarily.

For example, sodium nitrite and potassium nitrite are nitrites but not heavy metal salts.

Such as copper nitrite, lead nitrite is nitrite and heavy metal salt.

1. Heavy metals: Heavy metals refer to metals with a specific gravity greater than 5, including gold, silver, copper, iron, lead, etc., which accumulate to a certain extent in the human body and cause chronic poisoning.

Chemically, according to the density of the metal, the metal is divided into heavy metals and light metals, and the metal with greater density is often called heavy metal. Such as: gold, silver, copper, lead, zinc, nickel, cobalt, chromium, mercury, cadmium and so on about 45 kinds.

From the perspective of environmental pollution, heavy metals refer to heavy metals with significant biological toxicity such as mercury, cadmium, lead, chromium and arsenic. There are 5 types of poison that are the most toxic to the human body:

Lead, mercury, chromium, arsenic, cadmium. These heavy metals cannot be decomposed in water, and the toxicity is amplified after human drinking, and they combine with other toxins in the water to form more toxic organic or inorganic substances.

2. Nitrite: a general term for a class of inorganic compounds. The anion is NO2- (nitrite ion). Mainly refers to sodium nitrite.

Foods such as sauerkraut, kimchi, pickles, salted fish, ham, sausages, etc., all contain nitrates and nitrites. Nitrate in the human body can be reduced to nitrite under the action of microorganisms. After nitrite is eaten into the stomach, it reacts with secondary amines, a protein decomposition product, under the action of gastric acid to form nitrosamines.

There is also a group of bacteria in the stomach called nitrate-reducing bacteria, which can also combine nitrite with amines to form nitrosamines. In the case of lack of stomach acid, these bacteria thrive. Therefore, regardless of the amount of stomach acid, it is conducive to the production of nitrosamines.

Nitrosamines have a strong carcinogenic effect, mainly causing esophageal cancer, gastric cancer, liver cancer and colorectal cancer.

Therefore, heavy metal salts mainly look at whether the cation is a heavy metal ion, while nitrite is to see whether the anion is a nitrite ion.

Because nitrates have to be more acidic to work, nitrites react more easily.

Hydrochloric acid corrosion inhibitor is added to hydrochloric acid to slow down the corrosion of hydrochloric acid on metal matrix, and is suitable for hydrochloric acid of various concentrations and temperatures. It has a good corrosion inhibition effect in the chemical pickling process of various hydrochloric acids. Under normal use, the corrosion rate of the metal is greatly reduced, and it has the excellent ability to inhibit the hydrogen absorption of steel in the pickling process, avoid the "hydrogen embrittlement" of steel, and inhibit the corrosion of Fe3+ on the metal during the pickling process, so that the metal does not produce porosity.

It is suitable for pickling of metal materials such as carbon steel, copper and their assemblies of different materials.

Outstanding features: stable performance, simple operation, small dosage, high efficiency, low cost, non-toxic and odorless, no pollution to the environment; The corrosion of the metal matrix is small, the corrosion inhibition rate is high, there is no acid mist in the process, and it is safe to use.

How to use: 1. Preparation of working solution: the concentration of corrosion inhibitor is generally by weight). Measure the corrosion inhibitor 1:

10-20 mixed with water (preferably 50-60 warm water), stir until completely dissolved, then add the remaining metering water, stir evenly, slowly add the metered acid to the above-mentioned prepared liquid, and keep stirring to completely dissolve the acid, and the solution can be used after mixing evenly; 2. The corrosion inhibitor can also be directly added to hydrochloric acid, and it can be directly mixed with water when used, but it must be ensured that the effective concentration of the corrosion inhibitor in the working solution cannot be lower than the weight).

Look at the equipment for pickling what metals, there are also corrosion inhibitors suitable for a variety of metals, I am also concerned about the situation of corrosion inhibitors, and I am going to do experiments to test the performance of domestic mainstream corrosion inhibitors and the performance of new American products, you can send me an email to chat.

Changsha Military and Civilian Products Technology provides high-efficiency pickling and anti-fog corrosion inhibitors.

The process of hydrochloric acid pickling and rust removal on the surface of steel is widely used in steel pipe factory, galvanizing plant, electroplating workshop and electroless plating workshop, because hydrochloric acid is very volatile, the pickling workshop is filled with a large amount of acid mist, which has a strong irritating odor, which affects the working environment, corrodes the workshop equipment, and causes a large amount of useless consumption of hydrochloric acid; In addition, hydrochloric acid pickling can not only effectively and quickly remove rust, but also easily react with the steel matrix, release hydrogen, cause overcorrosion of the metal surface of the matrix, and easily produce hydrogen embrittlement, affecting the surface quality and strength of the workpiece. This product is a new type of high-efficiency and environmentally friendly hydrochloric acid pickling rust removal and fog inhibitor corrosion inhibitor specially designed for these problems in the existing hydrochloric acid rust removal process.