Regarding whether the ban on copper in ammonia-containing processes also applies to the use of copper cables and copper terminals?

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In ammonia synthesis plants, the prohibition of copper refers to materials that come into contact with the process media being prohibited from using copper, and it does not apply to the power supply cables of electrical equipment.

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The effect of ammonia on the corrosion of copper wires (excerpt from – Corrosion of copper in the water cooling system of generator sets). The corrosion rate of copper wires caused by ammonia is related to the ammonia concentration; when the ammonia concentration is high, corrosion progresses rapidly. Through experiments, it was found that when the ammonia concentration exceeds 10–100 mg/L, significant ammonia corrosion occurs ； The ammonia content in the condensate water is not high (usually around 1 mg/L, with the upper limit determined by the pH of the feedwater), and since the quality of the internal cooling water is controlled by its conductivity, no concentration of ammonia occurs. Therefore, adding condensate water to the internal cooling water generally does not lead to ammonia-induced corrosion. When desalinated water containing ammonia is added to the cooling water, the ammonia concentration can reach 10–100 mg/L; therefore, strict control of conductivity is necessary at this time to prevent ammonia-induced corrosion. Since ammonia can form stable copper-ammonia complexes with copper ions, thereby accelerating the corrosion of copper, in fact, ammonia’s effect on copper corrosion is conditional – copper corrosion occurs only when dissolved oxygen is present and the ammonia concentration is high ； Available data show that the corrosion rate of brass increases significantly only when the ammonia concentration exceeds 10 mg/L. The stress corrosion mechanism according to the surface film rupture theory. In ammonia-containing media, a \"tarnish\" (an oxide film primarily composed of Cu2O) forms on the surfaces of copper and copper alloys, with this film forming preferentially at the grain boundaries of the copper alloys. The dark membranous layer is brittle and ruptures under tensile stress. According to studies by Suzuki et al., the dull film on pure copper breaks at the grain boundaries, while the dull film on brass breaks at the grain boundaries. At the membrane rupture site, the solution corrodes the grain boundaries ； Subsequently, a new membrane is slowly formed again and grows along the grain boundaries; once the newly formed membrane reaches a certain thickness, the deformation amount becomes sufficient to cause the opaque membrane to rupture, and the new membrane ruptures as well. This cycle of repetition leads to stress corrosion cracking. Pure copper undergoes transgranular fracture, while brass experiences intergranular fracture. The fracture occurs discontinuously; the fracture surface should be stepped, and the fracture edge shows serrated stripes (there are images but I won’t upload them). Factors affecting copper stress corrosion cracking. Brass under tensile stress can suffer from stress corrosion cracking in fresh water, high-temperature and high-pressure water and steam, as well as in all media containing ammonia (or NH4+). The substances that most easily cause stress corrosion cracking in copper alloys are ammonia and those that can produce ammonia (or NH4+), as well as sulfides. Even trace amounts of ammonia (a few ppm) can cause stress corrosion cracking in brass under tensile stress. Moisture or humidity, oxygen, SO2, CO2, and cyanide are all substances that accelerate cracking. Brass with a zinc content of less than 20% generally does not suffer from stress corrosion cracking in natural environments. Brass with a zinc content of over 20% – the higher the zinc content, the greater the susceptibility to stress corrosion cracking. Adding aluminum, nickel, and tin to brass can reduce stress corrosion cracking. Generally, stress corrosion cracking of brass parts occurs under conditions of only residual stress (or even without any load). Brass parts that have been cold-worked and not annealed after processing have high residual stresses, which can easily lead to stress corrosion cracking in the aforementioned media. Therefore, annealing to relieve stress is the most common and effective measure to prevent stress corrosion cracking in brass.