Ammonia Measurement in Ternary Precursor & Cobalt Tetroxide Synthesis

In the co-precipitation of ternary precursors and cobalt tetroxide, ammonia is one of the most "hidden" process variables. The two routes have different control targets: the ammonia-complexing hydroxide route is usually built around "total amount + pH", while in the carbonate route free ammonia accounts for only a single-digit percentage of total ammonia — the three layers of in-situ free ammonia, method-defined value, and conserved quantity must be distinguished before choosing a measurement route.

• Two routes, two measurement logics: the ammonia-complexing route centers on "total amount + pH"; the carbonate route must use free ammonia as the primary measurement
• Three layers of "ammonia": in-situ free ammonia, method-defined value, and conserved quantity — avoiding data mismatch between analyzers, lab sheets, and process cards
• Principle-level comparison of seven measurement routes: lab titration, distillation–absorption–titration, alkalized ion/gas-sensing electrodes, gas diffusion membrane, headspace gas phase, online automatic titration, and pH + total ammonia estimation
• Four error sources: pH error amplification, state change during sampling, equilibrium-condition dependence, and solid-phase/complexation coupling
• Five-step methodology: measurement definition → method selection → condition adaptation → calibration & traceability → data loop