High Product Quality in Cobalt Oxide Synthesis

The demand for cobalt oxide is increasing worldwide. For a Chinese producer, accurately measuring pH during production was problematic. METTLER TOLEDO’s solution now means high product quality is a certainty, even in the harsh process conditions.   Increasing demand
Located in Gansu Province, China, Jinchuan Group Limited is a large-scale, non-ferrous metallurgical enterprise. They specialize in the production of nickel and cobalt materials such as cobalt (II,III) oxide (Co3O4), an important raw material in lithium ion batteries, the grade of which can directly affect the quality of the finished cells.   Wet synthesis
The production of Co3O4 comprises two processes: wet synthesis and thermal treatment. The wet synthesis process directly affects the microscopic pattern and chemical composition of Co3O4, so it must be conducted with great precision.   Using a water bath, the reactor vessel is kept at a stable temperature and reactants are fed at a constant rate. A specially designed agitator is used to ensure the evenness of the medium. Throughout the process, pH must be maintained at an exact level. As the reaction progresses, cobalt hydroxide precipitates and is converted into Co3O4 through heating. Monitoring system
The temperature inside the reactor, the pH value and the mixing speed are major control parameters. Due to the complexity of the precipitant solutions and given that the precipitation of cobalt hydroxide generated comprises micron level particles that easily adhere to and pollute pH electrodes, accurate measurement of the pH value is difficult.   To try and solve the problem, Jinchuan Group trialed several solutions from a number of manufacturers. They finally decided that a METTLER TOLEDO system best met their needs.   The selected solution comprised the following:   InPro 4800 pH electrode:
Its two electrolyte chambers and PTFE annular junction make it eminently suitable for use in applications where polluting materials and large changes in temperature are present.   pH 2100e transmitter:
An extremely stable and reliable unit which features SensoCheck for continuous monitoring of the glass and reference electrodes.   InTrac 777 housing:
The housing is air-powered and retractable, and includes a flushing chamber in which the electrode can be cleaned and calibrated. EasyClean 300 cleaning / calibration system:
In combination with the InTrac 777 housing the EasyClean 300 provides completely automatic electrode cleaning and calibration. Since installation at Jinchuan Group’s facility, the EasyClean 300 has been superseded by the even more advanced EasyClean 350e.   Excellent results
Engineers at Jinchuan Group report that the system runs very stably and reliably, and completely meets their requirements. The operation of the automatic pH measurement and control system has proven far superior to the previous method of manual cleaning and calibration. Now, pH control precision during the wet synthesis process reaches ±0.02pH. This helps Jinchuan Group ensure high product quality for their many customers, and assists them in keeping up with ever increasing demand.