Copper resources and development in China and abroad

Geological conditions of China's copper mine is better, the world's third largest copper metallogenic belt - Tethyan metallogenic belt, Central Asia (ancient Asia) metallogenic belt and the Pacific Rim have passed metallogenic belt in China. By the end of 2001, there were 974 copper mines i-----

pH meter maintenance and precautions

1) Maintenance of the pH test pen and precautions: This test pen is factory calibrated and ready for use. The following conditions must be recalibrated: Has been used (or placed) for a long time after calibration; Electrodes are used frequently; Measurement accuracy is relatively high;-----