Production method of spherical graphite

Abstract

The invention relates to a production method of spherical graphite, which is characterized in that spheroidizing equipment is used for processing the graphite into sphericity or potato shape with grain size of 10-45mu m; the spheroidizing equipment comprises n groups of devices; each group is formed by connecting a Roots blower, a dust collector, a cyclone separator and a pulverizer in turn; and a discharge outlet of the cyclone separator in the (n-1)th device is connected with a feed inlet of the pulverizer in the nth device. The method dispenses with personnel operation, is higher in yield and efficiency and lower in cost in unit time and realizes automatic closed production of the whole production line. Compared with the prior art, the method is characterized in that the spherical graphite produced by the method has better sphericity, higher tap density, large specific capacity being more than 350mAh / g, small specific area, excellent lithium intercalation and de-intercalation capabilities and cycle stability and 500-cycle capacity-keeping rate being more than 80%.

Description

technical field [0001] The invention relates to a production method of spherical graphite, in particular to a production method for producing spherical graphite used for negative electrode materials of lithium ion batteries in an on-line manner and the spherical graphite produced by the method. Background technique [0002] With the rapid development of economic globalization, the oil crisis and the continuous increase of population, the contradiction of resource shortage has become increasingly prominent, especially today when people pay more and more attention to environmental protection, green power has been developed rapidly. Lithium-ion batteries are a new generation of secondary batteries after nickel-metal hydride batteries since the 1960s. In the past ten years, with the wide application and rapid development of various portable electronic devices and electric vehicles, lithium-ion batteries are characterized by their high reversible capacity, high voltage, high ener...

AI Technical Summary

Problems solved by technology

During the production process, the material will stay in the lower part of the crushing chamber due to the increase of resistance. The increase of the material in the crushing chamber will hinder the air volume, affect the heat dissipation, and the temperature will rise. changes lead to damage

The bearings used by the main engine are generally imported SKF bearings, which will increase the maintenance cost, decrease the output, and reduce the production efficiency, which will directly affect the smooth production of the crushing and ball making workshop.

[0005] The purification process in the prior art has the following defects: the traditional purification reaction adopts a carbon steel agitator lined with anti-corrosion plastic and uses a motor-driven unidirectional mechanical agitation to mix the materials evenly; The minimum 7.5KW motor needs 7.5 degrees of electricity per hour; the second is that after the agitator is worn out, its anti-corrosion layer breaks, and the carbon steel reacts with the acid in the liquid material, which greatly increases the iron content in the material, which affects the product quality. Great influence, so that the product failure rate is greatly increased

The third is that once the anti-corrosion layer of the agitator is broken, it can only be replaced with a new agitator, which not only increases the maintenance cost, but also takes time and labor for the replacement (it takes 6-10 hours for 2-4 people to replace once).

The fourth is that the agitator should be resistant to acid corrosion and lined with PTFE, which is expensive and directly increases the production cost

In addition, HCl, H 2 SO 4 Al and Ca often exceed the standard in the production of three kinds of HF acids. When the carbon content reaches 99.96 or more, Al and Ca can still reach 150PPM, which seriously affects the electrochemical performance of spherical graphite as a negative electrode material.

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