Production material ratio of electrode paste
The production formula of electrode paste should not be changed easily, and the formula should be changed for many times. Small calcium carbide furnace or ferroalloy furnace can all use metallurgical coke or asphalt coke plus a small amount of natural graphite electrode paste, but the consumption is larger. For large or medium calcium carbide furnaces and ferroalloy furnaces, anthracite and metallurgical coke should be used to prepare their electrode paste. Adding a small amount of natural graphite or graphitized metallurgical coke to the electrode paste formula is conducive to improving the conductivity and thermal conductivity of the electrode paste. However, the preparation of earthy graphite for small and medium-sized factories should be strictly controlled.
It should be noted that too much asphalt will make the sintering speed of the electric paste unable to keep up with the consumption, which is easy to cause soft fracture. The electrode paste with too much binder has high porosity and low strength after sintering, and hard fracture occurs under specific conditions. When the amount of binder is too small, the electrode paste will be sintered too fast, and the bonding force between particles will be poor and the strength will be low after sintering, which will also easily lead to hard fracture. Compared with the two, the adverse consequences caused by soft fracture are more serious than hard fracture. In production, if the asphalt quality is not detected, the production quality fluctuates greatly, and users dare not easily use this electrode paste.
The kneading temperature should be stable, and the dry mixing and wet mixing time should be sufficient, so that the binder can fully penetrate into the pores of carbon raw material particles, and form a “bonding film” evenly on the surface of the particles. In addition, the high kneading temperature results in poor particle structure of the paste.
The ash content of electrode paste should be strictly controlled from the batching calculation. Due to poor calcination quality in some factories, the quality of electrode paste becomes poor. Because the increase of ash content in electrode paste will cause the increase of consumption.