Comparison of fixed furnace and tilting furnace brown corundum

- May 13, 2019-

Comparison of fixed furnace and tilting furnace brown corundum


 


First, the introduction

Brown fused alumina is one of the most basic abrasives. It has a strong resistance to crushing, oxidation, and corrosion, and has good chemical stability. In China, the production process of brown corundum is mature (the smelting method currently used in China has the fixed furnace frit method and the tilting furnace smelting method), the production cost is lower than other abrasives, and the cost performance is better than other abrasives. Therefore, after more than 60 years of development, brown fused alumina has gradually formed an industrial material system of a certain industrial scale, which has become an irreplaceable basic material for industrial development in China and an indispensable and important part of the national economy. Especially in the current domestic and international fixed abrasives, coated abrasives manufacturing and refractory production plays an important role.

The frit smelting technology was first introduced in China. The tilting method was only developed in the last two decades. Relatively speaking, the tilting furnace has high production efficiency and low energy consumption. In terms of chemical composition, the tilting furnace contains lower silica, and the price of the corundum product is slightly higher.

Although the chemical composition difference between the fixed furnace and the tilting furnace corundum is extremely small, there are large differences in crystallization rate and crystal size due to the difference in the smelting process. This difference will make the tilting furnace corundum and frit-form corundum have their most suitable fields in the application scenario.

Second, brown corundum manufacturing

Before introducing calcined brown fused alumina, it is necessary to mention the smelting of brown fused alumina. Brown corundum is made of high-quality bauxite as raw material, anthracite, iron filings, and is smelted in the arc furnace by the high temperature of 2000 degrees or higher. The melting method used is divided into tilting method and frit method. Different smelting methods have an effect on the properties of the resulting brown corundum blocks. Let us first look at the comparison of the 2 different methods used to smelt. Below is the data for sample 36# in different categories:


Type

Monocrystalline

Close aggregates

Aggregates

Tilting

25.84

12.18

62.18

Frit

58.83

20.14

21.03

                                    Table 2-1: Corundum structure analysis


type

Alumina

Glass

Titanium

calcium hex aluminate

Iron alloy

Tilting

94.56

2.36

1.81

1.09

0.06

Frit

94.03

1.29

1.19

2.58

0.91

Table 2-2´╝ÜCorundum phase analysis


From the table above, we can learn:

The corundum produced by the tilting furnace has a large number of crystal aggregates, a small crystal size, and a high glass phase and is distributed on the grain boundaries. Therefore, the toughness is poor, the brittleness is great, the abrasive grains are easy to fall off, the self-sharpness is good, and the ceramics are more suitable for the ceramic-solidified abrasives and refractory materials.

The corundum produced by the frit furnace has fewer crystal aggregates, large crystal size, and less glass. Therefore, the brittleness is poor, the toughness is great, the wear resistance is good, and it is more suitable for the resin abrasive and the coated abrasive.

Therefore, the brown corundum sand produced by the frit furnace method is the first abrasive material with the largest production capacity in the manufacture of resin grinding wheels and abrasive belts as long as the processing and processing methods are scientific.