**2. Experiment**

In our work, we used industrial pitches as binders. Pitch samples were taken in the production conditions of coke plants. The volume of the sample was up to 4 dm3 ; the pitches were mixed, quartered, and sieved through a sieve to a laboratory sample with a fraction of 0.5–0.25 mm. **Table 1** presents their characteristics.


## **Table 1.**

*Characteristics of the pitches that were used as a binder.*


**21**

destroyed.

*Determining the Filler Activity in the Sintering of Pitch Composites*

We used both carbon and noncarbon fillers. All the fillers were crushed to the size of particles passing through a sieve with a size of 0.5–0.2 mm holes. **Table 2** gives an overview of the filler characteristics. These are pitch coke (PC), shale cokes (SC), and shale coke after heat treatment (SC-T), which we preheated for 2 hours at a temperature of 250°C to remove moisture. For comparison, we took hardened

The photographs of the surface of the filler grains (**Figure 1**) clearly show the difference in their structure. For shale coke (**Figure 1a, b** and **e,f**), there are at least two types of structures: sponge (**Figure 1a**) and layered fibrous structures (**Figure 1b**). The grain sizes with a spongy structure in **Figure 1a** are about 180–450 μm, and the grains of shale coke with a layered structure are 100–300 microns in diameter and 800 μm in length. The thickness of the layers in the grains of the layered structure according to optical microscopy is <2–5 μm. The surface of the pitch coke grains is most rough with numerous pores (**Figure 1c, g** and **i**), which coincides with the data [20]. Lamellar anisotropic structures are visible on the pitch coke (**Figure 1g**). In the case of good wettability, the caking can give a strong adhesive bond and a significant proportion of

adhesion due to the capillary penetration of the pitch in the pores of the filler. The surface of anthracite grains is the smoothest. It is well visible that the surface is sometimes chipped with folded structures. Anthracite grains have a large variation in size from 20 μm to 100–160 μm. Anthracite dust is present on the

Samples of composites for mechanical testing were prepared as follows. Mixtures of pitch and an inert filler (anthracite, sand, glass, pitch coke (PC), shale coke (SC), and shale coke after heat treatment (SC-T) at 250°C) in different proportions (from 1:1 to 15:1) are charged in cells of ceramic cassette (**Figure 1**), preliminarily placed in a special coking chamber (**Figure 2**). One loading of the cassette camera allows to receive 14 samples of char from the pitch composites. The heat input in the coking chamber was carried out from below, since radial heating of the cylindrical sample has a temperature gradient along the radius of the cylindrical charge—the outer layers of the charge in the coking chamber undergo heat treatment for a longer time than in the central part. With one-sided heating (from below), the temperature gradient in the loading of the coke composition is available in the height of the load. Therefore, semicoke samples of the pitch composite for mechanical testing had a gradient of strength in height, but in the fracture region,

Isothermal aging at the final treatment temperature is designed to increase the

according to the procedure described in [4], using a cassette chamber (**Figure 2**). Each semicoke sample of the pitch composite was placed in the test cell (**Figure 3**), and mechanical strength tests were carried out so that the fracture region of all samples was in the semicoke plane heated to a temperature of 500°C. All the samples in the fracture region had the same final heating temperature, and the strength of the semicoke sample of the pitch composite was deter-

We believe that since the strength of the coke (filler) is higher than that of the semicoke matrix, the destruction of the sample during our tests was mainly carried out on the pitch matrix (cohesive failure), and the filler grains were not

Mechanical test samples of solid residue from the pitch composites are carried out

surface of the grains in the photographs (**Figure 1d**).

samples were prepared at the same temperature (500°C).

homogeneity of the composite in the radial plane.

mined in an isothermal layer.

*DOI: http://dx.doi.org/10.5772/intechopen.82012*

glass, washed bank-run sand, and anthracite.

**3. Results and discussion**
