JPS6245165B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides a granulation method using powdered coke generated from a coke manufacturing process and carbon powder such as fine coke powder and fine coal powder collected in a cloth dust collector as raw materials. Coke is normally generated during the production of city gas, but when producing coke for steel manufacturing, a single steelworks generates about 10,000 tons per day, or about 300,000 tons per month. In this case, the intended use is for blast furnaces, and particles other than those suitable for use in blast furnaces are sorted and separated, and depending on their particle size, they are used as raw materials for producing sintered ore as raw materials for blast furnaces, or as raw materials for carburizing agents in the steelmaking process. . However, these powdered carbons have a high dust-emitting property and are extremely difficult to handle, which makes them impractical and has limited applications. The present invention solves these problems and targets not only the surplus carbon powder but also the inevitable by-product powder carbon, with the aim of improving practicality and generality at a low cost and efficiently. The object of the present invention is to provide a method for granulating powdered carbon that can easily obtain the required strength and particle size. The gist of this is that when granulating powdered carbon, a water-soluble binder is used, and based on the relationship between the predetermined granule diameter of powdered carbon and the total water content at the time of granulation, The method involves determining the total required water content, calculating the raw material water content and the water-soluble binder water content from the obtained water content, and adding the insufficient water content to the water-soluble binder to knead and granulate the raw material powder carbon. Furthermore, as a second aspect of the present invention, we propose that the deficient water and a water-soluble binder are collided and mixed at the tip of a nozzle, and then dispersed onto the raw material powder carbon for kneading and granulation. The present inventor has conducted various experiments to solve the above problem, and has found that the particle size is almost uniform like that of powdered carbon, the viscosity does not vary greatly within a certain range, and it is thought to be relatively easy to granulate. However, it was discovered that by adjusting the amount of binder added to adjust the strength, the particle size of the granulated product changes, as if there is a correlation between binder concentration and particle size. In order to elucidate the root cause of this, we set various crushing strengths of the granulated product using various binders, and set binder concentrations for each strength that can obtain the same strength as those obtained by varying the concentration of each binder. A granulation test was conducted using the prepared materials. As a result, when using a water-soluble binder, the degree of granulation can be adjusted by adjusting the total water content during granulation, whereas when using a water-insoluble binder, heating is required to stabilize the degree of granulation, and this non-aqueous binder requires heating. Temperature of the binder
Depending on the viscosity characteristics, high-temperature heating is required, and as a result, the degree of granulation cannot be adjusted using only the total moisture, and is largely controlled by the temperature characteristics of the binder and the heating temperature, making it extremely difficult in practice to adjust the viscosity. I discovered that. In addition, water glass is used as a water-soluble binder,
Add the water required for total water to this solution and sprinkle it on the powdered carbon, or sprinkle the water on the same part of the powdered carbon at the same time as the water glass, or sprinkle the same amount of water on the powdered carbon at the same time as the water glass. There are significant differences in product granulation frequency, granulation time, and granulation yield when spraying the product at different locations, and while the former two provide extremely good granulation results in practical use, the latter Not only is the condition not much different from when the water-insoluble binder is used at room temperature, that is, the degree of granulation varies greatly, and even if the granulation time is increased, this tendency does not change.
The results showed that after drying, powdered carbon that was not pulverized and granulated was generated, making it completely impossible to carry out practical industrial implementation. Based on these phenomena, the present inventors further repeated experimental investigations and found that the degree of granulation substantially matched the target particle size, the yield was high, and the time required for granulation was shortened. The former group is where the binder concentration and total water content are always evenly distributed at the same location on the powdered carbon before granulation, and these are the entire process where the binder solidifies through granulation and drying and exhibits strength. Contrary to the fact that the binder concentration and moisture concentration of whole powder carbon follow the same course over time, in the latter case, segregation of binder concentration and segregation of moisture occur in various places, and after drying, grains with high moisture concentration break and become powder. I found out what to do. This is achieved by adding a binder and water to separate locations on the powdered carbon before granulation, so that the powdered carbon immediately granulates with the additives, and what is delayed in granulation becomes granulated with what is added later. It was discovered that this is due to the effect of This shows that grains with high moisture concentration have a binder concentration so low that it is virtually undetectable, and therefore the interparticle bonding force of the carbon powder, which was maintained simply by moisture during drying, is lost. Naware,
As a result, the reason why it turned into powder was revealed. The present invention is based on the above-mentioned knowledge, and aims to establish a granulation method with high granulation efficiency (granulation with small binder usage unit and short granulation time) and high target granularity yield. In addition, water-soluble binders such as water glass, waste molasses, and pulp waste liquid are required, and based on the relationship between total moisture and particle size, the total moisture required for the target particle size, and each moisture of raw material powder carbon and binder are calculated. In comparison, when water that needs to be added is added to powdered carbon, it is essential to spray it in the same location at the same time as the binder. Examples of the present invention will be described below with reference to the drawings together with comparative examples. FIG. 1 shows an example of an apparatus for implementing the present invention,
1 is a powder coke hopper, 2 is a water glass tank,
3 is a water tank, 4 is a mixing tank, 5 is a water glass aqueous solution pressure pump, 6 is a particle size and total moisture characteristic table, 7 is an arithmetic command unit that measures coke powder moisture from a neutron moisture meter 8, and a water glass moisture setting device 9 According to the particle size set from the target particle size setting device 11, subtract the moisture content of the water glass from the neutron moisture meter 10 and the moisture content of the carbon particles returned under the sieve from the target particle size setting device 11 from the total required moisture output from the table 6, and calculate the required moisture content for addition. It is calculated and output to the valve opening degree controller 12. 13 is a moisture adjustment valve,
14 is a kneading machine, 15 is a granulator, 16 is a vibrating sieve, 1
7 is a dryer, 18 is a chute, 19 is a belt conveyor, and 20 is a finished product hopper. FIG. 3 shows an example of another aspect of the binder aqueous solution dispersion method of the example in FIG. Although a spray liquid impingement type nozzle 21 is shown, other embodiments include a double tube, in which water glass is passed through the outer tube and water is passed through the inner tube, and the water glass is diffused by the water flow at the end of the nozzle. These methods are preferable because they have the same effect and can omit the mixing tank 4 and the water glass aqueous solution pressure pump 5 in the example shown in FIG. Fig. 2 shows a conventional device in which a comparative example was carried out. Items with the same symbols as those in Fig. 1 indicate the same devices, and the difference from the example in Fig. 1 is the nozzle 22. In the comparative example, water glass and water are completely removed. The structure is such that it is dispersed at different locations. FIG. 4 is a diagram showing the characteristics of total moisture and degree of granulation when coke powder of 0.5 mm or less is granulated using the apparatus of FIG. 1 using water glass as a binder. Table 1 shows the granulation results of the present invention example using the apparatus shown in FIG. 1 and the comparative conventional example using the apparatus shown in FIG. The respective implementation conditions are as shown in Table 2.

[Table] Table 2 Target particle size: 2 to 3 mm, average 2.5 mm Raw material: Coke powder less than 0.5 mm (moisture 0%)
…2000Kg Total moisture: 20.5% from Figure 4 …410Kg Water glass: No. 3 (moisture 62%) …359Kg Added moisture: 410− (359×0.62) …188Kg Granulation rotation speed: 40r.pm Evidently from Table 1 As can be seen, the target particle size yield in the present invention example was 80.4%, while in the comparative conventional example, 3-2 mm and 2-1 mm were approximately the same even though the kneading time was approximately doubled. quantity, target particle size, yield is 29.4
%, the example of the present invention has a high target particle size yield,
Moreover, the variation in crushing strength was small.

[Brief explanation of the drawing]

Figure 1 is the overall flow of the present invention, Figure 2 is the overall flow of the conventional example, Figure 3 is another embodiment of the present invention,
FIG. 4 shows a graph of the relationship between particle size and total moisture. 1: Coke powder, 2: Water glass, 3: Water, 4:
Mixing tank, 7: Arithmetic controller, 14: Kneading machine, 15:
Granulator, 16: Vibrating sieve, 21: Binder aqueous solution sprinkler.

Claims (1)

[Scope of Claims] 1. When granulating powdered carbon, a water-soluble binder is used, and the granule size is determined based on the relationship between the granule diameter of the powdered carbon and the total water content at the time of granulation, which is determined in advance. powdered carbon, characterized in that the total water required is determined, and the insufficient water obtained by calculating the raw material water and water-soluble binder water from the water is added to the water-soluble binder, and the raw material powder carbon is kneaded and granulated. granulation method. 2. When granulating powdered carbon, a water-soluble binder is used, and the required total water content is determined according to the granulation diameter based on the relationship between the granulation diameter of the powdered carbon and the total water content during granulation, which has been determined in advance. The carbon powder is characterized in that the water-soluble binder and the water-soluble binder are collision-mixed with the water-soluble binder and the water-soluble binder obtained by calculating the water content of the raw material and the water-soluble binder from the water content, and are dispersed on the raw material powder carbon for kneading and granulation. granulation method.