JPH0134902B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for loading raw materials such as ore, and more specifically, when unloading and bedding with a double-wheel bed reclaimer, raw materials can be loaded without quality variation in the cross-sectional width direction and longitudinal direction. This relates to the method of loading raw materials such as ore. The Japanese steel industry relies on imports of iron ore from overseas, and in order to secure stable quantities, it purchases iron ore and other raw materials from a wide range of sources. For this reason, many types of ore are blended together during use, and in order to stabilize product quality in processes such as blast furnaces and sintering, quality control of iron ore beds is strengthened and The quality of the blend of various ore raw materials is extremely important.
In this yard blending, as shown in FIG. 1, the materials are stacked in a bed stacker 1 and then discharged by a bed reclaimer 2, but the composition of the raw materials varies greatly, and improvements are needed. For example, when blending three types of raw materials A, B, and C, the stacker 1 is moved back and forth repeatedly to scatter and stack the raw materials in layers. After loading is completed, the double-wheel type bed reclaimer 2 is repeatedly moved laterally and forward in the width direction as shown by the arrows to blend and discharge the raw materials. However, when blending in this way, in the stowage bed,
It varies in (1) the cross-sectional inner width direction and (2) the longitudinal direction. For example, after the bed loading is completed, the bed reclaimer 2
The payout is performed as shown in FIG. For example, at first, the two foils of the bed cremer 2 are at A. The bed claimer 2 starts running from there, and after t ₁ minute has passed, it follows the arrow path and reaches point B. Furthermore, after t ₂ minutes, it reaches point C, and the payout of the unit cycle ends. Therefore, when raw materials are discharged by the bed reclaimer 2 in this way, when the raw materials are piled up as in the conventional example shown in FIGS. 1 and 2, for example, raw materials A, B, and C are Two types of raw materials A and B, which have different deposition angles (θ _A , θ _B , θ _C ) and have different chemical compositions, are deposited on both side walls 5 of the raw material yard.
It is stacked in layers with an isosceles triangular cross section between the two. Therefore, while the bed reclaimer 2 moves from A to C, the raw material A
In some cases, the raw material C does not exist, or in other cases, only the raw material C exists, and a large component variation occurs in the cross-sectional width direction. In addition, when three types of raw materials A, B, and C are stacked in the order of A → B → C as shown in Figure 3, raw materials A,
The loading amounts of B and C are determined based on the blending plan, and the loading start position and loading end position of each raw material do not coincide, and the blending ratio changes in the longitudinal direction. Incidentally, when dividing a range with the same blending ratio, it is divided into zones 1, 2, and 3, and changes in the blending ratio in the longitudinal direction cause longitudinal component fluctuations. The purpose of the present invention is to solve the above-mentioned drawbacks, and specifically, there is no variation in the cross-sectional width direction and longitudinal direction of the bed, and when the stacked bed is discharged by a reclaimer, the raw materials can be bedded uniformly. We propose a method for loading raw materials such as ore that can produce sintered ore with minimal quality deterioration. The present invention will be explained in detail below. First, for example, when three types of fine ores A, B, and C as raw materials are stacked in a bed using, for example, a bed stacker in a yard surrounded by side walls on both sides, among these ores,
An ore with a predetermined component, for example, SiO ₂ , is at or near the target average component value of the entire bed (usually about ±1% of the average component value) as the bed core, and the bed is sandwiched between the side walls. stowed on,
Thereafter, other raw materials are successively stacked in layers above this, particularly on the side walls. When bed stacking is performed in this manner, regardless of component fluctuations in the longitudinal direction of the bed and in the cross-sectional inner width direction, uniform bedding can be achieved by dispensing the reclaimer without any component fluctuations. First, looking at the longitudinal direction, for example, the loading order of ores A, B, and C is 3! There are =3×2×1=6 ways. Certain components in these ores, for example,
If the values of component i are X _A (i), X _B (i), and X _C (i), and the loading speeds (tons/hour) are W _A , W _B , and W _C , then the product for a given component i is The attaching speed is for each ore A, B, and C.
They are expressed as X _A (i)×W _A , X _B (i)×W _B , and X _C (i)×W _C. Therefore, we researched the loading order with the smallest longitudinal component variation of the bed among these six loading orders, and found that it is possible when the loading speed of the predetermined component i tends to increase or decrease. I found out something. That is, the inventors evaluated the six loading orders based on the deviation value σ of a predetermined component, for example, SiO ₂ .
In order to make this determination, we actually performed six different loading simulations for three types of ores A, B, and C using the following conditions.

[Table] The σ values of the results were as follows. σ _ABC = 0.08 σ _BAC = 0.01 σ _CAB = 0.01 σ _ACB = 0.06 σ _BCA = 0.07 σ _CBA = 0.03 The suffix for each σ value indicates the loading order of each ore. For example, ABC indicates the loading order of each ore. Pile ore A, then ore B and ore C on top of it
Indicates the case of stowing. Looking at the above results, the cases with the smallest σ are B→A→C and C→A→B, and the cases with the largest σ are A→B→C and B→C→A. It was found that component fluctuations in the longitudinal direction of the bed are minimized if the loading speed for each predetermined component increases or decreases uniformly. So, we started with three brands of ore A, B, and C.
In general, when the loading direction of n brands, for example, 20 brands or more, was evaluated in the same way, it was confirmed that they were similar. Second, looking at the inner width direction of the bed cross section, the bed cross section is stacked as shown in FIG. That is, first, a bed core part 3 having an isosceles triangular cross section is formed, and a bed upper part 4 (however, only one layer is shown in FIG. 4, but normally there are multiple layers. Reference numeral 5 is a side wall) is formed on top of the bed core part 3 having an isosceles triangular cross section. ) are stacked. In a bed with this structure, when the double wheel type bed cremer moves laterally in the cross-sectional inner width direction, the cross-sectional area cut by the two foils (indicated by P and Q in Figure 4 as in Figure 2) changes over time. ,
For example, it changes constantly at times t ₀ , t ₁ , t ₂ . At this time, since the bed upper part 4 has the shape shown in FIG. 4, a substantially constant amount of cutting can be achieved even if the foil moves laterally, whereas the bed core 3 has an isosceles triangular cross section, so that The cutting amount changes. In this regard, in the present invention, the upper part 4 of each bed is loaded with ore whose component value is far from the average value (i) of the entire bed, but since this part is a certain amount of cut out part, the composition of the cut raw material is There are no large fluctuations. On the other hand, the cutting amount in the bed core 3 constantly changes, but since the bed core 3 is loaded with ore of a type that is at or close to the average value (i) of the entire bed, composition fluctuations are suppressed. It will be done. In addition, when stacking on the bed core as the bed upper part, the ore in the bed core that is in contact with the bed top is selected to have a repose angle similar to that of the ore at the top of the bed within a range of ±2°C. is preferable. The present invention can be applied to the stacking of powder materials in general in addition to ores. Next, an example will be described. Example 1 First, as shown in Table 1, the planned loading amount, chemical composition, and loading speed (tons/hour) of each of the 24 brands of ore were specified in the bed mix plan. The target average component after blending these ores, that is, the SiO ₂ component, was X=4.53%, and based on this, the type of stacking of the bed core was selected as follows. In other words, for the stocking brand necessary to form the bed core with an isosceles triangle cross section, ore with a component value as close as possible to the average component of the entire bed, X = 4.53%, will be taken in preferentially. As a guideline, it is within 4.53±1%, and within that range, No. 1 to 9, No. 11, and
I selected No. 19 from each brand. Next, select the type of stowage that will form the upper part of the bed.For ores other than the ore stowed in the core of the bed, calculate the product of the SiO ₂ content and the stowage speed (tons/hour). The loading order was determined from the smallest product to the largest product as shown in Table 1. In this case, the brands were stacked in the core regardless of the order;
At the end of the loading process, No. 11 Carol B was loaded. The reason for this is that the angle of repose of Carol B is 32 degrees, and the angle of repose of No. 24 medium carbon ferromanganese, which is loaded last at the top of the bed, is 32 degrees, and the two coincide. When we calculated the component fluctuations in the longitudinal direction and cross-sectional direction of the bed loaded in the above loading order, we found that σT ²
= σ ² length + σ ² cross section = 0.020 ² + 0.080 ² = 0.082 ² . However, σT is the deviation value of the total bet. When stacking was carried out without any particular stipulation of the loading order, the deviation was as large as σT=0.102%.

【table】

[Table] Example 2 Five types of ores A, B, C, D, E shown in Table 2
Specify the planned loading amount, chemical composition, and loading speed (tons/hour) for each, and select the loading type for the bed core where the bed cross section is an isosceles triangle and the upper part of the bed above it, as shown in Table 3. However, when the deviation σ of the variation rate at that time was calculated, it was as shown in Table 3. As a result, SiO ₂ % and loading rate (tons/hour)
It was found that when the product is stacked in the order of increasing or decreasing, the deviation (σ) is small and there is no variation.

【table】

[Table] - indicates a case where the loading speed has decreased from the previous loading speed.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the loading and unloading work of a fine ore bed, Fig. 2 is an explanatory diagram of the movement of the double wheel type reclaimer during unloading in the cross-sectional width direction of the bed,
FIG. 3 is an explanatory diagram of the joining portion of different types of ores in the longitudinal direction of the bed, and FIG. 4 is an explanatory diagram of the movement of the upper part of the bed and the bed core similar to that in FIG. 2. Code 1: bed stacker, 2: bed cremer, 3: bed core, 4: bed upper part.

Claims (1)

[Claims] 1. When loading two or more kinds of raw materials such as ore in a yard surrounded by side walls on both sides, and unloading this stacked bed with a double-wheel bed reclaimer for bedding. , Prior to dispensing with this bed reclaimer, among the raw materials, the raw material whose target component is at or near the target average component of the entire bed is shaped into a shape with a cross-sectional shape close to an isosceles triangle between the both side walls. 1. A method for stacking raw materials such as ore, which comprises stacking raw materials such as ore, and then using this as a bed core and stacking other raw materials in layers on top of the bed core through the side walls.