JPS5924102B2 - How to add cement to steel dust - Google Patents

Description

[Detailed Description of the Invention] Summary of the Invention The present invention uses zinc-containing component dust, which is separated in the process of recovering effectively utilized components contained in dust discharged from a steelmaking furnace, to be added to cement and used as an auxiliary agent. The present invention relates to a method for treating iron-making dust, in particular, the addition of iron-making dust to cement in which the iron-making dust is used as a coloring agent to prevent whitening of cement, and the calcination is accelerated to prevent harmful components from scattering. This invention relates to a method.

<Prior art> In the past, ironmaking dust emitted during the ironmaking process in ironmaking furnaces has come to be separated and collected as pollution problems have come into focus in recent years. Systems for reusing active ingredients such as ingredients are being developed.

<Problems with the prior art> However, X-ray diffraction tests have shown that, in general, ironmaking dust contains metal components that are mostly in the form of compounds rather than single substances due to the high-temperature plastic furnace used in the steelmaking process. It is known from etc.

Therefore, when separating and recovering the active ingredients, flotation, magnetic separation, and gravity separation are extremely difficult, and even if leaching is possible, reuse has the disadvantage of being extremely expensive. .

For this reason, up until now, the steelmaking dust emitted from the above-mentioned steelmaking process had to be collected and disposed of after being subjected to primary treatment, but as the cumulative capacity has increased, it has become impossible to secure land for disposal. However, due to anti-pollution measures, it has become inconvenient that it cannot be disposed of.

By the way, in cement manufacturing, Cu slag discharged from the copper smelting process is generally added as a coloring agent in order to prevent the white appearance of cement due to lime raw materials and lower the melting temperature in the clinker firing process, and to improve reaction acceleration. We are trying to make effective use of it.

However, since the Cu slag contains highly toxic mineral components such as bismuth and arsenic, it has recently become impossible to add the Cu slag to cement production from the viewpoint of pollution and hygiene. There was an unavoidable problem.

To deal with this problem, the use of specially purified metal compounds such as zinc and iron as raw materials for colorants to prevent white appearance in cement production significantly increases the cost of cement products, and furthermore reduces construction costs. The disadvantage was that it increased the cost of things.

<Objective of the Invention> The object of the present invention is to solve the above-mentioned problem of disposing of iron-making dust, and also to solve the above-mentioned problem of additive colorants in cement production. After gas-solid separation of steelmaking dust, dust containing effective utilization components is used in cement production to recover useful metals and to produce paid cement, making it economically viable.
The purpose of this invention is to provide an excellent method of adding iron dust to cement that is beneficial to the field of effective resource utilization in the refining industry.

<Structure of the Invention> In accordance with the above-mentioned object, the structure of the present invention whose gist is the scope of the above-mentioned claims is to solve the above-mentioned problems by a separation process for separating useful components such as FeXZu and PbXC from dust from a steelmaking furnace. By mixing only the separated sludge containing these useful components as an additive to prevent white appearance in the lime calcination process in cement production without mixing it with anything else, it can be effectively used as a coloring agent for cement, and metal compounds such as Pb and Zn. The high melting point suppresses scattering due to melting and gasification to prevent pollution, and the Fe content improves thermal conductivity to prevent low temperatures during cement production.In addition, clinker combustion due to the inclusion of C components. Technical measures have been taken to promote this.

<Example> Next, an example of the present invention will be described below with reference to the drawings.

In the embodiment shown in FIG. 1, the ironmaking dust generated in the blast furnace 1 is firstly collected by an appropriate electrostatic precipitator 2, and then secondarily collected by a wet venturi scrubber 3, and the ironmaking dust collected from both The dust is collected in the thickener 4, and the overflow in the thickener 4 is appropriately treated in a waste liquid treatment device 5, while the solid-liquid separated mineral sludge is transferred to the drying device 6 together with the underthrown portion of the thickener 4. be done.

Thus, the Zn was dried in the drying device 6.

Steel dust sludge containing Fe, Pb, C, etc. is appropriately supplied to a line mixer 8 together with limestone 7 as a cement raw material, where it is mixed and agitated, and the mixture is transferred to a cement clinker firing process 9 where it is subjected to a predetermined firing process. submitted to the process.

Then, in the cement clinker firing step 9, TZn
, Fe, etc. act as a coloring agent to prevent the white appearance of cement, and the specific heat of the Fe component promotes the thermal conductivity of the firing raw material, and together with the combustion effect of the C component, the cement is thermophilically efficiently produced in an energy-saving state. In addition, since these metals are in a compound state, their melting point is higher than the firing temperature in the firing process, so they do not melt, and therefore,
There is no gasification and scattering, and no pollution problems occur.

Of course, no harmful components such as bismuth or arsenic are mixed into the ironmaking dust produced in the above-mentioned process, and there is no problem with environmental pollution or destruction during the working process.

As a product, a cement raw material 10 which is the same as the conventional product is obtained.

Next, in the embodiment shown in FIG. 2, as in the embodiment shown in FIG. 1 above, the underflow of the thickener 4 and the sludge from the waste liquid treatment device 5 are Zinc removal mechanism 11 having a priority crushing device, wet negative pressure cyclone, etc. disclosed in No. 51-101526
By Pb.

Zn, ZnO, and small amounts of Fe and C components are accumulated and precipitated in the seal tank 12 as overflow components.

On the other hand, the underflow portion containing active ingredients such as F e 203 of the zinc removal mechanism 11 was also disclosed in the earlier patent application filed in 1973.
The reprocessing mechanism 13 shown in Japanese Patent No. 1-101526 converts the steel into a predetermined recyclable state and reuses it in the blast furnace 1 as a raw material for iron making.

The overflow amount of chiller accumulated in the seal pump 12 is transferred to the waste liquid treatment device 14, and the solid-liquid separated sludge is transferred to the drying device 6, whereupon limestone and limestone are collected in the same way as in the embodiment shown in FIG. Clinker is stirred and mixed together with 7, and is fired to a predetermined value in a clinker firing step 9, and is made into a cement raw material 10 through a firing process similar to the above-mentioned embodiment.

Therefore, in this embodiment, not only can steelmaking dust be effectively utilized in a closed system similar to the embodiment shown in FIG.
This system is similar to that disclosed in Invention No. 26 and l1lli1, which solves all the zinc problems in the iron manufacturing process.

<Effects of the Invention> As described above, according to the present invention, in the process of sugar production and recovery of ironmaking dust collected from a steelmaking furnace, only sludge containing active ingredients such as zinc and iron is used during the cement clinker firing process without being mixed with other ingredients. By adding it to the lime raw material and supplying it as a coloring agent to prevent white appearance, it not only produces the dislocation color effect due to the lime content of cement, essentially the same as conventional copper slag, but also reduces the zinc in the ironmaking dust. Since iron is a compound and has a high melting point, it does not melt at the firing temperature and is confined in the cement, and as long as it is, there is no risk of it becoming gas and causing a pollution problem.

In addition, as a pollution control measure and as a maintenance measure for steelmaking furnaces, there are no problems with where to dispose of the collected steelmaking dust, and there are no problems with pollution, and it can be reused, making it extremely advantageous. Moreover, it has the advantage of being extremely low cost.

In addition, unlike copper slag, bismuth and arsenic are not mixed in the iron-making dust, which has the effect of not contaminating the working environment.

Furthermore, the Fe component contained in the steel dust increases the thermal conductivity of the cement raw material, which has the advantage of reducing the energy required for firing. Coupled with the combustion of

[Brief explanation of drawings]

The drawings show an embodiment of the invention, and FIG.
A schematic explanatory flowchart of the embodiment, FIG. 2 is an explanatory flowchart of another embodiment.

Claims (1)

[Claims] 1. In a method of processing dust collected from a steel furnace for effective use in the process of refining and recovering, only the separated component sludge containing active ingredients such as zinc and iron in the collected dust is processed into cement clinker without mixing with other components. - A method for adding cement to ironmaking dust, which is characterized in that it is added to a lime raw material in the firing process to color it, make heat conduction uniform, and prevent zinc from scattering.