Method and apparatus for treating high-temperature slag

Abstract

A method in which slag is cooled in a treatment step without generating strongly alkaline water and without necessitating a prolonged time for the treatment. Using this method, slag is efficiently recovered as a valuable material and the metal contained in the slag is efficiently recovered. Also provided is an apparatus for the method. High-temperature slag containing CaO is subjected to primary cooling and thereafter subjected to secondary cooling while being moved inside a cooler. Both the primary cooling and the secondary cooling are water cooling conducted to such a degree that no free water is generated. A rotary cooler comprising a housing equipped with projections on the inner surface thereof can be used as the cooler. Slag having a temperature as high as 500 DEG C or above is charged into the rotary cooler and cooled. The slag is separated into slag and a metal by means of the crushing that occurs due to impact when the slag falls due to the rotation of the housing and by the destruction caused by the rapid cooling of the slag.

Description

technical field [0001] The present invention relates to a processing method and a processing device for high-temperature slag discharged at a high temperature of 1200° C. or higher from a molten iron pretreatment process, a molten iron pretreatment furnace, a converter, an electric furnace, etc. in a steelmaking process. Specifically, it relates to a treatment method and a treatment device for effectively cooling molten iron pretreatment slag, converter slag, electric furnace slag, etc. containing CaO discharged at high temperature from a molten iron pretreatment furnace, a converter, an electric furnace, etc., and at a low cost. Furthermore, the pig iron contained in these slags is efficiently separated and recovered, so that the slags can be effectively used for roadbed materials, marine materials, and the like. Background technique [0002] A large amount of high-temperature slag containing CaO at 1200-1600°C is produced and discharged from the molten iron pretreatment pr...

AI Technical Summary

Problems solved by technology

[0008] However, cooling by spraying a large amount of water in a pit or field has the following problems: Since the cooling efficiency is low, it takes a long time for cooling, and, in order to Prevents scattering of dust generated from the surface of solidified slag, increasing dust collection cost

[0010] In addition, as mentioned above, the slag is separated into pig iron and slag by passing the slag several times through the crusher and the magnetic separator, but the solidified slag has a relatively high hardness, Therefore, if a powerful crusher is not used, it cannot be crushed sufficiently

In addition, there is also the following problem: the pig iron obtained in this way has a low iron content because the slag is not sufficiently separated, and even if it passes through a second-stage crusher, only 70 to 80% of the iron content can be obtained. Class crushers can only get 80-90% iron content

However, this method requires huge equipment and costs for high-temperature pressure vessels, and cannot avoid water vapor explosion accidents.

In addition, there are the same problems as those in JP-A-6-346161: the obtained slag lumps have a large particle size deviation, and mechanical crushing requires wind separation, and the iron content of pig iron is 50-90%, and the grade is low. Moreover, the deviation is large, and it is difficult to use it in a steelmaking furnace, etc.

[0018] In this way, although various methods related to the processing method of high-temperature slag have been proposed, they have not been put into practical use due to the above reasons. Such as Figure 6, Figure 7 shows the inefficient and costly method for steelmaking slag containing CaO and other high temperature slags for processing

This conventional method has left many problems as follows: the generation of dust after discharge from the slag pan and / or the occurrence of fire powder and flames is large, and the equipment is also degraded early. In addition, the remaining CaO in the slag is effectively used as a roadbed material. hindrance, etc.

However, this technology is a technology for recovering heat from slag, and there is no suggestion of efficiently cooling slag or recovering pig iron in slag

Images