CN1141955A

CN1141955A - Aluminum-dregs feeding method for iron-steel metallurgy

Info

Publication number: CN1141955A
Application number: CN96104960A
Authority: CN
Inventors: 丰田哲夫; 德原文雄; 金明官
Original assignee: MEISEI KAKO CO Ltd
Current assignee: MEISEI KAKO CO Ltd
Priority date: 1996-05-10
Filing date: 1996-05-10
Publication date: 1997-02-05
Anticipated expiration: 2016-05-10
Also published as: CN1067727C

Abstract

One (or more) of iron-contained powder of oxides as raw material for iron-steel-making, which contain iron dust, rust and slag etc., is mixed with aluminium slag according to a proper proportion to make a mixture which is bound by a binding agent to get a bound mixture which is then delivered into a steel-iron-making furnace by a electromagnetic conveying device. Said binding agent can be waste heavy oil. Advantage: simple operation, no need of extra equipment, and greatly reduced cost.

Description

Aluminum slag adding method for ferrous metallurgy

The invention relates to a steel smelting method, in particular to a steel smelting method using aluminum slag.

A method of smelting steel with aluminum slag, such as japanese patent No. 1750153; the mixture of iron-containing dust and aluminum slag, which is one or more than two of iron-containing dust, steel rust scale, refined steel slag, raw material oxides for iron and steel making, is put into an iron-making furnace and a steel-making furnace for smelting. The iron oxide in the mixture undergoes an oxidation reaction with the metallic aluminum. According to the method for iron and steel making, iron-containing dust and aluminum slag can be effectively recycled as metal resources so as to reduce the amount of industrial waste, and the energy efficiency is improved by utilizing the reaction heat, so that the method has practical value.

However, in order to implement the above technique, it is necessary to use iron-containing powderLast (FeO) Fe₂O₃And aluminum slag (hereinafter referred to as mixture) into a steel-making furnace or an iron-making furnace. In order to charge the mixture from the furnace opening, the mixture is processed into a shape that is easy to transport. In order to keep the bulk mixture, a collection box is required, and a conveyor belt is used to convey the mixture from the collection box to the furnace mouth. The furnace mouth is provided with a charging hopper for receiving the mixture conveyed by the conveyer belt and a metering device for charging. With the above apparatus it is possible to feed the mixture into an iron or steel making furnace. The conveying and charging equipment has large volume and occupies large space. The remaining space of a general steel mill is small, and the equipment required to be used is difficult to install, so that the method for smelting steel by using aluminum slag is difficult to popularize.

The invention aims to provide a method for adding aluminum slag during steel smelting by using the aluminum slag. The method can add the mixture of iron-containing powder and aluminum slag into a steel-making furnace or an iron-making furnace without increasing large-scale equipment.

The purpose of the invention is realized as follows:

the present invention relates to an aluminium-containing mixture which is formed bymixing any one or more than one of iron-containing powder and aluminium slag, necessary coke and coal powder (or not added according to requirements) of iron-containing dust, steel rust scale, steel refining slag, iron-making and steel-making raw material oxides, and an adhesive, then using a magnetic disk to suck the bonded mixture, conveying it to the mouth of iron-making and steel-making furnace and adding it into the iron-making and steel-making furnace.

The binder can be waste heavy oil.

The iron oxide in the mixture reacts with the metallic aluminum in the iron-making and steel-making furnace to finish the method for making iron and steel by using aluminum slag.

According to the requirement, the adding amount of one or more than one of the coke and the coal powder is 0-25% (weight percent) of the total weight of the iron-containing powder and the aluminum slag.

In the iron-making and steel-making method of the present invention, the iron-containing dust refers to dust generated during the production of iron-making, steel-making or steel products. I.e. the material collected in the dust separator.

In the process of cleaning rust on a steel plate or a steel rolling material by hydrochloric acid and sulfuric acid, the iron-containing substances recovered from the generated waste liquid are the same as the iron and steel dust, and can be used as a raw material in the invention. But the dust should be completely dried to form a powder.

The scale of iron and steel is iron oxide generated during continuous casting, heating of steel ingots, steel plates, etc., rolling or forging, etc.

The steel refining slag is a substance formed by cooling and solidifying slag covering the surface of a molten pool in the processes of iron making and steel making. It is pulverized intoproper size for application. These contain chemical components mainly composed of iron oxide and also contain alloying elements such as Si, Mn, Ni, Cr and the like contained in the base steel and iron.

The oxides of the raw materials for iron and steel making are oxides of alloying elements to be added in steel making with manganese dioxide, nickel oxide, etc.

The ferrous powder selected for use in the present invention must be attracted to a magnet.

The aluminum dross means a substance generated on the surface of molten aluminum during aluminum production. Usually a powdery substance. The chemical components of the aluminum dross used in the method are shown in Table 1. Usually because of the high cost of recovering such metallic aluminum, it is ultimately disposed of as industrial waste.

TABLE 1 chemical composition of aluminum dross (% by weight)

Metallic aluminium	Al₂O₃	SiO₂	MgO	AlN	Others
Metallic aluminium	Al₂O₃	SiO₂	MgO	AlN	Others	＜40％	＞30％	＜10％	＜10％	＜15％	＜5％

The aluminum dross cannot be attracted by the magnet. In the invention, the iron-containing powder and the aluminum slag are bonded by the adhesive and then can be attracted by the magnet. Therefore, the mixture is not processed and formed in advance. Directly using a crane with electromagnet equipment to suck the bonded mixture and putting the mixture into an iron-making furnace or a steel-making furnace. As most steel mills are provided with the hoisting equipment, the mixture with the aluminum slag is directly put into an iron-making furnace or a steel-making furnace by an electromagnetic crane without newly installing carrying equipment such as a conveying belt, thereby realizing the method of the invention.

Iron oxide contained in iron-containing dust, iron and steel scale and iron and steel slag is used to generate heat required for steel making by reacting the iron oxide with metallic aluminum contained in aluminum slag, and the iron oxide is reduced to iron. The iron is added into the iron-smelting and steel-smelting melt, thereby increasing the yield. Iron dust generated during the process of smelting steel containing alloying elements, such as stainless steel, contains oxides of alloying elements such as Ni and Cr in addition to iron oxide. When these oxides are used for the smelting of steel containingthe same alloying elements, the amount of expensive alloying elements added is reduced by the incorporation of the alloying elements reduced by metallic aluminum. Oxides of raw materials for iron and steel making are also reduced into alloy elements by metallic aluminum and added into the molten liquid.

The alumina in the aluminum slag and the alumina generated as a result of the above reaction remove harmful sulfur in steel together with lime used in the usual iron and steel making processes. Thereby acting as a flux.

Besides reacting with iron oxide and oxide of alloy element, the metallic aluminum also reacts with oxygen blown in during the steel-making process. These oxidation reactions are exothermic. The reaction heat can be used as energy for iron making and steel making, thereby improving the energy efficiency of the iron making and the steel making. Since there is no heating equipment in the LF furnace, the temperature of the molten steel drops with time. The temperature drop of the molten steel can be delayed when the above reaction is generated in the LF furnace. In the invention, besides the aluminum slag, one or a mixture of two of coke and coal powder can be added according to requirements.

The main component of the coke and the coal powder used in the invention is carbon which can be used for reducing iron oxide. The reduction reaction of carbon and iron oxide is an endothermic reaction, and thus, energy saving due to an exothermic reaction like aluminum cannot be expected. If the amount of iron oxide to be subjected to reduction reaction is large and a sufficient amount of aluminum dross cannot be secured, coke or pulverized coal and aluminum dross may be used to secure reduction of iron oxide.

In the present invention, the binder is a liquid having a certain viscosity, which solidifies on the surface of the powder upon drying. Any substance which does not have adverse effect on iron making and steel making can be used as the adhesive. In industrial practice, a substance which does not increase the cost is desired. Thus, in the present invention, the binder is a waste heavy oil containing heavy oil, which is not required in steel plants, as a main component, and the cost thereof is not generally increased. The waste heavy oil is effectively utilized, and the treatment capacity of the waste heavy oil can be reduced. In particular, iron-containing powders and waste oils are waste products produced in all steel works. Only the aluminum dross needs to be transported to the steel plant. Reduce the transportation cost and the waste treatment cost, thereby achieving the purpose of greatly reducing the cost of the whole plant. The adhesion of the iron-containing powder to the aluminum-containing powder using waste oil as a medium is not particularly limited. For example, in a steel plant, collected iron and steel scales are dried and then put into a mixer. For the weight of steel rust scale and the like, 5-10% of waste heavy oil is added, the rust scale and the like are scattered on the waste heavy oil, and then aluminum slag is added and mixed. The waste heavy oil acts as a binder to adhere the steel scale and the aluminum dross together, and the mixture is attracted by the magnet.

The weight of the mixture attracted by the magnet is determined by the power of the electromagnet arrangement. Experiments prove that the electromagnet crane can adsorb more than 400 kilograms of mixture at one time and put the mixture into the furnace. Therefore, when the waste heavy oil is used as the binder, a sufficient mixture can be transported by an electromagnetic crane.

The above is an explanation of the way of carrying out the present invention, and the present invention can be carried out by other ways.

(1) The ratio of the iron-containing powder to the aluminum-containingpowder is calculated according to the following formula:

……(1)

according to formula (1) Al: 1mol (27g) reduction of 3/8mol (87g) Fe₃O₄9/8(63g) Fe was produced. In terms of weight ratio, Al can reduce iron oxide by 3.2 times its weight, producing 2.3 times the weight of Al. Therefore, the amount of Al slag necessary for reducing 1000kg of steel rust was determined by the equation (2):

1000kg×(27/87)＝310kg ……(2)

when the aluminum content in the aluminum slag is 30%, the amount of the aluminum slag necessary for obtaining 310kg of aluminum is determined by the following equation (2):

310kg÷0.3＝1033kg ……(3)

assuming Fe in iron and steel scale₃O₄When the content is 90%, the required weight of Al slag is determined by the formula (4):

1033kg×0.9＝930kg ……(4)

it can be seen that Fe is present in the steel scale₃O₄The content of the rust scale is 90-100%, and when the content of the metallic aluminum in the aluminum slag is 30%, the weight ratio of the steel rust scale to the aluminum slag is about 1: 1.

(2) Electromagnet lifting holding test

500kg of the dried steel rust powder was put into a mixer, and 50kg of waste heavy oil containing heavy oil as a main component was added. The waste heavy oil is sprayed on all the steel rust scales.

Thereafter, 500kg of aluminum dross powder having an Al content of 30% was added thereto and mixed. The mixture is attracted by a lifting electromagnet in a steel plant. The electromagnet holds the entire mixture. The mixture was charged into a stock tank and the weight of the adsorbed mixture was measured, with the result that 400kg of the mixture was taken at a time.

The invention has the following effects:

as described above, according to the present invention, a mixture of iron-containing powder and aluminum-containing powder is not processed and molded. But is attracted by magnet and transported and put into the iron-smelting and steel-smelting furnace. The method for making iron and steel by using aluminum slag can be realized without conveying equipment such as a conveyor belt.

In addition, the iron and steel dust and the aluminum slag which are used as industrial waste and are not fully utilized can be effectively applied to the prior iron and steel making process without any additional equipment and external energy, the waste treatment problem is solved, resources are recycled, and the energy efficiency in the iron and steel making process is improved. And does not destroy the safety of the prior iron-making and steel-making processes. In particular, the invention does not add much or little cost, effectively utilizes the waste heavy oil as the adhesive, can reduce the treatment amount of the waste heavy oil and greatly reduces the whole cost.

Claims

1. A method for adding aluminium slag used for iron and steel metallurgy is characterized in that any one or more of iron-containing powder, iron and steel rust scale, iron and steel refining slag and oxides of raw materials for iron and steel making are mixed with aluminium slag according to a proper stoichiometric proportion to form a mixture, the mixture is bonded by a bonding material, and the bonded mixture is directly sent to an iron and steel making furnace by an electromagnetic transportation device.

2. The method of claim 1,wherein the weight ratio of iron-containing powder to aluminum dross is 1: 1.

3. The method of claim 1, wherein either or both of the coke and the coal fines are added to the mixture in an amount of 0 to 25% by weight of the sum of the weight of the mixture.

4. The method of claim 1, wherein the binder is present in an amount of 5 to 10% (wt%) based on the weight of the iron-containing powder.

5. The method of claim 1 or 2 or 3 or 4 wherein the binder is waste heavy oil.