SU834166A1 - Method of producing ferrolime - Google Patents

Description

(54) METHOD OF MANUFACTURE OF FERROUSRY

one

The invention relates to the preparation of raw materials for the steel industry.

A known method for producing a ferruginous flux involves burning a mixture of dolomite and iron-containing material in a rotary kiln 1.

The closest to the proposed technical essence and the achieved result is a method of producing ferrodeal, which includes loading limestone or dolomite into the rotary kiln, previously displaced with iron-containing pellets 2.

However, the known methods are expensive and difficult to operate, since the production of the pliers and their preparation for roasting require special technology. In addition, these methods do not provide a sufficient degree of iron transfer to lime (it is 62%).

The purpose of the invention is to increase the efficiency of the process.

This goal is achieved by applying iron-containing material in the form of pulp on the surface of limestone or dolomite pieces, previously displaced with burning additives that have an increased content of CaO and MgO, for example slurry with lime powder. The method is carried out as follows.

The iron-containing pulp is displaced with viscous additives, which have an increased content (more than 70%) of CaO and MgO (for example, slime pulp with lime dust), and apply this mixture on the surface of limestone pieces. Fluid mixture of iron-containing slime

The lime dust is distributed on the surface of the limestone pieces and provides the maximum amount of surface from touching the components of the mixture with a known color. The amount of this mixture, the ratio of its components and the humidity are determined experimentally and depend on the particle size distribution; mineral composition of the slurry and lime dust. The amount of iron-containing material added to limestone depends primarily on the content of FejOj in it. The reaction in the CaO system - proceeds at 800–1200 ° С with the formation of calcium ferrites. Calcium ferrites melt at relatively low temperatures (mixtures containing 25-75% CaO and 70-75%, melt at 1220 ° C) and cause a decrease in the melting point of the respective systems. At the same time, the viscosity of the liquid phase, which determines the ability to envelop the CaO grains, to form slow-absorbing lime, decreases.

The introduction of iron-containing sludge in an amount of up to 15% by weight of lime does not reflect on the quality indicators of the resulting ferro-extract. The moisture content of the slurry is selected from the conditions for its transportation and flow. The content of free water in the sludge may be 35-73%, which increases the total water content of lime by 5-10%.

Lime dust plays a role in the binding component, which helps to fix the mixture on the surface of limestone pieces and forms floccules that prevent the formation of dust. The formation of a strong stone during the hardening of the slurry-lime mixture occurs as a result of the drying of the calcium oxide hydrate gel and its subsequent carbonization due to the absorption of CO from the exhaust gases or air. The amount of limestone injected depends on the water content of the sludge. Usually one part by weight of lime dust should be added to two to three parts of water. The raw material obtained in this way is calcined at 900-1200 ° C in a rotary kiln, where the iron-containing material and limestone react with each other in the solid phase, resulting in the formation of ferrofin.

The yield of reaction products in the solid phase is mainly determined by the number of contact-reacting particles. The chemical affinity of the reactants in this case, tea plays a secondary role.

Calcium ferrites occur at low temperatures (500-600 ° C) still in the heating zone of the charge. It has been established that the rate of calcium ferrite formation in the solid phase is extremely high. At 1200 ° С, 74% of a mixture of powders of lime and hematite transforms ferrous iron-containing sludge of CCFs of a horizontal settler 64.8 24.4 63.0 5.4O, 09

Lime dust

Slows to calcium ferrite in 1 min. Therefore, for any basicity, due to the large number of CaO-Re O contacts, the low temperature of the onset of the reaction and the high rate of its occurrence in the solid phase, calcium ferrites are predominantly formed.

TttKHM In principle, the maximum contact surface of the iron-containing material and lime (dolomite) increases the speed of the process in the solid phase and leads to an increase in the degree of iron transfer to lime. In addition, the use of metallurgical wastes as an iron-containing material improves the efficiency of the proposed method.

Example. The proposed method was tested in laboratory conditions. Lime to a particle size of 12 mm is treated with a mixture of slurry pulp gas cleaning oxygen converter shop with a solid content of 600 g / l and waste production of lime.

0 The consumption of iron-containing sludge (dry weight) is 0.2 kg, lime dust-0.1 kg, lime-2.0 kg. Chemical and granulometric composition of the input components are given in Table. 1 and 2. The resulting raw material is calcined in a muffle furnace at 1050 ° C for 3 hours. As a result of the calcination, ferro lime with a Fe content of 5.5% is obtained, and the degree of iron transfer to lime is.

0 1 | the current method can be implemented on the basis of the existing limestone firing technology.

The use of suitable ferrous in oxygen-converter production, and screening in sinter production reduces the cost of products, and the rational use of iron and lime waste allows you to create waste-free 7fi "iftiK) ferro-production and get an economic effect of more than 10 p. per ton of recycled waste.

T blitz 1

62.71 13.44 3.32

17.55

0.333 1.9 0.96 0.027 O, 23

KKU Iron Sludge from Horizontal

Claims (2)

Claim 1. A method of producing ferroall, including calcining a mixture of calcium-containing and iron-containing material, characterized in that, in order to increase the efficiency of the process, the iron-containing material is applied to the surface of the calcium-containing material in the form of a slurry. 2. The method according to claim 1, characterized in that the slurry before applying to the surface table 2 pieces of calcium-containing material are biased with calcium and magnesium oxide-containing additives. Sources of information taken into account in the examination 1. US Patent No. 4099964, cl. 75/52, 1978. 2. US patent N ° 4092406, cl. 423/594, 25 1978.