Method of handling pulverulent materials or their mixtures

 

(57) Abstract:

The invention relates to metallurgy, in particular to methods for processing particulate matter containing alkali and heavy metals. In the processing method of pulverulent substances or their mixtures, containing compounds of alkali and heavy metals, for example, pulverulent substances from the steel mill, blast furnace, ore fines, particulate matter serves on or in a bath of liquid metal and liquid oxide slag or under the surface of the slag by blowing into the stream of carrier gas. The heavy metal compounds, for example, oxides of Zn and/or Pb, converted into the gas phase, separated from her, and compounds of alkali metals transferred to the slag. The basicity of the processed liquid slag installed on level 1-1,4. The technical result - the creation of a method of efficient processing of dust-like substances or mixtures thereof and enabling the processing of slag further their use in cement production. 8 C.p. f-crystals, 4 PL.

The invention relates to a method for processing various kinds of dust, or their mixtures which contain compounds of alkali and heavy metals, for example, various powdered materials steel mills, ore fines or pistorasiaan installations, as well as residues and ash from plants burning and hardening of plants.

During the blast furnace and steel processes, as a rule, there is a considerable amount of dust, the processing of which is associated with a number of problems. Because depending on the origin of this dust, it usually contains significant amounts of heavy metals, the concentration of which, as a rule, is too small for direct economical processing. In particular, the dust on the filters steelmaking plant may contain more than 10% of zinc oxide and lead oxide.

During processing of oxide slag has already been proposed a number of ways in which not only set the basicity data toxins from the point of view of possible applications respectively as grinding in the cement industry, but also do the cleaning and removal of excessive amounts of undesirable components, which can partially pass into the metal mold in a liquid metal bath and again to fall partially in the form of secondary or dust can again be removed from the gas phase. In methods of this kind, in which the oxide slag, depending on their composition should be optimized to further their ability and with the help of such methods cannot reliably remove harmful substances and in particular organic dietary fibre.

From SU 789619 known way of handling pulverulent materials that contain zinc oxide order to obtain liquid iron, in which the pulverulent material is introduced into contact with the iron melt by injection or download to the surface, and zinc compounds are transferred into the gas phase. However, in this way will not receive the slag suitable for use in the technology of cement production, so this solution differs from the stated.

Also known document WO 9916917 A1, which describes a method of separation of waste and by-products of metallurgical production of heavy non-ferrous metals, including zinc, cadmium and lead. The known method includes the supply of metallurgical wastes, including dust, or dewatered sludge containing heavy non-ferrous metals, or a bath of liquid metal, and volatile heavy metal compounds are excreted in the gas phase and then deposited from it, forming a product with a high concentration of heavy non-ferrous metals, which is the raw material for cost-benefit processing.

The objective of the invention is to provide a method economical machining dust is thus, in order to facilitate their use in the manufacture of cement. To accomplish this, the method proposed according to the invention consists mainly in the fact that particulate matter serves on or in a bath of liquid metals and liquid oxide slag, in particular, is blown into the surface or in the bath, and volatile heavy metal compounds, for example, oxides of Zn or Pb, stand out in the gas phase and then deposited it, and compounds of alkali metals transferred to the oxide slag. Due to the fact that such particulate matter or dust from the filters make on or in the liquid metal bath here in the first place, from liquid pig iron or liquid oxide slag, succeed with extremely high selectivity to produce the separation of the phases, and in particular compounds of alkali metals contained in the original dust-like substances remain, mostly, toxins, and heavy metals type zinc and lead primarily in a concentrated form can again be found in secondary pulverulent substances, and at the same time the total number of deposited dust in the ground and especially full can be restored to the amount average of below half the original quantity. Along with the BA to cause the formation of secondary particulate matter, economical re-use due to the presence of high concentrations of the individual components (regeneration which seems celebrates) is greatly facilitated, while simultaneously enriching the oxide slag compounds of alkali metals gives the corresponding product of improved properties in connection with possible further use in the manufacture of cement.

In the framework of the proposed method is preferred to the basicity of the liquid slag before making dust was at the level of, for example, 1-1,4. Oxide liquid slag with such basicity, which float on the surface of the bath of pig iron, are particularly high selectivity for the desired separation of the compounds of alkali metals with simultaneous reduced tendency to capture heavy metals. At the same time in such a way can reduce the content of iron oxide in the input pulverulent substances or pulverulent substances with filters, resulting in possible to regenerate the liquid iron from such particulate matter as a side effect, which increases the efficiency of the method. In addition, there is a significant decrease obscenely metals in the secondary dust what creates particularly favorable conditions for the economic regeneration of the individual components of secondary particulate matter.

Especially favorable is the introduction of particulate matter pneumo transporting, the advantage of which is that particulate matter is pneumatically fed to the surface of the metal or slag or under it and wauwautosa using a carrier gas, in particular a hot blast.

This pneumo transporting allows for the introduction of particulate matter simultaneously to produce uniform mixing with additives, which result in, first, facilitate the pneumo transporting, and secondly, at the same time allow you to enter the desired components in the oxide slag. Particularly preferred is the mixing of the processed powdered substances with additives such as, for example, coal, sand and/or bauxite, which, for example, with the introduction of coal, along with improving the ability to pneumo transporting, at the same time is also subject to reduction potential for continuous selection of metallic iron from iron oxides contained in the pulverulent substances. Adding sand and Bo is temporarily can serve to adjust the desired target basicity of oxide slag and to establish in this case, the desired high content of aluminum oxide in the slag.

In the framework proposed in the invention method, it is also possible simultaneously to reliably handle a number of other problematic substances, such as, in particular, organic pollutants and, in particular, suspensions and slurries. When such additives are simultaneously used to improve the pneumo transporting pulverulent substances by preventing the formation of agglomerates. With the introduction of a similar, mixed with organic pollutants, substances able to burn organic components, and can be provided with further reduction potential for the reduction of iron oxides from particulate matter.

It is appropriate in the framework of the proposed method is used as a liquid metal bath tubs in the pig iron. In particularly advantageous implementation of the method tub contains liquid slag and liquid pig iron in a weight ratio of 1:3-1:6, preferably 1:4.

Especially simple way flow of dust-like substances and their mixtures are produced in such a way that they can be passed into your Converter through the bottom nozzle. After the reaction, which in particular occurs at the interface between the slag and incometested, namely below 10% of the original number.

Below the invention is explained in more detail by the example of its implementation. In the Converter in a bath of 10 tons of liquid pig iron was loaded with 2 tons of slag with the following composition (table.1):

These toxins are basicity, suitable for subsequent use in the cement industry and contain, as a rule, only a small number of compounds of alkali metals. For certain properties of the cement and, in particular, for the strength properties, such as strength with the rapid hardening obtained from such slags as grinding (concrete) mortar or concrete mixes, it would be quite desirable high content of compounds of alkali metals.

Through the bottom nozzle in such a bath was breathed 1 ton of steel pulverulent substances with the following composition (table.2):

Dust filters meltshop contained a remarkable number of compounds of alkali metals and heavy metals. The penetration of the bath was the separation of the phases, and compounds of alkali metals contained in the original dust-like substance, with high selectivity contacted terouanne form in the secondary dust-like substance. The composition of the slag was found after treatment of particulate matter from the filters meltshop using the following control analysis (table.3):

In an amount of about 264 kg was obtained secondary powdered substance with the following composition (table.4):

From the comparison of the composition of the introduced particulate matter from a steel mill, a composition of secondary particulate matter from the filter and comparing the compositions of slags, it follows that K2About could be detected in the secondary dust-like substance from the filter in an amount up to about 3.2 wt.%, of which 96.8% of the content of the K2O introduced powdered substances could be detected in the slag obtained in the form of the product. Similar remains the distribution source of the content of Na2O, and 4.5 wt.% the original parts were found in the secondary dust-like substance from the filter and 95.5 wt.% in the slag obtained in the form of the product.

The opposite is the case with the contents of the oxides of zinc and lead, which again could be detected in the secondary dust-like substance from the filter up to 99,7 or 99.9 wt.%. Due to a General decline in the number of secondary particulate matter from the filter toward entered RIT now the share of heavy metals, which talks about the economic feasibility of processing. Exclusively about 0.3 or 0.1 wt.% the content of zinc oxide or lead oxide introduced particulate matter from a steel mill can be set up in the slag produced in the form of the product.

1. The method of processing pulverulent substances or their mixtures, containing heavy metal compounds, including the supply of pulverulent substances or mixtures thereof at or in the bath of liquid metal with the release of volatile compounds of heavy metals in the gas phase, characterized in that before applying pulverulent substances or their mixtures, containing additional compounds of alkali metals, form a liquid oxide slag basicity which is set at the level of 1-1,4, pneumotransport and blown into the stream of carrier gas dust-like substances or mixtures thereof at or in the bath of liquid metal and liquid oxide slag or under the surface of the slag, moreover, after the transition of volatile compounds of heavy metals in the gas phase separated from the gas phase, and compounds of alkali metals transferred to the oxide slag.

2. The method according to p. 1, characterized in that compounds of heavy metals are oxides of zinc and/or lead.

3. The method according to p. 1, featuring the TV or ore fines.

4. The method according to p. 1, characterized in that the injection of pulverulent substances or their mixtures are used the hot blast.

5. The method according to p. 1, characterized in that the processed powdered substance mixed with additives, such as coal, sand and/or bauxite.

6. The method according to any of paragraphs.1-5, characterized in that particulate matter is mixed with substances containing organic constituents.

7. The method according to any of paragraphs.1-6, characterized in that as the bath of liquid metal used a bath of pig iron.

8. The method according to p. 7, characterized in that the weight ratio of liquid pig iron or liquid oxide slag is 1:3-1:6, mainly 1:4.

9. The method according to any of paragraphs.1-8, characterized in that the bath of liquid metal and liquid oxide slag is organized in the Converter, and the pulverized substance or mixture is blown into it through the bottom nozzle.



 

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