RU2544376C1 - Method to create anti-filtration screen of hydraulic structure for storage of industrial wastes - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: when creating an anti-filtration screen of a hydraulic structure for storage of industrial wastes, for instance, a sludge reservoir, layers of the screen on the base of the sludge reservoir are formed using a suspension of industrial wastes, containing finely dispersed particles, with compaction of layers. The base of the sludge reservoir is made from clay or loam, compacted, the compacted layer is poured with a water suspension of finely dispersed dust of gas treatment from electrothermal production of silicon and/or siliceous ferroalloys with the solid to liquid ratio within 3÷10:1. The suspension is maintained until absorption into the layer of the sludge reservoir base. The clay or loam layer is laid on top and compacted. The water suspension is poured in the amount of 50-100 l/m².

EFFECT: invention will make it possible to prevent contamination of soil layer adjacent to storages due to reduction of coefficient of filtration of insulating material, to recycle anthropogenic wastes in the form of a finely dispersed dust of gas treatment of electrically thermal production of silicon or siliceous ferroalloys.

2 cl, 1 tbl

Description

The invention relates to methods for preventing contamination of soil and groundwater by components of industrial waste, in particular to the creation of anti-filter screens for landfills and waste storage, sludge fields.

A known method of forming a protective screen, which consists in preparing a waterproofing mixture containing waste polyethylene, laying it on the base of the storage and heat treatment, in which prepare a mixture of waste polyethylene 70-99% and polypropylene 1-30%, after laying it on the base of the storage heat treatment at the melting temperature of the mixture or the surface layer of the storage (patent RU No. 225178, E02D 3/12, E02B 3/16, publ. June 27, 2005). The implementation of this solution requires significant costs, both for the preparation and formation of the waterproofing layer, and energy costs for the manufacture of this layer.

A known method of erecting an airtight curtain, including the development of a trench under the protection of a clay suspension and filling the trench with a clay-cement solution with the simultaneous displacement of a clay suspension, in which before filling the trench with a clay-cement solution, the latter is foamed by mixing it with technical foam (AS USSR No. 987010, E02B 3 / 16, 1990). This solution requires significant costs, both material (cement, technical foam), and the preparation of an clay-cement mortar and mixing it with technical foam, while high anti-filtration properties are not ensured, since “local voids are formed in the body of the curtain, which lengthens filtration path ”, which over time can lead to the formation of filtration channels, to pollution of groundwater and the environment.

The known composition of the antifiltration screen used on sludge collectors of alumina refineries, consisting of a double layer of a polyethylene film with protective soil (Tsekhovoy AI, etc. The use of asphalt-polymer concrete in waterproofing coatings of sludge collectors. "Non-ferrous metals", 1978, No. 11, p. 58-59). The implementation of this solution requires significant costs, both for the preparation and formation of the waterproofing layer, and energy costs for the manufacture of this layer.

A known method of creating waterproofing elements of hydraulic structures, including the delivery of material, its preparation and installation, in which the material of the waterproofing element is used sludge from bauxite processing according to the Bayer method, leaving the process with humidity T: W = 1: 2-10, which before laying by preparing by dehydration to a moisture content T: W = 1: 0.5-0.6, while the content of fractions +50 microns in the sludge is not more than 10 wt.%, after which the prepared material is compacted to a porosity of not more than 0.60 - 0.65 (A.S. USSR No. 1564257, E0 2B 3/16, 1990).

The main disadvantages of this technical solution, adopted for the closest analogue, are the significant costs of dewatering the suspension, the difficulty of preparing, laying and compacting wet material, insufficiently high antifiltration properties of the screen.

The objective of the proposed solution is to reduce the cost of creating an anti-filter screen of a hydraulic structure for storing industrial waste and increasing the environmental safety of the storage.

The technical result is the use of natural materials and industrial waste as part of the anti-filter screen, increasing the anti-filter properties of the screen.

The technical result is achieved by the fact that in the method of creating an anti-filter screen of a hydraulic structure for storing industrial waste, for example a sludge collector, comprising forming screen layers on the basis of a sludge collector using a suspension of industrial waste containing fine particles, compaction of the layers, the base of the sludge collector is made of clay or loam, compacted , an aqueous suspension of fine dust of gas purification of electrothermal production is poured onto a compacted layer and silica and / or siliceous ferroalloys with respect to its G: T within 3 ÷ 10: 1, the suspension is maintained until it is absorbed into the slurry tank base layer stack top layer of clay or loam and condense it.

In this case, an aqueous suspension is poured in an amount of 50-100 l / m ² .

A comparative analysis of the solution for the closest analogue and the proposed solution shows the following.

The known solution and the proposed are characterized by similar features:

- a method of creating an anti-filter screen of a hydraulic structure for storing industrial waste, including:

- formation of screen layers;

- the use of a suspension of industrial waste;

- use of industrial wastes containing fine particles;

- compaction of the layers.

The proposed solution differs from the closest analogue in the following features:

- the base of the hydraulic structure for storing industrial waste - sludge collector - is made of clay or loam;

- the base of the sludge collector from clay or loam is compacted;

- pour on a compacted layer an aqueous suspension of fine dust of gas treatment of electrothermal production of silicon and / or silicon ferroalloys;

- in suspension support the ratio W: T within 3 ÷ 10: 1;

- maintain the suspension until absorbed into the underlying layer;

- lay on top a layer of clay or loam;

- the upper layer of clay or loam is compacted.

In this case, an aqueous suspension is poured in an amount of 50-100 l / m ² .

The presence in the proposed technical solution of signs that are different from the signs of the solution according to the closest analogue allows us to conclude that the proposed patentability condition of the invention is “novelty”.

The technical essence of the proposed solution is as follows.

As part of the antifiltration screen, natural material is used, including clay or loam, and an aqueous suspension of fine dust from gas purification of electrothermal production of silicon and / or silicon ferroalloys is used as industrial waste.

Finely dispersed dusts of gas purifications of electrothermal production of silicon and / or silicon ferroalloys contain finely dispersed particles, mainly silicon dioxide, and have the following composition, wt.%:

SiO ₂ 80.0-95.0 Al ₂ O ₃ 0.2-0.5 Fe ₂ O ₃ 0.2-0.5 Cao 1.2-4.0 MgO 0.8-3.0 C _free 3.0-8.0 Na ₂ O up to 0.1 SO ₃ 0.1-0.2 P ₂ O ₅ 0.1-0.15 K ₂ O 0.1-0.4 TiO ₂ up to 0.02 SiC 3.0-5.0

The chemical composition of dusts can vary, depending on the initial types of raw materials and technology, however, the content of the main component - silicon dioxide, is within the specified limits.

Dusts have the following particle size distribution fractions:

μm % 0-1 13.0 1-3 13.8 3-5 8.4 5-10 10,4 10-20 14.8 20-29 7.0 > 30 32.6

The specific surface is 15-28 m ² / g. The bulk density is 0.2-0.25 g / cm ³ .

Finely dispersed dusts of gas purifications of electrothermal production of silicon and / or silicon ferroalloys belong to the group of subliminal dusts formed during evaporation in the high temperature zone and subsequent condensation of sublimates. Particles of such dust carry the same static electric charge.

The increase in the antifiltration properties of the material is associated with the presence of microparticles that overlap the existing pores and with a high specific surface area of dusts.

The screen is formed in layers with compaction of the layers of natural material in the form of clay or loam. At the same time, an aqueous suspension of finely dispersed dust of gas purification of the electrothermal production of silicon and / or silicon ferroalloys is poured onto the compacted layer with a ratio of 3: 10: 1 in it W: T, the suspension is kept until absorbed into the underlying layer. When the ratio W: T less than 3: 1, the suspension has a high viscosity, it is difficult to uniformly apply the material to the compacted layer of clay or loam. When the ratio W: T more than 10: 1, the amount of dust in the suspension is small, the anti-filter properties of the screen are reduced.

The use of industrial waste in the construction of a sludge collector allows not only to efficiently dispose of them, but also to reduce the cost of construction of a sludge collector by reducing construction costs both by reducing the cost of materials and by reducing energy and labor costs. At the same time, the antifiltration properties of the resulting screen fully meet the requirements.

The results of testing the creation of an anti-filter screen by the proposed method are shown in the table.

No. p / p Screen Screen specifications Suspension absorption time, hour Filtration coefficient, m / day one 2 3 four 5 one Compacted loam 300 mm - 3.2 · 10 ^-4 2 Compacted loam - bottom layer 200 mm 2.0 1.3 · 10 ^-4 Aqueous suspension of dust gas purification electrothermal production of silicon W: T = 5: 1 30,0 l / m ² Compacted loam - top layer 100 mm 3 Compacted loam - bottom layer 200 mm 3,5 9.5 · 10 ^-5 Aqueous suspension of dust gas purification electrothermal production of silicon W: T = 5: 1 50.0 l / m ² Compacted loam - top layer 100 mm four Compacted loam - bottom layer 200 mm 12.0 2.7 · 10 ^-5 Aqueous suspension of dust gas purification electrothermal production of silicon W: T = 5: 1 100,0 l / m ² Compacted loam - top layer 100 mm 5 Compacted loam - bottom layer 200 mm 64.0 2.9 · 10 ^-5 Aqueous suspension of dust gas purification electrothermal production of silicon W: T = 5: 1 200,0 l / m ² Compacted loam - top layer 100 mm 6 Compacted clay 300 mm - 7.2 · 10 ^-6 7 Compacted clay - bottom layer 200 mm 3.0 5.7 · 10 ^-6 Aqueous suspension of dust gas purification electrothermal production of silicon W: T = 5: 1 30,0 l / m ² Compacted clay - top layer 100 mm 8 Compacted clay - bottom layer 200 mm 6.0 4.9 · 10 ^-6 Aqueous suspension of dust gas purification electrothermal production of silicon W: T = 5: 1 50.0 l / m ² Compacted clay - top layer 100 mm 9 Compacted clay - bottom layer 100 mm 27.0 1.5 · 10 ^-6 Aqueous suspension of dust gas purification electrothermal production of silicon W: T = 5: 1 100,0 l / m ² Compacted clay - top layer 100 mm 10 Compacted clay - bottom layer 200 mm 80.0 1.45 · 10 ^-6 Aqueous suspension of dust gas purification electrothermal production of silicon W: T = 5: 1 200,0 l / m ² Compacted clay - top layer 100 mm

During the research, clay loams, clay and an aqueous suspension of dust from the gas treatment of electrothermal silicon production were used. The ratio of W: T adopted 5: 1. With a W: T ratio of less than 3: 1, dust is poorly and unevenly distributed over the surface. The ratio of W: T more than 10: 1 is impractical, since the volume of the suspension increases, the effectiveness of the dust in the composition of the screen decreases. The use of a suspension in an amount of less than 50 l / m ^{2 of the} surface gives an insignificant effect on increasing the antifiltration properties of the screen, and with an increase in the amount of a suspension of more than 100 l / m ^{2 of the} surface, the efficiency does not increase, but the absorption time of the suspension into the lower layer of the constructed anti-filter screen increases significantly.

Using the proposed technical solution allows to reduce the cost of construction of the sludge collector, to prevent contamination of the soil layer adjacent to the storages by reducing the filtration coefficient of the insulating material, to utilize large-tonnage industrial waste in the form of fine dust from gas purification of electrothermal production of silicon and / or silicon ferroalloys.

Claims (2)

1. A method of creating an anti-filter screen of a hydraulic structure for storing industrial waste, for example, a sludge collector, comprising forming screen layers on the basis of a sludge collector using a suspension of industrial waste containing fine particles, compaction of the layers, characterized in that the base of the sludge collector is made of clay or loam, compacted, an aqueous suspension of fine dust of gas purification of electrothermal production of silicon and / or silicon is poured onto a compacted layer ferroalloys with respect ies therein W: T within 3 ÷ 10: 1, the suspension is maintained until it is absorbed into the slurry tank base layer stack top layer of clay or loam and condense it. 2. The method according to claim 1, characterized in that the aqueous suspension is poured in an amount of 50-100 l / m ² .