SU1643361A1 - Method of preparing sludge to hydraulic transport operations - Google Patents

Abstract

The invention relates to hydrotransport, in particular to a method for preparing slag and hydrotransportation. The purpose of the invention is to increase the safety of the material. The percentage of particles with a size of 5-80 mm in the slag is brought to the level of 45-50%, with a size of 0.315 5 mm - to the level of 49-54%; less than 0.315 mm in size - to the level of 1%. Slag is mixed with the carrier medium, which is used as an aqueous suspension of fly ash with a particle size of up to 0.063 mm at an ash concentration of 1.51 mass by mass, while the amount of slag in the suspension does not exceed 50% of 1 tab.

Description

The invention relates to hydrotransport, in particular to a method for preparing slag for hydrotransportation.

The purpose of the invention is to increase the safety of the material.

The method includes grinding and classification of particles, in which the percentage of particles in the slag with a size of 5-80 mm is adjusted to a level of 45-50%, with a size of 0.315-5 mm - to a level of 54-49%, with a size of less than 0.315 mm - to 1% . As a carrier medium, an aqueous suspension of fly ash with a particle size of up to 0.063 mm is used at an ash: liquid ratio of 1.5: 1 by weight. The slag is mixed with the carrier medium at a slag concentration of up to 50%.

Waste power plants, represented by ash and slag, are a good building material. Large slags (5–20 mm) are a substitute for natural rubble, small (0.315–5 mm) sand substitute. Slag fractions less than 0.315 mm in size are an undesirable impurity in slag gravel and sand and are not used.

The proposed method allows to significantly increase the yield of large slags (5 mm), slightly reduce the yield of small slags (0.315-5 mm) and virtually eliminate the production of fine particles (0.315 mm), since practically the content of these particles in slag sorting products is slag rubble and slag sand, their content is significantly lower than acceptable.

Example. Fly ash from a power plant with a particle size of less than 0.063 mm is 85-90% mixed with water in a 1.5: 1 weight ratio, in a mixer with a cross-shaped working element. The resulting suspension is mixed in a mixing chamber with slag, with particle sizes in the range of 0.315-80.0 mm

WITH

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pumped by a plunger pump through an annular pipeline with a diameter of 203 mm for a conditional distance of 3 km. After pumping, the slurry is drained on a CLC-3 laboratory centrifuge with the suspension separated. The dehydrated slag is dried and screened on the Rotap laboratory apparatus. The research results are shown in the table (starting material size: 5.0–80.0 mm — 48.0%; 0.315–5.0 mm — 51.8%; 0.315 mm - 0.2%).

These tables show that the optimal conditions for the slag hydrotransport are: a slurry formed by dry fly ashes in a ratio m: W - 1.5: 1. At this slurry density, the smallest slag grinding and the best particle size preservation are obtained. This is due to the fact that the bulk of the solid material of the suspension moves along the lower part of the pipeline, creating a dense layer that the transported material moves in a suspended state, not touching the pipeline. With a decrease in the ratio m: l 1.51 (experiments 1–4) due to a decrease in the density of the suspension, the effect of gravity begins, which causes abrupt movement of the material being transported, and slag abrasion on the pipeline walls is inevitable and the slag particles also collide with each other. grinding

Increasing the density (t: W 1.6: 1) requires an increase in supply pressure to

1.3 bar (critical), while the flow rate is reduced to 0.8 m / s, and consequently, there is a decrease in the performance of hydrotransport; supply pressure of 0.7-0.9 bar and flow rate of 0.9-1 m / s (runs 6, 7, 10 and

12); Concentration of transported material is 40-50%.

With a decrease in concentration to 30%, the quality indicators of hydrotransport do not change, but at the same time they decrease.

Claims (1)

hydrotransport performance. With an increase in the concentration of the transported material up to 60-70% (experiments 14 and 15), the grinding of the material increases. Invention Formula The method of preparing slag for hydrotransportation, which consists in grinding the slag, classifying and mixing it with a carrier medium at a concentration of up to 40-50%, characterized in that, in order to increase the material preservation, the percentage of particles in the slag of 5–80 mm in size is brought to the level of 45–50%, 0.315–5 mm in size to 49–54%, and less than 0.315 mm in size The level is 1%, while an aqueous suspension of fly ash with a particle size of up to 0.063 mm is used as a carrier when the concentration of ash: liquid is 1.5: 1 by weight.