RU2236314C1 - Method of lithifying visco-plastic industrial wastes - Google Patents

Abstract

FIELD: lithifying of visco-plastic industrial wastes and bottom slime and sediments.

SUBSTANCE: proposed method includes introduction of coagulating additives into reservoir containing visco-plastic industrial wastes and acting on them with electric current by means of metal electrodes; used as reservoirs for visco-plastic wastes are accumulating ponds; wastes are subjected to action by alternating current; metal electrodes are immersed in pods. For obtaining required hardness of wastes being lithified, depth of submergence of Vicat needle is measured before action of current h₀ and in the course of action of current h_t; relative coefficient of mechanical strength of medium being lithified is determined by the following relationship: K=h_t/h₀; time of passing of electric current required for obtaining the required hardness of wastes being lithified is found from the following relationship: t=1/J(1-K), where t is time of passing of alternating current, J is force of current; used as coagulating additives are vinyl pyrrolidone or cetyl pyridinium chloride.

EFFECT: enhanced efficiency; low cost of process.

1 dwg, 1 ex

Description

The invention relates to geochemistry, and in particular to the technology of lithification of viscoplastic industrial wastes and bottom sediments, sludges, etc., and can be used in various fields, for example, in construction in the manufacture of artificial soils.

A known method of processing solid domestic and industrial waste, including loading and heat treatment in a bath of slag melt and providing for primary treatment, neutralization and cooling of the exhaust gases. The temperature of the slag bath is maintained by passing electric current through the molten slag using immersed electrodes (RF Patent No. 2117217, IPC F 23 G 5/00).

The disadvantage of this method is the impossibility of processing and lithification of viscoplastic industrial waste. In addition, the technology of the method requires the investment of large funds and material costs.

A known method of purification of a capillary-porous medium contaminated with oil and oil products, in accordance with which a solution of oil-oxidizing organisms is introduced into the purification zone, the electrodes are the anode and cathode, then water. A constant electric current is passed between the electrodes to create an electroosmotic fluid movement in the cleaning zone (Patent No. 212905, IPC B 09 C 1/10).

However, this method cannot be effective in the lithification of viscoplastic industrial waste, as it does not allow to increase the mechanical properties of the material being lithified.

A known method of lithification of household and industrial waste, as well as bottom sediments, based on the use of a mixture for the disposal and lithification (RF Patent No. 2162068, IPC C 04 B 33/00). This mixture provides neutralization of sludge and waste and turns them into environmentally friendly soil.

The disadvantage of this method is the significant consumption of expensive components, as well as the complexity of the conversion technology.

The closest in technical essence to the present invention is a method for producing granular organic products, including thickening an aqueous suspension with separation of the filtrate, simultaneous granulation and drying by spraying in a fluidized bed and collecting dust in the exhaust gases after granulation, while drying is carried out, for example, by flue gases or natural gas. The aqueous suspension is thickened by electrocoagulation and electrodialysis to a moisture content of not more than 70%, releasing pure water, and granulation and drying are carried out while the suspension is fed into the granulator at a speed of 1750-4100 kg / h and gas for fluidization with a flow rate of 22900-63000 m ³ / h at a pressure of sawing air of 2.0-3.0 kg / cm ² . (RF patent No. 2172728, IPC C 05 F 3/00)

However, this method is a complex multi-stage process, characterized by significant energy consumption and requiring a special expensive technological line.

The objective of the proposed solution is to simplify the method of lithification of viscoplastic industrial waste while increasing the efficiency of lithification and reducing material costs.

The problem is solved in that in the method of lithification of viscoplastic industrial waste, including the introduction of coagulating additives into a container with viscoplastic waste and exposure to electric current through metal electrodes, according to the proposed solution, storage ponds are used as a reservoir for viscoplastic waste, the effect is carried out by alternating electric current and metal electrodes are immersed directly in the storage ponds, while the transmission time is electrically of current required to obtain the desired hardness litifitsiruemyh wastes determined from the relationship:

t = 1 / J (1-K),

where t is the transmission time of alternating electric current, J is the current strength, K is the relative coefficient of mechanical strength of lithified waste.

As coagulating additives, polyacrylamide or vinylpyrrolidone or cetylpyridinium chloride is used.

The change in the mechanical properties of a viscoplastic lithified medium was studied using a Wick device designed to determine the setting time of cement slurries during well cementing. The immersion depth of the needle of the device at the same load was an indirect indicator of the degree of increase in the strength properties of the material being lithified.

In the process of implementing the method achieve:

- activation of geochemical processes by affecting viscoplastic industrial wastes and coagulating additives with alternating direct electric current, which ensures uniform mass transfer of electrode materials and additives;

- accelerated synthesis, artificially reproducing the process of particle cementation and mineral formation, which are extremely slow in natural conditions;

- a significant change in the chemical and mineralogical composition, including the formation of new solid phases and, as a consequence, an increase in the strength of the treated viscoplastic material.

From the scientific, technical and patent literature, it is not known about the existence of a technical solution with the listed set of distinctive features, which gives reason to conclude that the claimed object meets the criteria of the invention.

The invention is illustrated in the drawing.

The drawing shows a graph showing the lithification process depending on the transmission time of the electric current.

The method is as follows.

Coagulating additives are introduced into a viscous-plastic medium, current electrodes are immersed, which are connected to a direct current source. The activation of geochemical processes that affect the process of lithification of the medium is caused by passing through it an alternating electric current, the modes of which are selected based on the Faraday law: m = kJt, where m is the mass of the substance released from the electrodes during the passage of electric current, k is the proportionality coefficient, depending on the nature of the substance being licensed, J is the current strength, t is the transmission time of alternating pulses of electric current. In this case, the lithification process is controlled until the required hardness of the material is obtained, depending on its further use (for example, in the construction of roads, etc., or in disposal). The necessary time for passing an electric current is determined by the formula:

t = 1 / J (1-K), where K = h _t / h _o

where K is the relative coefficient of mechanical strength of the medium being lithified, h _t is the depth of immersion of the needle of the Vika device after passing the current, h _o is before passing the current.

As a lithification zone, ponds-storages of viscoplastic industrial waste are selected.

Example

The lithification method was tested on a sample, which was taken as a viscoplastic industrial waste from the Nitron production association. The moisture content of the sample was 75%. As electrodes, aluminum plates were used. The current strength was 30 mA, the voltage was 30 V. The transmission time was 8 hours, while the determination of the mechanical properties of the medium to be charged was carried out after 2.5; 4; 5; 7 and 8 hours from the beginning of transmission of electric current with a duration of alternating pulses of 0.5-2 hours. Substances such as polyacrylamide, vinylpyrrolidone, cetylpyridinium chloride were used as a coagulant.

The results of experimental studies are presented in the drawing, on which the abscissa shows the relative distance from the cathode l / l _about , where l is the distance from the cathode to the place of determination of the depth of immersion of the needle of the Vick device; l _o - the distance between the cathode and the anode. The ordinates show the relative penetration depths of the Vika needle into the test material before (h _o ) and after passing an electric current (h _t ).

An analysis of the obtained data shows that the mechanical properties of the test sample increase with increasing current transmission time. The stabilization of the sample is not limited to the zone of electrodes, but captures the entire volume of a viscoplastic medium. The sample reaches its greatest hardness in close proximity to the electrodes.

Using the proposed method allows to increase the efficiency of lithification of viscoplastic industrial wastes and significantly reduce material costs for their disposal.

Claims (1)

A method of lithification of viscoplastic industrial waste, including the introduction of coagulating additives into a container with viscoplastic waste and exposure to electric current through metal electrodes, characterized in that storage ponds are used as a reservoir for viscoplastic waste, exposure is carried out by alternating electric current, and the metal electrodes are immersed directly in storage ponds, to obtain the required hardness of lithified waste, measure the depth of immersion of the needle Vika’s device before exposure to electric current h ₀ and during exposure to electric current h _t and determine the relative coefficient of mechanical strength of the medium being lithified by the ratio K = h _t / h ₀ , the transmission time of the electric current required to obtain the required hardness of the lithified waste is determined from the ratio t = l / J (l-K), where t is the transmission time of alternating electric current; J is the current strength in this case, vinyl pyrrolidone or cetyl pyridinium chloride is used as coagulating additives.