RU2118561C1 - Method of granulating organochlorosilane synthesis waste - Google Patents

Abstract

FIELD: silicon compoundsТ technology; waste disposal. SUBSTANCE: waste is balled into granules under effect of water-based agent. Granules are then dries and calcined. Invention is distinguished by that nonaqueous component of agent (5-40 wt %) is sodium hydroxide and/or sodium silicate, and/or calcium hydroxide. When waste is being balled, it is advantageous to use, as binding agent, bentonite and/or lime, and/or opoka, and/or dolomite flower, and/or clay, and/or their mixtures. Thus processed waste may find use, for example, in metallurgy. EFFECT: increased mechanical strength of granules meeting requirements of metallurgical conversions. 3 cl

Description

 The invention relates to the field of chemical technology of organosilicon compounds, and in particular to methods of processing solid waste direct synthesis of organochlorosilanes.

The use of the resulting commodity passivated granular contact mass (PGKM) is possible:
- for reuse of copper and silicon in copper metallurgy;
- for reducing silicon smelting with the addition of up to 20% PHCM in the main charge;
- in metallurgical processes as a source of ferrosilicon, copper, etc.

 Granulation is the process of formation of solid particles of certain sizes, shapes and specified physico-chemical properties, accompanied by a densification of the structure of the substance.

 Modern methods of granulation (Klassen P.V., Grishaev I.G. Fundamentals of granulation technology. - M .: Chemistry, 1982) provide a large number of products with improved physical properties: good flowability, high strength structures, uniform particle size distribution, if granulation carried out from the liquid phase, from the gaseous phase, from a mixture of liquid and gaseous phases.

 According to the patent technical literature, in domestic and foreign practice, for granulating powders, methods are mainly used using various humidifiers, binders with simultaneous mechanical impact on the mass (pressing, crushing, rolling, rolling through rolls, etc.) followed by granular drying mass from the humidifier.

 Currently, in existing organosilicon industries, the spent contact mass (OKM) is deactivated (AS USSR 852875, 04/07/81) and sent to the dump, which causes significant harm to the environment. In addition, the expensive metal - copper is irretrievably lost.

 Previously, for the disposal of OKM, methods for the regeneration and recycling of OKM were proposed (US Pat. No. 4,307,242 of 11.24.80). However, the use of regenerated contact mass reduces the selectivity of the process so much that it becomes economically impractical.

 Closest to the proposed method is the granulation of solid waste synthesis of organochlorosilanes (EPO, 0201200), including pelletizing them under the influence of a liquid agent - water, followed by drying of the formed granules at a temperature provided by the heat released during the interaction of the synthesis waste organochlorosilanes with water.

 The disadvantage of this method is that the obtained granules do not have the strength necessary for their long transportation and satisfying the requirements of metallurgical processing in terms of the strength of the granules (90-150 kg / gran).

 The technical task of the proposed solution is to obtain granules whose strength meets the requirements of metallurgical processing.

The specified technical result is achieved by the fact that the proposed method for granulating solid wastes of the synthesis of organochlorosilanes involves pelletizing them under the influence of a liquid agent based on water, followed by drying the granules formed, and an additive is added to the liquid agent, which is used as sodium hydroxide and / or sodium silicate, and / or calcium hydroxide, in the following ratios of components, wt.%:
Additive - 5 - 40
Water - Else
After drying, the obtained granules are calcined at elevated temperature.

 Granulation can be carried out using a binder.

 As a binder, it is advisable to use bentonite and / or lime, and / or flask, and / or dolomite flour, and / or clay, or mixtures thereof.

 It should be noted that the spent contact mass in its natural form is not pelletized, droplets of water supplied to the granulator practically do not serve as centers for nucleation, and, ultimately, with an excess of moisture, all material coagulates into a single continuous mass.

The essence of the proposed method consists in the formation of agglomerates from particles uniformly moistened with a liquid agent of the specified composition, or in the layering of dry particles on wetted cores by treating solid and pulverized OKM waste and cyclone dust with a binder in a rotary drum granulator or another, for example, a plate granulator with subsequent drying and calcination. At the same time, granulation of the entire waste mixture occurs with the receipt of a marketable product in the form of spherical granules 5-40 mm in size. Studies have shown that binders, for example, bentonite, flask, dolomite flour, lime, clay can be introduced into solid waste in dry form (powders) before irrigation and pelletizing of the entire mass. In this case, granulation proceeds normally if the dispersed composition of the waste is in the range of 5-500 microns. The size of the granules reaches 5-40 mm, and their strength after drying is 0.5-3.0 kg / gran. Subsequent calcination of the granules with a gradual increase in temperature in order to avoid cracking of the granules, significantly increases the strength of the latter. Calcination can be carried out at a temperature of from 130-200 ^o C to temperatures at which the chemical destruction of the granulate begins. The strength of the granules increases and reaches values of 90-150 kg / gran. that fully satisfies the requirement for granules as a commercial product for further processing by the metallurgical industry.

 Example 1

In a drum rotating at a speed of 10 rpm, having successively arranged sections for loading dust and irrigation with a liquid agent, granulating and drying granules, 5 kg of a mixture of solid waste of direct synthesis of methylchlorosilanes (MCS) consisting of 80% spent silica-copper contact mass (OKM) from the reactor and 20% cyclone dust of spent contact mass with a particle size of 3-500 μm with continuous irrigation in the loading zone with a 30% aqueous solution of sodium silicate (liquid glass) in an amount of 20% of the total ce the solids. The temperature in the drying section is 115 ^o C. After 1 hour received 5.320 kg of granulated commercial product with a residual moisture content of 0.3% with spherical granules of 4.0-45 mm. Then, the granules were aged for 5 days at ambient temperature. The strength of the obtained granules 30-35 kg / gran.

 Example 2

In a drum rotating at a speed of 10 rpm, having successively arranged sections for loading dust and irrigating it with a solution, granulating and drying the granules, 5 kg of a mixture of solid waste from the synthesis of MHS, consisting of 50% OKM and 50% cyclone, are loaded uniformly for 30 minutes dust with a particle size of 3-500 microns with continuous irrigation in the loading zone with a 10% aqueous solution of lime - lime milk, the total amount of which is 25% of the total mass. The temperature in the drying section is 50 ^° C. After 2.5 hours, 5.104 kg of a granulated commercial product with a residual moisture content of 0.4% with spherical granule sizes of 8.0-34 mm are obtained. Then, the granules were calcined on an industrial conveyor roasting machine with a smooth rise in temperature to 600 ^o C. The strength of the calcined granules to crush 85 kg / gran.

 Example 3

5 kg of a mixture of solid waste from the synthesis of MXS with the addition of dolomite flour in an amount of 20% by weight of a mixture of solid waste with continuous irrigation in the loading zone of 20% are uniformly loaded into the same drum, rotating at a speed of 10 rpm, for 30 minutes aqueous solution of caustic soda in an amount of 25% to the total weight of the solid mixture. The temperature in the drying section was 85 ^o C. After 1.5 hours, 6.420 kg of a granulated commercial product with a residual moisture content of 0.25% with spherical granule sizes of 5.0-48 mm were obtained. Then, the granules were calcined on an industrial conveyor roasting machine with a smooth rise in temperature to 800 ^o C. The strength of the calcined granules to crush 90 kg / gran.

 Example 4

To the OKM waste loaded onto the granulator plate in an amount of 20 kg was added 2.2 kg of dry slaked lime and mixed until a homogeneous state. The resulting dry mixture with continuous rotation of the plate at a speed of 8-10 vol. / min was irrigated with water in an amount of 12-15% by weight of the mixture for 0.5 hours. Got a mass rolled into spherical granules with a diameter of granules of 8-14 mm, after which the granules were dried. The temperature in the drying chamber is 115 ^o C. The strength of the dry granules is up to 2.0 kg / gran. Then, the granules were calcined on an industrial conveyor roasting machine with a smooth rise in temperature to 1180 ^° C. The strength of the calcined granules for crushing was 80 kg / gran.

 Example 5

To the OKM waste loaded onto the granulator plate in the amount of 20 kg was added 2.2 kg of concrete and mixed to a homogeneous state. The resulting dry mixture with continuous rotation of the plate at a speed of 8-10 rpm./min was irrigated in the loading zone with a 10% aqueous solution of lime - milk of lime, the total amount of which is 12-15% of the weight of the mixture for 0.5 hours. Got a mass rolled into spherical granules with a diameter of granules of 8-14 mm. Then the granules were dried. The temperature in the drying chamber is 115 ^o C. The strength of the dry granules is up to 2.0 kg / gran. Then, the granules were calcined on an industrial conveyor roasting machine with a smooth rise in temperature to 1180 ^o C. The strength of the calcined granules crushing 130-150 kg / gran.

 Example 6

 Similar experiments were carried out with the addition of 3.0 kg of dolomite flour to the same amount of OKM. Received granules in size similar to the previous ones. The strength of the granules after drying was 0.5-0.6, and after calcination, 65-80 kg / gran.

 Example 7

 Similar experiments were carried out with the addition of 3.0 kg of a binder mixture consisting of 1.1 kg of lime and 2.0 kg of clay to the same amount of OKM. The size of the obtained granules was 22-38 mm. The strength of the granules after drying was 2-3 kg / gran, after calcination, 120-140 kg / gran.

 Tests were also carried out on the contact masses of other compounds. The results are similar to those presented.

 Thus, a method for producing granular form of a commodity product in granular form from dry solid waste by the method of wetting and pelletizing with the addition of binders is proposed, the granules in terms of chemical composition and strength meeting the technical requirements.

Claims (3)

1. The method of granulation of solid waste synthesis of organochlorosilanes, including pelletizing them under the influence of a liquid agent based on water, followed by drying the granules formed, characterized in that an additive is added to the liquid agent, which is used sodium hydroxide and / or sodium silicate, and / or calcium hydroxide in the following ratio, wt.%:
Additive - 5 - 40
Water - Else
the resulting granules after drying are calcined.  2. The method according to claim 1, characterized in that the rolling is carried out with a binder.  3. The method according to claims 1 and 2, characterized in that bentonite, and / or lime, and / or flask, and / or dolomite flour, and / or clay, and / or mixtures thereof are used as a binder.