WO2012134341A1

WO2012134341A1 - Method for producing a granulated sorbent

Info

Publication number: WO2012134341A1
Application number: PCT/RU2011/001027
Authority: WO
Inventors: Виктор Геннадиевич СЕРЖАНТОВ
Original assignee: Serzhantov Viktor Gennadievich
Priority date: 2011-04-01
Filing date: 2011-12-27
Publication date: 2012-10-04
Also published as: AU2011363658B2; EA023487B1; AU2011363658C1; RU2462305C1; AU2011363658A1; EA201300552A1; UA106334C2

Abstract

The invention relates to technology for the production of sorbents, in particular to methods for producing a binder consisting of natural glauconite for manufacturing granulated sorbents, and can be used for the removal of technogenic pollutants from drinking water and industrial effluents, and for purifying gases to prevent harmful emissions into the atmosphere. The method comprises preheating and sifting glauconitic sand, subsequently dividing said sand with the aid of magnetic separation into a magnetic and a nonmagnetic fraction, grinding the magnetic fraction, mixing the ground magnetic fraction with water to form a plastic compound, granulating said compound, drying the granules produced, crushing said granules, sifting the latter with granules of the required granulometric composition being extracted, calcining and cooling said granules, and packaging the finished product. The technical result is an increase in the sorption capacity and sorption volume of the granulated sorbent owing to the use of the magnetic fraction of the glauconite as the binder.

Description

METHOD FOR PRODUCING GRANULATED SORBENT

The invention relates to a technology for the production of sorbents, in particular, to methods for producing a binder from natural glauconite for the manufacture of granular sorbents intended for use as a filtering and sorption filling, capable of replacing activated carbon, anionic cationic resins, reverse osmosis membranes, and can be used with purification of drinking water and industrial effluents from technogenic pollutants (heavy metals, oil products, organics, pesticides, radionuclides, etc.), purification and gases of harmful emissions into the atmosphere, including the exhaust gases from vehicles.

State of the art

A known method for producing granular sorbent, comprising mixing calcium oxide or carbonate and aluminum oxide, calcining the mixture at a temperature of 1300-1700 ° C, grinding, adding carbonate or calcium oxide to it in a mixture with 0.3-4 wt.% Mineral fiber, and the ratio of fiber length to its diameter is taken to be 50-500, the resulting mixture is further milled, then granulated, then subjected to hydrothermal treatment and then heat treatment (see RF patent for invention J b 2006285, IPC B 01 J 20/04, publ. 30.01 .1994 g.).

The disadvantage of this method is the complexity of the process, since in the process of its implementation it is necessary to calcinate the mixture at high temperature and its hydrothermal treatment. In addition, the granular sorbent obtained by a known method has a narrow spectrum of use, since it can only adsorb metal anions without adsorbing organic compounds, which narrows the scope of its application.

The initial component used as a natural binder in the preparation of combined granules (granular sorbent) according to the invention is glauconite. It is widely known that glauconite is a clay mineral of variable composition with a high content of ferrous and trivalent iron, calcium, magnesium, potassium, phosphorus, which, as a rule, contains more than twenty trace elements, including copper, silver, nickel, cobalt, manganese, zinc, molybdenum, arsenic, chromium, tin, beryllium, cadmium, and others. All of them are in easily removable form of exchangeable cations, which replaced by abundant elements in the environment. This property, as well as the presence of a layered structure, explains the high sorption properties of glauconite in relation to oil products, heavy metals, radionuclides. At the same time, glauconite is characterized by a low percentage of desorption (removal from liquids or solids of substances absorbed by adsorption or absorption) and prolonged action, high heat capacity, plasticity, etc. However, with all the positive qualities of natural glauconite, there is a problem of granulating it in in its pure form, without using an external binder, due to the presence of a ballast fraction (quartz, feldspar, etc.) of 40 to 90%, as well as a large fraction of glauconite (from 0.65 to 0.1 mm) of 20 to 40% .

A known method of converting glauconite, characterized by a radically large sorption capacity when water is softened and capable of recovery with less salt. The method is carried out by heating glauconite to temperatures above 454 ° C for a period of time sufficient to radically change the granules chemically and physically, including removing most of the water, with a large increase in porosity and sorption capacity and subsequent treatment with a hot concentrated solution of sodium hydroxide. When glauconite is treated with a hot concentrated solution of sodium hydroxide, which creates new and greater porosity and sorption capacity, quartz dissolves and sodium precipitates on the surface of the pores of glauconite (see US patent for invention jVe US 2139299, IPC C 01B 33/46, C 01B 33 / 00, published on December 6, 1938).

The disadvantage of this method is that the treatment of glauconite with a hot concentrated solution of sodium hydroxide complicates and increases the cost of converting glauconite, which is used narrowly to soften water, and also significantly reduces the sorption potential relative to other pollutants, since glauconite obtained by the known method can partially absorb heavy metals, but will not be able to fully absorb organic compounds, which narrows the scope of its application.

A known method of restoring glauconite in the form of pure unchanged natural grains of normal composition, which includes sorting and mechanical cleaning of glauconite ("green sand") in a series of consecutive water flows and chemical solutions to remove absorbed and adsorbed impurities. In the preparation of pure, unchanged glauconite, there is water that sorts and thoroughly cleans caustic soda, sodium silicate, acids, removes to the end a rough, oversized material. As a result, normal granular glauconite remains without random absorbed or adsorbed foreign materials (see U.S. Patent No. J57 ° 1757374, IPC C 01B 33/46, C 01B 33/00, publ. 05/06/1930).

However, as a result of applying the known method, the most valuable clay fraction of glauconite is washed out, capable of subsequent granulation without the use of additional binders. The granulometric composition of such natural granular glauconite is uneven, which reduces the filtration and sorption ability. It also narrows its scope.

Known methods for granulating glauconite with preliminary mixing with various types of binder. For example, there is a known method for producing granular glauconite (options), according to which natural glauconite is dried, sieved, quartz impurities are removed, then crushed, re-sieved with a fraction of less than 40 microns and a binder additive is introduced, in the first embodiment, a zirconia sol, and in the second embodiment, aluminophosphate sol, after granulation, the product is dried, subjected to heat treatment, cooled to 40-50 ° C and packaged (see RF patent for invention J4 ° 2348453, IPC B 01J 20/12, B 01J 20/30, publ. March 10, 2009).

However, the disadvantage of this method is the need to use a third-party binder, which complicates the technology for producing glauconite granules, increases energy consumption, reduces sorption capacity. As a result, the cost of the final product increases due to the high price of the third-party binder, which ultimately greatly affects the competitiveness of the product and narrows its scope.

The closest in technical essence to the proposed invention is a known method for producing granular nanosorbent, comprising mixing the starting components with subsequent addition of water to form a plastic mass, granulating the mass, heat treatment of the obtained granules with their subsequent cooling, while bentonite clay, thermally expanded carbon and glauconite are used as initial components in the following ratio of components, wt.%: bentonite clay - 10-40, glauconite - 10-50, thermally expanded carbon - 10-60, while the heat treatment involves drying the granules with infrared radiation at at a temperature of 70-150 ° C and microwave heating of granules previously placed in a closed thermally insulating volume of quartz ceramics to a temperature of not more than 1000 ° C (see RF application for a patent for invention M> 2009126840/05, IPC B 01J 20/20 , 01J 20/16, 82V 3/00, publ. 20 .01.2011).

The disadvantage of this method is the need for a third-party binder. This complicates the technology for producing glauconite granules, increases the cost of the final product due to the high price of the third-party binder, which ultimately greatly affects the competitiveness of the product and narrows its scope.

An object of the present invention is to provide a method for producing a granular sorbent based on a binder from glauconite.

The technical result achieved in solving this problem is to increase the sorption ability and capacity of the granular sorbent by using the magnetic fraction of glauconite as a binder.

Disclosure of invention

The specified technical result is achieved by the fact that in the method for producing granular sorbent, including preheating and sifting of glauconite sand, granulating the mass, firing the obtained granules with their subsequent cooling, packaging of the finished product, according to the invention, the separation of glauconite by magnetic separation into magnetic and non-magnetic fractions, grinding the magnetic fraction of glauconite, mixing the ground magnetic fraction of glauconite with water to form a plastic mass, drying the obtained granules after the granulation, crushing of granules, sieving the granules with a release required granulometric composition.

It is advisable that the concentration of glauconite in the magnetic fraction of glauconite is at least 95%. It is also advisable that the grinding of the magnetic fraction of glauconite was carried out to obtain particle sizes of glauconite from 1 to 100 microns.

It is advisable to mix the ground magnetic fraction of glauconite with water until a plastic mass with a moisture content of at least 28% is formed.

It is advisable to dry the granules in a natural way at a positive ambient temperature of at least 20 ° C to a moisture content of not more than 10%.

It is advisable to crush and sift the granules to separate fractions having a size across and a length of 0.8 to 100 mm.

It is advisable that after crushing and sieving of the granules the waste is returned to the re-grinding and further use as a binder in the granulation.

Glauconite in its structural and geochemical properties is a mineral raw material for multipurpose use. However, the use of untreated glauconite sand as a sorbent, with all its enhanced sorption properties, seems impossible due to peptization of the clay fraction of glauconite.

The use of the magnetic fraction of glauconite from glauconite sand as a binder in the manufacture of granules allows to obtain a granular sorbent with increased sorption capabilities and capacity, which will expand the scope.

Glauconite sand comes from a quarry wet or frozen crumpled, etc., and contains various debris in the form of roots from grass, flask, etc., therefore it is preheated (dried), and the temperature in the range from 70 to 100 ° C. The main condition for this should be that the sand is dry and easily sifted through a sieve to separate mechanical impurities and flask. The sieve can be with cells from 0.8 to 0.25 mm, while the main condition is that the fraction of glauconite is sieved, and the maximum fraction of glauconite should be from 0.65 mm and below.

The composition of glauconite ore depends on the deposit, while the concentration of glauconite in the ore can be from 15 to 75%, the rest is ballast in the form of quartz, feldspar, etc. Glauconite can be magnetized at high magnetic field strengths. By passing glauconite ore through a magnetic separator, glauconite is separated from the ballast fraction. Availability iron in glauconite indicates a high concentration of glauconite. This can be seen from table 1, which shows the element-by-element composition of the separated by magnetic separation of glauconite into magnetic and non-magnetic fractions. From table 1 it is also seen that in the magnetic fraction of iron is much more than in non-magnetic. Thus obtained mixture with a concentration of glauconite in the separated magnetic fraction of glauconite is at least 95%.

The grinding of the magnetic fraction is carried out in order to obtain flour from the magnetic fraction for the manufacture of granules (mainly granules need grinding of green earth with fraction sizes ranging from 30 to 50 microns).

Table 1

The ground magnetic fraction is mixed with water until a plastic mass is formed.

The granulation of the mass is carried out to obtain granules of cylindrical shape, having a diameter in the size of 0.8 to 100 mm, a length of 50 to 100 mm, which results in “noodles”, which, depending on the dies used, can have a different diameter and length. Granules are needed of various sizes in diameter and length, the resulting "noodles" are dried naturally with a positive ambient temperature of at least 20 ° C to a moisture content of not more than 10%. This is necessary to remove excess moisture before the operation of crushing the resulting "noodles", from which granules of the desired particle size are obtained. If the crushing of “noodles” is carried out after firing at 650 ° C for at least 1 hour, then when crushing these granules, the resulting waste is difficult to dispose of, and when dried to a moisture content of 10%, the resulting waste from crushing "noodles" is sent back to the grinding and secondary receipt of "noodles" for the production of granules of the desired size. There is no waste with this technology.

The crushing and sieving of granules is carried out to select fractions having a diameter across and in length from 0.8 to 100 mm, since the consumer sizes of granules for water treatment have these granulometric parameters, and the shape of the granules should be irregular, but tending to round. The maximum filtering ability of the final product is achieved by obtaining irregularly rounded granules for any particle size distribution.

The pellets are fired in a furnace at a temperature of not more than 650 ° C for no more than 1 hour, since at this temperature the pellets have consumer hardness and when placed in water do not fall apart, but remain solid. Sufficient time for firing can be at least 1 hour.

Isolation of the magnetic fraction of glauconite from the total mass allows one to obtain a binder, which is the main material in the manufacture of granular sorbent.

A method for producing granules gga based on natural binder glauconite, which can be used as a full sorbent. The presence of a ballast fraction and a large percentage of the large fractional composition of glauconite prevent direct granulation of glauconite sand without additives. Therefore, granulation of glauconite in the known technical solutions was carried out using a variety of binders, for example zirconia or bentonite clay, which on the one hand contributed to the normal granulation of glauconite, and on the other hand contributed to a decrease in sorption properties.

The proposed technical solution makes it possible to obtain a fraction of glauconite separated by means of magnetic separation and used as a binder in granulation. At the same time, the maximum sorbing effect of the final product for an extended spectrum of pollutants is achieved.

Experimental measurements were made of the sorption index of the combined granules, which included bentonite glygg, glauconite and thermally expanded carbon with a ratio of components, wt.%: bentonite clay - 40, glauconite - 40, thermally expanded carbon - 20, in which the binder was clay, compared to glauconite granules based on glauconite binder, the concentration of glauconite in which was 95%. The measurements were carried out on the sorption of ferrous iron from water before and after passing through granules. Passing a model solution of ferrous iron through combined and glauconite granules was carried out simultaneously. MPC of iron in drinking water is 0.3 mg / L. The equipment used is a KFK-3 photometer. The measurement results are presented in table 2.

Table 2 shows that the sorption of glauconite granules based on a glauconite binder almost three times exceeds the sorption of combined granules with bentonite clay, glauconite and thermally expanded carbon and, therefore, the sorption capacity increases.

table 2

Brief Description of the Drawings

The invention is illustrated by a photograph showing the morphology of glauconite granules (view of the side surface of a sample of glauconite powder, magnification - 20 kx). Morphology studies were performed using a TESCAN MIRA II LMU scanning electron microscope. The sample consists of glauconite - containing at least 95% of the magnetic fraction of glauconite, made using

Microwave expansion, has the appearance of elongated structures, light brown in color, solid. The surface of the sample is complex, developed and poststructural. The sample contains interspersed crystalline structure. Embodiments of the invention

The proposed method for producing granular sorbent based on natural binder glauconite is as follows.

Pre-made binder glauconite base in the form of glauconite flour according to the following technology.

From glauconite sand, previously heated to a temperature of 70-100 ° C and sifted through sieves having a size of 0.8 to 0.25 mm, the weakly magnetic mineral glauconite is extracted using magnetic separation. During separation, ballast fractions (quartz, feldspar, non-magnetic glauconite, etc.) are separated from magnetic glauconite. The separated magnetic glauconite is crushed on any grinding device that allows to obtain glauconite flour fractions from 1 to 100 microns. The obtained glauconite flour of a fraction from 1 to 100 μm is mixed in a homogenizer with the addition of water until a clay glauconite mass of moisture of at least 28% is obtained, which is used to obtain sorption granules based on natural glauconite.

The preparation of granules based on the ground magnetic fraction of glauconite is carried out according to the following technology.

Glauconite binder in the form of flour obtained after separation of the magnetic fraction of glauconite and its grinding, is mixed with water to a moisture content of not less than 28%. The resulting mass is sent to a granulator, from which granules with a diameter of 0.8 to 100 mm, a length of 50 to 100 mm are obtained, which, after leaving the granulator, are naturally dried at a positive ambient temperature of at least 20 ° C with a humidity of not more than 10%. The dried granules are fed to a crusher, where they are transformed into irregularly shaped granules having a cross-sectional dimension of 0.8 to 100 mm and a length also of 0.8 to 100 mm. As a result of crushing, various particle size distribution is formed. Granules are sieved through sieves having a size of from 0.8 to 100 mm. The sifted granules are sorted by particle size distribution and sent to the kiln at a temperature of not more than 650 ° C for no more than 1 hour. After heat treatment, the granules are cooled by natural cooling to ambient temperature, then the granules are packed in containers.

Defective granules, screenings and flour formed during the crushing operation are sent back to the grinding device, which allows to obtain glauconite flour fraction from 1 to 100 microns. After grinding, glauconite flour is sent to the stage of mixing with water. With this technology, waste is not generated.

The best embodiment of the invention

Glauconite ore, which is glauconite sand, is pre-dried at a temperature of not more than 100 ° C until a moisture content of at least 8% throughout the volume is reached. Dried glauconite ore is sifted through sieves of various particle sizes to separate mechanical impurities in the form of grass roots, flasks, etc. from glauconite sand. Sifted glauconite sand is sent for separation, which is carried out on a high-intensity magnetic roller separator SVMI with induction of 1.5 T or a dry magnetic enrichment plant MBSOU-154/200. During magnetic separation, the magnetic fraction of glauconite is separated from the non-magnetic part, which is a ballast fraction consisting of quartz, feldspar, etc. The separated magnetic glauconite fraction is sent to a grinding device (for example, a centrifugal mill MT-700, manufacturer TZDO, Tula), which allows grinding glauconite to a fraction of not more than 50 microns. Water is added to the ground magnetic fraction of glauconite and the resulting mass is mixed with a homogenizer until a residual moisture content of at least 28% is reached. The resulting mass is sent to a mixing extrusion granulating device of any type to obtain granules with a diameter of 1.4 mm, a length of 80 mm, which is achieved by installing dies with holes with a diameter of 1.4 mm. For other sizes, dies with the required holes are installed. The remaining ballast fraction (quartz, feldspar, etc.) is deposited for use in another technology for obtaining a useful product. The obtained granules are naturally dried at a positive ambient temperature of at least 20 ° C to a moisture content of not more than 10% and are sent to a hammer mill, where they are crushed into smaller fractions having a diameter across from 1.2 to 1.4 mm, sieved and sorted by particle size distribution. Then granules are fired at a temperature of not more than 650 ° C for 1 hour. The yield of finished granules is 15%. Defective granules, screenings and flour formed during crushing are sent back to the grinding device, which allows to obtain glauconite flour fractions from 1 to 100 microns. After grinding, the resulting glauconite flour is sent to the stage of mixing with a homogenizer with water and to secondary granulation. With this technology, waste is not generated.

The technology used allows to obtain glauconite granular sorbent, which reaches a high sorption capacity.

Claims

Claim

1. A method of producing a granular sorbent, including preheating and sifting glauconite sand, granulating the mass, firing the obtained granules with their subsequent cooling, packaging of the finished product, characterized in that the separation of glauconite using magnetic separation into magnetic and non-magnetic fractions, grinding the magnetic fraction glauconite, mixing the ground magnetic fraction of glauconite with water until a plastic mass forms, drying the granules obtained after granulation, crushing gra zero, sieving with the allocation of granules of the desired particle size distribution.

2. The method according to p. 1, characterized in that the concentration of glauconite in the magnetic fraction of glauconite is at least 95%.

3. The method according to p. 1, characterized in that the grinding of the magnetic fraction of glauconite is carried out to obtain particle sizes of glauconite from 1 to 100 microns.

4. The method according to p. 1, characterized in that the mixing of the ground magnetic fraction of glauconite with water, before granulation, is carried out until a plastic mass with a moisture content of at least 28% is formed.

5. The method according to p. 1, characterized in that the drying of the granules, after granulation, is carried out naturally with a positive ambient temperature of at least 20 ° C to a moisture content of not more than 10%.

6. The method according to p. 1, characterized in that the crushing and sieving of the granules is carried out to isolate fractions having a size across and in length from 0.8 to 100 mm.

7. The method according to PP. 1 and 6, characterized in that after crushing and sieving of the granules, the waste is returned for re-grinding and further use as a binder in the granulation.