AU2011363658A1

AU2011363658A1 - Method for producing a granulated sorbent

Info

Publication number: AU2011363658A1
Application number: AU2011363658A
Authority: AU
Inventors: Viktor Gennadievich SERZHANTOV
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-04-01
Filing date: 2011-12-27
Publication date: 2013-11-21
Anticipated expiration: 2031-12-27
Also published as: EA023487B1; WO2012134341A1; RU2462305C1; UA106334C2; EA201300552A1; AU2011363658B2; AU2011363658C1

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 OF GRANULATED SORBENT PRODUCTION Technical field The invention refers to sorbents production technology, particularly, to the means of binding agent production from natural glauconite for producing 5 granulated sorbents meant for use as filtering and sorption filling capable of replacing activated carbon, anionic and cationic resins, reverse-osmosis membranes, and can be used for drinking water purification and sewage treatment from technogenic pollutant (heavy metals, oil-product, organics, pesticides, radionuclides, etc.), gases purification from atmospheric emission of 10 pollutants, including motor transport emissions. Prior knowledge There is a method for the granulated sorbent production that includes mixing calcium oxide or carbonate and aluminum oxide, calcination at the temperature of 1300-1700 0 C, grinding, adding calcium oxide or carbonate in 15 mixture with 0,3-4% wt of mineral fiber; the proportion of fiber length to fiber diameter is taken as 50-500; the obtained mixture is grinded additionally, then grained, and after that it is subject to hydrothermal treatment (see the Russian Federation utility patent No 2006285, M1-IK B 01J 20/04, published on 30.01.1994). 20 The drawback of the known method is complexity of technological process, because in the course of running it is necessary to perform high temperature calcination of mixture and its hydrothermal treatment. Besides, the granulated sorbent produced through this method has a very narrow range of use, because it can absorb only metal anions without absorbing the organic compounds, 25 therefore its field of use is narrowed. The original component used as a natural binding agent at producing the combination granules (granulated sorbent) according to the present invention is glauconite. It is a well-known fact that galuconite is a variable composition clay mineral with high content of divalent and trivalent ferrum, calcium, magnesium, 30 potassium, phosphorus, which, as a rule, contains over twenty micro-elements, among which are copper, silver, nickel, cobalt, manganese, zinc, molybdenum, arsenic, chromium, stannic, beryllium, cadmium, etc. They are all in the readily retrievable form of exchangeable cations, which are substituted by the excess elements of the environment. This peculiarity, together with the layer structure, 5 is the reason why glauconite has higher absorption characteristics than other oil products, heavy metals, and radionuclides. At the same time it is very typical of glauconite to have a low desorption percent (removal of the adsorbed or absorbed substances from liquids or solid bodies), prolonged action, high effective heat capacity, plasticity, etc. However, with all the positive 10 characteristics of natural glauconite, there is a problem of its isolate granulation without the use of foreign binding agent, as a consequence of its ballast fraction (quartz, field spar, etc.) composing from 40 to 90% and also a massive glauconite fraction (from 0,65 to 0,2 mm) composing from 20 to 40%. There is a means glauconite conversion, which is radically different 15 because of its high sorption capacity at water demineralization and capability to restore with less amount of salt. This process is carried out by heating glauconite up to the temperature over 454 0 C during the period of time, which is long enough to change he granules radically in terms of chemistry and physics including the removal of the most part of water with large increase in pore 20 volume and sorption capacity and further treatment with hot sodium hydroxide concentrated solution. In the course of glauconite treatment with hot sodium hydroxide concentrated solution, which creates new and increased pore volume and sorption capacity, there occurs dissolution of quartz and deposition of sodium on the surface of glauconite pores (see USA patent for an invention N2 25 US 2139299, M-IK C 01B 33/46, C 01B 33/00, published on 06.12.1938). The drawback of the method described above is that treating glauconite with hot sodium hydroxide concentrated solution complicates and dears the glauconite conversion technology used narrowly for demineralizing of water. This process also decreases sorption capabilities in comparison to other 30 pollutants, as the glauconite produced with this method can partially sorb heavy metals but cannot fully sorb the organic compounds, which narrows its area of use. There is a method of restoring glauconite in the form of pure unchanged natural grains of the normal composition, which includes sorting and mechanical 5 cleaning of glauconite ("green sand") in the course of consequential water streams and chemical solutions for removing the absorbed and adsorbed impurity. In the course of preparation of pure unchanged glauconite, there is a certain amount of water, which sorts and thoroughly cleans sodium hydrate, sodium silicate, acids, removes uneven and oversized material. As a result we 10 get normal granulated glauconite without accidentally absorbed or adsorbed foreign materials (see the USA patent for an invention N2 US 1757374, M1-IK C 01B 33/46, C 01B 33/00, published on 06.05.1930). However, the result of the method described above is outwashing of the most valuable clay fractions of glauconite capable of further granulation without 15 the use of additional binding agent components. Granulometric composition of such natural granulated glauconite is heterogeneous, which is decreasing its filtration and sorption capability. It also narrows its area of use. There are means of glauconite granulation with preliminary mixing with different types of binding agents. For example, there is a method for producing 20 granulated glauconite (versions) according to which the natural glauconite is parched, riddled, cleaned from quartz impurities, crushed, re-riddled with fractionation less than 40 pm and the binding agent additive is introduced. In the first version it is zirconium dioxide sol, in the second version it is aluminophosphate sol; after doing the graining the product is dried, heat-treated, 25 cooled down to 40-50 0 C, and then packed (see the Russian Federation patent for an invention N2 2348453, IMIK B O1J 20/12, B 01J 20/30, published on 10.03.2009). However, the drawback of the method described above is the necessity to use a foreign binding agent, which makes for increase in power consumption 30 and decrease in sorption capacity. As a result, the prime cost of the final product rises because of the high price of the foreign binding agent. As a consequence, it seriously affects the competitive ability of the product and narrows its area of use. In terms of technical essence, the closest to the suggested invention method 5 of granulated nanosorbent production involves mixing of the original components with the further adding of water until the plastic material is formed, granulation of this mass, heat-treatment of granules with their further cooling. As the original components we use bentonite clay, thermal expanded carbon, and glauconite with the following proportion of components, wt%: bentonite 10 clay - 10-40. glauconite - 10-50, thermal expanded carbon - 10-60; at this thermal treatment includes drying of grains put into the closed thermal insulating volume made of quartz ceramic up to the temperature not higher than 1000 0 C (see the Russian Federation application for the grant of a patent for an invention N2 2009126840/05, IMIK B 01J 20/20, B 01J 20/16, B 82B 3/00, 15 published on 20.01.2011). The drawback of the described method is the necessity to use the foreign binding agent. It complicates the technology of producing the glauconite granules, increases the prime cost of the final product because of the high price of the foreign binding agent. As a consequence, it greatly affects the competitive 20 ability of the product and narrows its area of use. The objective of the present method is to invent a method of granulated sorbent production based on the binding agent from glauconite. Technical result achieved at the present problem solving is the increase in sorption and absorption capacity of the granulated sorbent through using 25 magnetic fraction of glauconite as a binding agent. Disclosure of the invention The stated technical result is accomplished by the following: in the means of granulated sorbent production that includes heating and riddling of glauconite sand, granulating of mass and baking of granules with further cooling, and 30 packing, according to the invention, splitting of glauconite with the help of magnetic separation on magnetic and non-magnetic fractions, milling of magnetic fraction of glauconite, mixing of the milled glauconite magnetic fraction with water until the formation of plastic material, drying of granules obtained after granulation, screening with extraction of granules of the required 5 granulometric composition. It is appropriate for concentration of glauconite in glauconite magnetic fraction to be not less than 95%. It is also appropriate for the milling of glauconite magnetic fracture to be performed until the size of particles is from 1 to 100 pm. 10 It is appropriate to mix milled glauconite magnetic fraction with water until the formation of plastic material with humidity not less than 28%. It is appropriate to dry the granules naturally at the positive air temperature not lower than 20 0 C up to the level of humidity not more than 10%. It is appropriate to split and screen the granules for extraction of fractions 15 with cross-sectional and length dimension from 0,8 to 100 pm. It is appropriate to return the waste for re-milling after the graining and use it as a binding agent in further granulating. Glauconite is a multipurpose material by its structural and geochemical characteristics. However, the use of non-processed glauconitic sand as a sorbent 20 with its increased sorption characteristics seems to be impossible because of peptisation of glauconite clay fraction. The use of glauconite magnetic fraction from glauconitic sand as a binding agent, while producing the granules, allows to obtain granulated sorbent, which possesses increased sorption and adsorption capacities which can widen its area 25 of use. Glauconitic sand comes from quarry in wet or frozen and chunked condition etc. and contains different rubbish in the form of grass roots, gaize etc., that is why it is preheated (dried), with the optimal temperature in the range from 70 to 100C. The main condition for this is that sand must be dry and easily 30 sifted through a sieve to separate mechanical admixture and gaize. The sieve may have mesh from 0,8 to 0,25 mm, the main condition is that fracture of glauconite must be sieved, and maximum fracture of glauconite must be from 0,65 mm and lower. The composition of glauconiteore depends on mine field, at that concentration of 5 glauconite in ore may be from 15% to 75%, all the rest is ballast in the form of quartz, feldspar etc. Glaucotite can be magnetized at high magnetic field strength. When glauconite ore is passed through magnetic separator, glauconite is separated from ballast fracture. The presence of metal in glauconite indicates high concentration of glauconite. This can be seen from Table 1, which 10 represents the elemental composition of the separated magnetic by separation of glauconite on the magnetic and non-magnetic fraction. Table 1 also shows that the magnetic metal fraction is considerably more than the non-magnetic one. Thus, the obtained mixture with the concentration of glauconite in separated magnetic fraction is not less than 95%. 15 The milling of magnetic fraction is carried out in order to obtain the flour for making grains from magnetic fraction (mainly for grains glauconite milling with the size of fractions in the range from 30 to 50 microns). Table 1 N2 Composition of magnetic fraction of non-magnetic elements glauconite, % fraction of glauconite, % 1 Fe2O 3 23,09 3,39 2 SiO2 33,59 64,30 3 Al20 3 21,79 17,67 4 K20 19,40 13,20 5 CaO 1,24 0,81 6 TiO2 0,65 0,45 7 ZrO2 0,08 0,06 8 SrO 0,02 0,02 9 SO 3 0,06 0,06 10 Ta20 5 0,05 0,03 11 Rb20 0,03 0,01 Milled magnetic fracture is mixed with water in order to form plastic mass. The graining mass is carried out to give cylindrical grains, which have the size in diameter from 0.8 to 100 mm and the length from 50 to 100 mm, thus, the 5 "noodles", which according to the usage of die may have different diameter and length, are obtained. Grains of different diameter size and length are needed and the obtained "noodles" are dried naturally at positive surrounding air not lower than 20 0 C and air humidity not more than 10%. It is necessary in order to remove the excessive humidity before the operation of milling of the obtained 10 "noodles", from which granules of needed granulometric size are produced. If the milling of "noodles" is done after baking under 650 0 C for at least 1 hour, then, as a result of milling these grains, the obtained waste is hard to utilize, and during the drying to humidity of 10%, the obtained waste as the result of milling "noodles" is sent back to milling and second obtainment of "noodles" for 15 production of grains of necessary size. Waste is not formed with such a technology. Graining and screening of granules is done in order to get fractions, which have size in diameter and length from 0,8 to 100 mm, because consumer sizes of granules for water purifying have these granulometric parameters, and the form 20 of granules must be of irregular shape, but closer to the round shape. The maximum filtration capacity of the final product is achieved by getting irregular round form of granules for any granulometric composition. Baking of granules is carried out in a furnace at the temperature not exceeding 650 "C, in the course of not longer than 1 hour, because at this temperature 25 granules have consumer hardness and do not fall into pieces when they get into water and stay hard. The period, which is long enough for baking, can be not less than 1 hour.

Isolation of magnetic fraction of glauconite from the main mass allows us to obtain the binding agent, which is the main material of granulated sorbent production. We suggest a method of granules production on the basis of natural glauconite 5 binder, which can be used as full sorbent. The presence of ballast fraction and high percentage of large fraction composition of glauconite hampers direct granulating of glauconite sand without any additives. That is why glauconite granulation in known technical solutions was made with different blinders, for example, zirconium dioxide or bentonite, which, on the one hand facilitated 10 normal granulating of glauconite, and on the other hand contributed to decrease of its sorbent characteristics. The proposed technical solution provides an opportunity of getting separated milled fraction of glauconite with the help of magnetic separation, which is used as a binding agent for granulation. This achieves the maximum sorbent effect of 15 the final product for extended range of pollutants. Experimental measurements of sorption indice of combined grains were carried out, in the composition of which we used: bentonite clay, glauconite and thermally expended carbon at the ratio of components, mass %: bentonite clay 40, glauconite - 40, thermally expended carbon - 20; where bentinite clay was 20 the binding agent, in comparison with glauconite granules on the basis of glauconite binder, where the concentration of glauconite was 95%. Measurements were carried out on ferrous metal sorption from water before and after passing through granules. Passing model solution of ferrous metal through combined and glauconite grains was carried out simultaneously. Underwater 25 production unit of metal in potable water is 0,3 mg/l. Used equipment is photometer of creatine phosphokinase-3. Results of measurements are represented in Table 2. Table 2 shows that sorption of glauconite granules on the basis of glauconite binder is three times higher than sorption of combined granules with bentinite clay, glauconite and thermally expended carbon, therefore, the sorption capacity increases. 5 Table 2 Residual Present concentration Adsorbent Indice concentration, after cleaning, mg/l mg/l Combined grains with bentinite clay, Io(I)10,75 0,26 glauconite, thermally expended Glauconite grains on the base of glauconite Iron (II) 10,75 0,09 binder Short description of ketches The invention is illustrated with a photograph, which shows the morphology of 10 glauconite granules (side view of the surface of the powder sample of glauconite, amplification - 20 kt). Morphology research was done on the scanning electronic microscope TESCAN MIRA II LMU. The sample consists of glauconite, which contains not less than 95% of magnetic fraction of glauconite, and is made with SHF expansion and has the form of elongated 15 structures, light-brown color, hard. The sample surface is comprehensive, developed and nanostructured. There are disseminations of crystallized structure in the sample. Embodiment of invention The proposed method of producing granulated sorbent on the basis of natural binder of glauconite is as follows. Previously glauconite binder basis is made in the form of glauconite flour according to the following technology. 5 Feebly magnetic mineral glauconite is obtained from glauconite sand (with the help of magnetic separation), which has been preheated at the temperature of 70 100 0 C and screened through the sieve, which has the size from 0,8 to 0,25mm. During the separation ballast fractions (quartz, feldspar, glauconite non magnetic, etc.) separate from magnetic glauconite. Separated magnetic 10 glauconite is reduced to fragments in any milling equipment, which allows to get glauconetic flour fraction from 1 to 100 microns. Obtained glauconetic flour fraction from 1 to 100 microns are mixed in homogenizer with addition of water in order to obtain clay glauconite mass with humidity not less than 28%, which is used in obtaining of sorption granules based on natural glauconite. 15 The obtaining of grains based on milled magnetic fraction of glauconite is done according to the following technology. Glauconite binder in the form of flour obtained after separation of magnetic glauconite fractions and its milling is mixed with water to humidity of the obtained mass not less than 28%. The obtained mass is directed into the 20 granulating machine, from which granules with the diameter from 0,8 to 100mm and length from 50 to 100mm come. After leaving the granulating machine they are naturally dried at above-zero surrounding temperature not lower than 20 0 C with humidity not more than 10%. Dried grains are directed to the milling machine, where they become granules of irregular form, which have size in 25 diameter from 0,8 to 100mm and length from 0,8 to 100mm. As a result of milling, different types of granulometric composition are formed. Granules are screened through sieves, which have the size from 0,8 to 100 mm. Screened granules are sorted according to their granulometric composition and directed into the furnace for baking at the temperature not more that 650 0 C in the course 30 of not longer than 1 hour. After thermal treatment, natural cooling of granules is carried out until they reach the temperature of the environment, then granules are packaged in containers. Defective grains, siftings and flour, which are formed during the fragmentation rocess, are directed back into the granulating machine, which allows to get 5 glauconite flour fraction from 1 to 100 microns. After milling, glauconite flour is directed to the stage of mixing with water. With this technology no waste is formed. Preferred Embodiment Glauconitic ore, which is represented by glauconitic sand, is preliminarily 10 dried under temperature not higher than 100 0 C to the point of reaching humidity not less than 8% throughout the volume. Dried glauconitic ore is screened with screen plates of various granulometric sizes, in order to separate mechanical impurities, i.e. grass roots, gaize, etc. from glauconitic sand. Screened glauconitic sand is sent for separation, which is performed with the help of high 15 intensity magnetic roller separator CBM with the induction of 1,5 tesla, or with the help of dry magnetic beneficiation system MCOY-154/200. In the course of magnetic separation, the process of separation of glauconitic magnetic fraction from the non-magnetic part, which is a ballast fraction consisting of quartz, feldspar, etc., takes place. Separated magnetic glauconitic fraction is then 20 delivered to the milling system (e.g. three-stage centrifugal mill II-700 produced by ZAO "TZDO", city of Tula), which allows to reduce glauconite to fractions not more that 50 micron. Water is added into the milled magnetic fraction of glauconite and the obtained mass is mixed with the help of homogenizer until it reaches residual humidity not less than 28%. The obtained 25 mass is delivered to mixing extrusion-type granulating system of any type for obtaining granules with a diameter of 1.4 mm, length of 80 mm, which can be achieved through installing nozzles with openings (opening diameter 1.4 mm). For other sizes nozzles with the required openings are to be installed. The remaining ballast fraction (quarz, feldspar, etc.) is deposited and stored for 30 utilization in other types of technology for scavenging. The obtained granules are naturally dried under positive surrounding temperature not less than 20 0 C and humidity no more than 10% and are then delivered to the hammermill, where they are broken into smaller fractions, with the cross-sectional size ranging from 1.2 to 1.4 mm; the granules are screened and sorted according to 5 their granulometric composition. The granules are then baked under the temperature not higher than 650 0 C in the course of 1 hour. The output of the finished granules is 15%. Defective granules, plus mesh, and powder formed in the course of breaking are sent back to the milling system, which allows to obtain glauconite powder with a fraction from 1 to 100 micron. After milling 10 the obtained glauconite powder proceeds to the stage of mixing with homogenizer with water and for secondary granulation. There is no waste when this technology is used. The applied technology allows to obtain glauconite granulated sorbent, which reaches high sorptive capacity.

Claims

1. Method for producing granulated sorbent includes preliminaty heating and screening of glauconite sand, mass granulation, baking of the obtained granules with further cooling down, packing of the finished product, which is 5 different due to the fact that separation of glauconite is performed with the help of magnetic separation into magnetic and non-magnetic fraction, milling of glauconite's magnetic fraction, mixing of the milled magnetic fraction of glauconite with water until plastic mass is formed, drying of the granules obtained through granulation, splitting of granules, screening of granules, which 10 allows to obtain granules of the required granulometric texture.

2. Method according to claim 1 wherein the concentration of glauconite in the magnet fraction of glauconite is not less than 95%.

3. Method according to claim 1 wherein the milling of the magnet fraction of glauconite is carried out until glauconite particles sized from 1 to 100 micron 15 are obtained.

4. Method according to claim 1 wherein before granulating mixing of milled magnetic fraction of glauconite with water is carried out until plastic mass with humidity not lower than 28% is formed.

5. Method according to claim 1 wherein the drying of granules after 20 granulating is carried out naturally under positive surrounding temperature not lower than 20 0 C and humidity not more than 10%.

6. Process according to point 1 is different in that splitting and screening of granules is carried out for obtaining granules with a cross sectional size and length from 0.8 up to 100 mm. 25

7. Method according to claim 1 wherein after splitting and screening of granules, the waste is returned for secondary milling and further utilization as a binding agent for granulation process.