RO135380A0 - Product for treating an acid soil, plant and process for its preparation and use of the so-prepared product - Google Patents

Abstract

The invention relates to a product for treating an acid soil, to a plant in which the product is prepared and to a process for preparing the product which starts from a raw material consisting of a useful mineral substance. According to the invention, the product has the following content: 20...25% struvite resulting from the reaction between the reactive Mg oxide contained in a ratio of 20...25% in a brucite concentrate and the phosphate and ammonium ions contained in sewage water, with which it is kept in contact for maximum 60 minutes, 30...35% Ca oxide, 1.5...2% micro-elements of Co, Cu, Ni, Zn and B, and for the remainder up to 100% metal oxides with a grain size of 0.04...3 mm, the percentage being expressed by weight. The claimed plant consists of a subassembly (A) for processing the activated concentrate of brucite limestone, a subassembly (B) for manufacturing the product and one or more reaction vessels (C) in a fluidized bed where the activated concentrate is brought into contact with sewage water. The claimed process consists in processing brucite limestones, comprising a two-stage crushing followed by their calcination, to result in a mixture of reactive Mg oxide, Ca oxide, microelements and other metal oxides with a beneficial role in plant growth, and, by using a denitrification device in fluidized bed, it provides the continuous processing of some sewage water flows through which approximately 90% of the ammonium and phosphate ions are recovered from the water, to finally obtain a product with the role of fertilizer and neutralizer of acid soils.

Description

k-k.J-. HENlrtU hivEilȚH And MÂ? ! Application for invention

DESCRIPTION OF THE INVENTION ^Ν / ··; ......:; ϊγ <202ϊ

PRODUCT FOR THE TREATMENT OF AN ACID SOIL, INSTALLATION AND PROCESS FOR OBTAINING IT AND USING THE PRODUCT SO OBTAINED

The invention relates to a product for the treatment of acidic soil, obtained in an installation by applying in it a process starting from a raw material consisting of a useful mineral substance as well as to the use of the product obtained.

A product containing magnesium, phosphate and ammonium ions is called "rubbed" for ammonium and magnesium hexahydrate, with the chemical formula: (NH4) Mg (PO4) -6 (H2O). This product can be obtained directly from all types of liquid or solid residues containing phosphate and ammonium ions in the presence of magnesium ions which may be found in water or which come from the dissociation of various magnesium salts, such as oxide, magnesium hydroxide or chloride which are soluble in aqueous medium.

In general, the compound formed is sparingly soluble, white, yellowish-white or white-brown in color, with a specific density of 1.7 kg / dm ³ and a molecular weight of 245.41 g.

The precipitation reaction is:

Mg ²⁺ + NH4 ⁺ + PO4 ³ = MgNH4PO4 in the conditions where precipitation takes place, many chemical elements such as Hg, Ag, Pb, Al, Fe, Mn, Zn are still removed from the wastewater, partly by coprecipitation or adsorption . Arsenic ions also precipitate under the same conditions, but in the form of AsO4 ³ .

The solubility product also indicates a very low solubility of residual ammonium and phosphate ions remaining in solution:

Ps = [Mg ²⁺ ] · [NH ₄ ⁺ ] · [Ρθ4 ³ ] = 2.5 · 10 ¹³

The residual concentration of ammonium and phosphate ions is about 1 · IO ⁵ mol / l, but in industrial conditions no residual concentrations lower than 0.1 mg / l were obtained.

Also, the ratio of ammonium ions to phosphate should be 18:95 according to the stoichiometry of the precipitation reaction. Any deviation from this ratio will result in the excess reagent remaining in the water.

The magnesium required for precipitation should not be added as a precipitating reagent. Dissolution of magnesium occurs only to a small extent due to its solubility:

Ps = [Mg ²⁺ ] · [CO3 ⁺² ] = 2.6 · ^10-5

The solubility product allows a solubility of magnesium of 0.005 mol / l. Magnesium dissolves to a greater extent as a result of the reaction with carbon dioxide:

Mg (CO3) + CO ₂ + H2O = Mg (HCO3) 2

The fructose that forms in these reactions, if it is not contaminated with heavy metals, can be successfully used as a chemical fertilizer with phosphorus and ammonium.

The chemical composition of pure brine is:

NH3-23.29%; PO4 ³ -69.34%; Mg ² <7.37%.

Products for the improvement and fertilization of the soil are known to come from the treatment of wastewater, from which phosphate and ammonium ions, also called nutrients, are precipitated by the addition of various magnesium salts, in the form of double ammonium phosphate and magnesium, a compound known as the name of rubbing. The product obtained in granular form, with granules between 0.5-1 mm in annual quantities of 500-550 kg / ha is used as such or mixed with various complex phosphate fertilizers, in soil fertilization.

The disadvantages of these products are that they contain only crushed and act only as a fertilizer, to increase its efficiency, requiring the addition of complex fertilizers. (http.7 / www.stowa-selectedtechnologies.nl - 27.08.2006).

Installations are known in which products based on frying are obtained, comprising a cylindrical vertical reactor with a fluidized bed, in which this product is obtained. The installation includes anaerobic fermentation decanters, filter for drying the obtained sludge, centrifugal pumps, silos for magnesium oxide and sodium hydroxide, vertical reactor for denutrification, separator for rubbing and silo for its storage. The daily processing capacity with two vertical reactors is 45,000 m ³ / day.

The disadvantages of these installations are that they have a relatively complicated construction and require relatively large wastewater storage capacities to ensure continuous flow operation, pH control requires special attention, and the degree of corrosion of the reactor must be carefully monitored. To obtain the fertilizer based on rubbing, magnesium hydroxide is used as a source of magnesium ions, a substance as expensive as the resulting final product and also, as a pH regulator of the solution, another substance is dosed. chemical, respectively sodium hydroxide. Another disadvantage is the long retention time of the wastewater in the reactor (approx. 10 days), the time required for crystallization and deposition of the granular form, with particles between 0.5-1 mm.

Processes for obtaining a product based on magnesium ions, ammonium ions and phosphate ions in a plant are known.

By the Japanese process mentioned in the documentary material, (http://www.stowaselectedtechonolies.nl - 27.08.2006) domestic wastewater representing filtered water from sludge filtration, with nutrient concentrations of 100-150 mg / 1 PO? and 100-110 mg / 1 NH4 is

introduced into a vertical cylindrical reactor with fluidized bed. To achieve the Mg / P molar ratio of 1, sodium hydroxide is added to the reactor. The retention time is around 10 days, during which time, the formed grout is obtained in granular form with a grain size of 05-1 mm, and the efficiency of the process of recovery of nutrients (phosphate and ammonium ions) from wastewater is over 90%.

The disadvantages of these processes are that they use pure, relatively expensive chemicals in the crystallization process of the fry, a long reaction time to obtain the fry and to obtain a final product with a limited field of use.

The technical problem solved by the inventions in the group of inventions is the increase of the activity of neutralization and fertilization of an acidic soil in the conditions in which it is necessary to balance the contents of microelements, especially copper, zinc, cobalt, nickel, selenium. natural in the product with which the acid soil is treated. The process of removing nutrients from the water in the form of brushing, using minerals that can release magnesium ions, such as dolomite or brucite, has proven to be very advantageous because technologically it is sufficient to pass contaminated water over a bed of material containing these minerals. .

As a result of laboratory and pilot tests, in order to obtain a raw material with a minimum of 20% MgO, 35% CaO, manganese oxides, aluminum, titanium, sodium, potassium, phosphorus, iron, silicon, under the conditions in which naturally contains a concentration of 2% trace elements, the raw material consists either of the by-product rich in calcium carbonate resulting in the phase of secondary pneumatic concentration to which a part of the raw material which is previously ground is subjected, in a process for processing brucitic limestone to obtain a magnesium concentrate with a purity of at least 98%, or from a by-product rich in calcium carbonate resulting from the filtration of the residual product from the final carbon dioxide solubilization phase of limestone processing brucitic, either from the product obtained by calcination at a temperature of 800-850 ° C, of the material resulting from the disintegration with a size of 0-3 mm. (Official Bulletin of Industrial Property, no. 7/2006 - Bodea Ana, “Process for processing some brucitic limestones and the related installation”, Patent of invention no. 121554 / 3.11.2007).

In this way the concentrations of magnesium and calcium oxide and the respective micromelements in stable form are ensured.

It was also surprisingly found that any of the raw materials or mixtures thereof in any proportion, could be subjected to a treatment with phosphate and ammonium ions preferably present in domestic wastewater, resulting in crushing, with a concentration of approx. -30%, as well as a concentration of 70-80% CaO and 1-2% micronutrients, the rest up to 100% being made up of oxides of manganese, aluminum, titanium, sodium, potassium, phosphorus, iron, silicon.

It was also found that the presence of micronutrients leads to the realization of crystallization nuclei, so that the crystals obtained have a shape and dimensions similar to the mass of rubbing.

The product according to the invention eliminates the disadvantages shown above, in that it has a crushing content of 20-25% by weight, resulting from the reaction between the reactive magnesium oxide contained in a proportion of 20-25% by weight in a brucitic concentrate and phosphate and ammonium ions contained in the sewage with which it is kept in contact for up to 60 minutes, as well as 30-35% calcium oxide, 1.5-2% trace elements the rest up to 100% being made up of metal oxides, both micronutrients and oxides belonging to brucite concentrate whose granule size is 0.04 to 3mm.

Another object of the invention is that the trace elements consist mainly of cobalt, copper, nickel, zinc, boron.

Another object of the invention is that metal oxides consist of 38-48.5% oxides of manganese, aluminum, titanium, sodium, potassium, phosphorus, iron, silicon, preferably consisting of 0.42% SiO2; 0.01% TiO ₂ ; 0.03% A1 ₂ 0 ₃ ; 0.02% MnO; 0.13% Fe2O ₃ ; 0.09% Na 2 O; 0.06% Κ2θ; 0.18% Ρ ₂ Θ5.

Another object of the invention is that it is a polydisperse product, has a grain size of 0.04-3 mm, an average density of 2.26 kg / dm ³ , humidity of 3%, is a product that is difficult to soluble in water at room temperature and has a white-yellow or white-brown color.

The installation according to the invention, in which the product is obtained, removes the disadvantages shown above, in that the subassembly for processing the activated concentrate of said brucitic limestone is mounted in conjunction with a subassembly for the manufacture of the product which comprises a vibrating dispenser with predetermined flow rates of one or more fluidized bed reaction vessels in which the activated concentrate is brought into contact with domestic wastewater, each vessel C consisting of 16 and 17 upper cylindrical and lower frustoconical mantles in a chamber delimited by the upper cylindrical jacket 16, being placed axially with a supply pipe 18 with activated concentrate whose lower end b, is located in a fluidized layer containing activated concentrate maintained in a basket 19 whose lower wall c is consisting of a perforated plate in front of which a feeding funnel 10 is arranged with domestic wastewater, from a pipe 21, a side cylindrical wall d of the chimney 19 being in contact with the lower wall c by a lower circular guide e and being supported at the top by some bars 22 and 23 placed diametrically opposite protruding an upper wall 24 of the vessel C, the pipe 21 passing through the lower jacket 17 and entering a lower chamber f, delimited by the lower jacket 17, the lower chamber f being able to be communicated with the outside by a valve 25, mounted in a the cylindrical neck of the lower mantle 17, in the immediate vicinity of the upper wall 24, of the upper mantle 16, being arranged a short pipe 26, fixed tangentially by a hydrocyclone 27, from which, at a lower end, the passed through a filter 28 with drum, with depression, in front of the valve 25 being arranged a duct 29 located above a vibrating sieve 30, the coarse product being taken from the sieve 30 and conducted in a dry 32 of which the product is transported in a silo 34.

Another object of the invention is that the fine product of the filter with a vacuum drum 28 is taken up and discharged by the trough 31 mounted between the sieve 30 and the dryer 32, the water resulting from the filter 28 being transported through a pipe 36 to In another pipe 37, connected to the h end of the hydrocyclone 27, and the water collected from the sieve 30 is taken through another pipe 38 and introduced into the pipe 21 through which the wastewater is conveyed.

Another object of the invention is that the vibrating screen 30 has a size of the surface of the drainage mesh between 0.9-1.5 mm.

The process according to the invention, applied in the installation for obtaining the product, removes the disadvantages shown above, in that the brucitic limestone subjected to primary crushing, has a humidity of up to 3% and contains 23.18% MgO; 33.12% CaO; 0.42% SiO2; 0.01% TiO2; 0.03% A12Q ₃ ; 0.02% MnO; 0.13% Fe2O ₃ ; 0.09% Na 2 O; 0.06% K 2 O; 0.18% P ₂ O _s , the remaining up to 100%, ie 42.28%, representing losses on calcination, and the brucitic concentrate obtained from said calcination, contains the entire amount of reactive MgO and CaO, this brucitic concentrate being cooled to a temperature of 50-60 ° C and stored, after which it is dosed in order to undergo a phase of denutrification in contact with the environment consisting of domestic wastewater containing ammonium ions 150-200 mg / l and phosphate ions 80- 100 mg / l, the ratio between the flow rate of calcined concentrate and that of domestic waste water being between 2/1 and 2.2 / 1, the contact time being up to 60 minutes and preferably 20-30 minutes, given that the supply of calcined concentrate is gravitational and that of wastewater is countercurrent with an ascending velocity between 0.0012-0.03 m / s, the smoothing obtained in a fluidized bed with a grain size of 0.3 -3 mm are subjected to desiccation in the presence of a vibrating field du which are dried to a moisture content of up to 3% at a temperature of 100-150 ° C for 15-20 minutes, and the fine product resulting from drying is reintroduced into the domestic wastewater circuit. smaller than 0.3 mm, being subjected to hydrocyclonation from which the fine product is filtered in the presence of a depression of 0.8-0.9 bar and finally mixed with the coarse product resulting from drying.

Another object of the invention is that the magnesium oxide in the brucitic concentrate contains 5-7% by weight, granules with a size of less than 40 microns which form crystallization centers of the fluidized bedrock, after which the formation takes place. a reaction mass between the polydispersed mixture in which the reactive magnesium oxide is bound to granules larger than 40 microns in size and the part of the mixture consisting of a mixture of water and particulate matter to be smaller than 0.3 mm, and with a falling limit speed lower than the ascending speed of the wastewater stream are entrained to the surface and subjected to the mentioned hydrocyclone and filtration phase.

The product according to the invention is used to neutralize acid soils with a pH of 4.5-5.5 at the same time as fertilizing these soils.

The use of the product according to the invention comprises the spreading on the acid soil simultaneously with its plowing, of an amount of 400-500 kg / ha, this treatment being done for 2-4 agricultural seasons.

The installation, process and use of the product according to the invention have the following advantages:

- ensures the obtaining of a complex product with the role of fertilizer and neutralizer of acid soils, with natural contribution of microelements and metal oxides necessary for plant metabolism;

- reduces production costs by not requiring the addition of pH-regulating chemicals to the crystallization process of frying and does not require the addition of trace elements needed to enrich acidic soils;

- allows the continuous flow of wastewater treatment, loaded with ammonium and phosphate pollutant ions, which usually cannot be recovered from polluted water, except by applying expensive and therefore unsuitable procedures;

- ensure an increase in the efficiency of the process of recovery of brucitic limestones by treating them in several chained stages, with a beneficial role both in the treatment of wastewater and in fertilizing and reducing the acidity of acidic soils whose surface is increasing due to growth the degree of pollution of the atmosphere by emissions of sulfur dioxide and carbon dioxide.

The following are examples of embodiments of the invention within the group of inventions in connection with Fig. 1, Fig. 2, Fig. 3 and Fig. 4, which represent:

- fig. 1 - Scheme of the sequence of steps in the process of obtaining brucitic limestone from a raw material containing magnesium oxide, calcium oxide, trace elements and metal oxides;

- fig.2 - Scheme of the installation for obtaining the fertilizer product;

fig.3 - Denutrificator;

- fig.4 - Interdependence between the hydrodynamic criteria Li, Re and log Ar.

The product according to the invention, in the conditions in which it starts from brucitic limestone and after disintegration results particles with a size of 0-3 mm, which are subjected to calcination at a temperature of 800-850 ° C, a raw material containing in the higher calcium carbonate, magnesium hydroxide, contains 25% MgO, 1.5% trace elements consisting of cobalt, copper, nickel, zinc, boron, metal oxides of manganese, aluminum, titanium, sodium, potassium, phosphorus, iron, silicon and the rest CaO. This raw material, brought into contact with domestic wastewater, containing ammonium and phosphate ions in the following concentrations: NH4 ⁺ = 200 mg / dm ³ , PO4 ^3- = 80 mg / dm ³ , forms a grout in a weight of 25 % associated with 1.5% trace elements and the rest up to 100%, calcium oxides and oxides of other metals. The product has a white, white-yellow or white-brown color with an odor specific to the content of ammonium ions, is sparingly soluble in water and has a specific density of 1.7 kg / dm ³ .

The process according to the invention comprises a primary crushing of a brucitic limestone whose composition is shown in Table 1, and the humidity of the brucitic limestone is up to 3%.

Results of general chemical analysis on burnt limestone sample (basic elements)

Table 1

ELEMENT LD UM stock SiO ₂ 0.01 % 0.42 TiO ₂ 0.01 % 0.01 AhOa 0.01 % 0.03 MnO 0.01 % 0.02 FeiOa 0.01 % 0.13 MgO 0.01 % 23.18 As a 0.01 % 33.12 NaaO 0.01 % 0.09 K2O 0.01 % 0.06 p ₂ or ₅ 0.05 % 0.18 P.C. 0.10 % 42.28

This primary crushing results in brucitic limestone granules up to 40 mm in size.

Then follows a secondary crushing of the material resulting from the primary crushing, so that a polydispersed mixture with a granulation between 0-10 mm results. This crushing phase is in a closed circuit with a volumetric grading phase at 10 mm, which controls the material, so that the larger granules of this size are recirculated in the secondary crushing feed, and the smaller ones are directed to the phase. next.

the whole mixture of material with dimensions between 0-10 mm is subjected to crushing by mechanical disintegration up to the size of 3 mm, in which case a disassociation of the burning particles from the mass of raw material is achieved.

Brucitic limestone granules from decay are ensiled in ambient conditions.

Next, they are preferably dosed at a flow rate of 50-100 t / h, in order to supply the predetermined quantity, which is subjected to a calcination phase, which takes place at a temperature of 800-850 ° C, until, upon release of water and release of carbon dioxide, brucite is converted to reactive magnesium oxide and calcium carbonate is converted to calcium oxide, both oxides being found in the presence of trace elements shown in Table 2.

Results of general chemical analysis on brucitic limestone sample (microelements)

Table 2

ELEMENT LD UM stock them 0.2 PPm 0 Be 0.2 PPm 0

V 1 PPm 5 -R o, l Ppm 1.9 Co. 0.5 ppm 293 us 0.5 ppm 2.7 With 0.1 ppm 143 Zn 1 PPm 42 I would 0.1 PPm 0 Rb 0.1 PPm 0.2 Sr. 1 PPm 86 γ 0.1 PPm 1.1 Zr 1 PPm 11 Nb 0.1 PPm 0.6 Mo 0.1 PPm 0.3 CD 0.1 PPm 0.4 Sn 0.4 PPm 3.6 Sb 0.5 PPm 0.5 yourself 0.01 PPm 0 Cs o, l PPm 0 nay 1 PPm 10 W 0.25 Ppm 0 Pb 1 PPm 15 Bi 0.1 PPm 0.1 Th 0.1 PPm 0.4 U 0.1 PPm 0.4 IT 0.2 PPm 0 Ga 0.1 PPm 0 it 0.1 ppm 0.1

The calcination losses representing 35-45% and consisting of water and carbon dioxide, were also confirmed by the thermodifferential analysis of brucitic limestone.

The carbon dioxide resulting from the calcination phase can be recovered in a manner known per se, so as not to pollute the external environment, which is not the subject of the process according to the invention.

The calcined concentrate is taken up by an open screw conveyor for cooling and discharged at a temperature of 50-60 ° C into a silo.

From the silage phase, the calcined concentrate is taken up and dosed in order to undergo a denutrification phase, during which it is brought into contact with an environment consisting of wastewater containing: NH4 ⁺ = 150-200 mg / dm ³ and PO ? = 80-100 mg / dm ³ . The ratio between the flow of calcined concentrate and that of domestic wastewater has values between 2: 1 and 2.21: 1.

The contact time is up to 60 minutes and preferably 20-30 minutes, given that the supply of calcined concentrate is gravitational and that of domestic wastewater is countercurrent, with an ascending speed shown in Table 3. , in which are presented the values that characterize the main technical parameters of the denutrification phase.

Designed technical parameters of the denutrificator

Table 3

PARAMETER UM WASTEWATER FLOW [m ³ / day] 500 1000 1500 2000 2500 Active concentrated consumption kg / day 1041.7 2083.3 3125.0 4166.7 5208.3 kg / hour 43.4 86.8 130, 173.6 217.0 Fluidized bed surface m ² 0.19 0.39 0.58 0.77 0.96 Pat race m 0.22 0.35 0.43 0.50 0.55 Ascending speed THX 0.03 0.03 0.03 0.03 0.03 Dl / D2 = 3 Radius m 0.74 1.05 1.29 1.49 1.66 Surface m ² 1.74 3.47 5.21 6.94 8.68 Ascending speed THX 0.0033 0.0033 0.0033 0.0033 0.0033 d m 0.000041 0.000041 0.000041 0.000041 0.000041 Dl / D2 = 4 Radius m 0.99 1.40 1.72 1.98 2.22 Surface ^ -2 m 3.09 6.17 9.26 12.35 15.43 Ascending speed THX 0.0019 0.0019 0.0019 0.0019 0.0019 d m 0.000027 0.000027 0.000027 0.000027 0.000027 Dl / D2 = 5 Radius m 1.24 1.75 2.15 2.48 2.77 Surface m ² 4.82 9.65 14.47 19.29 24.11 Ascending speed THX 0.0012 0.0012 0.0012 0.0012 0.0012 d m 0.000021 0.000021 0.000021 0.000021 0.000021 Dl / D2 = 6 Radius m 1.49 2.10 2.58 2.97 3.33 Surface m ² 6.94 13.89 20.83 27.78 34.72 Ascending speed THX 0.0008 0.0008 0.0008 0.0008 0.0008 d m 0.000018 0.000018 0.000018 0.000018 0.000018 Dl / D2 = 7 Radius m 1.74 2.45 3.01 3.47 3.88 Surface m ² 9.45 18.90 28.36 37.81 47.26

Ascending speed THX 0.0006 0.0006 0.0006 0.0006 0.0006 d m 0.000016 0.000016 0.000016 0.000016 0.000016

wherein: D1 is the diameter of the cylindrical part of the reaction vessel C, D2 is the diameter opposite the cylindrical basket 19, and d is the average size of the granules entrained in the upper part of the reaction vessel C.

As can be seen in the analysis of the values of the parameters presented in Table 3, during the denutrification phase, there is a start of the process of formation of the crystallization centers of the fry by the reaction of ultrafine particles of magnesium oxide with dimensions smaller than 40 microns representing 5-7% of the total amount of brucitic limestone, after which the crystals grow and immediately, the formation of a reaction mass between the polydispersed mixture in which the reactive magnesium oxide is bound to fine particles to be rubbed with a size smaller than 0.3 mm and with a lower speed limit than the rising speed of the sewage stream, it is hydrocycled in order to recover the bottom of the fine product and the top of the denutrified water at the top.

The denutrification phase takes place under the conditions in which, the parameters of the clarification zone, for sedimentation in any flow regime, the sedimentation rate is calculated, starting from formula (1):

«- - ^{Re2 p} ~ ^Pm ^ (pp ^ p ^ g

Ar = Ga - = —-------- 5 ---- (1)

Pm Fr p _m where: d - particle diameter, m;

p - particle density, kg / m ³ ;

p _m - environmental density, kg / m ³ ;

Ga - Galileo's criterion;

Fr - criterion (figure) Froode;

q _m - dynamic viscosity of the environment, N s / m ² ;

g - gravitational acceleration, m / s ² .

From some nomograms (a) and (b), represented in figure 4 and which represent the interdependence between the hydrodynamic criteria Li, Re and log Ar, the sedimentation rate of the particles is calculated according to their size, according to the parameters shown in table 4.

Table 4

d [m] It them (Osed [m / s]

0.000001 1.60258 x 10 ^'05 3.99664 x IO ^{09 4.02104} x 10-05 0.000002 0.000128207 4.48268 x IO ⁰⁸ 9,00089 x IO ⁰⁵ 0.000003 0.000432698 1.84355 x IO ⁰⁷ 0.000144209 0.000004 0.001025654 ^5.02782 x 10-07 0.00020148 0.000005 0.00200323 1.09485 x IO ⁰⁶ 0.00026115 0.000006 0.003461582 2.06775 x ΙΟ ⁰⁶ 0.000322804 0.000007 0.005496863 3.53977 x IO- ⁰⁶ 0.000386158 0.000008 0.008205231 5.63926 x IO- ⁰⁶ 0.000451004 0.000009 0.011682838 8.50386 x ΙΟ ⁰⁶ 0.000517184 0.00001 0.016025841 ^1.22799 x 10-05 0.000584572 0.00002 0.128206728 0.000137733 0.001308536 0.00003 0.432697706 0.000566443 0.002096484 0.00004 1,02565382 0.001544826 0.002929091 0.00005 2,003230118 0.00336398 0.003796565 0.00006 3.461581644 0.006353279 0.004692875 0.00007 5,496863444 0.010876142 0.005613899 0.00008 8,205230564 0.017326937 0.006556624 0.00009 11.68283805 0.026128605 0.00751874 0.0001 16.02584094 0.037730753 0.008498419 0.0002 128.2067276 0.423192129 0.019023286 0.0003 432.6977055 1.740427142 0.030478362 0.0004 1025,65382 4.74656783 0.042582671 0.0005 2003,230118 10.3360205 0.055193863 0.0006 3461,581644 19,52081553 0.068224285 0.0007 5496,863444 33.41757152 0.081613994 0.0008 8205,230564 53.23800851 0.095319174 0.0009 11682.83805 80.28163772 0.109306271 0.001 16025,84094 115.9299028 0.135548695 0.002 128206,7276 1300.282093 0.276557558 0.003 432697,7055 5347,562234 0.443089665

The denutrification phase takes place in the conditions in which a thickening area of the groove coexists consisting of depleted brucitic limestone, placed at the bottom, a zone of clarification of the denutrified wastewater placed at the top and a separation zone placed at the middle whose ratios between diameters are shown in table 3, in the conditions in which the realization of the denutrification in fluidized bed were considered, in the conditions in the realization of some values of the characteristic parameters, given in table 5.

The main functional parameters

Table 5

PARAMETER UM WASTEWATER FLOW [m ³ / day] 500 1000 1500 2000 2500 Consumption kg / day 1041.7 2083.3 3125.0 4166.7 5208.3 kg / hour 43.4 86.8 130.2 173.6 217.0 Reaction time dry 3600 3600 3600 3600 3600 Bed radius m 0.25 0.35 0.43 0.50 0.55 Bed surface m ² 0.19 0.39 0.58 0.77 0.96 Volume bed m ³ 0.039 0.078 0.118 0.157 0.196 bed height m 0.204 0.204 0.204 0.204 0.204

The plant according to the invention in which the process is applied comprises a subassembly A for processing the activated brucite limestone concentrate and a subassembly B for manufacturing the product. Subassembly A consists of crushers 1 and 2 with front and rear jaws, with the possibility of adjusting the discharge of the crushed material up to 40 mm and up to 10 mm, respectively, joined together by means of an inclined trough, not shown in the figure.

The crusher 2 is connected by means of another inclined trough, not shown in the figure, with a vibrating screen 3 with the size of the surface of the grading meshes of 10 mm from which the refuse is driven by means of a conveyor belt 4, to the feed trough of the crusher 2 .

The passage of the sieve 3 is guided through a trough 5 in a crusher 6 with hammers from which the crushed material, having a size of less than 3 mm is taken by a conveyor belt 7, in order to feed on the top of a silo 8 .

The silo 8 is connected by means of a conveyor belt 9 with an inclined rotary kiln 10, in which the fuel, preferably consisting of methane gas, is introduced through a pipe 11. The active concentrate in the furnace 10 is taken up by a conveyor 12 wedged and placed in another silo 13. The latter is in communication at its bottom with a conveyor belt 14 which leads the fine concentrate to a dispenser 15 which distributes the concentrate in some packages, a situation not shown in the figures, which ensures storage for transport, active concentrate, either in containers transportable by rail or car.

Subassembly B consists of a vibrating dispenser 15 in which the active concentrate is discharged from the packaging or containers and which is supplied at a predetermined flow rate with values given in Table 3 of one or more fluidized bed reaction vessels C between the active concentrate and wastewater. Each vessel C consists of a top 16 cylindrical jacket and a lower 17 frustoconical jacket. In an upper chamber a delimited by the jacket 16, is placed axially, a supply pipe 18 with activated concentrate, the lower end of which is located in a fluidized layer containing activated concentrate, maintained in a basket 19, a whose lower wall c consists of a perforated plate in front of which is arranged a funnel 20 for domestic wastewater supply, conveyed through a pipe 21, connected to the funnel 20. A side cylindrical wall d of the basket 19 is in contact with the wall c, through a lower circular guide and is joined at the top by bars 22 and 23 placed diametrically opposite, which protrude outside an upper wall 24 of the vessel C. Conduit 21, passes through the lower mantle 17 and enters a lower chamber f, delimited by mantle 17. Chamber f, can be communicated with the outside by a valve 25 mounted in a cylindrical neck g, of the mantle 17. in the immediate vicinity of the wall 24, the mantle 16 is corded a short pipe 26 fixed tangentially to a hydrocyclone 27 from which at one end h is discharged water without ammonium and phosphate ions, and at one end and end is discharged a fine product containing fine particles to be crushed which in turn is passed through a vacuum drum filter 28. In front of the valve 25 is arranged a pipe 29 located above a vibrating screen 30 with the mesh size of the drainage surface between 0.9-1.5 mm. The coarse product resulting from the sieve 30 is taken up by a trough 31 and taken to a dryer 32 in which a temperature of between 150-200 ° C is maintained from which the product with a humidity of less than 3% is taken up by a conveyor 33 with scrapers or worm and transported in a silo 34. The fine product from the filter 28 is taken by a conveyor 35 with a belt and discharged into the trough 31. The water resulting from the filter 28 is transported through a pipe 36 to another pipe 37 connected to the upper h end of the hydrocyclone 27. The water collected from the sieve 30 is taken through a pipe 38 and introduced into the pipe 21.

In another constructive variant, the installation according to the invention comprises trough 31 from which the product with a maximum humidity of 18-20% is loaded into containers for transport to the place of use.

The product according to the invention has in its composition 20-25% crushed, 30-35% calcium oxide, 1.5-2% microelements consisting of cobalt, copper, nickel, zinc, boron, the rest up to 100% being composed of oxides metallic manganese, aluminum, titanium, soda, potassium, phosphorus, iron, silicon. The rub is found in the form of a polydisperse mixture with granule sizes ranging from 0.04 mm to 2 mm. In the dry state, the humidity is a maximum of 3%, and in the wet state, the product has a humidity of 18-20%. The chemical composition of pure rubbing is: NIL · - 23.29%; PO? 69.34%; Mg ²⁺ - 7.37%. The fry has a white, yellowish-white or white-brown color with a specific odor of ammonium ion content, is sparingly soluble in water and has a specific density of 1.7 kg / dm ³ .

The use of the product consists in treating acid soils with a pH between 4.5-5.5 at a specific consumption of 400 kg / ha.

The treatment begins by plowing to a depth of 20-35 cm at the same time as mechanized spreading the product as evenly as possible. After the treatment applied, the pH must reach a value equal to 7. Simultaneously with the activity of neutralizing the acidity, the activity of fertilizing the soil due to the nutrients in the product also takes place.

The product according to the invention allows the use separately or together with other fertilizers, preferably consisting of a complex fertilizer based on nitrates and phosphates and preferably phosphates and trace elements. Consumption of phosphites and trace elements per hectare is well known.

BIBLIOGRAPHY SHEET

Patent no. 121554 / 03.11.2007, holder Bodea Ana, name “Process for processing some brucite limestones and the related installation” published in the Official Bulletin of Industrial Property no. 07/2006.

Claims (11)

demand 1. A product for the treatment of acidic soil, characterized in that it has a crushing content of 2025% by weight as a result of the reaction between the reactive magnesium oxide contained in a proportion of 2025% by weight in a brucitic concentrate and the phosphate ions and ammonium contained in the wastewater with which it is kept in contact for up to 60 minutes, as well as 3035% calcium oxide, 1.5-2% trace elements the rest up to 100% being made up of metal oxides, both trace elements and oxides belonging to brucitic concentrate with a grain size of 0,04 to 3 mm. Product according to Claim 1, characterized in that the trace elements consist mainly of cobalt, copper, nickel, zinc, boron. Product according to Claim 1, characterized in that the metal oxides consist of 38-48.5% oxides of manganese, aluminum, titanium, sodium, potassium, phosphorus, iron, silicon, preferably consisting of 0.42% SiO ₂ ; 0.01% TiO ₂ ; 0.03% Α1 ₂ Θ ₃ ; 0.02% MnO; 0.13% Fe ₂ O ₃ ; 0.09% Na 2 O; 0.06%; 0.18% P ₂ Os. Product according to claim 1, characterized in that it is a polydisperse product, has a grain size of 0.04-3 mm, an average density of 2.62 kg / dm ³ , humidity 3%, is a heavy product soluble in water at ambient temperature and has a white-yellow or white-brown color. Plant for the production of the product, in which the product according to claims 1,2,3,4 is obtained, comprising a subassembly (A) for processing the activated brucite limestone concentrate, comprising crusher with front and rear jaws joined together by means of an inclined trough, the rear crusher being connected by means of another inclined trough with a vibrating screen, from which the refusal is led to a feed trough of the rear crusher, the passage of the screen being led into a hammer crusher from which the material The crushed material is processed and placed in a silo, from which, through a conveyor belt, the material is placed in an inclined rotary kiln and the activated concentrate from the kiln in another silo, characterized in that the subassembly ( A) for processing the activated concentrate of said brucitic limestone, it is mounted in connection with a subassembly (B) for the manufacture the product comprising a vibrating dispenser (15) which supplies one or more reaction beds (C) in a fluidised bed in which the activated concentrate is brought into contact with the waste water, each vessel (C) , consisting of upper (16 and 17) upper cylindrical and lower frustoconical mantles, in an upper chamber (a) delimited by the upper cylindrical mantle (16), being placed axially with a feed pipe (18) with activated concentrate of whose lower end (b) is located in a fluidized layer containing activated concentrate held in a basket (19) whose lower wall (c) consists of a perforated plate in front of which a feed funnel (20) is arranged with domestic waste water, from a pipe (21), a side cylindrical wall (d) of the chimney (19) being in contact with the lower wall (c) by a lower circular guide (s) and being supported at the top by some bars (22 and 23) placed diam the opposite ether protruding from the outer wall (24) of the vessel (C), the pipe (21) passing through the lower mantle (17) and entering a lower chamber (f), bounded by the lower mantle (17), the chamber ( f) lower can be communicated with the outside by a valve (25), mounted in a cylindrical neck (g) of the lower jacket (17), in the immediate vicinity of the upper wall (24), the upper jacket (16) , a short pipe (26) is connected, fixed tangentially to a hydrocyclone (27), from which, at one upper end (h), water without ammonium and phosphate ions is discharged, and at one end (s) below, the screw is discharged and passed through a vacuum filter (28) with a vacuum, a pipe (29) is placed next to the valve (25) located above a vibrating screen (30), the coarse product being taken from the screen ( 30) and driven in a dryer (32) from which the product is transported in a silo (34). Installation according to claim 5, characterized in that the fine product of the vacuum drum filter (28) is taken up and discharged by a trough (31) mounted between the sieve (30) and the dryer (32), the water resulting from filter (28), being transported through a pipe (36) to another pipe (37), connected to the h end of the hydrocyclone (27), and the water collected by the sieve (30) is taken through another pipe (38) and introduced into the pipe (21) through which the wastewater is conveyed. Installation according to Claims 5 and 6, characterized in that the vibrating screen (30) has a mesh size of between 0.9 and 1.5 mm. The process for obtaining the product which is applied in the installation according to claims 5,6,7, for obtaining the product according to claims 1,2,3,4, which comprises a primary crushing of brucitic limestone up to granules with a size of 40 mm , which are then subjected to a secondary crushing resulting in a polydisperse mixture with a grain size of between (010) mm, this crushing phase being in closed circuit with a volumetric grading phase at a grain size of 10 mm which makes a control of the material, so that granules larger than this size are recirculated in the feed of the secondary crushing, and those with a size of (O-10) mm are subjected to a crushing by mechanical disintegration with a grain size of 3 mm, phase in which takes place and disassociation of the crushed particles from the mass of raw material, the crushed limestone granules from the disintegration being ensiled in the conditions of the environment, after which it has the calcination at a temperature of 800-850 ° C of these brucitic limestone granules, preferably dosed at a flow rate of 50-100 t / h so that, by releasing water and carbon dioxide, the brucite is transformed into reactive magnesium oxide , and calcium carbonate is converted to calcium oxide, characterized in that the brucitic limestone subjected to primary crushing has a moisture content of up to 3% and contains 23.18% MgO; 33.12% CaO; 0.42% SiO ₂ ; 0.01% TiO ₂ ; 0.03% A1 ₂ 0 ₃ ; 0.02% MnO; 0.13% Fe ₂ O ₃ ; 0.09% Na ₂ 0; 0.06K ₂ Q; 0.18% P ₂ O ₅ ; the remaining up to 100%, ie 42.28%, representing calcination losses, and the brucitic concentrate obtained from the mentioned calcination, contains the entire amount of reactive MgO and CaO, this brucitic concentrate, being cooled to a temperature of 50-60 ° C and stored, after which it is dosed in order to undergo a phase of denutrification in contact with the environment consisting of domestic wastewater containing ammonium ions 150-200 mg / l and phosphate ions 80-100 mg / l, reported between flow rates of calcined concentrate and domestic wastewater being between 2/1 and 2.2 / 1, the contact time being up to 60 minutes and preferably 20-30 minutes, provided that the supply of concentrate calcined is gravitational, and the one with wastewater is countercurrent with an ascending speed between 0.0012-0.03 m / s, the cold obtained in the fluidized bed with the size of the granules of 0.3-3 mm are subjected to desiccation in the presence a vibrating field after which, are u drops to humidity of up to 3% at a temperature of 100-150 ° C for 1520 minutes, and the fine product resulting from drying is reintroduced into the domestic wastewater circuit, particles to be rubbed smaller than 0.3 mm , being subjected to hydrocalcination from which the fine product is filtered in the presence of a depression of 0.08-0.9 bar and finally mixed with the coarse product resulting from drying. Process according to Claim 8, characterized in that the magnesium oxide in the brucitic concentrate contains 5-7% by weight, granules with a size of less than 40 microns which form crystallization centers for the fluidized bed rub, after which it has a reaction mass is formed between the polydispersed mixture in which the reactive magnesium oxide binds to granules larger than 40 microns in size and the part of the mixture consists of a mixture of water and particulate matter with a size of less than 0.3 mm. and with a speed limit of fall lower than the ascending speed of the wastewater stream, they are entrained to the surface and subjected to the mentioned hydrocyclone and filtration phase. The product obtained according to claims 1,2,3,4, is used to neutralize acid soils with a pH of 4.5-5.5 at the same time as fertilizing these soils. The use according to claim 10 of the product according to claims 1,2,3,4 comprises spreading on the acid soil simultaneously with its plowing, an amount of 400-500 kg / ha, this treatment being done for 2-4 agricultural seasons. .