Method of processing the mixture of pentaerythrite formate mother liquors and evaporation plant for realization of this method
FIELD: concentration of pentaerythrite formate mother liquors in the multi-case evaporation plant with vertical heat exchange tubes for production of high-quality lacquers, additives for oils and other products.
SUBSTANCE: proposed method includes concentration of pentaerythrite formate mother liquors at the first stage by evaporation to saturation state by pentaerythrite and crystallization of pentaerythrite from saturated solution; concentration at the first stage is performed at film flow solution; crystallization is carried out at two stages at forced circulation of suspension thus formed. Secondary vapor is divided into two flows after first stage of evaporation: one flow is delivered to the first stage of crystallization and second flow is delivered to the second stage of crystallization. At the second stage of crystallization boiling point of suspension is maintained at temperature of 45-53°C which is below that at the first stage by 7-20°C. Evaporation plant for processing the pentaerythrite formate mother liquors has two stages of evaporators connected in succession in way of flow of vapor and solution and provided with vertical tubes. Second stage of evaporation plant is just crystallizer provided with circulating loop with pump and vapor separator connected with final condenser by means of vapor pipe line. First stage consists of film liquid flow evaporator; second stage is provided with additional crystallizer with circulating loop and pump and additional condenser connected with vapor separator of additional crystallizer; it is also provided with non-condensable gas discharge unit. Last evaporator of the first stage is provided with additional pipe line for discharge of secondary vapor which is communicated with heating chamber of additional crystallizer. Solution volume of additional crystallizer exceeds that of the first one by 1.5- 2.5 times.
EFFECT: improved quality of crystalline products; increased degree of extraction of pentaerythrite from solution; increased rate of processing the solutions.
6 cl, 1 dwg, 1 tbl
The invention relates to the technology of polyols and can be used for concentration PENTAERYTHRITE-formiate solutions in a multi-effect evaporator plant with vertical heat exchange tubes with the aim of crystallization and obtain pentaerythritol used in the production of high quality paints on the condensation basis, additives to oils and other products.
The concentration process plays an important role in the technology of producing pentaerythritol. Indicators stage of concentration largely determines the economic performance of the production of pentaerythritol. Thus the efficiency of evaporators is largely due to the level of perfection of technology of the evaporation process, as well as the design of evaporators.
The process of concentrating by evaporation PENTAERYTHRITE-formiate solutions with the crystallization of pentaerythritol has a number of features that make it difficult for instrumentation and economical carrying out of this process. Features PENTAERYTHRITE-formiate solutions are their complexity and thermolability. To prevent decomposition, the maximum temperature should not exceed 130°C. whereas large values of depression solution economically justified minimum temperature is andsinging him in the last case evaporator is 50-55° C. These limits define the range of temperatures accessible in the evaporator plant, 75-80°from which taking into account losses (depression, steam etc) on each of the evaporating apparatus, there are on average only 10 to 12°C. This limits the possibilities of economical applications traditionally used evaporators when the optimal ratio of capital and operating costs.
Set (Zagidullin AGRICULTURAL and other Research solution in the system pentaerythritol - water to optimize the crystallization process. Russian journal of applied chemistry, 1995, t, B.4. S; Mosheva L.A. Physico-chemical principles of crystallization of pentaerythritol from water and water-salt solutions. Abstract. Kida. Diss. Perm, 1997 and others), which upon evaporation of these solutions the formation and growth of crystals occurs at high solution solution for pentaerythritol, which increases with increasing concentration of sodium formate dissolved impurities, and increase the rate of creation of supersaturation (i.e. the rate of evaporation from a solution of water and cooling the suspension) and the reduction of the initial saturation temperature. Maintenance of a large supersaturation due to the extremely low velocities of the mass transfer in the formed suspension in which a fairly complete selection of crystallizable substances requires a long time.
slojnee process the need for crystallization from the reaction of pentaerythritol solutions which contain 20-40% of pentaerythritol, 30-45% of sodium formate and 10-25% of organic impurities. In the presence of such amounts of dissolved substances greatly increases the viscosity of the liquid phase and expands the metastable zone of the existence of supersaturated solutions of pentaerythritol. This reduces the efficiency of the moulds.
In the production of pentaerythritol was often used molds of periodic action, which is a cylindrical apparatus with conical bottom and cooling jackets, supplied frame mixers (Schnaible, Lhamodeva, Vahdat, Ergashev, Vigego, Eco. "Development and implementation of the mould of continuous operation in the production of pentaerythritol". "Chemical industry", 1995, No. 2, p.8). To ensure continuous operation, the molds are sometimes connected in a cascade of 3-5 degrees. However, due to the stepped nature of the cooled suspension was deteriorating conditions of crystallization. Because of frequent clogging perechodnik channels between the individual steps required decrease in the initial concentration of the solution with a corresponding decrease in the level of separation of pentaerythritol. These molds was low specific heat exchange surface, imperfect hydrodynamics of mixing and a number of other disadvantages. The possibility of intensifica the AI operation of the apparatus by replacing low-speed frame stirring speed is limited to high effective viscosity of the suspension and the low mechanical strength of crystals of pentaerythritol.
These drawbacks have led to low intensity of crystallization, which duration exceeded all other technological operations. The resulting crystals due to the heterogeneity of the mixing of the suspension and the duration of the process was additionally worn with the formation of small fractions of particles with sizes less than 100 microns. Such nonuniform particle size distribution of the sediment had increased hydraulic resistance, which reduces the performance of the filter equipment and worsened conditions of the washing product.
Known mold of a continuous action by the patent RF №2035195, IPC 01D 9/02, publ. 20.05.95, the Mold is a horizontal rectangular case with pipes for feeding the starting solution and output production suspension. Inside the housing lower part in koridoram order is heat-exchange surface in the form of direct heat exchange tubes placed longitudinal rows. This annular space is partitioned transverse vertical partitions are provided with adjustable side openings located on opposite sides of the adjacent partitions. Mixing device made in the form of combs mounted on horizontal rods and installed between the partitions with vozmozhnostuvelichivat-and-forth movement in a horizontal plane along the rows of pipes.
The reaction solution before crystallization is evaporated and the temperature of 80-85°and the density 1290-1320 kg/m3served in the first section of the mold, where it consistently moves by gravity through all ten sections. Countercurrent through the pipes moving coolant. In each section a high quality of mixing of the suspension. The presence of seed crystals greatly facilitates the process of heterogeneous removal of the precipitate, which improves the crystal structure of pentaerythritol.
The disadvantages of this method of processing solutions in the machine with the mold according to the patent of Russian Federation №2035195 are low intensity of the crystallization process and, consequently, low productivity of the mold, due to the low driving force generated by the saturation, achieved only by reducing the temperature of the suspension, and slow mass transfer in solution due to a low crystallization temperature.
Closest to the claimed is a method of processing a mixture of uterine PENTAERYTHRITE-formiate solutions and trehkorpusny once-through evaporator installation described in the Technological regulation No. 15 production of pentaerythritol Gubakha JSC "Metafrax".
These technical solutions adopted C is the applicant for the prototype. This method of processing includes at the first stage, the concentration of the mixture of mother solutions by evaporation until a state of saturation by pentaerythritol, and the second stage crystallization of pentaerythritol from a saturated solution. Evaporation system for implementing the method-prototype contains two stages connected in series in the course of the solution and a pair of evaporators with vertical pipes. The first step of the installation contains two evaporator with natural circulation. The second stage is a mold with forced circulation and includes a circulation loop with a pump and a steam separator, steam line connected with an end capacitor.
Advantages of the method and device prototypes are a large initial velocity of crystallization, due to the increased driving force, because the saturation is created not only by reducing the solution temperature at the inlet to the mould and to a much greater extent by evaporation of water in the mould.
The disadvantages of these known methods, and evaporator are as follows. The evaporators with natural circulation in the conditions of evaporation of highly concentrated PENTAERYTHRITE-formiate solutions work with low intensity heat transfer and require stable is large useful temperature difference (more than 15-20° C). As a result, they have a large heat transfer surface and, consequently, greater intensity and cost, as well as dimensions. Specific working surface of these devices is small and equal 69-71 m2/t the evaporating water. In addition, because of the relatively small effective temperature differences, due to a limitation of the operating temperature range installation (the limit of the boiling temperature in the first evaporator apparatus and molds), evaporators unstable.
Upon receipt of a saturated solution in the crystallizer is a rapid boil and vigorous boiling of the solution with the formation of large quantities of steam (up to 50% of the flow entering the device solution) simultaneously cooling the boiling solution at 30-40°C. Due to these factors, there is a very significant saturation of the solution on pentaerythritol and a large number of embryos microcrystals centers of crystallization, for further significant growth which do not have neither the mass of the substance, which continues to crystallize from the solution, no time supersaturated slurry in the mould. The last factor is very important, as due to the decrease of the temperature of the solution, the increase in solution concentration of sodium formiate and restorany the impurities, the rate of mass transfer decreases drastically and also decreases the driving force of mass transfer. In these conditions, even the presence of a large number of small crystals during their stay in the device does not lead to a fairly complete selection of pentaerythritol.
Study of the causes of unsatisfactory operation of the prototype allowed the authors of the present invention to eliminate the aforementioned disadvantages and to create a method and an evaporation system that meets modern requirements to the processes of concentration of solutions and crystallization.
We examination a method of processing a mixture of uterine PENTAERYTHRITE-formiate solutions and evaporation plant for its implementation, while retaining all the advantages of the method and device of the prototype regarding the sequence of connection of evaporators for a couple and mortar, have significant differences from them regarding the types of evaporators at all stages of concentration that achieve the required modern technical result, improve the quality of the crystalline product and the degree of extraction of pentaerythritol from the treated solution, the intensity of the work and performance of the equipment while increasing the efficiency of the process and reduction of energy consumption and capital cost of equipment is.
The inventive method of processing a mixture of uterine PENTAERYTHRITE-formiate solutions includes the first stage of concentrating the mixture by evaporation until a state of saturation by pentaerythritol, and the second stage crystallization of pentaerythritol from a saturated solution. The new method is that in the first stage, the concentration is carried out at a film flow of the solution and the crystallization process is carried out in two stages with forced circulation of the resulting suspension, and the secondary steam after the first stage of evaporation is divided into two streams, one of which is served on the first stage of crystallization, and the other on the second. In addition, in the second stage crystallization temperature boiling suspension support in the range of 45-53°, 7-20°With less than at first. The ratio of the volume of water evaporating on the first and second stages of crystallization, is between 4:1 to 1.5:1, and the duration of crystallization on the first level is 1.5-2 hours, and the second 1.5-2.5 times more. The first stage of crystallization can be carried out mechanical dogomania suspension.
Evaporation system for implementing the method of processing a mixture of uterine PENTAERYTHRITE-formiate solutions, as well as the prototype contains two stages connected in series in the course of solution and vapor evaporation is paratov with vertical pipes. The second stage of the installation is a mould provided with a circulation loop with a pump and a steam separator connected to the steam line and a limit to the condenser.
New in the proposed evaporator plant is that the first stage consists of devices with a film flow of liquid, for example from the evaporators falling film, and the second step is provided with an additional mold with a circulation loop with a pump, and an additional capacitor connected to a steam separator additional mold and is equipped with a device for output of non-condensable gases, the latter apparatus of the first stage is provided with an additional secondary exhaust tube couple, communicated with the heating chamber for more of the mold. In addition, additional secondary steam pipe can be installed in a device to regulate the flow. Another difference in the installation is that the mortar amount of additional mold 1.5-2.5 times longer than the first. The first mold may be provided made by the cyclone, the inlet pipe which is connected with the pressure chamber of the circulating pump, sand - suction pump chamber and the outlet of the clarified solution from the nozzle output oparino what about the solution. In addition, the exhaust device for removing non-condensable gases from the secondary condenser is in communication with the terminal capacitor.
The technical result of the proposed technical solution is that the implementation of the pre-evaporation in a film flow of the solution allows to reduce the share of specified operating temperature range is used for this purpose, and accordingly, to increase the share for the crystallization process, which gives the opportunity to manage this process to the extent necessary to create optimal conditions to perform in two (main and additional) evaporating crystallizers with forced circulation of heated simultaneously and distinguished: functional (the first operator to obtain crystals, and the second as crystallinities), as well as operating conditions and design parameters, which creates the necessary conditions for obtaining high-quality - coarse homogeneous product with lower than in the prototype, capital and operating costs.
The inventive method and evaporating installation meet all the criteria of patentability. They are new, as in the prior art is not known solutions with the same sets of essential features, as evidenced by the above analysis is the means and facilities for processing mixtures of uterine PENTAERYTHRITE-formiate solutions. Offer for the patent examination process of the invention involve an inventive step, as for the specialist they do not follow explicitly from the prior art, that is, from the known prior art has identified effects prescribed these inventions transformations, characterized by distinctive features of the prototype the essential features to achieve a technical result. Indeed, conducted by the applicant for patent research has shown that among the famous in the world science and technology solutions designed for processing a mixture of uterine PENTAERYTHRITE-formiate solutions do not exist such that, having distinctive essential features of the proposed method and installation, already would have resulted in their use to ensure technical result, which sent a group of inventions in the present application.
Moreover, the problem of processing thermolabile PENTAERYTHRITE-formiate solutions more complex, still has not been resolved, although the need to solve it for a long time. The proposed method and evaporation plant made it possible to solve this problem, satisfying the existing demand, and given the opportunity to resolve the bottleneck in a complex chain of production of pentaerythritol. Thanks to the proposed solution, there is no need to stop blasting the study every twenty hours of work and carry out cleaning of heat transfer surfaces, reducing productivity and causing increased energy consumption.
The claimed group of inventions is industrially applicable and the way, and install all the sets of characteristics is feasible and reproducible; nothing in the proposed invention does not interfere with their use in the industry with achievement of the expected technical result.
We present a description of the specific performance of the evaporator and implement it proposed method proof.
To be attached to the application diagram - drawing of the inventive evaporator, which implements the inventive method. The pattern is given chetyrehkorpusnoj evaporator.
Evaporation system for processing a mixture of uterine PENTAERYTHRITE-formiate solutions contains two stages connected in series along the vapor and solution evaporators 1, 2 and 3 with vertical heat exchange tubes, placed in the heating chambers. The first stage consists of two evaporators 1 and 2 film type. The second stage contains the mold 3 with the circulation pipe 4, a pump 5 and a steam separator 6, forming a circulation loop. The separator 6 steam line 7 is connected with an end of the capacitor 8.
The second stage of the installation is equipped with additional mold 9 with the circulation pipe 10 by pump 11 and the additional capacitor 12, United steam pipe 13 to the separator 14 and is equipped with a device 15 for removal of non-condensable gases. The last evaporation apparatus 2 of the first stage is provided with an additional pipeline 16 secondary steam outlet communicated with the heating chamber 17 additional mold 9. Mortar amount of additional mold 9 1.5-2.5 times more mortar volume of the mold 3. The mold 9 is an evaporation apparatus with forced circulation of the suspension, vertical pipes and the circulation path formed by the pipe 10, a pump 11, a heating chamber 17 and the separator 14. For extra pipeline 16 is a device 18 for controlling the flow of steam.
The mold 3 is equipped issued by the hydrocyclone 19, the inlet pipe 20 which is connected with the pressure chamber of the circulating pump 5, the sand pipe 21 is connected with the pipe 4 connected to the suction of the pump chamber 5 and the outlet 22 of the clarified solution is connected to the pipe 23 o one stripped off solution. The mold 9 has a socket 24 for removal of concentrated suspensions using a pump 25.
For submission to the evaporator set the initial mixture uterine PENTAERYTHRITE-formiate solutions from the tank 26 to serve as a pump 27 and pipe 28. The evaporators 1 and 2 of the first stage are connected to parastou pipe 29, and a pair of conduit 30. Evaporating device 2 is supplied by a pump 31 for supplying saturated solution on the pipe 32 into the mold 3. The molds 3 and 9 of the second stage communicated between a solution of a pipe 33, and to output the concentrated slurry from crystallizer 9 provides a pipeline 34. The pipe 35 sequentially connects on a couple of the last device 2 of the first stage with the first mold 3 of the second stage. The device 15 for removal of non-condensable gases reported by pipe 36 to limit the capacitor 8.
Multi-effect evaporation system works as follows. The initial mixture uterine PENTAERYTHRITE-formiate solutions from the tank 26 by the pump 27 is served by pipeline 28 in the first evaporation apparatus 1 with a falling film of the first stage, where with the help of switchgear solution is formed in a thin film flowing down along the inner surface of the vertical heat exchange tubes. Flowing down in the form of a film on the tubes, the solution boils rapidly and partially concentrated. Evaporation is carried out due to the heat of condensation of steam coming from the boiler, on the outer surface of heat exchanger tubes. The mixture was partially concentrated solution and the resulting secondary steam from the lower ends of heat exchange tubes into the separator, where razdelau is as follows: the solution for further concentration by pipeline 29 is directed to the second evaporation apparatus 2 with a falling film, operating at a lower boiling point than the first.
The secondary steam from the separator evaporator 1 via line 30 is directed into the heating chamber evaporator 2 as a medium for carrying out the process of evaporation of the solution. The solution is concentrated to saturation state on pentaerythritol, pumped by pump 31 through pipe 32 into the first mold 3 of the second stage. The secondary steam from the separator evaporator 2 is divided into two streams: the first stream pipeline 35 is directed into the heating chamber of the first mold 3 and the second pipeline 16, equipped with a regulating device 18, is directed to a heating chamber 17 additional mold 9 and use these devices for further evaporation.
In the first crystallizer 3 evaporation of the solution followed by separation of the crystals (seed crystals) of pentaerythritol and the formation of a suspension of these crystals, which are covered emitted from the liquid phase of the pentaerythritol. In the initial period of operation, or when sudden variations in the residue concentration of the crystals produced in the first mold 3 may be less than the values, determining the conditions for long-term non-scum. To maintain the concentration of crystals in the optimal range (20-30%) in the first crystal is isatori 3 circulation loop is provided by mechanical dogomania made using hydrocyclone 19, the inlet pipe 20 which is connected with the pressure chamber of the circulating pump 5, the sand pipe 21 is connected with the pipe 4 connected to the suction chamber of the circulating pump 5, and the pipe 22 clarified solution from the nozzle 23 to output one stripped off suspension.
A concentrated solution containing a certain number of crystals, the pipe 33 flows into the second mold 9 for the final concentration and crystallization of pentaerythritol. The process of evaporation in the second mold 9 is carried out in conditions providing a deposition released crystalline product mainly on the crystals formed in the first mold 3. The driving force of crystallization - saturation necessary for crystal growth level is provided by the following actions: reducing the boiling temperature of the second mold 9 7-20°compared with the boiling point of the suspension in the first mold 3; evaporation of water from the treated slurry in the amount of 1.5-4 times less than in the first mold 3. Under such conditions in the mould 9 is not initiated mass formation of new centers (nuclei) of crystallization, that is not formed small crystals, but supported the saturation necessary to fairly intensive growth of the crystals. To ensure the growth of crystals and obtaining the mass of the product in the form of large crystals directed the claimed ratio of mortar volume of the molds 3 and 9, providing increasing crystallization time in the second crystallizer 9 1.5-2.5 times more than in the first.
When the concentration in the second mold 9 in the liquid phase of the suspension is achieved concentration of dissolved sodium formiate 40 - 45%, and the boiling point of the suspension is 45-53°s, which corresponds to approaching the saturation state by sodium formate. As the analysis shows graphs of solubility of the basic components PENTAERYTHRITE-formatage solution, built on the results of the research, the claimed process conditions allow crystallization to provide the maximum practically achievable in terms of production allocation from a solution of pentaerythritol. The residual content of pentaerythritol in the liquid phase of a concentrated suspension of 6.5-7.5 percent.
At higher temperatures and lower content of sodium formate decreases the degree of extraction from a solution of pentaerythritol, i.e. decreases the production capacity of the plant to the finished product, and at a higher content of sodium formiate in the liquid phase is achieved condition MONIKI, and RA the creators along with crystals of pentaerythritol begin to form crystals of sodium formiate, then there is the contamination of the target product - crystalline pentaerythritol. Carrying out the crystallization at temperatures below the declared will not allow to achieve significant advantages in performance and quality of pentaerythritol, but it will be costly for the cooling water and equipment to create a vacuum in the mould.
A concentrated suspension from the second mold 9 through pipe 24 to the pipe 34 by the pump 25 serves to filter or centrifuge to separate the crystals of pentaerythritol as the finished product. The mother liquor solution of pentaerythritol after separation of the crystals of pentaerythritol is sent for further processing to highlight sodium formate as a commercial product.
The secondary steam from the steam separator 14 and the second mold 9 through the pipeline 13 is sent to an additional condenser 12 where it is condensed on the flow of water supplied from a water recycling system. Non-condensable gases from the condenser 12 is sucked off device 15 and the exhaust pipe 36 is directed to a terminal of the capacitor 8, and into the atmosphere. This scheme is o non-condensable gases from the supplementary capacitor 12 can reduce the cost of creating and maintaining a better vacuum and, therefore, more of lowtemperature test the boil in the second mold 9. This significantly reduces the consumption of the necessary cooling water, and therefore, the size and metal of the capacitor.
The advantages of the proposed method and evaporation plant for its implementation clearly seen from the comparison of the main indicators of the known installation, adopted for the prototype, and claimed evaporator intended to implement for the production of pentaerythritol (see table).
In the inventive installation is more complete recovery of pentaerythritol from the treated solution, which increases the productivity of its product, and also provides a more qualitative product (larger and more homogeneous crystals)that reduces the cost of subsequent technological redistribution - in the separation of crystals from solution.
|Indicators||The placeholder||The inventive installation|
|1. Capacity, kg/h|
|the original solution||16600||18000|
|on crystalline pentaerythritol||1374||1800|
|2. Operating temperature range when the evaporation, °||83||77|
|3. Surface heat evaporators and heaters, m2||558||314|
|4. Specific steam consumption, kg/kg of product||2,86||2,80|
|5. The specific productivity of product, kg/m2||2,46||5,73|
|6. The specific flow rate of cooling of the circulating water, m3/t of product||422||144|
1. A method of processing a mixture of uterine PENTAERYTHRITE-formiate solutions, including the first stage of its concentration by evaporation in two stages in a film flow of solution to the saturation state on pentaerythritol, and the second stage is crystallization of pentaerythritol from a saturated solution, which is carried out in two stages with forced circulation of the resulting suspension, the boiling temperature at the second stage of crystallization is supported in the interval 45-53°, 7-20°With less than primary, secondary pairs after the first stage of evaporation is divided into two streams, one of which is served on the first stage of crystallization and the other on the second stage of crystallization.
2. The method according to claim 1, characterized in that the ratio of the volume of water evaporating on the first and second stages of crystallization, is between 4:1 d is 1,5:1.
3. The method according to claim 1, characterized in that the duration of crystallization on the first level is 1.5-2 h, and the second 1.5-2.5 times more.
4. The method according to claim 1, characterized in that the first stage of crystallization conduct mechanical dogomania suspension.
5. Evaporation system for processing a mixture of uterine PENTAERYTHRITE-formiate solutions, including sequentially connected in the course of the solution and a pair of two evaporator with vertical pipes and film for the solution, as well as two of the mold, each of which is provided with a circulation loop with a pump and a steam separator connected to the pipeline end capacitor, and end the second capacitor during the solution and the pair of the mold is equipped with a device for output of non-condensable gases, mortar amount of additional mold 1.5-2.5 times more volume during the first solution and the pair of the mold, and the latter in the course of solution and vapor evaporating device connected piping exhaust secondary steam from the heating chambers of both molds.
6. Evaporation system according to claim 5, characterized in that the secondary piping secondary steam installed device for flow control.
7. Evaporation system according to claim 5, characterized in that the first crystallizer equipped with ennennum hydrocyclone, the inlet pipe which is connected with the pressure chamber of the circulating pump, sand the pipe with the suction chamber of the pump and the nozzle clarified solution from the nozzle output one stripped off solution.
8. Evaporation system according to claim 5, characterized in that limit additional capacitor of the mold is connected with an end of the first capacitor during the solution and the pair of the mold.
FIELD: inorganic synthesis.
SUBSTANCE: invention relates to preparation of salts of transition metals with organic acids, in particular to formic acid ferric salt. Method is accomplished via oxidation of ferrous formate with hydrogen peroxide in presence of formic acid and in absence of any dorm of iron as reducer in order to prevent reduction of ferric salt into original ferrous salt. As reducer, ferrous formate is used preliminarily recrystallized and dried or filtered off from reaction mixture suspension. Process is carried out in upright bead mill in two steps. In the first step, ferrous formate powder or precipitate is combined, stepwise or in one go, with 85% formic acid or mixture of filtrate with wash water formed during isolation of desired product to form pasty slurry ensuring stable functioning of bead mill. Second-step operation is effected in bead mill functioning mode involving forced cooling through side surfaces of reactor and continuous introduction of 12.5-25% hydrogen peroxide solution at a rate of 3.25-4.24 g H2O2 per 1 kg starting charge until degree of Fe(II) salt conversion achieves 85-90%. Supply velocity is then lowered until complete conversion is reached. Resulting product slurry is separated from beads and filtered. Filter cake is washed with 85% formic acid and recrystallized in saturated ferric formate solution containing 20-30% of formic acid. Wash liquid is combined with filtrate and used in the first step as described above.
EFFECT: increased yield of target product and simplified its isolation step.
1 tbl, 8 ex
FIELD: inorganic synthesis.
SUBSTANCE: invention relates to preparation of salts of transition metals with organic acids, in particular to formic acid ferric salt. Method is accomplished in bead mill provided with mechanical blade-type stirrer in aqueous formic acid solution (5-10 mole/kg). Iron is used in the form of steel sidewall across the height of reactor and also as particles of reduced iron stirred with stirrer together with glass beads, and/or as broken steel cuttings, and/or yet as split cast iron in any weight proportions. Method is accomplished by continuously introducing 10-20% hydrogen peroxide solution at a rate of 0.015-0,030 mole peroxide/min per 1 kg liquid phase (salt slurry) in presence of stimulating additive, in particular iodine, bromine, alkali metal or ferrous iodides or bromides in amounts (on conversion to halogens) 0.1-0.15 vole per 1 kg reaction mixture. When 1,2-1,5 mole/kg of ferrous salt is accumulated in reaction mixture, stirring and addition of hydrogen peroxide solution are stopped, product slurry is separated from unreacted iron and/or its alloys as well as from glass beads and filtered. Filtrate is recycled into process and precipitate is recrystallized from saturated iron formate solution of aqueous formic acid solution (1-2 mole/kg).
EFFECT: simplified finished product isolation stage, reduced total process time, and reduced power consumption.
1 tbl, 11 ex
FIELD: chemical industry; methods of production of the salts of iron and the organic acids.
SUBSTANCE: the invention is pertaining to the field of chemical industry, in particular, to the method of production of the salts of iron and the organic acids, in particular, to production of the salt of the ferrous iron and the formic acid. The method is realized by the direct interaction of the acid with the iron, its alloys and the ferric oxides. The crumber with the beads and the backflow condenser is loaded with the organic solvent, the formic acid and the water in the mass ratio of 100:(85÷100): (15÷0). As the organic solvent they use ethylcellosolve, butyl acetate, butyl and amyl alcohols, ethylene glycol. The mass ratio of the beads and the liquid phase is 1:1. Ferric oxideFe2O3 orFe3O4 and the iodine are loaded in the amount of 0.40-0.56 or 0/21-0.42 and 0.03-0.1 mole/kg of the liquid phase accordingly. The iron is introduced in the form of the steel shell along the whole height of the reactor and additionally in form of the reduced iron, the fractions of the broken cast iron with dimensions of up to 5 mm and the steel chips in any ratio among themselves at total amount of 20 % from the mass of the liquid phase. The process is conducted at the temperature of 35-55°С practically till the complete consumption of the ferric oxide. The gained suspension is separated from the beads and the metal particles of the greater dimensions and subjected to centrifuging or sedimentation. The clarified liquid phase is returned to the repeated process, and the solid phase is dissolved at stirring action and warming up to 85-95°С in the water solution of the formic acid saturated by the ferric formiate (II) up to 1-2 mole/kg. The present solid impurities are removed at the hot filtration process and the filtrate is cooled and the salt crystals are separated. The technical result of the invention is simplification of the technology of the production process with utilization of the accessible raw.
EFFECT: the invention ensures simplification of the technology of the production process with utilization of the accessible raw.
3 cl, 17 ex
FIELD: chemical industry; methods of production of the salts of iron and the organic acids.
SUBSTANCE: the invention is pertaining to the field of chemical industry, in particular, to the method of production of the salts of the metals of the organic acids, in particular, to production of the salt of the ferrous iron and the formic acid. The method is realized by the direct interaction of the formic acid water solution with the iron and/or its alloys and the ferric oxidesFe2O3 and Fe3O4 in the bead crumber of the vertical type along the whole its height with the steel shell, with the heat supply and equipped with the mechanical stirrer and the backflow condenser-refrigerator. The apparatus is loaded with 23-46 % water solution of the formic acid as the liquid phase in the mass ratio with the glass beads as 1:1.25 and then introduce the oxide - Fe3O4 orFe2O3 in amount of 0.27-0.49 or 0.48-0.64 mole/kg of the liquid phase accordingly, and besides in amount of 18 % from the mass of the liquid phase they add the powder of the reduced iron and-or the crushed cast iron, and-or the crushed steel chips in any mass ratios. Switch on the mechanical stirring and heating and keep the temperature in the reaction zone within the limits of 55-75°С. The process is terminated, when practically the whole loaded oxide is completely consumed. The suspension of the salt is separated from the non-reacted iron, its alloy and the beads and dilute with the water up to the contents of the formic acid within the limits of 1-2 mole/kg. The gained mass at stirring action is slowly heated up to temperature of 85-95°С, controlling transformation of the solid phase into the solution. The gained solution is subjected to the hot filtration, evaporation, cooling and separation of the salt crystals. The filtrate and the earlier the gained distillate are sent back to the repeated process. The technical result of the invention is simplification of the technology of the production process with utilization of the accessible raw.
EFFECT: the invention ensures simplification of the technology of the production process with utilization of the accessible raw.
FIELD: production of salts of organic acids, salt of ferrous iron and formic acid in particular.
SUBSTANCE: proposed method consists in loading preliminarily prepared aqueous solution of formic acid at concentration of 4.5-10 mole/kg into reactor provided with bladed mixer, back-flow condenser-cooler and air bubbler. Then, powder of reduced iron and/or broken iron and/or steel chips at any mass ratio in total amount of 20.0-30.6% of mass of liquid phase and stimulating iodine additive in the amount of 0.016-0.164 mole/kg of liquid phase are introduced. Reactor may be provided with steel or cast iron ferrule over entire height. At mechanical mixing, consumption of air for bubbling is maintained between 1.2 and 2.0 l/(min·kg of liquid phase). Working temperature range is 45-65°C which is maintained by external cooling. Process is discontinued when content of iron salts (II) in reaction mixture reaches 1.8-2.0 mole/kg. Suspension of salt in liquid phase is separated from unreacted iron particles and is filtered afterwards. Filtrate is directed for repeated process and salt sediment is re-crystallized from aqueous solution saturated with iron formate by formic acid at concentration of 1-2 mole/kg at heating to temperature of 95°C followed by natural cooling.
EFFECT: enhanced efficiency.
1 tbl, 9 ex
FIELD: chemical industry; methods of production of the ferric formiate (III).
SUBSTANCE: the invention is pertaining to the field of chemical industry, in particular, to the method of production of the ferric formiate (III). The invention is dealt with the organic salts of the transition metals, in particular to production of the salt of the ferric iron and the formic acid. The method is realized by the direct interaction of the regenerated iron powder with the formic acid at presence of the molecular iodine and oxygen of the air as the oxidizing agents. The process is running in the medium of dimethylformamide as the dissolvent for preparation of the necessary liquid phase with the concentrations of the formic acid and iodine of 4.5-10 and 0.03-0.11 mole/kg accordingly. The mass ratio of the liquid phase and the powder of the regenerated iron is 3:1. The process starts at the room temperature and is conducted in the conditions of the forced cooling at the temperature of 50-80°С at the rate of the air consumption for the bubbling of 0.6-1.2 l\minute per 1 kg of the liquid phase. The process is terminated at accumulation of the ferric formiate (III) in the suspension up to 1-1.2 mole/kg. The suspension is separated from the particles of the non-reacted iron and then filtered. The filtrate is recycled to the repeated process, and the ferric formiate (III) (salt) is dried and either is used as required, or additionally is purified by the recrystallization. The technical result of the invention is simplification of the method with improvement of the economic indicators and the increased purity of the final product.
EFFECT: the invention ensures simplification of the method with improvement of the economic indicators and the increased purity of the final product.
FIELD: anti-conglomeration agents.
SUBSTANCE: invention relates to loose product based on potassium formate, which contains 0.1 to 1% water and 0.5-5% water-soluble conglomeration-preventing agent, such as potassium carbonate or potassium hydroxide, which possesses affinity for water and corresponds to equilibrium humidity below equilibrium 15% relative humidity (22°C) for potassium formate.
EFFECT: provided modifying and conglomeration preventing agents for potassium formate to allow it to achieve looseness under practical storage and processing conditions.
3 cl, 4 tbl, 4 ex
FIELD: crystal growing.
SUBSTANCE: method comprises using inner and outer systems of circulations. The inner system of circulation is mounted inside the crystallizer provided with the classification zone that receives the crystals of material. The classification zone is made of a sedimentation zone. The portion of the dispersion outflowing from the crystallizer is directed to the outer circulation system through the classification zone. The crystals are dissolved in the outer circulation system by means of the device for dissolving crystals. The dispersion or solution is directed back to the inner circulation system. A portion of the dispersion flow is withdrawn from the inner circulation system and introduced into the outer circulation system, and/or a portion of the dispersion flow is withdrawn from the inner circulation system and then is introduced again in the inner circulation system.
EFFECT: enhanced quality of crystals.
6 cl, 5 dwg