Method of regeneration of activated carbons
(57) Abstract:Usage: in the coal sorption technology for the recovery of precious metals from solutions and slurries. In the method of regeneration of activated carbons, including high-temperature treatment in an inert atmosphere, the treatment is carried out in the field of ultrahigh frequency (UHF), mainly at 915 - 5800 MHz. Reduces the loss of activated carbon up to 0.4 to 1.1% after holding respectively 1 to 5 cycles, "sorption-regeneration" by reducing Amhara while maintaining the mechanical strength of the coal, reduces the process time and energy consumption. 1 C.p. f-crystals, 3 tables. The invention relates to hydrometallurgy, in particular coal sorption technology for the recovery of precious metals from solutions and slurries.In sorption technology for the extraction of gold and silver known way to restore the sorption properties of activated carbons by treatment with mineral acids .Also there is a method for autoclave treatment of alkaline solutions at elevated temperatures (150-200oC) , combined with desorption of noble metals.The disadvantages of these methods is the lack of completeness of no is I the way of regeneration of the sorption properties of activated carbons J. Klein. Regeneration von Aktivkohlen// Technische], 1984, Nr.77, s.513 - 519] by high-temperature processing in furnaces of various designs - reel, mnogoporodnyj, pouring, coal, fluidized bed, etc. in which the coolant are the combustion products of hydrocarbon fuel, infrared rays, teploelektronagrevatel.The disadvantages of this method of regeneration are the following. First, low energy and thermal parameters lead to the loss of activated carbon because of Amhara and abrasion up to 15%, decrease of mechanical strength, resulting in repeated use of coal increased loss of adsorbed noble metal as a result of abrasion a busy coal. Secondly, carrying out this treatment, activated carbon requires complex and bulky equipment.The technical result of the invention is to reduce losses of activated carbon by reducing Amhara while maintaining the mechanical strength of the coal, the reduction of the process time and energy consumption.It is achieved by the fact that in the proposed method, the regeneration of activated carbons, including high-temperature treatment in an inert atmosphere processing Provo is the relationship with the prototype shows the proposed method differs from the known fact that the processing of activated carbon is carried out in the microwave.Thus, the proposed method meets the criteria of the invention of "novelty."Unlike traditional methods of thermal treatment of activated carbons using the energy of the electromagnetic field of ultra high frequency allows instantaneous, volumetric heating of the material in the dense layer, regardless of its dispersion. The consequence is a high rate of heating of the coal, creating a need for regeneration of an inert or reducing atmosphere, the ability to control the process parameters in a wide range, higher conversion efficiency of electric power of the microwave generator (70%) and in the reactor (up to 98%), a substantial reduction in heat losses.Activated carbons after desorption of noble metals are a heterogeneous material that consists of several components that are in solid, liquid and gaseous phase, which have different properties. Accordingly, depending on the location in the substance of the charges of the molecules of the dielectric environment can be polar and Nepal is iesa in conducting or semi-conducting inclusions begin to move within each inclusion, which acquires a dipole moment and behaves like a giant polarized molecule. Due to the structural inhomogeneity of the dielectric constant of such mixtures, as a rule, is much larger than the dielectric constant of individual components.The main causes of decreased sorption properties of activated carbons and affecting the efficiency of use of them in circulation after removing the known methods of noble metals are present in the sorbent various impurities, especially organic substances (nefteprombanka, oil, humic substances, and so on), fine silt and sludge, calcium carbonate. The process of regeneration of wet waste coal is gradual. At the beginning of the moisture is removed and the azeotropic mixture of water with the above organic and inorganic compounds, after which there is an intense heating of the coal to the desired temperature.In industry and some areas of the economy are allowed to use the following frequencies : 461,04 MHz,2%, 433,2 MHz,2%, 91550 MHz, 245050 MHz, 580050 MHz, 2212550 MHz [Posner, Heat energy ultra-high frequencies.- M: Energy, 1968, S. 8]. For these I'm in heat (active energy fields Po) increases in proportion to the operating frequency (f) and the square of the electric field strength (E) according to the equation
Po= 0,55610-12ftgE2, [W/cm2],
where is the relative permittivity of the substance;
tg - loss tangent [Netusil A. Century. and other high-Frequency heating of dielectrics and semiconductors.- M: Gosenergoizdat, 1959, S. 77].At ultrahigh frequencies should also consider the effect of the frequency of the field and the frequency of relaxation of the substance in General, the dielectric constant of the processed material. The dielectric constant becomes maximum when the frequency of the field with the relaxation rate, in this case, fluctuations of the electron orbits or ions increase dramatically, i.e., is a phenomenon of resonance. At frequencies above resonance, the polarization component is out of phase relative to the external field and the dielectric constant of the material is reduced.The application fields of the microwave regeneration of activated carbons predominantly in the range of 915 -5800 MHz is explained as follows. Regeneration of coal at the frequency of the microwave less than 915 MHz inefficient due to the lack of transformation electrolye 5800 MHz is also inefficient due to the decrease of the dielectric constant of the material and therefore, reducing the amount of heat emitted.Thus, in the proposed method, the regeneration of activated carbons in the processing of coal in the microwave is effectively instantaneous, volumetric heating of the material with high speed and creating favorable conditions for recovery of the sorption properties of coal, thereby reducing loss of coal due to the reduction of Amhara while maintaining their mechanical strength, reduce processing time and reduce energy consumption. The presence of the aggregate of distinctive properties determines the relevance of the proposed solutions to the criterion of "inventive step".The method is as follows.Activated charcoal after carrying out desorption of noble metals are placed in a reactor, in which the coal is subjected to processing in the microwave.Hardware technology regeneration of activated carbons in the laboratory implemented at the facility, including a microwave generator, power supply, and control the reactor in the form of a squirrel-cage resonator mode standing waves. Excitation was carried out using a horn antenna.Example 1. Power generator temperature Control was carried out using thermocouples. The value of the specific heating power was established, using the supply voltage generator.In the work of the used activated charcoal brand TALKO CW 814G (Japan). Heating of the coal in the microwave carried out at frequencies 433, 461, 915, 2450, 5800 and 22125 MHz to a temperature of 600oC.In table. 1 shows the results of time-heat activated carbon, depending on the frequency field of the microwave.The data table. 1 shows that the most effective heating of aktivirovannogo coal occurs at frequencies in the range of 915 -5800 MHz, the maximum heating rate corresponds to a frequency of 2450 MHz.Example 2. Regeneration of activated carbon in the microwave was carried out at a frequency of 2450 MHz.Evaluation of the sorption properties was performed with removal of the isotherm and kinetic sorption curves. The mechanical strength was evaluated by the method IIA-60-8 (by abrasion in the rod mill).In table. 2 shows data on the kinetics of adsorption of gold from cyanide solutions depending on the temperature-time regime of regeneration in the microwave field in comparison with fresh sorbent. Conditions of the experiments: linkage coal 2.0 g, volume of a solution of 700 ml, the initial gold concentration of 35.0 mg/lExperimental data table. 2 pok the H-field for 10 min at 600oC. thus the mechanical strength of the activated carbon remains unchanged compared with fresh coal.Example 3. For comparison, the spent regeneration of activated carbons by known methods.Thermal regeneration of activated carbon were carried out in a muffle furnace without air at 650oC and a duration of 40 minutesAutoclave processing of spent sorbent alkaline solutions of 0.4% NaOH at 170oC, 10 specific volume of eluent within 1 hThe acid treatment was carried out by 0,6 NHCl, passing through a column of 4 specific volumes of the solution within 30 minutes of the Coal after the acid treatment was washed until neutral with water.Regeneration efficiency was evaluated from the results of adsorption of gold from cyanide solutions by activated carbon, passed 1-5 cycles "sorption-desorption". For comparison, data on the sorption of gold fresh sorbent. Conditions of the experiments : linkage coal 0.5 g, solution volume of 0.5 l, initial concentration of gold 12 mg/l, pH 11, the NaCN concentration of 0.4 mg/l, the duration of the sorption 28 PMExperimental data table. 3 indicate the possibility of full recovery sorption acticle of 5 cycles sorption-regeneration" and almost without reducing the mechanical strength of the sorbent. Thermal regeneration of activated carbon according to the traditional technology in the same conditions of temperature leads to decrease in mechanical strength of the sorbent 5% loss of coal to 9.6% after 5 cycles "sorption-regeneration" at the expense of higher Obara, as well as partial decontamination of coal by increasing the total time of heat treatment. Autoclave alkaline and acid treatment of the sorbent allow you to restore the sorption activity of coals only 65-87% of the original.Thus, the use of the proposed method for the regeneration of activated carbons provides compared to prototype the following benefits : reduces loss of activated carbon up to 0.4 to 1.1% after, respectively, 1-5 cycles "sorption-regeneration" by reducing Amhara while maintaining the mechanical strength of the coal, to reduce the process time and energy consumption. 1. Method of regeneration of activated carbons, including high-temperature processing of coal in an inert atmosphere, wherein the treatment is carried out in the field of ultra-high frequencies.2. The method according to p. 1, characterized in that the processing in the field of ultrahigh frequency is carried out at 915 - 5800 MHz.
FIELD: noble metal hydrometallurgy.
SUBSTANCE: invention relates to method for acid leaching of platinum method from secondary raw materials, in particular from ceramic support coated with platinum metal film. Target metals are leached with mixture of hydrochloric acid and alkali hypochlorite at mass ratio of OCl-/HCL = 0.22-0.25 and redox potential of 1350-1420 mV.
EFFECT: decreased leaching temperature, reduced cost, improved platinum metal yield.
FIELD: metal recovery, in particular noble metals from technologically proof raw materials.
SUBSTANCE: method includes raw grinding to 0.2 mm; blending with batch containing halogen salts and/or oxygen-containing salts, and mixture opening: cake cooling, leaching with simultaneous reaction pulp agitation with hot water, and metal recovery from solution and insoluble residue. Opening is carried out in electrical furnace at 100-120oC preferably at redox potential of 1.8-2.6 V, by elevating of temperature up to 450-560oC at rate of 8-10oC/min and holding for 1-7 h at highest mixture redox potential. Opened and cooled cake is grinded and leached in opened agitator.
EFFECT: environmentally friendly method with increased yield; utilization of unconventional noble and non-iron metal sources.
1 cl, 2 tbl
FIELD: non-ferrous metallurgy; leaching-out polymetallic hard-to-open materials.
SUBSTANCE: proposed method includes treatment of material with chlorine in aqueous solution containing chlorine ions which is stirred in anode space of electrolyzer with separated anode and cathode spaces; as a result pulp is obtained; leaching-out operation is performed in anode space of electrolyzer separated from cathode space by cation-exchange membranes; operation is performed in aqueous solution containing hydrochloric acid in presence of nitrogen oxides at additional delivery of chlorine-containing gas by suction of this gas into rarefaction zone formed by impeller stirring the pulp. Gas formed during leaching-out process is combined with chlorine-containing gas; layer of finely-dispersed particles formed on surface of pulp is removed and is fed to stirring zone in lower part of anode space; productive leaching-out solution obtained after separation of it from insoluble residue is delivered to cathode space of electrolyzer; leaching-out process is performed at anode potential ensuring discharge of chlorine ions and cathode potential not exceeding the potential of discharge of hydrogen ions. Device proposed for realization of this method has housing with cover; interior of housing is divided into anode and cathode spaces with anodes and cathodes located inside them, units for loading the initial materials and discharging pulp formed during leaching-out process and units for mixing and feeding the chlorine-containing gas; anode space is made in form of chamber and cathode chambers are located on its opposite sides; anode chamber walls contain cation-exchange membranes; stirring unit is provided with impeller located below lower edge of anodes; vertical fins are provided on inner surface of anode chamber at level of impeller.
EFFECT: increased rate of extraction of beneficial components from initial material into solution for further extraction of them from solution.
17 cl, 3 dwg, 1 tbl, 8 ex
FIELD: mining art; hydro-metallurgical processing of ores and concentrates; extraction of beneficial components by underground leaching, heap leaching, vessel leaching and tank leaching.
SUBSTANCE: proposed method includes preparation of material for leaching-out process, delivery of leaching solution, discharge, collection and reworking of productive solution; intensification of leaching-out process is performed through ultrasonic treatment of material which is preliminarily saturated with solution of reagent (or water)inert to beneficial component and dissolving harmful admixtures. After discharge of leaching solution (or water), beneficial component is leached-out by leaching solution till reduction of its concentration in productive solution corresponding to maximum level obtained during standard leaching-out process. Then periodic ultrasonic treatment of material is performed again at contact with leaching solution till concentration of beneficial component in productive solution gets equal to permissible level for reworking of this solution in settling plant. Periodicity of ultrasonic treatment is determined by special relationship; radiators are mounted in cylindrical cavities (wells) or on surface of material.
EFFECT: enhanced intensification and efficiency due to increased rate of extraction of beneficial components; reduced consumption of reagents.
5 cl, 3 dwg,1 ex
FIELD: metallurgy; production of platinum and palladium concentrates and silver from platinum-containing raw materials.
SUBSTANCE: proposed method includes sulphatizing roasting and/or sulphatizing of platinum-containing raw material at temperature of 200-600 C for 1-17 hours. Cinder is molten with sodium chloride at mass ratio of 1:(1-10) at temperature of 600-900 C; fusion cake is leached-out with water at mass ratio of fusion cake to water equal to 1: (1-10) at temperature of 80-90 C. After filtration of this pulp filtrate and residue are obtained; filtrate settles separating the silver concentrate in form of sediment of insoluble salt of silver chloride from liquid phase. Silver concentrate is washed with solution of concentrated hydrochloric acid and water at mass ratio of 1:10; leaching residue is washed with solution of concentrated hydrochloric acid and water at ratio 1:1, after which it is washed with water. Washing water is mixed with liquid phase obtained after separation of silver chloride from filtrate and sediment in form of platinum-palladium concentrate is let to settle; this sediment is separated by filtration and is washed with water.
EFFECT: complete primary extraction of platinum metals from platinum-containing raw material; reduced toxicity; reduced duration of process; reduced power requirements.
1 tbl, 1 ex
FIELD: sludge recovery from surface depositions of chemical equipment.
SUBSTANCE: invention relates to method for recovery of sludge containing platinum-group metals from equipment using platinum metal-based catalysts. Method includes treatment with aqueous solution of active chemical agent (e.g. sodium-ammonium-substituted ethylenediaminetetraacetic salts) while controlling pH value and removing sludge retained on treated surface with diluted aqueous solution of mineral salts or mixture thereof. pH value is adjusted at 2-10, preferably at 3-9 by adding of organic acid selected from group containing citric, oxalic, maleic, phthalic, adipic, glutaric, succinic acids or basic agents selected from sodium hydroxide, potassium hydroxide, sodium carbonate or potassium carbonate, and hydrochloric acid, sulfuric acid or phosphoric acid is used as mineral acid.
EFFECT: recovery platinum-group metal with improved yield.
4 cl, 1 tbl, 12 ex
FIELD: noble metal metallurgy, in particular method for gold content determination in natural solid organic materials such as divot, state coal, brown coal, and black coal.
SUBSTANCE: claimed method includes sampling the probe of starting material, grinding, mixing with massicot, smelting to form bullion, parting of gold-silver globule, weighting of gold sinterskin. Probe is sampled from starting natural solid organic material. Before smelting mixture is packaged in lead foil, established in full-hot scorifying dish, and padded with borax and table salt.
EFFECT: precise method for gold content determination in natural solid organic materials.
1 tbl, 1 ex
FIELD: precious metals technology.
SUBSTANCE: method comprises treatment of initial material with reagent solution under microwave irradiation to transfer precious metals into solution. Initial material is preliminarily subjected to mechanical activation during 5 to 120 min while maintaining ratio of mechanical power supplied to specific surface area of activated material within a range of 0.0133 to 25 W-kg·m2. Microwave treatment starts directly after mechanical activation using acid and/or oxidant to form slurry from activated material and reagent solution. Irradiation is carried out to boiling temperature. Acid and/or oxidant is selected from HCl and/or Cl2, HCl and/or H2O, HCl and/or Br2, HCl and/or NaClO3, HCl and/or HNO3, HF and HCl and/or NaClO3, mixtures of H2SO4 and HCl and/or H2O2, mixtures of HCl and HBr and/or H2O2, mixtures of HCl and HI and/or NaClO3 and J2, HCl and/or Cl2 and Br2.
EFFECT: increased degree of precious metal recovery.
3 cl, 13 ex
FIELD: waste water treatment and hydrometallurgy.
SUBSTANCE: invention relates to recovering palladium from nitric acid, nitric acid-hydrochloric acid, and nitric acid-fluoride-hydrochloric acid solutions used for etching parts and units of equipment for isotope separation chambers. Palladium is sorbed from solutions having nitric acid concentration 30 to 250 g/L with mixture of epoxypolyamine-type low-basicity anionite, containing alternating groups of secondary and tertiary amines, ethers, and alcohols, and high-basicity anionite with quaternary ammonium base groups, content of low-basicity anionite (e.g. AN-31) being 98-99% and that of high-basicity anionite (e.g. AV17*8) 1-2%. Thereafter, anionites are subjected to stepped combustion: first for 2-4 h at 350-400°C and then for 2-4 h at 950-1000°C to produce metallic palladium, which is cooled under vacuum or in an inert gas atmosphere.
EFFECT: increased selectivity of refining process removing polyvalent metal impurities and increased degree of recovery.
6 tbl, 5 ex