Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
  • C01D9/00—Nitrates of sodium, potassium or alkali metals in general
  • C01D9/08—Preparation by double decomposition
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
  • B01D61/42—Electrodialysis; Electro-osmosis ; Electro-ultrafiltration; Membrane capacitive deionization
  • B01D61/44—Ion-selective electrodialysis
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
  • B01D61/42—Electrodialysis; Electro-osmosis ; Electro-ultrafiltration; Membrane capacitive deionization
  • B01D61/44—Ion-selective electrodialysis
  • B01D61/46—Apparatus therefor
  • B01D61/50—Stacks of the plate-and-frame type
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
  • C01D9/00—Nitrates of sodium, potassium or alkali metals in general
  • C01D9/08—Preparation by double decomposition
  • C01D9/10—Preparation by double decomposition with ammonium nitrate
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
  • C01D9/00—Nitrates of sodium, potassium or alkali metals in general
  • C01D9/08—Preparation by double decomposition
  • C01D9/14—Preparation by double decomposition of salts of potassium with sodium nitrate
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2313/00—Details relating to membrane modules or apparatus
  • B01D2313/14—Specific spacers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2313/00—Details relating to membrane modules or apparatus
  • B01D2313/28—Specific concentration chambers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2313/00—Details relating to membrane modules or apparatus
  • B01D2313/30—Specific dilution or de-ionizing chambers

Definitions

• the invention concerns a method of production of potassium nitrate by means of electrodialysis, consisting in the exchange of ions between solution of potassium chloride and solution of ammonium nitrate, nitric acid or sodium nitrate.
• the invention also concerns a apparatus to perform this method.
• the produced potassium nitrate has a wide range of use: in agriculture as a fertilizer, in glassmaking and in production of explosives and pyrotechnics, in food-processing industry as a preservative or in pharmacy as an ingredient in toothpastes.
• KN0 3 Potassium nitrate
• NaN0 3 sodium nitrate
• HN0 3 nitric acid
• NNLN0 3 ammonium nitrate
• the method of production of potassium nitrate by means of electrodialysis contributes to resolving these disadvantages while keeping the progressive features of the electrolytic process.
• the principle of the invention consists in the fact that the exchange of ions between solution of potassium chloride and solution of ammonium nitrate, nitric acid or sodium nitrate occurs in electric field in a system of ion-exchange membranes, containing at least one sequence of anion-exchange membranes and cation-exchange membranes, alternating and creating at least four intermembrane spaces.
• solutions of the said chemical compounds flow in the following manner: solution of input potassium chloride flows in the first intermembrane space before the first anion- exchange membrane; solution of ammonium nitrate, nitric acid or sodium nitrate flows in the third intermembrane space between the first cation-exchange membrane and the second anion-exchange membrane.
• Solution of the main product - potassium nitrate - flows in the fourth intermembrane space between the second anion-exchange membrane and the second cation-exchange membrane, and solution of by-product - ammonium chloride, hydrochloric acid or sodium chloride - flows in the second intermembrane space between the first anion- exchange membrane and the first cation-exchange membrane.
• the concentrations of input solutions of potassium chloride and ammonium nitrate, nitric acid or sodium nitrate should be between 0.01 and 0.3 mol/L, and the concentration of output solutions of products - potassium nitrate and ammonium chloride, hydrochloric acid or sodium chloride - is higher than 1 mol/L.
• the operating temperature of solutions should range between 10 and 80 °C, preferably between 20 and 50 °C.
• the device to perform the method according to the invention consists of electrodes, between which there is a system of ion-exchange membranes, containing at least one sequence of anion-exchange membranes and cation-exchange membranes, alternating and creating at least four intermembrane spaces (CI, C2, Dl, D2) for solutions of input and output chemical compounds of the dialytic exchange of ions.
• Ion-exchange membranes should be of a homogeneous or heterogeneous type with the thickness of 0.1 to 1 mm and permselectivity of more than 90%, and between them there are spacers with the thickness of 0.1 to 2 mm, made of polymeric material to secure distribution and mutual non-mixing of solutions, and mechanical support of intermembrane spaces.
• the voltage between electrodes should range between 0.5 to 2 V on the sequence of four membranes - membrane quadruplet - with current density from 40 to 400 A/m 2 .
• Advantages of the method of obtaining potassium nitrate according to the invention consist in getting a highly purified K O 3 solution with a high level of conversion.
• the conversion itself occurs in the device of electrodialyser, made of noncorrosive components based on polymeric materials.
• Fig. 1 shows the functional scheme of the method of production of potassium nitrate by means of electrodialysis on one (basic) sequence of ion-exchange membranes
• Fig. 2 shows an example of arrangement of five sequences of four membranes - membrane quadruplets.
• the laboratory unit P EDR-Z/4x (by the MemBrain company) for electrodialysis- metathesis was used (hereafter only EDM).
• the unit contained 5 tanks with the volumes from 0.25 to 2 litres and 5 centrifugal pumps with magnetic inserts for circulation of solution in intermembrane spaces CI , C2, D_i, D2, created by sequences of anion-exchange membranes AMI, AM2 and cation-exchange membranes CM1, CM2 (for a scheme of one basic sequence, see Fig. 1).
• these were the following solutions: • diluate 1 - solution of input potassium chloride (KC1), flowing through the first intermembrane space Dl before the first anion-exchange membrane AMI,
• the unit was equipped with tools to measure flow rates, temperature, conductivity and pH for each individual circuit and with direct current supply with the output of 90 W.
• the EDM module was equipped with 11 cation-exchange membranes CM (RALEX CM-PES) and 10 anion-exchange membranes AM (RALEX AM-PES), alternating and creating 5 sequences of membranes (quadruplets) - see the scheme in Fig. 2. Each of these sequences was arranged according to Fig. 1. The effective area of one membrane was 64 cm 2 .
• the test was performed analogously and on a device similar to Example 1, but in a continuous manner with recycling (feed and bleed).
• the testing unit was supplemented with 2 external tanks for concentrated solutions of KCl and NH 4 N0 3 and 2 peristaltic pumps. Suction of peristaltic pumps was from the external tanks and outlet was connected to working circuits of KCl or ⁇
• solution of KCl was added with concentration 0.2 mol L.
• NH 4 N0 3 third intermembrane space D2 with concentration 0.03 mol/L
• solution of ⁇ 3 ⁇ 4 ⁇ 0 3 was added with concentration 0.2 mol/L.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Organic Chemistry (AREA)
• Water Supply & Treatment (AREA)
• Agronomy & Crop Science (AREA)
• Materials Engineering (AREA)
• Inorganic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Health & Medical Sciences (AREA)
• Urology & Nephrology (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Separation Using Semi-Permeable Membranes (AREA)
• Water Treatment By Electricity Or Magnetism (AREA)

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Citations (13)

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• 2013
  • 2013-03-28 CZ CZ2013-234A patent/CZ2013234A3/cs not_active IP Right Cessation
• 2014
  • 2014-03-21 WO PCT/CZ2014/000030 patent/WO2014154189A1/en not_active Ceased

Patent Citations (13)

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