Sodium, calcium and magnesium chlorates are still used as non-selective herbicides - for cleaning railway tracks, industrial sites, etc.; as defoliants in cotton harvesting. Acid decomposition of chlorates is used in the production of chlorine dioxide "in place" (on-site) for bleaching high-strength pulp.
K2 Unfortunately, a serious disadvantage of this method is the low quality of household disinfectants and bleaches. After softening the "mandatory standardization" policy, manufacturers of "whiteness" products began to use their own specifications, lowering the hypochlorite content in the product from the standard 5% wt. up to 3% or less. Now, to get the same amount of chlorate in a good yield would require not only using up a lot more "whiteness" but also removing most of the water from the solution. Perhaps the most convenient may be to pre-concentrate the "whiteness" by partial freezing.
Professional liquid neutralizers for marine effluents contain up to 40% sodium hypochlorite.
K3 The disproportionation of hypochlorite to chloride and chlorate proceeds at a high rate at pH
K4 Indeed, a high-efficiency power supply of significant power for electrolysis is half the success of the case and a topic for special discussion.
Here I would like to remind you of the need to follow the rules of electrical safety.
Works involving electrolysis on a significant scale are considered to be particularly dangerous with regard to electric shock. This is due to the fact that contact of the experimenter's skin with the conductive electrolyte is almost inevitable. Gassing at the electrodes causes the formation of corrosive electrolyte aerosols that can deposit on electrical components, especially when forced air cooling is used. The consequences can be very sad - from corrosion of metal parts and failure of the power supply to insulation breakdown with mains voltage on the cell and all the consequences for the experimenter.
Under no circumstances should high-voltage parts of the plant be installed in the immediate vicinity of the electrolytic cell. All components of the power source should be located at a sufficient distance from the cell and in such a way as to completely exclude both the ingress of electrolyte on them in the event of an accident of the cell, and the deposition of conductive aerosols. In this case, high-current wires from the source to the electrolyzer must have a sufficient cross section corresponding to the process current. All conductors (and their connections) directly connected to the mains must be hermetically sealed with moisture-resistant insulation.
Mandatory galvanic isolation of the cell from the mains. An ordinary transformer provides adequate insulation, but it is strictly forbidden to power the electrolyzer directly from autotransformers of the LATR type, etc., since in this case the electrolyzer may be directly connected to the phase wire of the network. However, LATR (or household autotransformer) can be used to regulate the voltage on the primary winding of the main transformer. You just need to make sure that the power of the LATR is not less than the power of the main transformer.
For long-term operation of the installation, protection of electronic components from overheating and short circuits would be useful. To begin with, it is quite possible to limit yourself to installing a fuse in the primary winding of the transformer for a current corresponding to its rated power. It is also reasonable to supply power to the cell through an appropriate fuse (preferably an adjustable electromagnetic release), bearing in mind that a short circuit in the cell is quite possible.
The question of the need to ground the installation in this case is not so simple. The fact is that in many residential premises, grounding is initially absent and it is not easy to arrange it on your own. In some cases, instead of grounding, cunning electricians organize "zeroing", connecting the ground bus and the network neutral directly at the consumer. In this case, the "grounded" device is directly connected to the current-carrying circuit of the network. Under our conditions, it can be recommended to give priority to the high-quality isolation of the electrolyzer from the network and the experimenter from the entire installation.
Safety rules should not be neglected for the reason that a long experiment in an amateur laboratory always attracts the attention of other people whose skills and behavior the experimenter cannot control. Be aware of those around you and work safely.
Cl(=O)=O]
sodium chlorate- inorganic compound, sodium metal salt and chloric acid with the formula NaClO 3 , colorless crystals, highly soluble in water.
Receipt
- Sodium chlorate is prepared by the action of chloric acid on sodium carbonate:
texvc not found; See math/README for setup help.): \mathsf(Na_2CO_3 + 2\ HClO_3\ \xrightarrow(\ )\ 2\ NaClO_3 + H_2O + CO_2\uparrow )
- or by passing chlorine through a concentrated sodium hydroxide solution when heated:
texvc not found; See math/README for setup help.): \mathsf(6\ NaOH + 3\ Cl_2\ \xrightarrow(\ )\ NaClO_3 + 5\ NaCl + 3\ H_2O )
- Electrolysis of aqueous solutions of sodium chloride:
texvc not found; See math/README for setup help.): \mathsf(6\ NaCl + 3\ H_2O \ \xrightarrow(e^-)\ NaClO_3 + 5\ NaCl + 3\ H_2\uparrow )
Physical properties
Sodium chlorate - colorless cubic crystals, space group P 2 1 3 , cell parameters a= 0.6568 nm, Z = 4.
At 230-255°C it passes into another phase, at 255-260°C it passes into a monoclinic phase.
Chemical properties
- Disproportionates when heated:
texvc not found; See math/README for tuning help.): \mathsf(10\ NaClO_3 \ \xrightarrow(390-520^oC)\ 6\ NaClO_4 + 4\ NaCl + 3\ O_2\uparrow )
- Sodium chlorate is a strong oxidizing agent; in the solid state, mixed with carbon, sulfur and other reducing agents, it detonates when heated or on impact.
Application
- Sodium chlorate has found application in pyrotechnics.
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Literature
- Chemical Encyclopedia / Ed.: Knunyants I.L. and others. - M .: Soviet Encyclopedia, 1992. - T. 3. - 639 p. - ISBN 5-82270-039-8.
- Handbook of a chemist / Editorial board: Nikolsky B.P. and others. - 2nd ed., corrected. - M.-L.: Chemistry, 1966. - T. 1. - 1072 p.
- Handbook of a chemist / Editorial board: Nikolsky B.P. and others. - 3rd ed., corrected. - L.: Chemistry, 1971. - T. 2. - 1168 p.
- Ripan R., Chetyanu I. Inorganic chemistry. Chemistry of metals. - M .: Mir, 1971. - T. 1. - 561 p.
| Chemical vessels | This article about inorganic matter is a stub. You can help the project by adding to it. |
An excerpt describing sodium chlorate
- Well, where did you "walk", Madonna Isidora? my tormentor asked in a mockingly sweet voice.“I wanted to visit my daughter, Your Holiness. But she couldn't...
I didn't care what he thought, or whether my "outing" made him angry. My soul hovered far away, in the amazing White City, which Easten showed me, and everything around seemed distant and miserable. But Caraffa, unfortunately, did not allow me to go into dreams for a long time ... Immediately sensing my changed mood, the "holiness" panicked.
– Did they let you into Meteora, Madonna Isidora? - Caraffa asked as calmly as possible.
I knew that in his soul he was simply “burning”, wanting to get an answer faster, and I decided to torment him until he told me where my father was now.
“Does it matter, Your Holiness?” After all, you have my father, whom you can ask everything, which is natural, I will not answer. Or have you not had enough time to interrogate him yet?
– I do not advise you to talk to me in such a tone, Isidora. How you intend to behave will largely depend on his fate. Therefore, try to be more polite.
– And how would you behave if instead of mine, your father turned out to be here, Holiness? .. – trying to change the topic that had become dangerous, I asked.
“If my father was a HERETIC, I would burn him at the stake!” - Caraffa answered quite calmly.
What kind of soul did this “holy” person have?!.. And did he even have one?
“Yes, I was in Meteora, Your Holiness, and I am very sorry that I will never get there again ...” I answered sincerely.
“Have you really been expelled from there too, Isidora?” Caraffa laughed in surprise.
“No, Holiness, I was invited to stay. I left on my own...
- It can not be! There is no such person who would not want to stay there, Isidora!
- Well, why not? And my father, Holiness?
I don't believe he was allowed to. I think he should have left. It's just that his time is probably over. Or the Gift wasn't strong enough.
It seemed to me that he was trying, by all means, to convince himself of what he really wanted to believe.
- Not all people love only themselves, you know ... - I said sadly. “There is something more important than power or strength. There is still love in the world...
Caraffa brushed me off like an annoying fly, as if I had just uttered some complete nonsense ...
- Love does not control the world, Isidora, well, but I want to control it!
– A person can do anything... until he starts trying, Your Holiness – I “bite” without restraining myself.
And remembering something that she definitely wanted to know, she asked:
– Tell me, Your Holiness, do you know the truth about Jesus and Magdalene?
– Do you mean that they lived in Meteora? I nodded. - Yes, of course! That was the first thing I asked them about!
– How is this possible?!.. – I asked dumbfounded. – Did you also know that they were not Jews? Caraffa nodded again. – But you don’t talk about it anywhere, do you? Nobody knows about it! And what about the TRUTH, Your Holiness?! ..
- Do not make me laugh, Isidora! .. - Caraffa laughed sincerely. You are a real child! Who needs your "truth"? .. The crowd that never looked for it?! .. No, my dear, Truth is needed only by a handful of thinking people, and the crowd should just "believe", well, what - it no longer has much values. The main thing is that people obey. And what is presented to them at the same time is already secondary. The TRUTH is dangerous, Isidora. Where the Truth is revealed, doubts appear, well, where doubts arise, a war begins... I am waging MY war, Isidora, and so far it gives me real pleasure! The world has always been based on a lie, you see... The main thing is that this lie should be interesting enough to be able to lead "narrow-minded" minds... And believe me, Isidora, if at the same time you start proving to the crowd the real Truth that refutes them “faith” is unknown in what, and you will be torn to pieces, this same crowd ...
– Is it really possible for such an intelligent person as Your Holiness to arrange such self-betrayal? .. You burn the innocent, hiding behind the name of the same slandered, and the same innocent God? How can you lie so shamelessly, Your Holiness?!..
Chlorates are salts of one of the oxygen acids of chlorine, chloric acid - HClO3. Perchloric acid and its salts, when heated, easily decompose with the release of oxygen, turning into salts of perchloric acid - perchlorates. All chlorates are more or less soluble in water. The solubility of sodium chlorate in water is 50.2% at 20° and 69.7% at 100°. In aqueous solutions, chlorates are extremely stable even in the presence of many oxidizing substances.[ ...]
Sodium chlorate can change the organoleptic qualities of water, giving it a bitter-salty taste. To establish the threshold concentrations of the studied salt in water by taste, several series of experiments were carried out according to the generally accepted method with aqueous solutions of sodium chlorate at temperatures of 20 and 60°. The results of the experiments are presented in table. one.[ ...]
Sodium chlorate is a white or yellowish crystalline powder that is ho-. It absorbs water well and decomposes when heated to 300°C.[ ...]
Sodium chlorate - low toxicity for warm-blooded animals, LD50 for rats 1.2 g per 1 kg, however, there have been cases of fatal poisoning of people abroad when sodium chlorate is used to control weeds. It acts on the blood, causes the breakdown of red blood cells and converts hemoglobin into methemoglobin. Clinic of poisoning: jaundice, vomiting of bile, gastrointestinal disorders, skin rashes, fever.[ ...]
Sodium chlorate is a white crystalline substance, Ty 248 ° C, density 7.49 g / cm3, decomposition begins at 265 ° C, freely soluble in water, ammonia, alcohol, glycerin, acetone, poorly - in hexane and toluene. [. ..]
Maximum allowable concentration of sodium chlorate in the air of the working area is 5 mg/m3.[ ...]
Our studies of sodium chlorate included acute and subacute toxicological experiments, as well as a chronic sanitary-toxicological experiment.[ ...]
To study the effect of sodium chlorate on the mineralization of organic pollution, several series of experiments were carried out to determine the dynamics of BOD under the influence of sodium chlorate concentrations of 20 and 100 mg/l. Experiments were carried out both with 5-day and 20-day duck incubation. The results of the experiments are presented in table. 2.[ ...]
In animals treated with sodium chlorate at a dose of 500 mg/kg, there were no changes in the morphological composition of the blood (number of erythrocytes, leukocytes, reticulocytes) that could be associated with exposure to sodium chlorate, and there were also no changes in hemoglobin content. , in the ratio of protein fractions of blood serum. The weight gain of the animals was the same as the weight gain of the control group.[ ...]
There is also a combined preparation containing sodium chlorate, borax and THA.[ ...]
Acute experiments to study the effect of sodium chlorate on the body of warm-blooded animals with a single oral administration were carried out on whites, mice, white rats and guinea pigs. The experiments used 50 mice, 24 rats and 30 guinea pigs. The substance was administered to animals in an aqueous solution on an empty stomach. The clinical picture of poisoning was characterized by severe shortness of breath, cyanosis of the tip of the nose and paws, tonic convulsions during the period of agony. These phenomena were especially pronounced in white mice, weaker in rats and very little in guinea pigs. Animals that received lower doses died with the same phenomena, but at a later date. The data from acute experiments were subjected to statistical processing according to the method of Miller and Teinterag. The lowest value of the ■ average lethal dose was observed in white mice (3600±705 mg/kg). In white rats and guinea pigs, it was approximately at the same level (respectively 6500±417 mg/kg and 6100±383 mg/kg).[ ...]
The product should consist mainly of sodium chlorate and be white or slightly colored crystals, free from foreign impurities or introduced modifying agents.[ ...]
The results of acute experiments allow classifying sodium chlorate as a moderately toxic substance and confirm the literature data that chlorate poisoning causes methemoglobinemia. It turned out that the highest level of methemoglobinemia reaches 4-6 hours after poisoning.[ ...]
In the US, defoliants containing sodium chlorate are common. To reduce the flammability of sodium chlorate, sodium polyborates or metaborates are added to preparations. The most widely used is sodium chlorate-pentaborate, containing 40% sodium chlorate and 60% sodium pentaborate.[ ...]
The determination is based on the reaction of sodium chlorate with benzidine chloride in a sulfuric acid medium and subsequent photometric measurement of the absorbance of the yellow-colored reaction product at 430 nm.[ ...]
Hydrazine is obtained by reacting ammonia with sodium chlorate.[ ...]
In the United States, sodium chlorate compounds with borates in ratios of 1: 4 are most widely used.[ ...]
The method is selective. Substances accompanying the preparation of sodium chlorite (sodium chlorate, etc.) do not interfere with the determination.[ ...]
The absence of death of animals during the experiment allows us to attribute sodium chlorate to non-cumulative substances.[ ...]
Summarizing the results of the subacute experiment, we can conclude that systematic administration of sodium chlorate can cause an increase in the level of methemoglobinemia, but this increase is insignificant, although there are individual fluctuations. An increase in the level of methemoglobinemia under the influence of high doses (at the level of 1/3 Obbo) is not accompanied by a red blood cell reaction or hemolysis. There was no effect of chlorate on the general condition of the body, on its growth.[ ...]
The ability to move through the tissues of the plant was established in sodium chlorate and ammonium sulfamate, although these drugs are toxic when applied to the soil.[ ...]
The study of the conditioned reflex activity of rats under the influence of sodium chlorate was carried out according to the method of developing temporary connections against the background of the action of chlorate in a Kotlyarevsky chamber with a Losev integrator. To select groups that were equivalent in terms of the characteristics of their nervous activity, a conditioned reflex to a positive sound signal (bell) was developed in all rats before exposure. At the same time, the rate of appearance and strengthening of the conditioned reaction, the magnitude of the latent period, the magnitude of the conditioned and unconditioned reactions, and the percentage of loss of the reflex were taken into account.[ ...]
Example 3. Oxidative delignification of aspen wood with sodium chlorate was studied in laboratory conditions. Wood in the form of shavings was subjected successively to oxidative treatment with sodium chlorate solution in the presence of hydrochloric acid and alkaline extraction with sodium hydroxide solution. Independent variables: X1 - concentration of sodium chlorate in solution, g/l (X!° = 50; = 6); X2 is the concentration of hydrochloric acid in the solution, g/l (X2° = 85; Ar = 15); Xs - temperature of oxidative treatment, °C (Xs ° = 70, Az = 5); X4 - duration of oxidative treatment, min (X4°= 180; A4 = 30); X5 - consumption of NaOH for extraction as a percentage of the original wood (X5° = 2.5; A5 = 0.5); Xa - extraction temperature, °C (X6° = 92; R6 = 8; X7 - extraction time, min (X7° = 30; = 10). As an output parameter, the example considers the yield of solid residue as a percentage of the original wood. Variables X-, varied in accordance with the plan DFE ti-ia 27 3 (/a PFE replica) with generating ratios: x5=x,xsx4;.x6 = x1x2xs; x7 = x.1x2x3x4.[ ...]
Experimental substantiation of the maximum permissible concentration of sodium chlorate in the water of reservoirs. VT Mizaev Experimental-toxicological materials for the study of the complex action of chemical agents polluting both water and air. SM Pavlenko Comparative evaluation of bromsulfalein test and other functional tests for the liver in conditions of subacute experimental hepatopathy. V. E. Miklashevsky, V. N. Tugarinova, I. A. Akundinova, A. N. Novikova, G. A. Savonicheva, G. G. Skobtsova.[ ...]
Summing up the results of sanitary and toxicological studies, we can say that sodium chlorate is a substance characterized by relatively low toxicity and does not have cumulative properties. Systematic administration of it in high doses (up to 73 OB50) does not cause the death of animals, but is manifested only by a slight increase in the amount of methemoglobin. At the same time, a day after the next administration of the substance, the amount of methemoglobin returns to normal. The latter fact indicates that in this case the body copes with the neutralization of the substance by the physiological mechanism of demethemoglobinization (K. S. Kosyakov, 1939).[ ...]
The difference in the values obtained has no practical significance, and the concentration of Sodium chlorate 20 mg/l can be recognized as a threshold in terms of the effect on the organoleptic properties of water.[ ...]
Application forms. Borax is used both in pure form and in mixtures, especially with sodium chlorate, reducing the risk of ignition of the latter (for example, 9 parts of borax plus 1 part of chlorate for soil sterilization) (Grigsby B. H. et al, Mich. [ ... ]
The data obtained indicate that a taste with an intensity of 1 point is imparted to water by sodium chlorate at a concentration of 21.9 mg/l at a temperature of 20° and at a concentration of 19 mg/l at a temperature of 60°.[ ...]
Salts of chloric acid, in particular sodium chlorate, can be used as a general herbicide. It is used in doses of 300-500 kg per 1 ha at a water consumption of 1500-2000 liters per 1 ha. However, the use of this herbicide is limited due to its toxicity to humans and animals, as well as its explosiveness and ability to cause corrosion of metals. Sodium chlorate itself is safe for plants, but in plant tissues it turns into toxic compounds - chlorites and hypochlorites. To avoid the threat of an explosion, calcium chlorate and magnesium chlorate are used - non-explosives.[ ...]
Of some interest is the formation of chlorine dioxide during the reduction of sodium chlorate (No. C103) with hydrochloric acid, obtained by electrolysis of sodium chloride at a temperature of 60 ° C.[ ...]
For the experiment, 20 white rats were taken (10 experimental, 10 control). The seed was made at the rate of 7s Sbbo (2200 mg/kg) of sodium chlorate daily for 30 days. Subsequently, the content of methemoglobin was determined 4.6 hours and 1 day after the first seeding, then on the 10th, 20th and 30th days of the experiment. The determination of methemoglobin a day after the start of the experiment was carried out before the introduction of the next dose of sodium chlorate, subsequent determinations - 4-5 hours after the next injection of salt.[ ...]
When conducting a subacute toxicological experiment, we set the task, firstly, to study the ability of sodium chlorate to accumulate in the body, and secondly, to find out the features of the effect of this substance when systematically introduced into the body compared to acute poisoning and, on the basis of this, select tests that were it would be expedient to test in the conditions of a chronic sanitary-toxicological experiment.[ ...]
Initially, inorganic substances were used for chemical weed control: copper sulfate, iron sulfate, sodium arsenite, sodium chlorate, sulfuric acid, etc.[ ...]
Figure 5 shows the technological scheme for obtaining CO2 by the Matheson method. Concentrated sulfuric acid and sodium chlorate solution are fed into the primary reactor. A mixture of 80 g with air is pumped into the lower part of the reactor. The contents of the reactor are cooled to a temperature of 40 °C using a water jacket. Chlorine dioxide is blown out of the solution with air and sent to the absorber, where it is absorbed by chilled water. The resulting chlorine dioxide solution is collected at the bottom of the absorber. The liquid from the primary reactor flows into the secondary reactor, where unreacted chlorate interacts with 80g. The spent liquid from the secondary reactor is purged with clean air to separate the remaining dissolved CO2 and is pumped out into the tank for the acidic reactor residue.[ ...]
Application forms. For weed control, some specifications call for 98% NaCl03, but formulations are commercially available in which sodium chlorate is mixed with other salts, such as sodium chloride, to reduce flammability.[ ...]
This method eliminates the formation of chlorine as a by-product and significantly reduces the amount of sodium sulfate forming compared to other methods based on the use of sodium chlorate.[ ...]
Tests of desiccants in wheat crops carried out in Primorsky Krai, the Western Urals and other regions of the country showed that magnesium and calcium chlorates are the most effective. Of the large number of desiccants tested in Japan, sodium chlorate proved to be the most acceptable. In many countries, reglolon, which is a fast-acting effective drug, is being tested for this purpose, however, in some cases, small residues of reglolon (0.05-0.07 mg / kg) were found in the grain. The drug was not found in flour and bran.[ ...]
The liver, kidney and spleen of experimental animals were examined pathomorphologically. At the same time, only in some animals treated with sodium chlorate at a dose of 500 mg/kg, accumulations of macrophages filled with pigment granules were found in the spleen, giving a positive reaction for iron when stained according to Pearls (hemosiderin). In animals treated with sodium chlorate at doses of 1 and 10 mg/kg, as well as in control animals, macrophages containing hemosiderin are found in units not in all fields of view. In other organs, no morphological changes that could be attributed to the influence of sodium chlorate were noted. These data allow us to conclude that chronic exposure to sodium chlorate at a dose of 500 mg/kg can cause moderate hemolysis.[ ...]
The production of chlorine dioxide by the Holst method, first mastered in our country at the Bratsk CPP, takes place in one reactor, into which a solution of sulfuric acid and sodium chlorate are periodically fed from a diluent. The use of chlorate does not exceed 88-89%.[ ...]
The electrochemical production of white is easier to implement using baths with diaphragms. In such baths, a lead salt solution is obtained in the anode space, and a sodium hydroxide solution is obtained in the cathode space. In a special apparatus, anolyte and catholyte are mixed while passing carbon dioxide. White lead precipitates and sodium chlorate is regenerated.[ ...]
Warehouses are categorized according to the fire hazard of the materials they contain. So, category A includes: warehouses of flammable liquids, turpentine, odorant sulfane, solvents for varnishes, alcohol varnishes and nitro-varnishes. Warehouses of liquid sodium chlorate and oxygen belong to category B. Warehouses for wood chips, reeds, straw, waste paper, rags and other combustible materials belong to category C, and warehouses of non-combustible materials - to category D.
Also registered with: USA
Basic information:
| Broad spectrum, systemic that travels to all parts of the weed. Phytoxic to all businesses. |
| White powder |
Release:
sodium chlorate: behavior in the environment
| Index | Meaning | Explanation | ||
| Solubility in water at 20 o C (mg/l) | 650000 A5 High||||
| Solubility in organic solvents at 20 o C (mg/l) | Insoluble A5 - Most organic Solvents -||||
| Melting point (o C) | 255A5-||||
| Boiling point (o C) | Decomposes to boil A4 -||||
| Decomposition temperature (o C) | 260A3-||||
| Flash point (o C) | Flammability is not high A5 -||||
| Partition coefficient in octanol/water at pH 7, 20 o C | P: 1.26 X 10 -03 Calculated -||||
| Specific Gravity (g/ml) / Specific Gravity | 2.499 L3-||||
| Dissociation constant (pKa) at 25 o C | -2 A4 -||||
| Note: Very strong acid | ||||
| Vapor pressure at 25 o C (MPa) | 5.2 X 10 -06 A2 Intermediate state||||
| Henry's law constant at 25 o C (Pa * m 3 / mol) | 5.2 X 10 -09 A3 - Not volatile||||
| Henry's law constant at 20 o C (dimensionless) | 3.50 X 10 -16 Calculated Not volatile||||
| Decay period in soil (days) | DT50 (typical) 200 F3 Stable||||
| According to laboratory studies of the European Union, DT50 is 46.7-314.6 days | ||||
| Aqueous photolysis DT50 (days) at pH 7 | Value: Stable A5 Stable||||
| - | ||||
| Aqueous hydrolysis of DT50 (days) at 20 o C and pH 7 | Value: Stable A5 Very stable||||
| Not sensitive to pH | ||||
| Water precipitation DT50 (days) | - - -||||
| Water phase only DT50 (days) | - - -||||
| GUS washout potential index | 6.90 Calculated High Leaching||||
| Concentration growth index in groundwater SCI (µg/l) at an application rate of 1 kg/ha (l/ha) | Value: 4.51 X 10 +01 Calculated -||||
| - | ||||
| Potential for particle bound transport index | - Average is calculated||||
| Koc - organic carbon partition coefficient (ml/g) | 10 F3 Very mobile||||
| pH resistance: | ||||
| Note: | ||||
| Freundlich adsorption isotherm | kf:-- | -|||
| - | ||||
| Maximum UV absorbance (l/(mol*cm)) | - - -||||
sodium chlorate: ecotoxicity
| Index | Meaning | Source / Qualitative indicators / Other information | Explanation | |
| Bioconcentration factor | BCF:-- | -|||
| Bioaccumulative potential | - Calculated Low||||
| LD50 (mg/kg) | > 5000 A5 Rat Low||||
| Mammals - Short term food NOEL | (mg/kg): -- | -|||
| Poultry - Acute LD50 (mg/kg) | 2510 A5 Mallard Duck Low||||
| Birds - Acute toxicity (CK50 / LD50) | - - -||||
| Fish - Acute 96 hour CK50 (mg/l) | 10000 G2 Unknown species Low||||
| Fish - Chronic 21 day NOEC (mg/l) | 500 A5 Danio rerio -||||
| Aquatic Invertebrates - Acute 48 hour EC50 (mg/L) | 919.3 A5 Short||||
| Aquatic Invertebrates - Chronic 21 day NOEC (mg/L) | 500 A5 Daphnia magna (Daphnia large, Water flea large) -||||
| Aquatic crustaceans - Acute 96 hour CK50 (mg/l) | - - -||||
| Bottom microorganisms - Acute 96 hour CK50 (mg/l) | - - -||||
| NOEC , static, Water (mg/l) | - - -||||
| Bottom microorganisms - Chronic 28 day NOEC , Sedimentary rock (mg/kg) | - - -||||
| Aquatic plants - Acute 7 day EC50 , biomass (mg/l) | 134 A5 Lesser duckweed Short||||
| Algae - Acute 72 hour EC50 growth (mg/l) | 1595 A5 Green algae (Scenedesmus subspicatus) Short||||
| Algae - Chronic 96 hour NOEC , growth (mg/l) | - - -||||
| Bees - Acute 48 hour LD50 (mcg/individual) | > 75 A5 Oral Moderate||||
| Earthworms - Acute 14-day CK50 (mg/kg) | > 750 A5 Moderate||||
| Soil Worms - Chronic 14-Day Maximum Inactive Concentration, Reproduction (mg/kg) | - - -||||
| Other Arthropods (1) | LR50 (g/ha): 84.4 A5 predatory mite Moderately hazardous at 1 kg/ha||||
| Other Arthropods (2) | LR50 (g/ha): 250.6 A5 Rider Moderately hazardous at 1 kg/ha||||
| Soil microorganisms | Mineralization of nitrogen: -47Action (%)||||
| Available data on the mesoworld (mesocosm) | NOEAEC mg/l: - - -||||
sodium chlorate: human health
Main characteristics:
| Index | Meaning | Source / Qualitative indicators / Other information | Explanation | |
| Mammals - Acute oral LD50 (mg/kg) | > 5000 A5 Rat Low||||
| Mammals - Dermal LD50 (mg/kg body weight) | > 2000 A5 Rat -||||
| Mammals - Inhalation CK50 (mg/l) | > 3.9 A5 Rat -||||
| ADI - acceptable daily dose (mg / kg body weight per day) | Not defined A5 -||||
| ARfD - average daily intake (mg/kg body weight per day) | Not defined A5 -||||
| AOEL - tolerable systemic exposure level for an operator | 0.35 A5 Rat, SF=200 -||||
| Skin absorption (%) | - - -||||
| Hazardous Substances Directive 76/464/EC | - - -||||
| Types of restrictions | - - -||||
| by category | General:||||
| , | ||||
| Examples of European | ||||
The invention relates to the production of sodium chlorate, widely used in various industries. The electrolysis of sodium chloride solution is carried out first in chlorine diaphragm cells. The resulting chloride-alkali solutions and electrolytic chlorine gas are mixed to form a chloride-chlorate solution. The resulting solution is mixed with the mother liquor of the crystallization stage and sent to non-diaphragm electrolysis, followed by evaporation of chloride-chlorate solutions and crystallization of sodium chlorate. The products of diaphragm electrolysis can be partly diverted to obtain hydrochloric acid from chlorine gas for acidification of chlorate electrolysis and the use of chloride-alkali solutions for irrigation of sanitary columns. The technical result is a reduction in power consumption and the possibility of organizing autonomous production. 1 z.p.f.
The invention relates to the production of sodium chlorate, widely used in various industries. World production of sodium chlorate reaches several hundred thousand tons per year. Sodium chlorate is used to produce chlorine dioxide (bleach), potassium chlorate (Bertolet salt), calcium and magnesium chlorates (defoliants), sodium perchlorate (an intermediate for the production of solid rocket fuel), in metallurgy during the processing of uranium ore, etc. A known method for producing sodium chlorate by a chemical method, in which solutions of sodium hydroxide are subjected to chlorination to obtain sodium chlorate. According to its technical and economic indicators, the chemical method cannot compete with the electrochemical method, therefore, it is practically not used at present (L.M. Yakimenko "Production of chlorine, caustic soda and inorganic chlorine products", Moscow, from "Chemistry", 1974, p. .366). A known method for producing sodium chlorate by electrolysis of a sodium chloride solution in a cascade of non-diaphragm electrolyzers to obtain chloride-chlorate solutions, from which crystalline sodium chlorate is isolated by evaporation and crystallization (K. Wihner, L. Kuchler "Chemische Technologie", Bd.1, "Anorganische Technologie", s.729, Munchen, 1970; L.M. Yakimenko, T. A. Seryshev "Electrochemical synthesis of inorganic compounds, Moscow, "Chemistry", 1984, pp. 35-70). This method is the closest The main technological stage, diaphragmless electrolysis of sodium chloride solutions, proceeds with a current output of 85-87%. hydrochloric acid Before entering the stage of isolation of the solid product, the electrolyte is alkalized to an excess of alkali of 1 g/l with the addition of a reducing agent to destroy the corrosive sodium hypochlorite, always present in the products of electrolysis. A side anode process in the electrolysis of chloride solutions is the release of Cl 2 , which not only reduces the current efficiency, but also requires the purification of electrolysis gases in sanitary columns irrigated with an alkali solution. The implementation of the process is therefore associated with a significant consumption of hydrochloric acid and alkali: 1 ton of sodium chlorate consumes ~120 kg of 31% hydrochloric acid and 44 kg of 100% NaOH. For the same reason, chlorate production is organized where there is chlorine electrolysis, which supplies caustic soda and electrolytic chlorine and hydrogen for the synthesis of hydrochloric acid, while there is often a need for autonomous production of sodium chlorate at points remote from chlorine production. But even where chlorine production and chlorate electrolysis are located nearby, when chlorine electrolysis is stopped and turned off for one reason or another, a forced shutdown of chlorate electrolysis occurs. Thus, the known method has significant drawbacks: high energy costs (not very high current efficiency ) and the impossibility of organizing autonomous production. The objective of the invention is to create a method for producing sodium chlorate by electrolysis of sodium chloride solutions with reduced energy costs. The problem is solved by the proposed method, in which, first, sodium chloride is processed in chlorine diaphragm electrolyzers to produce gaseous chlorine gas and electrolytic lye compositions of 120-140 g/l NaOH and 160-180 g/l NaCl, which are then fully or partially subjected to interaction between itself with obtaining a chloride-chlorate solution of 50-60 g/l NaClO 3 and 250-270 g/l NaCl, sent to bezdiaphragm electrolysis. The process of chlorate non-diaphragm electrolysis is carried out by acidification with hydrochloric acid. The resulting chlorate solution, which also contains sodium chloride, is sent to the stage of evaporation, and then crystallization of the chlorate. The mother liquor from the crystallization stage, together with the products of the interaction of alkali and chlorine from diaphragm electrolysis, is sent to non-diaphragm chlorate electrolysis. Before being fed to the stage of isolation of the solid product, the electrolyte is alkalized to an excess of alkali of 1 g/l with the addition of a reducing agent to destroy sodium hypochlorite. With partial withdrawal of electrolysis products from chlorine diaphragm electrolyzers, chlorine is used to produce hydrochloric acid, which is used to acidify chlorate electrolysis, and alkali is used to irrigate sanitary columns during the purification of electrolysis gases. With this scheme, 30-35 g of sodium chloride out of 300-310 g contained in each liter of the initial solution is processed under the conditions of chlorine electrolysis. Such a scheme causes a reduction in energy costs, because. the current efficiency of chlorine electrolysis is higher, and the voltage on the electrolyzers is lower than in chlorate electrolysis, and when partially electrochemically oxidizing sodium chloride to chlorate under conditions of chlorine electrolysis, the performance of the whole process improves. In addition, when using the described scheme, the cost of electrolysis cooling is reduced, since chlorine electrolyzers do not need cooling. Note that a deeper activation of chloride under the conditions of chlorine electrolysis than specified (about 10%) leads to the impossibility of balancing the technological scheme for chlorides, chlorates and water and therefore does not make sense. Within the framework of the proposed scheme, it is possible to obtain an additional effect when applying solutions with an increased NaClO 3 concentration to chlorate electrolysis, obtained from alkali solutions more concentrated in NaOH than diaphragm lye, for the chlorination of which chlorine containing inerts can be utilized. Electrolytic chlorine electrolysis can be mixed with chlorine gas not completely, but partially. At the same time, part of the electrolytic lye from diaphragm electrolysis, which is not directed to chlorination, is assigned for use in sanitary columns, and the equivalent part of electrolytic chlorine can be used for the synthesis of hydrochloric acid. The direction of electrolytic lye from diaphragm electrolyzers to sanitary columns, and electrolytic chlorine gas to produce hydrochloric acid solves the problem of autonomous chlorate production, since the supply of alkali and acid from outside will no longer be required. The proportion of sodium chloride processed in chlorine electrolyzers is determined by whether the resulting products will be used only to obtain chloride-chlorate liquors as a result of their interaction, after mixing with the mother liquor from the crystallization stage to non-diaphragm electrolysis, or the electroliquor of chlorine electrolyzers will be used only for alkalization, and electrolytic chlorine - for the synthesis of perchloric acid for acidification in the chlorate electrolysis circuit, or some of the products will be used in one direction, and some in the other. The advantages of the proposed method are: 1) reduction of energy costs due to the initial stage of electrolysis with a high current output and at a lower voltage than in conventional chlorate electrolysis: current output 92-94% and voltage 3.2 V in chlorine electrolysis against 85 -90% and 3.4 V and above, respectively, in chlorate; 2) the possibility of obtaining simultaneously with the main product - sodium chlorate - alkaline solutions required by the technological scheme for alkalizing and irrigation of sanitary columns; 3) the possibility of using chlorine produced in chlorine electrolyzers to produce hydrochloric acid in situ for acidification of chlorate electrolysis. Example In an experimental cell, a chlorine diaphragm electrolysis of a sodium chloride solution with a concentration of 300 g/l is carried out on ruthenium oxide anodes at a current density of 1000 A/m 2 and a temperature of 90 o C. The obtained electrolytic liquors containing 140 g/l NaOH and 175 g/l NaCl, mixed with anode chlorine gas and receive chloride-chlorate solution composition of 270 g/l NaCl and 50 g/l NaClO 3 . This solution is then fed to a non-diaphragm chlorate electrolysis carried out in a cascade of 4 electrolyzers with ruthenium oxide anodes at a current density of 1000 A/m 2 and a temperature of 80 o C to obtain a final solution of the following composition: 105 g/l NaCl and 390 g/l NaClO 3 . Thus, from one 1 liter of the initial chloride solution, taking into account a 10% decrease in the volume of the solution due to the entrainment of water vapor with electrolysis gases and the evaporation of 355 g of sodium chlorate, of which 50 g (14.1%) was obtained after mixing the products of chlorine diaphragm electrolysis , and 305 (85.9%) were produced in the process of chlorate electrolysis. The voltage across the chlorine cell was 3.3 V with a current output of 93%. The average voltage across the chlorate cell was 3.4 V with a current output of 85%. Specific power consumption W (kWh/t) calculated according to the experimental data using the formula W = 1000E/mBT, where E is the cell voltage (B); m - electrochemical equivalent (g/Ah); BT - current output in fractions of a unit,
amounted to 2517 kWh / t for chlorine electrolysis, and 5996 kWh / t for chlorate electrolysis, which, taking into account the share of chlorate produced as a result of mixing chlorine electrolysis products, gives 5404.9 kWh / t. Electricity consumption without the use of a chlorine electrolyzer was 6150 kWh/t at the same plant. Thus, the reduction in energy costs amounted to 12.1%.
Claim
1. A method for producing sodium chlorate by electrolysis of a sodium chloride solution, followed by evaporation of chloride-chlorate solutions and crystallization of sodium chlorate with the return of the mother liquor of the crystallization stage to the process, characterized in that, first, the electrolysis of a solution of sodium chloride is carried out in chlorine diaphragm electrolyzers to obtain alkali-chloride solutions and electrolytic chlorine gas, which are mixed to obtain a chloride-chlorate solution and, after mixing with the mother liquor of the crystallization stage, are sent to non-diaphragm electrolysis. 2. The method according to claim 1, characterized in that the products of diaphragm electrolysis are partly removed to obtain hydrochloric acid from chlorine gas for acidification of chlorate electrolysis and the use of chloride-alkali solutions for irrigation of sanitary columns.
