Showing papers on "Sodium chlorate published in 2013"

Fast and Effective Gold Leaching from a Desulfurized Gold Ore Using Acidic Sodium Chlorate Solution at Low Temperature

Abstract: The effects of various leaching conditions for gold extraction from sulfur-containing gold ore using acidic sodium chlorate solution were investigated. The contents of gold and sulfur from the ore were 55.7 g/ton and 11.67 wt %, respectively. It was found that the presence of sulfur greatly inhibited gold extraction. The optimal desulfurization temperature, desulfurization time, leaching temperature, leaching time, adding rate of NaClO3, HCl concentration, weight ratio of NaCl to sample, agitation speed, and ratio of liquid lixiviant volume to solid sample weight were 650 °C, 2 h, 40 °C, 45 min, 0.25 mL/min, 3 M HCl, 0.2, 250 rpm, and 10, respectively. The gold extraction percentage and the weight loss percentage of the sample were 97% and 8.8%, respectively, under these optimal conditions. Gold leaching by this method was very fast and effective, and the temperature was low. These characteristics made it possible to apply this method in continuous operation mode in industry.

Sodium hypochlorite pentahydrate crystal and method for manufacturing the same

Abstract: Disclosed is a sodium hypochlorite pentahydrate crystal having a reduced content of sodium chlorate, which is considered to be harmful to health, and a method for producing the same. A sodium hypochlorite pentahydrate crystal has a sodium chlorate content of 200 ppm or less. The method for producing sodium hypochlorite pentahydrate crystals according to the present invention includes a first step of reacting a sodium hydroxide aqueous solution with chlorine gas to obtain a mother liquor, and a step of solid-liquid separating sodium chloride from the mother liquor. 2 steps, a third step of adding seed crystals to the mother liquor set to a predetermined cooling start temperature, and sodium hypochlorite 5 by cooling the mother liquor at a cooling rate of 1 to 20 ° C./hour to a predetermined cooling end temperature. A fourth step of precipitating hydrate crystals and a fifth step of solid-liquid separation of sodium hypochlorite from sodium hypochlorite pentahydrate crystals are provided. [Selection] Figure 1

Preparation of Chlorine Dioxide by Electrocatalytic Reduction of Sodium Chlorate

Abstract: Preparation of chlorine dioxide by electrocatalytic reduction of sodium chlorate with Ti/IrO2 anode and Ti cathode was studied in a three-electrode cell without any diaphragm but with a sandwich bath by galvanostatic electrolysis. Classic iodometry was used to determine the concentration of ClO2 in the electrolyte. The change of space-time yield with current density, the concentration of H2SO4, the concentration of NaClO3, reaction temperature and electrolysis time were studied through single factor experiment in order to determine the optimal conditions of electrolysis. It shows that the optimal conditions of ClO2 preparation by electrocatalytic reduction of sodium chlorate were: i=60 mA/cm2, [H2SO4]=4.5 mol/L, [NaClO3]=1.0 mol/L, T=30 °C, t=30 min. Under these conditions, the space-time yield of ClO2 reached 1.50 mg/L·s.

Method for producing chlorine dioxide

Abstract: The present invention provides a method for producing chlorine dioxide by reducing sodium chlorate with a reducing agent in the presence of a strong acid comprising feeding ammonium salt to the reactor to produce also chloramine. The present invention also provides a method for disinfecting water.

Alloys of the type fe3alta(ru) and use thereof as electrode material for the synthesis of sodium chlorate or as corrosion resistant coatings

Abstract: Disclosed is an alloy of the formula: Fe3-xAl1+xMyTzTat wherein M represents at least one catalytic specie selected from the group consisting of Ru, Ir, Pd, Pt, Rh, Os, Re and Ag; T represents at least one element selected from the group consisting of Mo, Co, Cr, V, Cu, Zn, Nb, W, Zr, Y, Mn, Cd, Si, B, C, O, N, P, F, S, CI, Na and Ti; and Ta represents tantalum. Such an alloy can be used as an electrode material for the synthesis of sodium chlorate. It can also be used as a coating for protection against corrosion.

Preparation method of sodium chlorite

Abstract: The invention discloses a preparation method of sodium chlorite The preparation method comprises the following steps of (1) enabling sodium chlorate solution to react with hydrochloric acid to generate chlorine dioxide gas and chlorine; (2) leading chlorine dioxide gas and chlorine into sodium chlorite solution to further react, so as to generate chlorine dioxide gas; (3) leading the chlorine dioxide gas into sodium hydroxide solution, and adding hydrogen peroxide to react, so as to generate sodium chlorite at the same time; (4) crystallizing and drying sodium chlorite prepared in the step (3) to obtain a final product, wherein the concentration of the sodium chlorate solution in the step (1) is 25-33%, the concentration of hydrochloric acid solution in the step (1) is 31%, and the molar ratio of the hydrochloric acid to chlorous acid in the step (1) is (1-15) to 2 The preparation method of sodium chlorite disclosed by the invention does not utilize concentrated sulfuric acid of which the concentration is over 95%, is easy in control of the reaction process, not drastic in reaction, higher in safety coefficient, low in cost, and suitable for industrial large-scale application at the same time

Hydrometallurgical Pretreatment Process for the Recovery of Valuable Metals from the Lead Anode Slime

Abstract: After stacking pre-oxidation treatment, lead anode slime was leached in sulfuric acid added with sodium chloride and oxidant of sodium chlorate. The leaching rates of As, Te, Sb, Bi and Cu are more than 98% with potential controlled at 500mV. And noble metals are left in the residue, which are separated from the base metals effectively. Through cooling and crystallizing out arsenate, the solution is reduced with potential controlled. According to reducing slag, the recovery rate of Te is 96.52%. Sb is recovered by neutralizing hydrolysis and the recovery rate is 95.2%. By the effect of iron powder, As, Bi and Cu are entirely reduced with the recovery rates of Bi and Cu to be 91.56% and 83.49%, respectively. The total recovery of As from the crystalline product and reducing slag achieves 91.56%.

Method for producing chlorine dioxide

Abstract: The present invention provides a method for producing chlorine dioxide by reducing sodium chlorate with a reducing agent in the presence of a strong acid comprising feeding ammonium salt to the reactor to produce also chloramine. The present invention also provides a method for disinfecting water.

Effect of intravenous or oral sodium chlorate administration on the fecal shedding of Escherichia coli in sheep.

Abstract: The effect of gavage or intravenous (i.v.) administration of sodium chlorate salts on the fecal shedding of generic Escherichia coli in wether lambs was studied. To this end, 9 lambs (27 ± 2.5 kg) were administered 150 mg NaClO3/kg BW by gavage or i.v. infusion in a crossover design with saline-dosed controls. The crossover design allowed each animal to receive each treatment during 1 of 3 trial periods, resulting in 9 observations for each treatment. Immediately before and subsequent to dosing, jugular blood and rectal fecal samples were collected at 4, 8, 16, 24, and 36 h. Endpoints measured were fecal generic E. coli concentrations, blood packed cell volume (PCV), blood methemoglobin concentration, and serum and fecal sodium chlorate concentrations. Sodium chlorate had no effects (P > 0.05) on blood PVC or methemoglobin. Fecal generic E. coli concentrations were decreased (P 0.05). At 8 h, serum chlorate concentrations of gavaged lambs were greater (P < 0.05) than in i.v.-dosed lambs. Serum chlorate data are consistent with earlier studies indicating very rapid transfer of orally dosed chlorate to systemic circulation, and fecal chlorate data are consistent with earlier data showing the excretion of low to marginal concentrations of sodium chlorate in orally dosed animals. Efficacy of sodium chlorate at reducing fecal E. coli concentrations after i.v. infusion suggests that low concentrations of chlorate in gastrointestinal contents, delivered by biliary excretion, intestinal cell sloughing, or simple diffusion, are effective at reducing fecal E. coli levels. Alternatively, chlorate could be eliciting systemic effects that influence fecal E. coli populations.

Kinetics of the Reaction for Generation of Chlorine Dioxide from Sodium Chlorate and Hydrochloric Acid

Abstract: Based on the mechanism of ClO3-/Cl- reaction system, the kinetics for reaction of sodium chlorate and hydrochloric acid to generate ClO2 was studied. The rate equation of this reaction system was deduced and simplified as a formula with mixed-order (combination of first-order and second-order) towards ClO3-. This rate formula indicates that the initial rate of the reaction is the first-order with respect to ClO3-, and the reaction rate is the second-order with respect to ClO3- when [ClO3-] becomes close to zero. The rate constants of the first-order were determined as 0.0168s-1(30°C), 0.0221s-1(40°C), and 0.0279s-1(50°C), respectively, and that of the second-order were obtained for 0.0019L·mol-1·s-1(30°C), 0.0028L·mol-1·s-1(40°C), and 0.0060L·mol-1·s-1(50°C), respectively. The results of statistic test prove that the rate formula obtained in this work is credible.

Removing perchlorate from concentrated salt solutions using amphoteric ion-exchange resins

Abstract: FIELD: chemistry.SUBSTANCE: invention relates to a method of reducing concentration of perchlorate in an aqueous concentrated multi-component sodium chlorate solution primarily containing sodium chlorate. The method involves treating said sodium chlorate solution with an amphoteric resin to form adsorbed perchlorate on the resin which contains multiple anions and a perchlorate depleted solution; and removing said perchlorate depleted solution.EFFECT: selective method of separating perchlorate from concentrated solutions while ensuring cheap removal thereof without using chemical agents.24 cl, 5 tbl, 4 ex, 7 dwg

Method for digesting waste rhodium catalyst from olefin hydroformylation reaction

Abstract: The invention relates to a method for digesting a waste rhodium catalyst from an olefin hydroformylation reaction, which is characterized by comprising the following steps of: removing high-boiling-point organic matter from a waste rhodium catalyst discharged from an olefin hydroformylation reaction device and having the rhodium mass content of 0.01-0.1% through reduced pressure evaporation to obtain a rhodium-contained residue with the rhodium mass content of 4-10%; after adding concentrated sulfuric acid into the concentrated rhodium-contained residue for full carbonization, adding an alkali metal chlorate solid into the system, and controlling the temperature in the range of 160-220 DEG C during the adding process until the system solution is clear and transparent. At the moment, the organic matter is digested and removed in the form of carbon dioxide, and rhodium exists in the acid solution in the form of soluble salt. During the last step, the mass ratio of the alkali metal chlorate solid to the rhodium-contained residue is 5:1-30:1, and the alkali metal chlorates comprise sodium chlorate, potassium chlorate or a mixture of sodium chlorate and potassium chlorate.

Energy-saving device of chlorate electrolysis system

Abstract: The utility model discloses an energy-saving device of a chlorate electrolysis system. The energy-saving device of the chlorate electrolysis system is characterized by comprising the chlorate electrolysis system and a sodium chlorate crystallization system, wherein a heat exchanger is arranged between the chlorate electrolysis system and the sodium chlorate crystallization system; and a heat exchange pump is arranged between the chlorate electrolysis system and the heat exchanger, and another heat exchange pump is also arranged between the sodium chlorate crystallization system and the heat exchanger. Compared with the prior art, the technological requirements and characteristics of two procedures are combined; heat generated by the electrolysis system is transmitted to the crystallization system; and the heat generated in the electrolysis process is fully utilized. Therefore, the targets of saving energy and reducing the consumption are achieved.

Selection of nanocomposite reactive materials for using in oxygen and hydrogen generators

Abstract: 4Gas-generating solid compositions usually include a compound that decomposes at high temperatures and an energetic additive that provides heat for self-sustained combustion. The present paper investigates the feasibility of using nanocomposite reactive materials produced by arrested reactive milling as energetic additives in oxygen and hydrogen generators. In such reactive materials, components are mixed at the scale of about 100 nm, but are not chemically bound. Thermodynamic calculations of the adiabatic flame temperature and combustion products have been conducted for the mixtures of sodium chlorate and ammonia borane with various reactive compositions. Analysis of the obtained results indicates which additives are the most promising. Experiments with sodium chlorate/iron mixtures, ignited with a hot wire technique, have shown a reasonable agreement with thermodynamic calculations. An experimental facility for laser ignition of gas-generating compositions has been constructed. The facility involves infrared video recording and mass-spectrometry.

Oxidation leaching method and system

Abstract: The invention provides an oxidation leaching method which comprises the steps of 1) smashing a raw material, and mixing with sodium chlorate, potassium chlorate or potassium permanganate, 2) adding water and filling oxygen-bearing gas into a sealed system, and igniting with a combustible, 3) stopping filling the oxygen-bearing gas, spraying water mist into a reaction mixture and filling chlorine or oxygen for 20-600min, 4) stopping spraying the water mist till the reaction mixture does not generate steam any longer, adding an inorganic acid dissolution reaction mixture, and controlling a pH (Potential of Hydrogen) value of a solution to be 1-35, and 5) conducting solid-liquid separation on the reaction mixture and taking a liquid phase According to the method, harmful gas such as the chlorine is leached without a tail gas absorption facility any longer, mixed gas with lower percent by volume of the chlorine can be made full use of, oxidizing gas is effectively utilized while the operating cost of tail gas absorption is lowered, the utilization ratio of a reagent and a material is increased, the process control point is simplified, the operation is simple, and the process is easier to control

Method and apparatus for producing chlorine dioxide

Abstract: The invention relates to the production of chlorine-containing oxidants used as reagents in the decontamination and purification of drinking water, and specifically to the production of an aqueous solution of a mixture of chlorine dioxide and chlorine. The technical problem addressed is that of reducing the energy consumption and increasing the stability of the hydrodynamic regime of the apparatus. The problem is solved in that the method for producing a solution of chlorine dioxide and chlorine is realized by reacting a solution of sodium chlorate and sodium chloride with highly concentrated sulphuric acid and using a low-density atmosphere to remove the resultant vapour-liquid mixture of chlorine dioxide, chlorine and sodium sulphate solution from the reaction zone. The concentration of sodium sulphate is kept lower than the saturation level of the reaction medium, and an absolute pressure of 22-100 kPa is generated in the reaction zone. In order to realize the method, an apparatus is used which comprises a housing with pipes situated in the lower part thereof for introducing the reagents, and a pipe for removing the gaseous products and spent aqueous solution, which is situated in the upper part of the housing and communicates with an ejector connected to the apparatus. A circulating device in the form of a cowl is coaxially secured to the housing, and the pipes for introducing the reagents are situated in the end part of the housing, pass inside the circulating device and are coaxial with the axis of the housing.