201results about "Thiocyanic acid" patented technology

The invention discloses a method for preparing sodium thiocyanate by using desulphurization waste liquid of coke oven gas, and belongs to the technical field of utilization of desulphurization waste liquid of the coke oven gas. The method comprises the following steps: using the desulphurization waste liquid of the coke oven gas as a raw material, firstly, filtering the waste liquid in vacuum, using tributyl phosphate to extract thiocyanate radicals in the waste liquid, then using sodium hydroxide solution to back-extract the extract, and finally concentrating and crystallizing the extract, and washing and drying the crystals to obtain sodium thiocyanate crystals. The method uses the desulphurization waste liquid of the coke oven gas to prepare a sodium thiocyanate product with the purity as high as 93 to 95 percent so as to change waste into valuable and makes full use of waste resources; and the method is simple, saves energy, has no three-waste discharge, is favorable for environmental protection, has low production cost and good economic benefit, and develops a new path for the utilization of the desulphurization waste liquid resources of the coke oven gas. The sodium thiocyanate product prepared by the method can be widely applied in the industries of medicaments, textile, printing and dyeing, pesticide, chemistry and the like.

The invention discloses a method for extracting salt from coking desulphurization waste solution and a special device thereof. The method comprises the following steps of: heating raw material waste solution for decomposition, adsorbing and decolorizing, then heating, evaporating and concentrating to obtain concentrated solution, performing heat filtration at constant temperature to remove fine sulfur particles, cooling and crystallizing in a crystallizer, filtering at constant temperature, separating filtrate to obtain crystals, washing the crystals to obtain high-purity ammonium thiocyanate, dissolving mixed salt crystals in ammonium sulfate mother liquor, regulating the acidity to be below 20 percent, preheating to ensure that the temperature is between 90 and 110 DEG C, blowing air oroxygen, performing oxidative transformation for 1min to obtain ammonium sulfate transformation liquid, and adding ammonium sulfate production mother liquor to obtain an ammonium sulfate product. By the method, a high-purity product can be extracted from the waste solution through one-time operation, so that processing and treatment times are reduced; solid-phase impurities are effectively intercepted and prevented from transferring to the crystals at constant temperature; and the mixed salt is subjected to oxidative transformation treatment, all ammonium thiosulfate is transformed into the ammonium sulfate product with high nitrogen content, the process is simple, operation cost is low, and product marketing is broad.

The present invention relates to a method for recovering secondary salts from a desulfurization liquid and recycling the desulfurization liquid, which comprises the following steps of: adding CuSO4 to the desulfurization liquid discharged from a wet oxidative desulfurization system for treatment, filtering to obtain CuSCN precipitates and a sulfate solution; adding the CuSCN precipitates to caustic alkali for treatment to recover thiocyanate; and cooling and crystallizing the sulfate solution to recover sulfates and returning the clear liquid to the desulfurization system. The method provided by the present invention simplifies the treatment process of desulfurization liquid wastewater, reduces pollutant emission, recovers the secondary salts from the desulfurization liquid and realizes the recycling of the desulfurization liquid, has a simple process, is environmentally-friendly, realizes the recycling of resources and has a good application prospect.

The invention discloses a method for extracting ammonium thiocyanate from ammonia-process desulfurization waste liquid by an oxidation process, and belongs to the technical field of treatment of the desulfurization waste liquid. According to the method, an oxidation reaction is implemented by a way of blowing air or oxygen into ammonia-process desulfurization waste liquid; by the oxidation reaction, ammonium thiosulfate in the desulfurization waste liquid is oxidized into ammonium sulfate, but ammonium thiocyanate is not oxidized and is still reserved in the desulfurization waste liquid; and the ammonium thiocyanate is extracted by ways of evaporation and secondary crystallization. The method disclosed by the invention is applicable to the treatment of the desulfurization waste liquid which is generated from the process of desulfurization and decyanation of the gas by a catalytic oxidation process, and is suitable for the waste liquid treatment in the field of desulfurization process of hydrogen sulfide-containing gases such as coke oven gas, natural gas, coal-bed methane and refinery gas. By the method, the ammonium thiosulfate salt in the waste liquid is converted into the ammonium sulfate salt and the ammonium thiocyanate salt is protected, and the ammonium thiosulfate salt and the ammonium thiocyanate salt are separated from the waste liquid and purified into products.

The invention discloses a method for recovering sodium sulfocyanate from coke-oven gas wastewater that is desulfurized and decyanated through a sodium alkali method. Belonging to a pure physical separation technology, the method of the invention has no need for additional accessories to take part in a reaction and does not discharge any wastewater and waste material to the outside, thus really reaching the purposes of eliminating environmental pollution, utilizing waste materials, change waste materials into things of value and realizing circular economy. The method provided in the invention has the advantages of novel technology, simple process, low cost, advanced technique, and practical applicability.

The invention relates to a method for processing sulfur paste as a coke oven gas desulfuration by-product. The method is characterized in that a sulfur paste processing procedure comprises the steps of dissolving sulfur and removing impurities, decoloring and removing impurities, lowering temperature and crystallizing, drying the product and the like; and a waste liquid treatment procedure comprises the steps of decoloring and removing impurities, carrying out vacuum concentration on filtrate containing salt, separating ammonium thiocyanate, concentrating the ammonium thiocyanate ethyl alcohol filtrate for crystallization, drying an ammonium thiocyanate product, separating ammonium sulfate, concentrating the ammonium thiosulfate filtrate for crystallization, drying the ammonium thiosulfate product, and the like. The method can be used for thoroughly processing the sulfur paste and the waste liquid containing sulfur, the recycling rate of the product is high, no mixed salt and waste water are discharged without cause secondary pollution, so that the method is clean and environment-friendly. The method also has the outstanding characteristics of strong adaptive capacity, large production elasticity, high resource utilization ratio and the like.

The invention discloses a method for preparing high-quality sodium thiocyanate from a desulfurized and decyanated waste liquid of coke oven gas, which comprises the following steps: decolorizing and filtering the desulfurized and decyanated waste liquid through activated carbon, and adding an assistant A into the waste liquid while stirring, wherein the specific quantity of the assistant A is 50-200% of the molal quantity of sodium thiosulfate in the waste liquid; removing sodium thiosulfate ions in the waste liquid system, filtering to remove insoluble substances, and then adding a small quantity of assistant C into the filtrate to regulate the pH value to 5-10; distilling and concentrating to remove the moisture, and centrifuging to separate out inorganic salt impurities based on the difference of various substances in solubility under different temperatures and concentrations; and decolorizing through activated carbon, and further concentrating and crystallizing to produce the sodium thiocyanate finished product. According to the invention, the process is simple, the cost is low, and the weight content of the produced potassium thiocyanate is more than 99%.

The invention provides a method for selectively absorbing and separating thiocyanates and thiosulfates in water solution. The invention uses the difference absorption effect of the layered bihydroxide mixed metal oxide roasted products (LDO) on the ion absorption quantity of thiosulfate radicals and thiocyanate radicals, the LDO is used as absorbing agents to be placed into the water solution containing thiosulfates and thiosulfates, firstly, the thiosulfates in the solution are absorbed into the LDO, then, the replacement and the purification are carried out, and next, the thiosulfates in the rest solution are separated, so the goal of separating and purifying two salts is reached. The used LDO is obtained through roasting Mg-Al hydrotalcites with the constitutional formula of Mg<1-x>Alx(OH)2(An<->)x / 2.yH2O at 400 to 500 DEG C for 3 to 4 h. The method can be used for treating waste water in the solution containing the thiosulfates and the sulfates for solving the problem of water body and soil pollution by the thiosulfates and the sulfates, and at the same time, the two salts can be perfectly recovered.

The invention discloses a method for extracting ammonium thiocyanate from coking desulfurization waste liquid. The method comprises: adding 3-5% of activated carbon to the coking desulfurization waste liquid, heating the mixture to 70-90 DEG C, stirring the mixture for 1-3 hours and filtering the mixture; adding sulfuric acid to the filtrate in a closed container to ensure the pH value of the filtrate to be 3.5-4.5, heating the mixture to 60-80 DEG C and stirring the mixture for 1-3 hours, leading out the escaping SO2 with a conduit and absorbing the escaping SO2 with dilute ammonia water; filtering the reaction liquid, adding barium hydroxide octahydrate with mass being equal to the mass of ammonium sulfate in the filtrate, heating the mixture to 60-80 DEG C in a closed container, stirring the mixture for 1-3 hours, leading out the escaping ammonia with a conduit and absorbing the escaping ammonia with water; and carrying out filtering after completing reaction, and heating, evaporating and crystallizing the filtrate to obtain the ammonium thiocyanate product with purity being more than 97%.

Amorphous inorganic particles as a dental material includes silica and inorganic oxide(s) other than silica and has high x-ray impermeability. The inorganic particles as a dental material includes silica with the content in the range from 70 to 98 weight % and oxide(s) of one or more elements selected from the group of Zr, Ti, La, Ba, Sr, Hf, Y, Zn, AL, and B, wherein 5 to 70 weight % of the silica is originated from an acidic silicic acid solution and 30 to 95 weight % of the silica is originated from a sol of silica. The inorganic particles as a dental material have an average particle diameter in the range from 1 to 10 μm, specific surface area in the range from 50 to 350 m2 / g, pore volume in the range from 0.05 to 0.5 ml / g, amorphous crystallinity as observed by x-ray diffraction, and the refractive index in the range from 1.47 to 1.60.

The invention discloses a device and a method for extracting refined salt from waste liquid generated during wet ISS-J desulfurization. The device comprises a coarse salt drying assembly, a sodium thiocyanate separating and refining assembly, a sodium thiosulfate separating and refining assembly, a sodium sulfate separating and refining assembly and a solvent recycling assembly. The coarse salt drying assembly comprises a desulfurization waste liquid tank, a heat exchanger, an evaporation kettle, a crystallization kettle and a centrifugal machine; the sodium thiocyanate separating and refining assembly comprises a dissolving kettle, a filter-press kettle, an evaporation kettle, a crystallization kettle, a centrifugal machine, a drying machine and a packaging machine; the sodium thiosulfate separating and refining assembly comprises a dissolving kettle, a condensate tank, a filter-press kettle, a crystallization kettle, a centrifugal machine and a packaging machine; the sodium sulfate separating and refining assembly comprises a dissolving kettle, a concentrate sulfuric acid elevated tank, an evaporation kettle, a centrifugal machine, a drying machine and a packaging machine. The device and the method have the advantages that the waste liquid which can originally pollute environments and is generated by desulfurization systems can be thoroughly treated by the aid of the device and the method, industrial-grade products can be produced from the waste liquid, accordingly, wastewater emission can be truly prevented, and waste can be truly turned into wealth.