85results about "Alkali metal cyanides" patented technology

The invention provides an environment-friendly clean production method for high purity sodium cyanide. The production method comprises the following steps that: without removal of ammonia, hydrocyanic acid synthetic gas synthesized through ammoxidation is directly absorbed by and reacts with an aqueous sodium hydroxide solution to obtain a high purity aqueous sodium cyanide solution, and free ammonia remains in tail gas; the aqueous sodium cyanide solution is cooled and blended to obtain a high purity liquid sodium cyanide product, the high purity liquid sodium cyanide product undergoes condensation, crystallization and centrifugation to obtain a high purity solid sodium cyanide product, and mother liquor is indiscriminately used in liquid alkali absorption liquor; phosphoric acid or ammonium biphosphate is employed as a carrier for repeated cyclic indiscriminate application of ammonia so as to recover ammonia in the tail gas; and after recovery of ammonia, the tail gas is purified and absorbed with water or the aqueous sodium hydroxide solution, a small amount of the aqueous hydrocyanic acid solution or a crude aqueous sodium cyanide solution product is obtained while the tail gas is purified, the purified tail gas is burned with a tail gas boiler, and the aqueous hydrocyanic acid solution or the crude aqueous sodium cyanide solution product is indiscriminately used in the liquid alkali absorption liquor.

The invention relates to a method for recovering high-concentration cyanide and ammonia nitrogen in acrylonitrile waste water by utilization of the membrane absorption method. The method adopts the double-circulation process to adjust the pH value of the waste water to between 11 and 12 at first; the waste water enters into a tube pass of a hydrophobic hollow-fiber membrane after undergoing sand filtration and micro-filtration (MF) in turn to remove suspended particles; volatile NH3 gas in the waste water generates neutralization reaction with a H2SO4 solution on a boundary surface of the hollow-fiber membrane and an absorption liquid, and nonvolatile (NH4)2SO4 is generated and recovered; due to the hydrophobicity of the membrane, water and other nonvolatile substances are still kept in the waste water; and after the high-concentration ammonia nitrogen is recovered by the membrane absorption method, the pH value of the waste water is adjusted to between 5 and 6, an NaOH solution is used as the absorption liquid of HCN, and then the membrane absorption process is repeated. The membrane absorption method is simple and convenient to operate, has low energy consumption, can recover useful substances, and changes the high-cost treatment condition of the acrylonitrile waste water in the prior art to a certain degree.

A process for the production of sodium cyanide crystals comprising;

• • (a) contacting impure hydrogen cyanide and sodium hydroxide in a reactor with mixing for a maximum contact time of about 5 seconds;
  • (b) feeding the resulting mixture to a continuous evaporative crystallizer to produce a slurry of sodium cyanide crystals;
  • (c) passing the slurry of sodium cyanide crystals from the crystallizer over a hot surface to precipitate onto the surface and remove sodium carbonate, and passing said slurry back to the crystallizer; and
  • (d) separating the sodium cyanide crystals from the slurry.

The invention relates to a recovery processing method of cyanide barren solution, which comprises the following steps: at first, ammonia water is added in the cyanide barren solution, the mass ratio of the ammonia water and the cyanide barren solution is 0.5% to 2%; then the cyanide barren solution in which the ammonia water is added is pumped into an electrodialysis device, CN<-> in the cyanide barren solution passes through an anion-exchange membrane and enters a sodium cyanide recovery chamber under the action of a direct-current electric filed, metal cations such as Cu<2+> and Zn<2+> pass through a cation-exchange membrane and enter a metal ion recovery chamber, CN<-> is continuously released from a cyano complex in the cyanide barren solution along with the continuous decrease of CN<-> and heavy metal cations such as Cu<2+> and Zn<2+>, metal ions such as Cu<2+> and Zn<2+> and NH3 are continuously released from a copper-zinc metal ammino complex, so that cyanide ion CN<-> in the cyano complex is promoted to be released, and sodium cyanide and metal ions are recovered. The method can reduce the treatment cost of the cyanide barren solution, remarkably improves the recovery rate and the purity of cyanide ions in the cyanide barren solution, and removes the copper, zinc and other heavy metal ions in the cyanide barren solution.

A method for producing liquefied sodium cyanide by waste oil thermal cracking is carried out by vaporizing while mixing waste oil with liquid ammonia in proportion of 1:2-1:5, putting them into cracking reactor, taking petrol coke as heat carrier, thermal cracking at 1300-1500 degree to obtain pyrolysis gas containing oxygen-hydrogen acid, recovering pyrolysis gas waste heat by waste hot boiler, removing coke, cooling, absorbing continuously by liquid sodium hydrate to obtain liquid sodium cyanide product, firing by waste gas combustion system, recovering waste heat and absorbing tail gas from liquid sodium cyanide. It's safe, convenient, cheap and controllable and has no environmental pollution.

The invention relates to a cyanide-containing sewage multi-effect vacuum evaporation recovery method and a cyanide-containing sewage multi-effect vacuum evaporation recovery device. The cyanide-containing sewage multi-effect vacuum evaporation recovery method comprises the following steps: firstly, cyanide-containing sewage and sulfuric acid are sucked and escaped into a cyanide reaction tower under the action of vacuum negative pressure; secondly, when the cyanide-containing sewage is sprayed and declined from the upper part, hydrocyanic acid is evaporated and escaped from the sewage and separated out under the action of vacuum suction, sucked into a vacuum system, fully mixed with lye and absorbed, and subjected to chemical reaction to generate liquid sodium cyanide; and thirdly, the generated sodium cyanide is returned back to the process of cyanidation and gold extraction and reutilized. The method has simple technological process, performs one-off multi-effect vacuum evaporation recovery, has the recovery rate of 99 percent, solves the problems of high processing cost and easy generation of secondary pollution in the prior cyanide-containing sewage treatment process, achieves the aim of changing waste into valuable, directly recovers and reutilizes the cyanide-containing sewage, greatly saves the cost, and is energy-saving and environment-friendly.

The invention relates to a method for purifying the acetylene and side product, wherein it comprises that: feeding acetylene into stuff tower, using 15-20wt% NaOH solution to reversely spray and wash to remove the hydrogen sulfide and hydrocyanic acid, to obtain purified tail gas and the mixture with sodium sulfide and sodium cyanide; evaporating, crystallizing, separating to obtain their mixture crystal; extracting the crystal with carbinol, separating the sodium sulfide and sodium cyanide; then evaporating the sodium cyanide carbinol solution, to recycle the carbinol, to obtain the sodium sulfide and sodium cyanide crystals. The invention can recycle sodium sulfide and sodium cyanide and reduce the pollution, while the sulfur and phosphor contents in tail gas are both lower than 50mg/Nm3.

The invention discloses a sodium cyanide powder production system and a sodium cyanide powder production method. The production system comprises reactors, a reactor discharge pump, a reactor cooler, an evaporative crystallization system, a centrifugal separator, a flash drier, a cyclone separator and a molding packaging system; the production system is characterized in that the evaporative crystallization system comprises an evaporator, an evaporator condenser, an evaporator circulating pump, a crystallizer and an underflow pump; the reactors are arranged at a hydrocyanic acid inlet and a sodium hydroxide inlet; the reactors are communicated with the reactor cooler, an absorption segment at the upper part of the reactor and the evaporator through the reactor discharge pump separately; the reactor cooler is communicated with a mother liquor circulating inlet in the upper end of the reactor; the evaporator is communicated with the crystallizer; the crystallizer is communicated with the centrifugal separator through the underflow pump; the centrifugal separator is communicated with the flash drier; the flash drier is communicated with the cyclone separator; and the cyclone separator is communicated with the molding packaging system. The production system has the advantages that the structure is simple and reasonable, and safe, continuous and efficient industrial production of the sodium cyanide powder is ensured.

A method of making the inorganic gold compound, such as tetrachloroauric acid, sodium tetrachloroaurate, potassium tetrachloroaurate, sodium tetracyanoaurate, and potassium tetracyanoaurate, includes the step of: treating gold with a halogen-containing oxidizing agent in a hydrochloric acid to obtain the inorganic gold compound, wherein the halogen-containing oxidizing agent excludes chlorine gas. The method of making the inorganic gold compound is simple, safe, time-effective, cost-effective, and environment-friendly, and has the advantage of high yield.

The invention provides a treatment and reuse method for cupric-cyanide-containing waste water. The treatment and reuse method comprises a low-concentration cyanophoric material ion recovery process and a cuprous extraction process, wherein the low-concentration cyanophoric material ion recovery process mainly comprises the steps that: (1) the cupric-cyanide-containing waste water is subjected to cartridge filtration for removing impurities in the cupric-cyanide-containing waste water; and (2) the cupric-cyanide-containing waste water subjected to impurity removal is introduced into a cyanide ion recovering machine, cyanide complexes and free cyanogen in the cupric-cyanide-containing waste water are collected, and an analysis concentrated solution and cyanogen-removed waste water are obtained. The cuprous extraction process mainly comprises the steps that: (1) the analysis concentrated solution is pumped into an extraction sealing tank; (2) inert gas is injected into the extraction sealing tank so that the analysis concentrated solution boils, extraction agents formed by proportionally mixing H2SO4 and NaCl are added, and obtained HCN enters a cyanogen recovery tank; and (3) remaining backing materials in the extraction sealing tank are CuCl, and CuCl finished products are obtained after vacuum drying and centrifugation. Therefore cyanogen and copper in the cupric-cyanide-containing waste water are respectively recovered and reused.

The invention discloses a drying technique for preparing high-content industrial solid NaCl products, i.e. by controlling the feed quantity, it feeds sodium prussiate through a spiral transporter into the drying room with a rotary flash-vaporization drier, and at the same time, feeds normal-temperature air after filtered to an electric air heater for heating and then bellows the heated air through the bottom of the drying chamber into the drying chamber; makes the dried material powder leave the drying chamber together with the air flow, separates by a cyclone separator to discharge the material through a rotary valve to enter in the next working procedure. It shortens the technical flow, reduces energy consumption, and improves productivity and quality and simultaneously reduces the discharge of waste gas and waste water, and solves the problems of existing techniques, like high energy consumption, low output, high labor strength of workers, inconsistent product quality, etc.

The invention provides a hydrothermal preparation method of an editpotassium cyanide solution. According to the hydrothermal preparation method, potassium ferricyanide is used as a raw material. The hydrothermal preparation method comprises the steps of dissolution, hydrothermal reaction and separation of all units. The hydrothermal preparation method is characterized in that a K3Fe(CN)6 aqueous solution is put in a polytetrafluoroethylene lining of a hydrothermal kettle, after the hydrothermal kettle is sealed, the hydrothermal kettle is subjected to heat preservation for 24-72 hours at the temperature of 140-250 DEG C, after hydrothermal reaction, KOH solids, the amount of substance of which is three times as much as that of the K3Fe(CN)6, are added to the solution, after the KOH solids are dissolved by stirring, Fe2O3 precipitates are filtered out, and finally the KCN solution with corresponding concentration is obtained. By adopting the hydrothermal preparation method, equipment and technological processes can be simplified, and the cost is greatly reduced.

A process that can be used to produce NaCN is provided. The process comprises contacting hydrogen cyanide with sodium hydroxide solution to produce a NaCN solution and crystallizing the NaCN solution wherein the process is carried out in the presence of an acid or a metal salt of the acid in which the acid has a pKa≦4.4. The NaCN crystals can be separated from the slurry and dried.

Belonging to the technical field of energy conservation and environmental protection, the invention particularly relates to an energy-saving tail gas deamination process and equipment for production of sodium cyanide. Specifically, high-temperature softened water coming out of a cracking furnace serves as a heat source of a lithium bromide unit and returns to a softened water pool after being cooled so as to get ready for entering the cracking furnace again; tail gas enters the lower part of an ammonia absorption tower, spray water enters the upper part of the ammonia absorption tower for spray deamination on the tail gas, the generated dilute ammonia water is sent into a kettle liquid heat exchanger through a dilute ammonia water pump, and then enters a distillation tower, part of the kettle liquid subjected to distillation deamination by the distillation tower undergoes heat exchange by the kettle liquid heat exchanger, and is sent as spray water by a spray water pump to two circulating water plate heat exchangers for primary cooling by cooling water, after coming out of the circulating water plate heat exchangers, the spray water enters two cold water plate heat exchangers for secondary cooling through cold water generated by the lithium bromide unit, and then the spray water returns to the ammonia absorption tower again to spray the tail gas. Through the recycling, the ammonia content of the tail gas can reach the production requirement of 0.8% or below.

The invention discloses a production process and device for preparing high-purity sodium cyanide or potassium cyanide with high yield. The process comprises the following steps: 1) removing ammonia, and cooling to obtain ammonia gas removing HCN; 2) shunting the ammonia gas removing HCN; 3) carrying out an absorption reaction to obtain a crude cyanide solution; (4) carrying out decarburization reaction to obtain a decarburized solution; 5) adjusting the content of free alkali, and carrying out an absorption reaction on the decarburized solution obtained in the step 4) and the ammonia gas removing HCN entering an absorber II in the step 2) in the absorber II to obtain high-purity liquid sodium cyanide or potassium cyanide; and 6) carrying out tail gas treatment. The invention discloses a production device for preparing high-purity sodium cyanide or potassium cyanide with high yield. According to the invention, one part of HCN synthesis gas is utilized to generate a decarburized solution, the other part of HCN synthesis gas and the decarburized solution are subjected to continuous absorption reaction, and the content of free alkali in the decarburized solution is adjusted, so that the high-purity liquid sodium cyanide or potassium cyanide can be obtained, the cost is low, the yield is high, and the side reaction that the cyanide is decomposed at high temperature to generate formate is effectively inhibited.

The invention relates to the technical fields of comprehensive treatment and utilization of waste residues generated by cracking light oil, in particular to a method for preparing sodium cyanide co-production mixed sulfate from the waste residues generated by cracking the light oil. The main technical scheme of the invention comprises the following steps of: washing the waste residues generated by cracking the light oil, with 5-10 percent of a sodium sulfate solution below 30 DEG C; subjecting the washed waste residues to suck filtration; then placing the washed waste residues into a vacuum distillatory for vacuum distillation at the low temperature of 40-60DEG C; cooling to obtain a sodium cyanide crystal; and re-distilling the residual liquid to obtain the mixed sulfate. According to the invention, the preparation process and equipment are simple and feasible and the cost is low; and the invention eliminates the influence on the environment and simultaneously creates products with certain economic value.

The invention provides an environment-friendly clean process method for producing hydrocyanic acid derivatives by purge gas. The method is characterized in that: methane-containing purge gas is separated by a pressure swing adsorption device and other separation devices to obtain ammonia (or methanol), hydrogen, nitrogen, methane gas and tail gas; the ammonia (or methanol), hydrogen, and nitrogen are returned to an ammonia synthesis (or methanol synthesis) system for full utilization; the methane gas is used for synthesizing hydrocyanic acid derivatives; and the tail gas is used for argon recycle; the hydrocyanic acid synthesized by the methane gas is used for synthesizing various hydrocyanic acid derivatives: the methane gas is directly used for ammoxidation or ammonification dehydrogenation to synthesize hydrocyanic acid synthetic gas; an absorption reaction takes place between the synthetic gas and a sodium hydroxide aqueous solution to obtain sodium cyanide used for synthesizing downstream hydrocyanic acid derivatives; the synthetic gas reacts with formaldehyde and other organic aldehydes to synthesize hydroxy acetonitrile and other hydrocyanic acid derivatives used for synthesizing downstream hydrocyanic acid derivatives; the synthetic gas is subjected to absorption and dissolution purification by water or other solvents to obtain liquid hydrocyanic acid used for synthesizing downstream hydrocyanic acid derivatives.

The invention relates to the technical field of comprehensively treating and utilizing ammonia sodium residues, in particular to a method for preparing potassium cyanide co-production mixed sulfate by using the ammonia sodium residues. The method comprises the main technical schemes of: firstly putting the ammonia sodium residues and sodium sulfate in a low-temperature closed reaction kettle according to the pure substance mass radio of 1:(1.29-1.69) to react, filtering after the reaction and sending filter cakes and impurities to be incinerated; firstly sending the filtrate to a reduced pressure distiller to carry out low-temperature distillation, then crystallizing the filtrate in a low-temperature crystallizer and at last obtaining potassium cyanide crystals and mixed sulfate. The invention not only has the advantages of simple and practicable preparation process and equipment and low cost, but also can completely eradicate CN- in the residues, eliminate the impact on the environment and simultaneously create products with certain economic value.

The invention relates to a method for recycling gold and cyanides in a surface treatment wet-process cleaning solution, which comprises the following steps: filtering a plating solution or cleaning solution with a carbon fiber filter; carrying out electrodeposition treatment to precipitate gold and heavy metals to form a metal mixture, and carrying out separation treatment with a separating unit to adsorb residual gold; reacting white lime with boric acid to form a calcium borate precipitate, separating the calcium borate precipitate and citric acid with a nano filter membrane to form a regenerative solution, and storing the regenerative solution in a regenerative solution storage tank; dissolving gold in the metal mixture by using the regenerative solution, thereby forming a gold-containing solution; and separating the gold-containing solution with a reverse osmosis module to obtain an osmotic solution which osmoses through the reverse osmosis membrane and an unosmotic concentrated solution, wherein the osmotic solution is sent back to the regenerative solution storage tank. Therefore, the method provided by the invention can implement the goal of recycling gold by using the concentrated solution containing high-concentration gold potassium cyanide.