82 results about "Scorodite" patented technology

The invention discloses a method for precipitating and stabilizing As from As-containing solution. According to the method, ferrous salt is used as As precipitator; through the air oxidation in the As-containing solution in a weak acid condition, Fe<2+> is oxidized into Fe<3+>; and Fe<3+> reacts with As to generate precipitate with high stability and low As leaching toxicity. The method is simple in technology, and generates the precipitate which is ferric arsenate crystalline compound-scorodite crystal FeAsO4. 2H2O under the conditions that the pH value is 4-6, the temperature is 70-95 DEG C, the molar ratio between Fe and As is 1-1.5, the air flow rate is 120-200L/h and the reaction time is 5-7h; the precipitate As has the leaching toxicity concentration of 1-2mg/L which is lower than the limit value of Identification Standards for Hazardous Wastes-Identification for Extraction Toxicity (GB 5085.3-2007); and the harmless stabilizing treatment for the As-containing solution can be realized.

The invention relates to a method for obtaining high-leaching stability scorodite by precipitating an arsenic-containing solution. The method comprises the following steps: adding a ferrite solution as an arsenic precipitating agent in a continuous feeding mode, and simultaneously adding a neutralizing agent in a certain concentration; continuously introducing oxygen for oxidizing ferrous ions into ferric ions, and then reacting with arsenic in the solution, thus generating the high-leaching stability scorodite. The obtained scorodite can be stably stacked and stored within a pH (Potential of Hydrogen) value range of 2 to 11 and under a strong reducing condition.

The invention relates to an acid recycling and arsenic curing method for acidic waste water and belongs to the technical field of the non-ferrous metallurgical industry. The acid recycling and arsenic curing method comprises the following steps: performing size mixing on arsenic soot and acidic waste water, then pumping in air or oxygen to perform oxidation leaching, controlling the pH value of a leaching end point, and performing normal-pressure scorodite arsenic curing on an arsenic-containing leaching agent. According to the acid recycling and arsenic curing method, arsenic-containing soot and acidic waste water mixed size mixing, oxidation leaching and scorodite arsenic curing technologies are adopted to treat acidic waste water, a new thought is provided for recycling of acidic waste water and harmless arsenic treatment of the non-ferrous metallurgical industry, and the acid recycling and arsenic curing method mainly focuses on efficient utilization of acid in acidic waste water and harmless arsenic treatment. Arsenic-containing soot generated in the non-ferrous metal smelting process is taken as a neutralizer, and arsenic-containing soot and arsenic-containing acidic waste water are synchronously treated, so that effective utilization of acid in acidic waste water is realized, meanwhile, obtained scorodite crystals are convenient to pile up, and the characteristics of complete arsenic and acid separation, low treatment cost and the like are achieved.

The invention discloses a method for treating arsenic-containing wastewater and solidifying arsenic. The method comprises the following steps: separating and enriching arsenic in the arsenic-containing wastewater in the form of calcium arsenate or/and calcium arsenite precipitate; and oxidizing the obtained arsenic enriched product in a ferric sulfate or ferrous sulfate solution, and carrying outnormal-pressure reaction or pressurized hydrothermal reaction or normal-pressure hydrothermal reaction, so that arsenic in the arsenic enriched product is solidified in the form of scorodite crystals.The obtained scorodite crystals are complete in grain development, uniform in grain distribution and stable in structure under acidic conditions. The method has the advantages of high operation efficiency, good arsenic fixation effect, convenience in operation, low arsenic solidification treatment cost and the like, and is suitable for industrial application of harmless treatment of arsenic-containing wastewater.

The invention provides a method for removing trivalent arsenic, comprising the following steps: (1), oxidizing trivalent arsenic in an arsenic solution into pentavalent arsenic at pH of 0.9-1.5 by using ozone to obtain pentavalent arsenic solution; (2), adding a soluble divalent iron source into the pentavalent arsenic solution, oxidizing divalent iron at a temperature higher than 70 DEG C at pH less than 1.5 into trivalent iron, and reacting the pentavalent arsenic with trivalent iron to obtain a solution containing scorodite crystal precipitate, goethite precipitate and divalent iron; (3), adjusting pH of the solution obtained in step (2), oxidizing the divalent iron in the solution to form iron peroxide gel, and carrying out solid-liquid separation to obtain a purified solution.The method enables low-concentration arsenic in waste water to be removed, arsenic content of the purified solution is lower than 0.05 mg/L, the precipitates generated in the arsenic removal process are easy to remove, and the method is simple to perform and is widely applicable to purifying waste water containing low-concentration arsenic.

The invention relates to a method for the treatment of material containing at least one valuable metal and arsenic to form a valuable metal-depleted scorodite sediment and a pure aqueous solution to be discharged from the process. According to the method, the valuable metals are first removed from the material to be treated and then arsenic precipitation from the solution is performed in two stages. By means of the method, the aim is to obtain as low a valuable metal content as possible in the scorodite sediment that will be formed. Likewise, the arsenic and valuable metal content of the aqueous solution that is formed during arsenic precipitation also remains so low that the water can be released into the environment.

The invention provides a preparation method for an amorphous FeOOH water-purifying agent. The preparation method comprises the following steps: preparing a ferrous sulfate solution from industrial ferrous sulfate heptahydrate; adding a proper amount of sulfuric acid into the ferrous sulfate solution so as to provide an acidic environment; adding hydrogen peroxide into the solution and allowing ferrous sulfate to be oxidized into ferric sulfate under the condition of hydrolysis promotion by sulfuric acid; subjecting an industrial alkali source and the ferric sulfate solution to a precipitation reaction so as to produce iron hydroxide colloid; and dehydrating the iron hydroxide colloid under proper conditions so as to prepare the amorphous FeOOH water-purifying agent. The amorphous FeOOH water-purifying agent can effectively arsenic in water, has arsenic removal efficiency of 98% or above, does not contain aluminum ions or pose secondary pollution to a water body; after arsenic removal with the water-purifying agent, scorodite stably existing in the nature is produced, so pollution is not posed to the environment; moreover, raw materials used in the invention are of an industrial grade, and the preparation method is low in production cost and simple to operate.

A method is provided for the efficient stabilization, removal and disposal of arsenic-containing wastes generated in metal recovery processes that employ roasting techniques and the like. The conversion of the mostly trivalent arsenite compounds in the wastes to mostly pentavalent solid arsenate precipitates is accomplished by mixing the wastes with water and a ground iron-containing mineral, such as goethite, to form an aqueous slurry of wastes and ground iron-containing mineral, acidifying the slurry to a pH of less than about 1.0, treating the acidified slurry with oxygen gas in a pressurized vessel at a temperature higher than about 120° C. and providing an oxidation catalyst comprised of a water-soluble nitrate and a water-soluble iodide. The overall efficiency of the controlling chemical reactions is improved by the addition and use of the catalyst. The resulting solid arsenate precipitates, in the form of scorodite, are ideally suited for safe disposal with minimum or no further treatment. Unconverted soluble trivalent arsenic compounds remaining in solution may be converted and precipitated as additional scorodite by mixing and agitating the slurry with soluble iron salts under controlled conditions. The resulting precipitates meet or exceed environmental requirements for impoundment and safe disposal.

The invention provides a treatment technology for high-arsenic acid industrial wastewater. The technology comprises steps as follows: Step 1: an iron-containing material is added to the arsenic-containing acid industrial wastewater, and amorphous ferric arsenate sediment and a clear liquid A are formed; Step 2: the amorphous ferric arsenate sediment obtained in Step 1 is placed in a reactor with an ultrasonic wave source, and a slurry material is converted into fine-grain scorodite under the action of ultrasonic waves; Step 3: the fine-grain scorodite and the clear liquid A are led into a reaction tank and stirred to have reaction equilibrium for 0.5-8 h, and coarse-grain-scorodite-containing sediment (for harmless stockpiling) and a clear liquid B are obtained; Step 4: a neutralizer is added to the clear liquid B, the pH is adjusted to be neutral, a clear liquid C is produced (for reuse/discharge), and neutralization sludge produced in a neutralization reaction returns to Step 3 for reaction equilibrium. According to the treatment technology, an ultrasonic wave technology is applied to the grain form transformation process, a precipitation technology is designed again, contaminated acid treatment energy consumption is obviously reduced, and the self-cleanliness of the treatment process is improved.

The present invention provides a method for manufacturing scorodite in which scorodite may be obtained at high production efficiency and a high As concentration ratio. The present invention provides a method for manufacturing crystalline scorodite from acidic aqueous solution containing pentavalent As and trivalent Fe, the method comprising a step for adding a basic sodium compound to the acidic aqueous solution such that the sodium concentration in the acidic aqueous solution becomes larger than 0 g/L and equal to or less than 4 g/L.

The invention relates to a method used for treating high arsenic waste water. The method comprises following steps: trivalent arsenic containing waste water to be treated, an iron salt solution, and asulfate solution are mixed to be uniform, the pH value of an obtained mixed solution is adjusted to 1.2 to 2.0, the mixed solution is introduced into a reaction vessel, reaction is carried out at 135to 200 DEG C so as to generate a precipitate, and the precipitate is removed, wherein the precipitate comprises scorodite and tooeleite minerals. The stability of the method is excellent; no secondary pollution is caused; arsenic removing rate is high at the synergism effect of scorodite and tooeleite minerals, and is as high as 89.8 to 99.6%; arsenic toxicity leaching concentration is as low as2.2 to 29.82mg/L.

The present invention is to provide a process for producing a scorodite that can shorten the time required for synthesizing the scorodite, and further can improve the yield of arsenic and iron into the scorodite. Accordingly, a process for producing a crystalline scorodite from an acidic aqueous solution containing pentavalent As and trivalent Fe, wherein the synthesis of the crystalline scorodite is performed after the molar ratio of trivalent Fe to pentavalent As contained in the acidic aqueous solution is adjusted to be equal to or more than 0.9 and equal to or less than 1.1 is provided.

The invention provides an immobilization method of arsenic in arsenic-containing solution. The immobilization method of arsenic in arsenic-containing solution comprises following steps: under acidic conditions, an oxidizing agent is added into an arsenic-containing solution for oxidation so as to obtain a solution containing pentavalent arsenic; a ferrous salt is added, the pH value and the temperature of the solution are adjusted, the oxidizing agent is added for reaction so as to obtain scorodite crystal precipitate. According to the immobilization method, utilization of the strong oxidationperformance of ozone is adopted, oxidation of trivalent arsenic and ferrous is carried out successively, the scorodite crystal precipitate is obtained, crystal growth speed is accelerated, reaction process is simplified via controlling reaction conditions; and in addition, the immobilization method can be used for treating low concentration arsenic-containing solution, is suitable for treatment of most industrial arsenic-containing waste water, no pre-condensation treatment is needed, cost is low, and the application range is wide.

The invention relates to a method for co-processing arsenic sulfide slag and arsenic-containing smoke in copper smelting. The method comprises the following steps that copper, zinc, iron, arsenic and like enter a solution through normal-pressure acid leaching of arsenic-containing smoke, lead is recovered from leaching slag through a lead smelting system, copper in smoke acid leaching liquid is precipitated through sulfuration of the arsenic sulfide slag, ferrous sulfate is added into the solution after copper precipitation, high-stability scorodite is obtained through reaction under the condition of oxygen pressure, the loss of valuable metal in the arsenic precipitation process is small, and the arsenic-removed solution with few impurities can be directly fed to a zinc electrodeposition process to obtain electrodeposited zinc or evaporated and crystallized to obtain a zinc sulfate product. According to the method, the valuable metal recovery rate is high, operation is easy, the problems that the arsenic sulfide slag is low in value and difficult to treat are effectively solved through arsenic sulfide slag sulfuration copper precipitation, and efficient utilization of dangerous solid waste and harmless treatment of arsenic are achieved.

The invention discloses a method for treating acid waste water containing arsenic. The method comprises the following steps of (1) adding essential elements for growing of iron-oxidizing bacterium to waste water containing arsenic to obtain a culture medium, adding ferrite, adding seed crystal after the ferrite is totally dissolved, inoculating the iron-oxidizing bacterium, and adjusting the PH value to 1.2-3.0; (2) moving mixed liquid obtained in step (1) into a reactor, reacting for 5-10 days under normal pressure at a temperature below 55 DEG C, and depositing arsenic in the waste water in a scorodite state so as to finish the treatment of the acid waste water containing arsenic. According to the method disclosed by the invention, the waste water containing arsenic with the concentration of 0.1-5g/L can be treated, the removal rate of arsenic in the waste water can reach more than 97% within short treatment time, besides, the raw material used in the method is easy to get, the condition is mild, the operation is simple, the synthesized scorodite is a crystal particle, and is easy to separate, high in arsenic content, and good in stability, and secondary pollution is not caused.

The invention discloses a method of recovering cadmium from cadmium-containing high-arsenic soot. The method includes the following steps of firstly, oxidizing leaching, wherein oxidizing leaching isperformed on the cadmium-containing high-arsenic soot, and filtering is performed to obtain a leachate containing cadmium and arsenic and leach residues containing valuable metals; secondly, extracting, wherein extracting is performed on the leachate containing cadmium and arsenic after the pH is adjusted to be 2.5-3.0, and a cadmium-containing organic phase and a arsenic-containing extraction solution are obtained; thirdly, reverse extracting, wherein a cadmium sulfate solution is obtained after reverse extracting is performed on the cadmium-containing organic phase through a sulfuric acid solution; fourthly, cadmium precipitation, wherein precipitation reaction is performed on the cadmium sulfate solution through sodium sulphide to obtain cadmium sulfide; and fifthly, arsenic curing, wherein soluble ferrite is added to the arsenic-containing extraction solution, a gaseous oxidant is introduced for reaction, and scorodite crystals are obtained. According to the method, cadmium in thecadmium-containing high-arsenic soot is effectively extracted through an extracting method, cadmium is separated from lead, iron, bismuth and the like, meanwhile the safe disposal of arsenic is realized, highly toxic arsine gas is prevented from being generated in the technological process, and the method is economical and friendly to the environment.

A method of making scorodite includes the following steps: (1) an acidic aqueous solution containing pentavalent As and trivalent Fe is heated at a temperature for a time, the temperature and the time being effective for synthesis of crystalline scorodite; (2) the synthesized scorodite is separated from the post-reaction solution by solid-liquid separation; and (3) the scorodite is washed with water and is separated from the washing solution by solid-liquid separation. Step (3) is repeated until the concentration of at least one component of the post-reaction solution contained in the washing solution used for washing the scorodite decreases to a predetermined level.

The invention relates to a method for treating arsenic in nonferrous smelting waste acid by using magnetic Fe3O4, and belongs to the technical field of heavy metal arsenic pollution treatment. The method comprises the following steps: uniformly mixing magnetic Fe3O4 and contaminated acid, conducting pre-treating for 12-24 hours under a stirring condition to obtain a solution A, adding H2O2 and a scorodite crystal into the solution A, and conducting uniform mixing to obtain a solution B; carrying out an arsenic removal reaction on the solution B for 8-12 hours at the temperature of 70-90 DEG Cunder a stirring condition, and carrying out solid-liquid separation to obtain an arsenic-containing solid substance and a filtrate C; conducting ball milling and magnetic separation on the arsenic-containing solid substance to separate out magnetic Fe3O4 and pure scorodite, returning the magnetic Fe3O4 for circulation, and safely treating the pure scorodite. The method is simple in working process and obvious in arsenic removal effect, and the generated scorodite is stable in physical property.

The invention relates to a method for making copper slag gel be wrapped around and stabilize scorodite, and belongs to the technical field of heavy metal pollution treatment. The method comprises thefollowing steps that ground magnetite is screened to obtain magnetite slag powder; the magnetite slag powder and H2O2 are added into waste acid for uniform mixing, and stirring is performed for an oxidation pretreatment reaction for 6 h to 8 h under normal pressure at room temperature to obtain a solid-liquid mixture; the pH value of the solid-liquid mixture is adjusted to be 1.3 to 1.7, stirringis performed for the arsenic removal reaction for 12 h to 14 h under normal pressure at the temperature of 85 DEG C to 95 DEG C, solid-liquid separation is performed to obtain arsenic-containing magnetite and a filtrate, and the filtrate undergoes deep arsenic removal treatment; the arsenic-containing magnetite is dried, and then undergoes magnetic separation, so that the magnetite and the scorodite are separated out, and the magnetite returns back for the oxidation pretreatment reaction; a H2SO4 solution is slowly added into copper slag powder to be stirred until the copper slag gel is formed; and the copper slag gel and the scorodite are uniformly mixed to obtain copper slag-scorodite gel, and aging is performed for 10 h to 20 h at the temperature of 120 DEG C to 160 DEG C. According tothe method, the copper slag is adopted to be wrapped around the scorodite, then the gel is formed, and the subsequent stabilization treatment of the scorodite is realized.