6 results about "Scorodite" patented technology

This invention belongs to the field of non-ferrous metallurgy and hazardous waste treatment technology, proposing a method for reducing arsenic content using a synergistic hydrothermal reaction of low-grade lead-zinc ore and polluted acid. The method involves pre-decalcifying the low-grade lead-zinc ore with dilute hydrochloric acid to remove interfering calcium carbonate. Then, by controlling the mass ratio of active metals such as Pb, Zn, and Fe in the ore powder to As in the polluted acid, under specific hydrothermal conditions, the in-situ release and induced precipitation of metal ions within the ore are stimulated, constructing thermodynamically extremely stable onionite and onionite-like mineral phases. The arsenic removal rate of this invention is consistently above 95%, and the stability of the arsenic-fixed products far exceeds national hazardous waste landfill standards. This method not only solves the problem of arsenic pollution from polluted acid but also simultaneously realizes the resource utilization of low-grade ore, demonstrating significant environmental and economic benefits.

The application discloses a solid arsenic method of constructing an iron arsenate@cookeite core-shell structure by in-situ self-assembly, and relates to the field of non-toxic and harmless treatment of by-products containing arsenic in non-ferrous metal smelting. The application proposes that arsenic is precipitated by using iron salt of high-arsenic wastewater or waste residue, and arsenic source and ferrous source are added to prepare a slurry, and under the condition of hydrothermal oxygen pressure, an outer cookeite shell is formed on the surface of the iron arsenate by directional in-situ self-assembly through the way of arsenic-iron ion oxidation and co-precipitation, so that the core-shell structure of iron arsenate@cookeite is obtained. The arsenic concentration in the toxic leaching of the solid arsenic core-shell structure is lower than the value 5mg / L specified in the national standard (GB5085.3-2007), and the solid arsenic material is non-toxic and harmless. The dense outer shell layer of the cookeite which is crystallized by the oxidation and co-precipitation of arsenic-iron ions in the solution in the hydrothermal oxygen pressure environment is coated on the surface of the iron arsenate, which inhibits the dissolution of the iron arsenate and blocks the release of arsenic. The application solves the technical problems of poor stability and solid arsenic property of the iron arsenate residue, and achieves the non-toxic treatment of the iron arsenate residue.

The invention discloses a method for synergistically fixing arsenic from iron scale solid waste and high-arsenic hazardous waste, and relates to the non-toxic and harmless field of high-arsenic byproducts in non-ferrous metal metallurgy. According to the method, high-arsenic smoke dust is subjected to oxygen pressure acid leaching recovery to obtain lead-antimony concentrate, meanwhile, produced high-arsenic acid leaching liquid is completely transferred into a hydrothermal kettle, solid arsenic iron source iron scale powder is added, and regular octahedral scorodite is synthesized through oxidation and coprecipitation under the conditions of high temperature and high oxygen pressure. The arsenic concentration in the toxic leaching of the scorodite synthesized by the method meets the requirement of the specified value (less than or equal to 5mg / L) of the national standard (GB5085.3-2007), and the scorodite is a non-toxic and harmless solid arsenic product. The iron scale solid waste is dissolved in hydrothermal oxygen pressure to generate Fe < 2 + > and Fe < 3 + >, oxidation coprecipitation crystallization is promoted to obtain scorodite, and the efficient arsenic fixing effect is achieved. The method provided by the invention solves the problems of toxicity of high-arsenic hazardous waste and consumption of iron scale solid waste, and achieves the target of fixing arsenic with waste. The method has the advantages of simplicity in operation, high arsenic fixing efficiency, good arsenic fixing stability of scorodite and the like.

This invention discloses a combined pyrometallurgical-hydrometallurgical cascade separation method for arsenic-containing sludge from copper smelting, relating to the field of solid waste treatment technology. The method first involves low-temperature roasting of the arsenic-containing sludge at 300-600℃ in a reducing atmosphere to achieve preferential volatilization and recovery of arsenic, while copper and rhenium are retained in the roasted sludge. Next, the roasted sludge is subjected to pressure oxidative leaching, with copper and rhenium entering the leachate, and sulfur being enriched and recovered as elemental. Subsequently, arsenic is precipitated as stable arsenic crystals through ternary coupling control of redox potential, pH, and temperature. After deep removal of residual arsenic using barium / lead salts, rhenium is extracted using a co-extraction system to prepare ammonium perrhenate. Finally, copper is recovered from the raffinate by displacement or electrodeposition. This method can efficiently separate arsenic, sulfur, copper, and rhenium, with a sulfur recovery rate ≥92%, arsenic resource recovery rate ≥99%, rhenium recovery rate ≥92%, copper recovery rate ≥95%, solid waste reduction ≥80%, and no secondary pollution. It is suitable for the resource-based treatment of arsenic-containing sludge from copper smelting.

The invention relates to a method for producing scorodite from a solution comprising arsenic and sulfuric acid without the use of a neutralizing agent, comprising the following steps: i. Subjecting a first arsenic solution comprising arsenic and sulfuric acid in the form of a mixture of arsenite ions and arsenate ions to an oxidation treatment, oxidizing the arsenite ions into arsenate ions, a second arsenic solution is obtained; ii, adding a first solution containing ferrous ions into the second arsenic solution to generate a third arsenic solution; iii. Adding a first portion of magnetite to the third arsenic solution to adjust the molar ratio of iron ions to arsenate ions to 0.3-1 to generate a first arsenic slurry; iv. Adding to the first arsenic slurry a portion of the scorodite slurry recycled from step viii as a nucleation matrix for scorodite particles, obtaining a first scorodite slurry of from 2% w / w to 15% w / w; v, heating the first scorodite slurry to 80 DEG C to 90 DEG C; vi, the first scorodite slurry is kept at the temperature of 80 DEG C to 90 DEG C for 5 h to 48 h, and second scorodite slurry is obtained; vii, conveying the second scorodite slurry to a solid-liquid separation step to obtain third scorodite slurry and a treated solution; viii. Recycling a first portion of the third scorodite slurry to step iv; and (ix) filtering a second portion of the third scorodite slurry.

The application provides a method for comprehensively recovering calcium and arsenic from calcium-arsenic slag, comprising the following steps: S1: mixing and reacting calcium-arsenic slag and a sodium carbonate solution, and then filtering to obtain filtrate and filter residue containing calcium carbonate; washing the filter residue and collecting washing liquid A; the pH value of the mixing and reaction is 10-11; the temperature of the mixing and reaction is 25-60 DEG C; S2: mixing the filtrate and the washing liquid to obtain a sodium arsenate solution, adding ferrous sulfate, and controlling the oxidation-reduction potential to 400-550 mv by using hydrogen peroxide to precipitate arsenic. The application provides a method for comprehensively recovering calcium and arsenic from calcium-arsenic slag, the sodium-calcium replacement efficiency is improved by jointly controlling pH, temperature and liquid-solid ratio, the purity of the sodium arsenate solution is improved, then the pH-potential-iron-arsenic molar ratio is jointly controlled, under the conditions of relatively high pH, high potential and high iron-arsenic molar ratio, the tobermorite with a wheat grain shape is generated, and the leaching stability is good.