4 results about "Common-ion effect" patented technology

The application discloses a multi-sulfur-based heavy metal removal agent for steel plant ash washing wastewater, a preparation method thereof and a method for treating ash washing wastewater by using the same, and high-purity potassium chloride is produced by using high-salt solid waste ash generated by a steel enterprise. Meanwhile, based on the characteristics of the high-salt solid waste ash, such as high thallium, ammonia nitrogen and sulfate radical concentration in the water washing wastewater, a deep thallium removal idea based on weak reduction and complexation breaking, same ion effect precipitation and chelation thallium removal is first proposed, the multi-sulfur-based heavy metal removal agent is used to realize deep removal of thallium in the high-salt wastewater, and combined with the characteristics of the sintering flue gas purification and acid wastewater containing a large amount of sulfite ions and low acidity, the multi-sulfur-based heavy metal removal agent is used for removing sulfur, removing ammonia nitrogen and removing thallium in the ash washing wastewater, and the countercurrent evaporation and potassium and sodium separation are used for the synergistic effect, so that the collaborative treatment and resource utilization of the high-salt solid waste ash and the acid wastewater of the steel plant are realized, and the quality of the recovered potassium salt is greatly improved. Meanwhile, the technical scheme provided by the application also has the advantages of simple process conditions, low energy consumption, no wastewater discharge and the like.

This invention belongs to the field of manganese sulfate preparation and impurity separation technology, specifically relating to a method for preparing battery-grade manganese sulfate by calcium-manganese crystallization separation. This application provides a method for preparing battery-grade manganese sulfate by calcium-manganese crystallization separation, comprising the following steps: concentration of calcium-manganese-containing solution: concentrating the calcium-manganese-containing solution to obtain a concentrated solution; cooling and calcium precipitation: cooling the concentrated solution to allow calcium ions to crystallize and precipitate, followed by aging and filtration to obtain a calcium-removed manganese solution; high-temperature evaporation crystallization: crystallizing the calcium-removed manganese solution at high temperature; centrifugal separation: centrifuging the calcium-removed manganese solution after high-temperature crystallization to remove the solution adhering to the surface of the manganese sulfate crystals, further reducing the calcium content in the manganese sulfate product, and obtaining battery-grade manganese sulfate. This invention utilizes the common ion effect and seed crystal action to achieve efficient and thorough separation of calcium. The high-temperature crystallization method requires only one crystallization to achieve efficient crystallization of manganese sulfate to obtain battery-grade products.

This application relates to a low-alpha-ray silica and its preparation method. The method involves adding a high-purity sodium sulfate solution to water glass, followed by the sequential addition of dilute sulfuric acid solutions of varying concentrations for aging. The resulting precipitate is then calcined to obtain low-alpha-ray silica with Th ≤ 5 ppb and U ≤ 5 ppb. The sodium sulfate solution optimizes the precipitation process in two ways: first, it increases the ionic strength of the solution, compresses the colloidal double layer, and disrupts the metastable state of the system, thus promoting the aggregation and crystallization of the target precipitate; second, sulfate ions preferentially complex or inhibit the precipitation tendency of impurity cations based on the common ion effect; furthermore, the dilute sulfuric acid solution promotes the reaction and rapid precipitation of silicate ions with hydrogen ions, causing the Th and U ions encapsulated in the precipitate to precipitate out, thereby reducing the impurity content in the solution. This low-alpha-ray silica, due to its extremely low Th and U content and good thermal conductivity, can be widely used in high-performance and special-purpose chip packaging fields.

This invention discloses a desalination and concentration system and process for waste acid in the sulfuric acid process for titanium dioxide production. The waste acid solution containing ferrous sulfite is evaporated and concentrated to a sulfuric acid concentration of 75-85%, then mixed with the waste acid from the titanium dioxide production process to a sulfuric acid concentration of 35-45%. After filtration, the ferrous sulfite solid is recovered. The waste acid after sedimentation enters a multi-effect evaporation system, where it is evaporated and concentrated to a sulfuric acid concentration of 50-65%, with most of it recycled for production. A portion of the 50-65% sulfuric acid is further concentrated to a concentration of 75-85% and mixed with the ferrous sulfite waste acid solution. Due to the common ion effect, a large amount of inorganic salts, especially sulfates, precipitate and crystallize. After crystallization and precipitation, the inorganic salts are recovered by filtration, and the supernatant enters the multi-effect evaporation system. This avoids the problem of large amounts of crystalline salt generated during the evaporation and concentration process causing blockages in system pipelines or equipment, ensuring long-term stable operation of the system.