35results about How to "Coarse particles" patented technology

The invention discloses a process for improving the quality of phosphorus chemical industry waste smoke desulfurization gypsum, and the process comprises the following steps: mixing a desulphurized absorbent with slag washing water; stirring to form an even slag slurry; carrying out rotational flow separation on the slag slurry; removing bottom flow slag to obtain an overflowing liquid; configuring additive mixed liquor; mixing and stirring the additive mixed liquor and the overflowing liquid to obtain even size; contacting the size with the phosphorus chemical industry smoke; adsorbing sulfur dioxide and phosphorus compound in the phosphorus chemical industry smoke; carrying out airoxidation to form a gypsum liquid; carrying out the rotational flow separation on the gypsum to obtain top flow liquid and bottom flow desulfurization gypsum liquid; reusing the top flow liquid; and dewatering the bottom flow desulfurization gypsum liquid to obtain the desulfurization gypsum. According to the process disclosed by the invention, the problems of small desulfurization gypsum crystalline particle and difficulty in separation in the phosphorus chemical industry waste smoke desulfurization system are solved, gypsum crystal with big particle and low moisture content is obtained, and the filtering performance of the gypsum is improved.

A process for preparing sandy alumina by decomposing low-concentration seed includes such steps as mixing the refined liquid from settling workshop with the fine seeds from plate-and-frame filter press, stage-one decomposing, stage-two decomposing, classifying by hydraulic cyclone bed, filtering part of bottom stream to obtain finished product, filtering the rest to obtain seeds, filtering overflow liquid to obtain fine seeds, adding fine seeds to the stage-one decomposing reactor, adding coarse seeds to the stage-two decomposing reactor, and heat exchange between mother liquid and refined liquid.

The invention relates to a neutralization aluminum removing method for a sodium chromate alkali solution. The carbon dioxide is used as a neutralizer for the neutralization aluminum removal of the sodium chromate alkali solution, and a two-section neutralization method is adopted; in the first section, a neutralization pH value is controlled so that most of aluminum in the alkali solution forms and separate aluminium hydroxide sediment with thick and big particles; in the second section, the residual aluminum in the solution is completely neutralized and precipitated by continuously using thecarbon dioxide, and the aluminum sediment precipitated in the second section is returned to the first section; the solution after the neutralization aluminum removal by the carbon dioxide is neutralized and acidized by a by-product chromium-contained sodium hydrogen sulfate in the production process of chromium salt, the chromium-contained sodium hydrogen sulfate is comprehensively utilized, and the trivalent chromium is recycled. The invention has the advantages of easy separation and washing of aluminum mud, low water content, low chromium band loss, easy comprehensive utilization, and the like.

The invention discloses a device and a process for preparing salt through ionic membrane salt separation, concentration crystallization and freezing crystallization. The device for preparing salt through ionic membrane salt separation, concentration crystallization and freezing crystallization comprises a monovalent ionic membrane salt separation device, a heating and heat exchanging device with a water inlet connected with a concentrated water outlet of the monovalent ionic membrane salt separation device, a concentration crystallization device with a water inlet connected with a water outlet of the heating and heat exchanging device, a special ionic membrane salt concentration device with a water inlet connected with a fresh water outlet of the monovalent ionic membrane salt separation device, a cooling and heat exchanging device with a water inlet connected with a concentrated water outlet of the special ionic membrane salt concentration device as well as a freezing crystallization device with a water inlet connected with a water outlet of the cooling and heat exchanging device. The system recovery rate is increased, the salt separation effect is enhanced, high-purity NaCl crystal salt and mirabilite are obtained according to different qualities, the system is stable and reliable, the operation cost is low, and the investment cost is low.

The invention discloses a sodium chromate alkali solution impurity removal method and a preparation method of chromic oxide. According to sodium chromate alkali solution impurity removal, CO2 with rich resources and low cost serves as acidulant, aluminium and silicon are removed by continuous carbonating decomposition, and the removal rates of the aluminium and the silicon are high; new impurities are not introduced; and aluminium mud after sedimentation has thick and large particles, is low in chromium belt loss, and can be used in alumina industries after being filtered and washed, thus having a high added value. Impurities and sodium chromate solution are separated to obtain solution, cheap and rich starch and derivatives of the starch serve as reductants, and hydrated chromium hemitrioxide is prepared under a hydrothermal reducing condition, and then pigment-level chromium hemitrioxide is generated after dehydration and calcination. The reducing condition is mild, the conversion rate is higher than 90%, slurry easy to filter and wash, and final filtrate and alkaline rinse in production process can be returned to mix with chromite to enter a calcination process, thereby recycling sodium carbonate. According to the invention, the process adopted for generating the chromium hemitrioxide is simple and environment-friendly, the cost is low, and industrialization is easy to realize.

The invention provides a method for treating wastewater containing heavy metal ions through phase transformation of MgCO3.3H2O, and belongs to the technical field of wastewater treatment. The method comprises the following steps: taking wastewater solution containing heavy metal ions, regulating the temperature to 50-60 DEG C, regulating the pH value to 4-8, adding MgCO3.3H2O into the wastewater solution containing the heavy metal ions, and oscillating the solution at constant temperature, so as to obtain wastewater turbid liquid containing the heavy metal ions; heating the wastewater turbid liquid to 55-90 DEG C, stirring at constant temperature for 30-90min, standing, aging, and filtering obtained mixed solution containing precipitation, so as to obtain clear liquid and a filter cake, wherein the mass ratio of MgCO3.3H2O to the heavy metal ions is (4-50):(0.01-1); the heavy metal ion(s) is / are one or more heavy metal ions of Cr<3+>, Pb<2+>, Ni<2+>, Cu<2+>, Zn<2+> and Cd<2+>. According to the method, the wastewater containing the heavy metal ions is treated, the treatment cost is lowered, and the secondary resource recycling of heavy metals can be realized.

The invention discloses a method for decontaminating potassium sub-molten salt soluble crystal liquid and preparing chromic oxide. The method comprises the following steps: (1) introducing CO2 to potassium sub-molten salt soluble crystal liquid, neutralizing potassium hydroxide in the solution, then adding seed crystals, controlling the temperature of the solution at 30-90 DEG C and removing aluminum and silicon; (2) introducing CO2 to the solution obtained in the step (1) to carry out room-temperature pre-carbonation; (3) adding a reducing agent to pre-carbonated feed liquid obtained in the step (2), heating to 120-170 DEG C, and carrying out heat preservation and solid-liquid separation after reaction is ended, so as to obtain a chromium hydroxide filter cake; and (4) drying and calcining the chromium hydroxide filter cake obtained in the step (3), so as to obtain a chromium sesquioxide product. By adopting a pre-acidification mode, the reducing agent is not added in pre-carbonation; no CO2 is introduced after the pre-carbonated feed liquid and the reducing agent are mixed; the method is high in conversion rate of hydrothermal reduction, fewer in intermediate products, high in total yield of chrome, high in purity of the sintered chromic oxide and fewer in impurities by controlling a proper pre-carbonation condition.

The invention belongs to wet method metallurgy field of rare earth production, especially relates to a preparation method for cerium hydroxide. The method comprises: (1) adding raw cerium material into alkali liquor with stirring for creating precipitate Ce(OH)3 ensuring that the mol ratio of OH ion and cerium ion is 0.5-4:1; (2) adding oxidizing agent with stirring under normal temperature with mol ratio of oxidizing agent and Ce(OH)3 as 0.1-4:1 for creating Ce(OH)4 or Ce(OH)3OOH; (3) washing the Ce(OH)4 obtained in step (2), separating the solid from liquid, airing, and obtaining the cerium hydroxide product. The invention has a wide range of application. According to different purposes, cerium hydroxide products with different purities (80~99.9999%(CeO2 / sigma RE2O3)) depending to the raw material.

The invention discloses a preparation method of rare earth carbonate free of generation of ammonia-nitrogen wastewater, and belongs to the technical field of production of rare earth carbonate. The method comprises the following steps: deacidifying by a rare-earth solution; precipitating rare earth by using ammonium bicarbonate; collecting carbon dioxide bubbles generated during rare earth participation; carrying out chemical reaction on carbon dioxide and calcium peroxide to release oxygen and water; participating rare earth by using ammonium bicarbonate again; dewatering and washing a rate block which is crystallized when the pH value is greater than 7 until the rare earth carbonate is obtained; and carrying out environmental-friendly and energy-saving treatment on the left ammonia-nitrogen wastewater, thereby achieving pollution-free production when the deamination rate and the denitrification rate reach 99.9%. The preparation method has the advantages of fully utilizing the ammonium bicarbonate to participate the rate earth, and effectively processing non-environmental-friendly processes in the production process, and therefore, cyclic utilization of resources and environmental-friendly production are achieved.

The present invention relates to material technology and is mixed salt process to prepare in-situ reinforced Mg-base composite material. The process includes determining the alloy element components in the composite material, selecting the reinforcing phase based on the wettability between the substrate and the reinforcing phase whith ic controlled in 2-15 wt%, compounding and pretreating mixed salt system, smelting the magnesium substrate material and adding the pretreated mixed salt into the magnesium melt at proper temperature via stirring, and final casting after being let stand to form. The reinforcing phase is fine, homogeneously distributed and excellent in interface bindnig, and the Mg-base composite material has excellent mechanical and physical performance and may be used widely.

The invention discloses a method of preparing sodium dichromate, comprising the steps of (1), subjecting chromite and alkali solution to liquid oxidation, subjecting slurry to solid-liquid separation after reacting to obtain liquid phase A and solid phase B; (2), washing the solid phase B with circulatory alkali liquid, subjecting post-washing slurry to solid-liquid separation to obtain liquid phase C and solid phase D; (3), crystal-dissolving the solid phase D with sodium chromate crystal with water and iron residue washing liquid, carrying out solid-liquid separation to obtain crystal-dissolved liquid and iron residue, washing the iron residue with water, and returning the washing liquid to crystal dissolution; (4), preparing circulatory alkali liquid with the liquid phase C and crystal-dissolved liquid, adding an acid solution to the remaining crystal-dissolved liquid to adjust pH, and carrying out aluminum-silicon removal, acidifying, crystallizing and separating to obtain sodium dichromate and sodium sulfate; preparing. The process of the invention is simple, the flow is short, and the method is highly operable, low in cost and free of wastewater and is an effective way of chromium salt industry to make recycle use and reduce pollution.