146 results about "Bischofite" patented technology

A process for preparing high-purity magnesium sand from the bischofite of salt lake includes such steps as preparing high-concentration saline from bischofite, depositing magnesium by ammonia method including adding crystal seeds, controlled reacting, depositing particles of magnesium hydroxide, filtering, washing, drying and two-step calcining to obtain target product containing MgO (more than 99.95%).

The invention aims at providing a method for converting and storing solar energy with low-hydration magnesium chloride as an energy storage working medium and relates to effective utilization of magnesium in salt lakes and storage and conversion of solar energy. The method particularly includes: in the periods when solar radiation is sufficient in the daytime, the solar radiation is received through a flat solar thermal collector, heat is transferred to a one-time dehydration fluidized bed loaded with bischofite (MgCl2 6H2O), the temperature of the bed is increased to the dehydration temperature, then the MgCl2 6H2O loses the crystal water to form the low-hydration magnesium chloride (MgCl2 4H2O), conversion from the solar energy to chemical energy is achieved, and water vapor generated by the reaction is delivered to a steam turbine set to generate electricity; and in the nighttime or when the solar radiation is insufficient, the water vapor is enabled to enter the dehydration fluidized bed where the low-hydration magnesium chloride is stored, under the condition that the temperature and the partial pressure of the water vapor are controlled, the low-hydration magnesium chloride is enabled to be subjected to hydration reaction, the number of crystal water molecules is increased to form MgCl2 6H2O again, absorption (hydration) heat is released, the conversion from chemical energy to thermal energy is achieved, and the released heat is transferred to a heat preservation water tank so as to generate water vapor to drive the steam turbine set to generate electricity.

The invention discloses a method for producing potash magnesium sulphate fertilizer, comprising the following steps: a, crushing and grinding natural potash feldspar used as a raw material, screening the crushed raw material with a sieve of 150 meshes; b, adding proper amount of salt lake high-temperature salt of salt lake kalium extracting waste taking bischofite as a main component, baking for 2 to 3 hours at middle temperature under HCl protective atmosphere or sealed condition; c, after water quenching and solution leaching, adding salt lake kalium extracting waste epsomite into the solution obtained by filtrating, and evaporating the solution to concentrate and crystallize so as to obtain potash magnesium sulphate fertilizer. Compared with the prior art, the invention has advantages of taking magnesium salt lake kalium extracting waste as additive, having low baking temperature and simple separation process, recycling potassium chloride, potassium sulfate, picromerite and kainite left in the salt lake waste, being more feasible in economics, so that the potash magnesium sulphate fertilizer prepared by the method provides a plurality of nutrient elements for crops.

The invention relates to a method for preparing basic magnesium chloride and magnesium oxide by pyrolyzing bischofite. The method is characterized by adopting section calcining, recovering HCl in a section manner, particularly pressurizing and spraying the hot solution of refined bischofite under the temperature of 130 to 150 DEG C to a reaction kettle, carrying out primary calcining under the 250 to 300 DEG C after removing parts of crystal water with the calcining time of 1 to 3 hours, and obtaining the product of basic magnesium chloride (MgOHCl); absorbing the tail gas with water to obtain hydrochloric acid; the washing the calcining product which contains little amount of undecomposed magnesium chloride hydrate to obtain the basic magnesium chloride (MgOHCl); carrying out secondary calcining on the obtained MgOHCl under a temperature of 450 to 500 DEG C with the calcining time for 1 to 3 hours to obtain MgO, and cooling and recovering the produced HCl to obtain hydrochloric acid. The method has the advantages of low calcining temperature, little equipment corrosion, little energy consumption, high HCl recovery rate, simple technique, high product purity and low cost.

The invention relates to method to dewater to bischofite and electrolyse to obtain magnesium. Wherein, using improved reaction crystal coupling dewater technique to prepare anhydrous magnesium chloride with magnesia of 1-2% more cheaper, adding new electrolyte system with fluorides (such as, MgF2, LiF, NaF and CaF2) and rare-earth chloridate (such as, NdCl3, LaCl3) to increase effectively the solubility of MgO in complex electrolyte system and make the said anhydrous magnesium chloride fit to the require raw material, eliminating the negative effect of MgO in the process. This method can increase the current efficiency, makes the MgO impurity achieve 3%, and decease dewatering cost.

The invention discloses a method for preparing rod-like magnesium hydroxide from salt lake brine. The method comprises the following steps of: concentrating and crystallizing salt lake brine, from which elements such as potassium and lithium are extracted, serving as a raw material to obtain bischofite; dissolving the bischofite separated by crystallization into water to prepare magnesium chloride solution; introducing ammonia gas to perform magnesium precipitation reaction; when the pH value reaches 7-8, stopping introducing the ammonia gas, reacting at the temperature of 30-50 DEG C for 0.5-2 hours, aging and filtering to obtain alkaline magnesium chloride and magnesium precipitation mother liquor; dispersing the alkaline magnesium chloride in mixed solution of ethanol and water to obtain alkaline magnesium chloride suspension; adding sodium hydroxide to further precipitate to obtain rod-like magnesium hydroxide; filtering and separating to obtain magnesium precipitation mother liquor; replenishing the bischofite and circulating for precipitating the alkaline magnesium chloride; feeding to an ammonia still process along with concentration enrichment of magnesium precipitation mother liquor in ammonia chloride; performing ammonia still with lime; and circulating the produced ammonia gas to precipitate the alkaline magnesium chloride of a next batch and producing byproduct calcium chloride, wherein the magnesium content in the brine is not less than 93.4 g/L. The method has the advantages of high product purity, good economic benefit, no environmental pollution, high operability and easiness for industrial production.

The invention provides a method for preparing a composed calcined dolomite by taking the byproduct of brine ( a saturated liquor which is mainly magnesium chloride ) after potassium extraction or the bischofite separated out from the brine by naturally evaporating as the materials to react with excess lime to prepare the floccule mixture of magnesium hydrate and calcium hydroxide; then the mixture is calcined and dehydrated under the temperature of 400 to 1200 DEG C after the mixture is deposited, filtered, washed, dried and cracked. The materials of the invention are easily obtained and cheap; the production process is simply and easily controlled; no carbon dioxide is discharged; besides, the invention basically has no corrosion to a device. The mol ratio of MgO to CaO in the composed calcined dolomite is within the range of 1:0.8 to 1:1.2; the activity of water is 25 to 36 percent; the composed calcined dolomite is applicable for the areas rich in the resource of magnesium chloride to use a Pidgeon process to produce the metal of magnesium.

The invention discloses a method for preparing magnesium hydroxide, magnesium and magnesium aluminate spinel by bischofite and belongs to the field of magnesium metallurgy and chemical industry. The method comprises the steps of: taking bischofite as a raw material to produce magnesium hydroxide, hydrogen gas and chlorine gas through electrolysis, and then taking magnesium oxide, which is obtained by calcining magnesium hydroxide, as a raw material to produce magnesium metal and magnesium aluminate spinel through vacuum thermal reduction. The by-product, i.e., bischofite, during extraction of potassium salt and lithium salt in west salt lakes and in the salt manufacturing industry of the eastern coastal regions, is utilized for producing the magnesium hydroxide, magnesium oxide and magnesium aluminate spinel, therefore, the purpose of changing waste into valuable is realized. Compared with the traditional electrolysis technology of fused magnesium chloride, the method has the characteristics of low energy consumption, low cost, small environment pollution and the like.

The invention relates to the technical field of salt chemistry, particularly relates to a method of continuous dissolution of salt lake bischofite to prepare a high-concentration magnesium chloride solution, to a production device for achieving a process of large-scale bischofite dissolution to prepare refined brine, and provides a industrial demonstration effect route for developing magnesium series oxides in the Qinghai salt lake in the future. The method includes steps of: unloading bischofite, conveying and loading the material by conveying belts, feeding, dissolving into brine, allowing crude brine to overflow, performing magnesium chloride fine grain separation, buffering the brine, thickening and depositing the brine, obtaining a first-step clear liquid, subjecting the first-step clear liquid to first-step filter pressing, obtaining a second-step clear liquid, subjecting the second-step clear liquid to second-step filter pressing, squeezing and filtering the bottom material of a thickening machine, conveying mud cake, subjecting the brine to accident handling, and conveying and storing the refined brine so as to obtain the brine with technical indexes meeting requirements of ammonia gas combined reactions. The concentration of Mg<2+> in the refined brine is 115+/-3 g/L. The refined brine is clear, transparent and free of solid suspension impurities.

The invention relates to a method for preparing magnesia for magnesium cement by using bischofite and dolomite. The method comprises the following steps of: (1) grinding dolomite calcined at the temperature of 900-1,000 DEG C into dolomite powder, and digesting the dolomite powder into caustic dolomite lime milk with a calcium chloride solution; (2) preparing a magnesium chloride solution, dissolving bischofite with water into a magnesium chloride solution of which the specific weight is 1.19-1.23 g/cm<3>; (3) reacting the magnesium chloride solution obtained in the step (2) with the caustic dolomite lime milk obtained in the step (1) while stirring in a constant-temperature water bath to generate a magnesium hydrate precipitate; (4) washing the magnesium hydrate precipitate with water for multiple times, and performing suction filtration to obtain a filter cake; and (5) drying the filter cake, calcining at the temperature of 500-600 DEG C for 2-4 hours to obtain a sinter, naturally cooling the sinter, smashing and packaging to obtain magnesia for magnesium cement. The method has the advantages of simple process, good product quality, low cost and easiness for realizing industrial production.

The present invention relates to chemical and metallurgical technology, and is especially process of preparing anhydrous magnesium chloride through dewatering bischofite. The process includes the first reaction of aniline hydrochloride and bischofite to produce aniline hydrochloride-magnesium chloride hexahydrate complex salt, the subsequent spray drying and pelletizing the complex salt, and final eliminating crystallized water and aniline hydrochloride in a fluidized bed to obtain the anhydrous magnesium chloride product. The present invention has the advantages of low power consumption, simple technological process, easy industrial amplification, environment friendship, stable product quality, etc.

The invention provides a technology for producing and preparing high-purity lamellar magnesium hydroxide, which can solve the problem that the magnesium hydroxide is difficult to filter, so that the purity is difficult to improve. The basic technology comprises the following steps: taking bischofite or magnesium chloride as a main raw material, taking hydrogen sodium as a main precipitating agent, adding crystal seeds before the reaction, carrying out liquid phase precipitation reaction at 15-100 DEG C, simultaneously adding a crystal accelerator, and sequentially carrying out thermal insulation aging, filtering, washing and drying after the reaction is finished, thereby obtaining the lamellar magnesium hydroxide with the purity of more than 99%. The technology can solve the problem that the magnesium hydroxide is difficult to filter and has the advantages of simple technology, low cost and high utilization rate of magnesium.

The invention provides a method for continuously preparing highly pure magnesium hydroxide which relates to a method for continuously producing highly pure magnesium hydroxide with bischofite as raw material and ammonia as precipitant. The method is characterized in that: a treated bischofite is prepared into a solution with the concentration of 0.5 mol/L-4 mol/L, the bischofite solution and ammonia gas are added continuously after the reaction begins and the chemical reaction for depositing the magnesium hydroxide is carried out continuously. Characteristics of the reaction vessel utilization ratio, the productive capacity of unit volume, technical reliability and stability and so on of the method are greatly improved compared with intermittent reaction technology. The base liquid does not need to be replaced or heated repeatedly, thus energy-saving effect is distinct and labor productivity is high. The method can be used for obtaining magnesium hydroxide with the granularity of 10 microns-100 microns and the purity of 99 percent-99.999 percent. The ammonia nitrogen treatment of the tail solution adopts a commercial method that meets environmental protection requirement. The product produced by the invention has large granule size, high purity, more specifications, low cost, high equipment utilization rate and low one-time investment and has no pollution to the environment.

A process for preparing metal Mg from bischofite includes removing impurities, spray drying at 150-450 deg.C, calcining at 550-1200 deg.C to obtain MgO, proportionally adding calcium compound, ferrosilicon or silicoaluminium as reducer and fluorite as catalyst, mixing, sphericizing and vacuum reducing at 1150-1200 deg.C for 6-10 hr.

The invention provides a method for depositing highly pure magnesium hydroxide with a liquid ammonia-ammonia twofold-gang and relates to a method for continuously producing the highly pure magnesium hydroxide with a bischofite as raw material and ammonia and ammonia water as a precipitant. The treated bischofite is prepared into a solution with the concentration of 0.5 mol/L-4 mol/L, the precipitant is supplied by ammonia gas at the early stage of the reaction, then the precipitant is provided by the ammonia water reclaimed from the decomposition of the reaction product, ammonium chloride, the ammonia gas supplements the rest amount and the reaction process can be carried out continuously or intermittently. The method can be used for producing the magnesium hydroxide with the granularity of 10 microns-100 microns and the purity of 99 percent-99.999 percent. The product, ammonium chloride, adopts alkaline splitting and vacuum ejection flow to reclaim the ammonia gas, prepare the ammonia water for recycling utilization. The product produced by the invention has large granule size, high purity, more specifications, low cost, high equipment utilization rate, high reliability and stability of the technique, low one-time investment and has no pollution to the environment.

A method of preparing magnesium metal with bischofite, pertains to the field of metallic material. The invention is characterized in that it takes the bischofite as stock and prepare magnesium hydroxide with ammonia process under the following conditions: at the temperature between 45~55 DEG C for 20~30 minutes, with the proportion between magnesium and ammonia 1:1.2~1.5:2.2 and with the concentration of magnesium chloride about 35~55 g/L, calcinating the magnesium hydroxide under the temperature of 900~1000 DEG C for 3-4hours, getting the magnesia with the purity of more than 99.5%,in the molten salt electrolyte system of lanthanum chloride and magnesium chloride, the proportion between lanthanum chloride and magnesium chloride in moles is 10~30%, the solubility of magnesia is 5~10 mass%, thaw temperature is 700~750 DEG C, the tank voltage 4.5~6.5 volt, the current efficiency comes to 85~90%, the consumption of the direct current of magnesium is 11~12.5kWh per kilogram and the purity of magnesium is above 95%. The method avoids the dehydration process of bischofite and is characterized by the energy-saving and consumption-deducing, the highly effective and cleaning of electrolytic process, particularly for its not emitting chlorine and not polluting the environment.

A process for preparing low-Na carnallite by removing halogen includes such steps as sunning in salt field for natural evaporating to obtain bischofite, mixing it with unsaturated brine, stirring until the content of Mg ions is not less than 8%, adding carnallite, dehalogenating-crystallizing reaction, and filtering.

The invention discloses a method for preparing battery-grade lithium carbonate from lithium sulfate crude ores and recovering byproducts. The method comprises the following steps: preparing battery-grade lithium carbonate; preparing mixed salt of gypsum, bischofite and borate; and preparing salt cake. According to the method, lithium chloride mother liquor generated by lithium precipitation and asodium sulfate solution are adopted for primary pulp washing, so that the loss of lithium sulfate can be reduced, and the recovery rate is increased; a recycled solution L4 containing lithium carbonate is taken as a pulp washing solution to carry out secondary pulp washing, soluble calcium and magnesium ions are removed, and lithium in the recycled solution is recovered; the filtrate L5 obtained after solid-liquid separation of the secondary pulp washing contains lithium, and is returned to the primary pulp washing as supplement, the loss of the primary pulp washing is reduced while soluble impurity ions are dissolved; the secondary lithium sulfate concentrate is dissolved by mirabilite preparation mother liquor L6, NaCl mixed salt is separated out in the dissolving process, and lithium isprecipitated. According to the method, the crude lithium carbonate is subjected to pulp washing by adopting the recycling solution containing lithium carbonate, so that the lithium yield can be increased while the system discharge is reduced.

The invention provides a method for preparing anhydrous magnesium chloride. The method comprises steps of dehydrating bischofite so as to form magnesium chloride tetrahydrate, then dehydrating magnesium chloride tetrahydrate so as to obtain magnesium chloride dihydrate, fusing magnesium chloride dihydrate so as to obtain melt, keeping the melt warm and clarifying the melt so as to obtain supernatant liquid, and cooling the supernatant liquid so as to obtain anhydrous magnesium chloride. The method is simple, has low requirements on equipment, and is easy for industrial production.

The invention relates to a method for preparing magnesium hydroxide and chlorine by coupling magnesium chloride reactive crystallization and electrolysis. A magnesium hydroxide product is obtained by firstly adopting bischofite and sodium hydroxide as raw materials, adding a chloride as an additive and controlling crystallization. The purity of the magnesium hydroxide product is more than 99.5%, and the magnesium hydroxide product is uniform in grain size distribution and has better dispersibility. Sodium hydroxide and chlorine are prepared by electrolyzing the byproduct sodium chloride in the process. Sodium hydroxide is used as a raw material for reactive crystallization. Magnesium hydroxide and chlorine can be sold as products. Compared with the prior art, the method has the positive effects that the adding of the chloride as the additive is beneficial to improving the crystallization property and dispersing property of magnesium hydroxide, thus solving the problems that magnesium hydroxide filter cakes produced by original sodium hydroxide methods are difficult to filter and wash and have low purity; meanwhile, the process achieves comprehensive utilization of resources and promotes circular economic development; the method is simple in process flow and convenient to operate and easily achieves large-scale industrial production.