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Method of producing lithium titanate Invention can be used in making lithium cells used in rechargeable batteries. Lithium titanate of formula Li4Ti5O12-x, where 0<x<0.02, is obtained by preparing a mixture of titanium oxide and a lithium-based component, wherein the lithium-based component and titanium oxide are present in the obtained mixture in amounts required to provide atomic ratio of lithium to titanium of 0.8. The lithium-based component includes lithium carbonate powder and lithium hydroxide powder. The obtained mixture is used as a calcination precursor. Further, the mixture is sintered in a gaseous atmosphere containing a reducing agent to form lithium titanate. The sintering step causes a solid-phase reaction between the lithium carbonate powder and titanium oxide and a liquid-solid-phase reaction between lithium hydroxide powder and titanium oxide. |
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Lithium-cobalt-oxide material and method of its preparation Invention can be used in chemical industry. Lithium-cobalt-oxide material has composition Li1-xCo1+xO2, where x can take values from +0.2 to -0.2, constant sum of coefficients of atom content XLi+YCo=2.0 and represents diamagnetic matrix based on crystallites Li1-xCo1+xO2, partially containing cations Co3+ in octaedric oxygen coordination (Co3+ Oh) in highly spin state. Highly spin cations Co3+ Oh are localised in lithium positions of lithium layer in hexagonal (rhomboedric) structure of crystallites Li1-xCo1+xO2. Fraction of lithium positions, occupied by highly-spin ions Co3+ Oh, constitutes 0.1-0.2. Method of such material preparation includes mixing of lithium- and cobalt- containing precursors, humidifying precursor mixture, suspension evaporation, paste drying and further material burning. As cobalt-containing precursor used is nanodispersed Co2+ hydroxide, containing cations in tetraedric oxygen coordination Co2+ Td. Sum of coefficients of XLi+YCo=2.0 atom content in preserved constant in precursor mixtures. |
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Method of producing high-purity lithium hydroxide and hydrochloric acid Invention can be used in chemical industry to produce crystalline monohydrate of lithium hydroxide which is used in accumulator batteries, and lithium carbonate. The method of producing crystals of monohydrate of lithium hydroxide and hydrochloric acid involves purifying lithium-containing brine via ion exchange in order to reduce concentration of calcium and magnesium ions. The brine undergoes electrolysis to obtain lithium hydroxide solution containing less than 150 ppb of the total amount of calcium and magnesium to obtain gaseous chlorine and hydrogen as by-products. Hydrochloric acid is obtained by burning the obtained chlorine gas with excess hydrogen. Lithium hydroxide solution is concentrated and crystallised to obtain crystals of a monohydrate of lithium hydroxide. |
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Method of receiving monohydrate of lithium hydroxide Method includes causticisation of lithium carbonate by slaked lime with receiving of lithium hydroxide solution and insoluble calcium carbonate. After separating of lithium hydroxide solution from calcium carbonate it is implemented evaporation of lithium hydroxide solution, crystallisation of rough monohydrate of lithium hydroxide from evaporated solution, separation of rough monohydrate of lithium hydroxide from growth solution. Additionally lithium hydroxide solution from the stage of causticisation is evaporated per 85÷90% volume. Growth solution after crystallisation of rough monohydrate of lithium hydroxide is evaporated and from it there is crystallised technical monohydrate of lithium hydroxide. Technical monohydrate of lithium hydroxide is separated from growth solution, which is evaporated in closed loop in common to growth solution from the stage of crystallisation of rough monohydrate of lithium hydroxide. |
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Method for lithium hydroxide purification Claimed method includes lithium hydroxide dissolution in deionized water, three-step sorption purification from mercury and other impurities, filtration, the first boiling down at temperature up to 110°C before crystallization, secondary filtration, boiling down, separation of lithium hydroxide monohydrate crystals from mother liquor in inert gas, and vacuum drying. Boiling down is carried out at 105-107°C and elevated pressure to produce solid/liquid ratio of 1:1. After boiling down pulp is cooled to 25°C with rate of 1.6-1.7 °C/h. After separation of lithium hydroxide monohydrate crystals from mother liquor crystals are washed with lithium hydroxide solution filtered after the first boiling down, wherein washing solution and crystal volume ratio is 1:1. After drying lithium hydroxide monohydrate crystals are screened. |
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Method of cleaning of lithium-7 hydroxide The invention is methods of cleaning of lithium hydroxide. A solution of lithium-7 hydroxide is exposed to subevaporation till its haziness and falling out in a crystal of 0.7-1.0 % of lithium-1 hydroxide. Then the solution is filtrated and evaporated till production of a pulp. The filtration of the solution after subevaporation is carried out in succession in the tight filters with a fabric and metal-ceramic filtering layer with an average size of pores of 0.15 microns at vacuumization of the feeding pipeline. Production operations of crystals separation from a mother solution and their drying are carried out in one apparatus - a centrifugal machine till obtaining crystals of lithium - 7 hydroxide with the contents of the base substance of 55-56 %. The whole process of cleaning is carried out in the tight equipment in a noble gas medium. The method ensures cleaning of lithium - 7 hydroxide from a carbonate-ion up to the contents of ≤ 0.5 % and from the insoluble impurities, and also allows to obtain a product with the share of the base substance of 55-56 %. The product may be used in the capacity of the passivating additive in the contours of the heavy-water nuclear reactors. |
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Method of production of anhydrous lithium hydroxide The invention concerns technologies of production of A method of production of anhydrous lithium hydroxide used in chemical industry. The method of production of anhydrous lithium hydroxide provides for dissolution of the hydroxide, its physical and chemical purification on the mercury cathode from cations of alkali metals, sorption clearing from heavy metals, evaporation, filtration and drying on a steam screw-conveyor drier with a heated screw - dehumidifier. The lithium hydroxide drying is conducted in three stages. At the first stage the drying process is carried out at the temperature of 130-135°C and rarefaction of the air at an inlet in the dryer up to 10 mm of a water column within 30-33 hours till production of a product with a mass share of the base material of 69-73 %. At the second stage the drying process is conducted at the same parameters within 22-24 hours till production of a product with a mass share of the base material of 90-93 %. At the third stage process is conducted at the same parameters within 30-36 hours till production of a product with a mass share of the base material of no less than 98 %. The drying process at all its stages is carried out with a continuous reversible rotation of the screw - dehumidifier. The technical result is production of anhydrous lithium hydroxide with a mass of shares of the base material of no less than 98 % and a mass of ion carbonate shares of no more than 2 % at use of a simple equipment. |
Another patent 2513609.