CS263981B1 - Process for preparing double nickel-magnesium cyclo-tetraphosphates - Google Patents

Abstract

A method for synthesizing double cycling of nickel-magnesium tetraphosphates c-Ni2-xMgxP40i2, where x = (0; 2), lies in the calcination mixture oxide, hydroxide, carbonate or hydroxide nickel and magnesium carbonates and acid phosphoric, taking a heating rate is less than 45 ° C / min 1100 ° C and in the calcination area is the vapor pressure higher than 20 kPa.

Description

263981

BACKGROUND OF THE INVENTION The present invention relates to a process for the preparation of nickel (II) cyclobutyrophosphates.

The nickel-to-magnesium double cyclo-tetraphosphates are represented by the formula c-Ni2_xMgxP40i2, where x may range from near zero to near two. These compounds are distinguished by high router and chemical stability as well as yellow-green coloring, and their use can be color-specific hygienic and environmentally friendly pigments, or in various high temperature materials, or for agro-chemical purposes.

Until now, the only reported process for preparing these substances is their crystallization of the chilled melt, which contains, in the required amounts, phosphate anion together with nickel and magnesium cations. This process for the preparation of double cyclic nickel magnesium magnesium stearate, particularly suitable for preparative laboratory purposes. Thus, although very pure products can be prepared, however, this method is poorly suited for wider technological applications to prepare products for pigmentary or agrochemical purposes that do not require completely pure products. In this method, high energy demands arise, as it is necessary to convert the starting mixture into the melt of the high temperatures and then to leave it in a controlled manner (with constant heating). The technological implementation of this method is also complicated by the necessity of providing a dry atmosphere or vacuum. in the melt space.

The above-mentioned drawbacks are avoided by the preparation of double cyclic tetrafluorophosphates of nickel-magnesium with the formula C-N12-x, MgxP4O12, where x can range from near zero to near two, according to the invention characterized by in that the nickel carbonate oxide, hydroxide, carbonate or hydroxide, together with magnesium carbonate, hydroxide, carbonate or hydroxide-carbonate in the Ni / Mg ratio relative to each other (2-x) / x is calcined with phosphoric acid in the starting mixture, wherein the amount of phosphate anions to divalent cations is equivalent to 0.96 to 1.30, preferably from 1 to 1.04, preferably from 1 to 1.04, with a starting ratio of 0.96 to 1.30. treating the nickel and magnesium compounds with phosphoric acid, preferably a concentration of 30 to 95 percent by weight of H 3 PO 4, and the starting mixture being preferably continued for at least 1 hour freely react, preferably with stirring, and then heat up at a rate of less than 45 ° C / min, preferably at a rate of 1 to 8 ° C / min, to a temperature of 300 to 1100 ° C, preferably to a temperature of 400 to 750 ° C, wherein in the calcination area the water vapor is greater than 20 kPa, preferably 60 to 100 kPa.

The ratio of nickel and magnesium compounds in the starting mixture is selected as required for the content of nickel and magnesium cations in the product. The content of cationic cations (xj can range from near to zero to values near two. The values of nulaani two cannot be used, since then it is not a double product, but pure cyclo-tetraphosphate C-N12P4O12, respectively). o pure cyclo-tetraphosphate di-magnesium c-Mg 2 P 4 O 2.

The amount of phosphoric acid in the starting material, expressed as the molar ratio of P2O5 / (Ni-j-Mg), in the case of the purification of the purified raw materials, was most accurately used according to the stoichiometry (i.e., the stated ratio equal to one). However, depending on the purity of the phosphoric acid used (metal ion content) and the purity of the nickel and magnesium urea (metal admixture), it is necessary to prepare in the range of 0.96 to 1.30, more preferably being phosphate anion is a small excess (1 to 1.04), rather than being more markedly deficient than stoichiometry. The phosphoric acid concentration is thus more advantageous in terms of controlling the condensation reaction, and thus the yield and purity of the product more advantageously; however, this lower concentration, in turn, increases the energy demand of evaporating excess water and increases the bulk of the mixture, which in addition has the character of a thin suspension.

Its calcination then brings technical problems over the calcination of a smaller-volume mixture which is solid or pasty when phosphoric acid is used in the preferred range of 30 to 85% by weight. %. Leaving the mixture containing the phosphate, nickel, and magnesium ions to react for at least one hour is advantageous for the initial reaction of the starting niobium and magnesium compounds with phosphoric acid; this is the neutralization reaction of using hydroxides, or in particular the decomposition reaction of carbonates, since the carbon dioxide liberated and the leakage of the mixture caused by it have complicated the calcination itself. For this reason, it is also preferred to mix the reacting starting mixture. Mixture heating at less than 45 ° C / min. it is chosen that the individual dehydration and condensation reactions proceed in a slower manner at the temperatures (not near them) at which they occur and thus with the highest yield. Otherwise, the intermediates would be undesirably released to release the phosphorus component, which would then condense separately from the polyphosphoric acids, thereby contaminating the main product and reducing its yield. In selecting a very low speed, it is necessary to consider disproportionately prolonging the time of preparation of the product and thus increasing the material and energy costs. In addition, it will be more difficult in this case to keep the space calcined by the blend of water-vapor pressure and thereby prevent possible cleavage of the intermediates. The lower bound of the calcination temperature (300 ClC) is given by the temperature of the gradual formation of the first nickel-magnesium double cyclo-tetraphosphate particles. The upper boundaries of the calcination area (1100 ° C) are related to the thermal stability of the nickel-magnesium double-cyclo-tetrabosphates, which are melting at this temperature. The preferred calcination temperature in the range of 400 to 750 ° C is due to the fact that the double cyclotetrophosphates are formed at a temperature above 400 ° C already at a sufficient rate and initially amorphous products pass through the microcrystals, which are the most suitable form of the intended use. The upper limit of this preferred temperature region (750 ° C) is then due to the fact that at this temperature the formation of double-cyclo-tetra-phosphates took place (if suitable heating rates were used), even at higher water vapor tensions in calcination space. Keeping the water vapor pressure in the space-cooled mixture above 20 kPa is necessary to prevent the formation of undesired by-product condensation products and to prevent cleavage and separate condensation of the phosphorus component. The present water vapor slows down the individual condensation reactions, allowing for a more quantitative course and avoiding the formation of an undesirable non-porous crust of the surface of the particles calcined by the mixture to prevent the quantitative course of the dehydration reactions. It is advantageous to keep the tension vapors above 60 kPa, the pressure is sufficient in this direction. In particular, the upper limit for advantageous water vapor pressure in the calcined mixture space - WO kPa - is the need for increased design, material and energy requirements of the calcining device and the calcination conduit, when using higher pressures, the pressure is not spherical. In addition, the increased braking of condensation and dehydration reactions due to the water vapor pressure above 100 kPa bv again disproportionately prolonged the product preparation time.

The principle of the present invention furthermore comprises treating the product with hydrochloric, sulfuric, nitric or phosphoric acid, preferably a concentration of 0.5 to 10. Optionally, this operation is carried out as a purification of the product obtained in a needy manner. By the action of these acids, all undesirable byproducts and possibly residues of the starting mixture are removed and thus dissolved. The double-cyclo-tetrafluorophosphates have a resistance to these acids. If the nickel-magnesium cyanoboronates are prepared for use in pigmentary or agrochemical applications and are preferably prepared under the conditions of the invention, it is not necessary to carry out such purification.

The process makes it possible to prepare nickel-magnesium double-cyclo-tetraphosphates under technologically feasible conditions, with sufficient yield and with sufficient product purity. It also allows the use of low-quality raw materials - diluted and less pure phosphoric acid and less pure nickel compounds. Under the conditions of preparation of the products according to the invention, it is possible to prepare almost pure nickel-magnesium polycyclic tetraphosphates. In the case of obtaining less pure products, the process according to the invention can be purified. The following are examples of the preparation of double nickel-magnesium polyphosphates by the method of the invention. EXAMPLE 1 100 g of nickel carbonate (containing 49% Ni) and 70 g of magnesium carbonate (containing 29% Mg) were mixed with 508 g of phosphoric acid (65% H3PO4) and allowed to react for 5 hours at intervals. Then the mixture was heated at 3 ° C / min. 600 5C with 2 hours at this temperature. The water vapor pressure in the calcined mixture was maintained at 85-95 kPa. 332.9 g of product were obtained, which contained 90% by weight of double cyclo-tetrafluorophosphate c-NiMgP40l2. Example 2 100 g of nickel carbonate hydroxide (54% Ni) and 21.3 g of magnesium carbonate hydroxide ( with 35% Mg) was carefully mixed with 545 g of phosphorus concentration of 45 wt. % H 3 PO 4 and allowed to react freely for 6 h with occasional stirring. Thereafter, the mixture was heated to a rate of 6 "U / min for ten hours of 550 ° C for 3 hours at this temperature. The water vapor pressure in the space of the calcined mixture was maintained at 75 to 85 kPa. 255 g of product were obtained, which was further purified by curing with 4% by weight hydrochloric acid. % HCl After washing with water and drying at 160 ° C, 266 g of product containing 97% C-Ni, 5MgO 5 P40: 2 was obtained. Example 3 50 g of nickel carbonate (containing 49% Ni) and 126.9 g of magnesium hydroxide slurry

Claims (2)

263% (containing 24% Mg) was cautiously mixed with 393 g of phosphoric acid to a concentration of 85% by weight. % H3PO4 and allowed to stir for 3 hours spontaneously. Thereafter, the mixture was heated at 3 ° C / min at 500 ° C for 4 h at this temperature. A process for the preparation of nickel-magnesium double-cyclo-tetrabosphate c-Ni 2-xMgxP 40i 2, wherein x may range from near zero to near two, characterized in that the oxide, hydroxide, carbonate or nickel hydroxide carbonate, together with magnesium oxide, hydroxide, carbonate or hydroxide, in the Ni / Mg ratio relative to each other (2-x) / x, is calcined with phosphoric acid in the starting mixture, the amount of phosphate anions corresponding to divalent cations is a molar ratio of P 2 O 5 / µNi-1-Mg) of 0.96 to 1.3, preferably 1 to 81%, by weight. The water vapor pressure in the space of the calcined mixture was maintained at 80-90 kPa. 318.9 g of product were obtained, which contained 91.5% of cyclo-tetrafluorobutane-magnesium double c-Ni0.5Mg1.5P4O12. EXAMPLE 1.04, wherein the starting mixture is prepared by treating the nickel and magnesium compounds with phosphoric acid, preferably a concentration of 30 to 85% by weight of H 3 PO 4, and the starting mixture is preferably left for at least 1 hour, react freely, preferably with stirring, and then start with a heating rate of less than 45 ° C / min, preferably 1 to 8 ° C / min, to 300 to 1100 ° C, preferably 400 to 750 ° C, wherein in the calcination area the water vapor pressure is greater than 20 kPa, preferably 60 to 100 kPa. 2. A process according to claim 1, wherein the product is calcined with hydrochloric, sulfuric, nitric or phosphoric acid, preferably 0.5 to 10% by weight. Severografla, n. P “Plant 7, Most Price 2.40 KCs