摘要:
A novel anhydrous sodium tripolyphosphate, well adapted as an additive for foodstuffs and detergent compositions, has an Na/P ratio of essentially 1.667.+-.0.01, an apparent density of from 0.5 to 1.1, a mean agglomerate size of less than 100 microns, a phase I content ranging from 15 to 6% by weight, is devoid of insoluble fraction, and displays zero solidification or caking in a quiescent solvent medium.
摘要:
A process for treating a rock essentially constituted by calcium aluminophosphate, comprising the treatment of the ground rock with a concentrated sulfuric acid in stoichiometric excess with respect to calcium and aluminum, at a temperature of above about 120.degree. C., for a time between a few minutes and about 5 hours, followed by controlled water take-up. Subsequently, a residue containing substantially all the calcium and the aluminum of the rock and a solution of the acids serving to digest a tricalciumphosphate charge are separated. The process is particularly suitable for the treatment of Thies phosphate ore.
摘要:
A catalyst support and process for preparing same are provided wherein a metal substrate is coated with a layer of adherent alumina with a layer of chromium interposed between the alumina catalyst support and the metal substrate. The catalyst supports of the invention are especially useful in catalytic converters for the purification and control of exhaust gas emissions from internal combustion engines by the active catalyst oxidation/reduction of carbon monoxide, unburned hydrocarbons and nitrogen oxides.
摘要:
A neodymium hydroxynitrate, readily calcined into, e.g., neodymium oxide, Nd.sub.2 O.sub.3, has the formula (I):Nd(OH).sub.2 NO.sub.3.1H.sub.2 O (I)
摘要翻译:具有式(I):Nd(OH)2 NO 3·1H 2 O(I)的硝酸钕,易于煅烧成例如氧化钕Nd 2 O 3,
摘要:
Rare earth hydroxides are recovered from the rare earth ores, e.g., monazite, xenotime and/or bastnasite, by treating the ore with an aqueous solution of an alkali metal hydroxide, under agitation and essentially constant pressure, at a temperature of from about 100.degree. to 220.degree. C., and wherein the ratio by weight of alkali metal hydroxide/ore ranges from about 1.4 to 0.5, e.g., a weight ratio of sodium hydroxide/ore of from about 1 to 0.5, or a weight ratio of potassium hydroxide/ore of from about 1.4 to 0.7.
摘要:
Zeolites of type ZSM-5, well suited as absorbents/catalysts, are facilely prepared by (i) intimately admixing a source of alumina with a source of silica, in aqueous reaction medium having a pH ranging from 1 to 7 and wherein the molar ratio SiO.sub.2 /Al.sub.2 O.sub.3 ranges from 5 to 100, (ii) adding a source of alkali metal oxide to the reaction mixture resulting from said stage (i), said combined reaction mixture having a pH ranging from 8 to 12, and thence (iii) crystallizing a zeolite of type ZSM-5 therefrom.
摘要翻译:类似于ZSM-5的沸石,非常适合作为吸收剂/催化剂,通过(i)在pH为1-7的含水反应介质中将氧化铝源与二氧化硅源紧密混合而容易地制备,其中摩尔比 SiO 2 / Al 2 O 3的范围为5至100,(ii)将碱金属氧化物源加入到由所述阶段(i)产生的反应混合物中,所述组合反应混合物具有8至12的pH,因此(iii) ZSM-5型沸石。
摘要:
A fine powder of stabilized zirconia a process for its preparation and application of the powder in ceramic compositions to obtain good mechanical, thermomechanical and electrical properties.A zirconia hydrate sol having a pH between 0.5 and 5 and containing elementary acicular crystals having dimensions of from about 10 to 500 .ANG. which are agglomerated into submicron aggregates of from abuot 100 to 5000 .ANG. in diameter is mixed with a solution of a stabilizing agent, preferably yttrium; the suspension is dried; the dried suspension is calcined at a temperature of from about 700.degree. C. to 1,300.degree. C. for preferably from about 30 minutes to 24 hours; and if needed, the powder obtained is milled.
摘要:
Submicronic zirconia particulates containing stabilizing amounts of yttrium or cerium, well adapted for ceramics applications, are produced by (i) admixing an aqueous suspension of zirconium fluosulfate particles having a pH of from about 0 to 3 with an aqueous solution of a salt of yttrium or cerium, (ii) neutralizing the resulting mixture at a pH of at least 7, (iii) separating a mixture of zirconium/yttrium or zirconium/cerium hydroxides from the medium of neutralization, (iv) washing said mixture of hydroxides to eliminate sulfate and fluoride ions therefrom, and then (v) calcining said mixture of hydroxides.
摘要:
A fine powder of neodymium titanate or barium neodymium titanate, a process for its preparation and applications in ceramic compositions. A suspension of particles is formed by mixing a solution of neodymium nitrate or a solution of barium and neodymium nitrates with a sol of titania having a pH of from about 0.8 to 2.5 which contains elementary crystallites of TiO.sub.2 having a size of from about 10 to about 100 .ANG. in diameter which are agglomerated into submicron masses of from about 200 to about 1,000 .ANG. in diameter. The suspension obtained is dried, and the dried product is calcined at a temperature between 800.degree. C. and 1,300.degree. C., preferably for about 1 to 24 hours. If necessary, the powder obtained is milled. The fine powder obtained has a low fritting temperature and its density after heating for 2 hours at 1,300.degree. C. is greater than or equal to 95% of the theoretical density of the desired titanate powder.
摘要:
A novel sodium orthophosphate has the formula Na.sub.5 H.sub.4 (PO.sub.4).sub.3 wherein the Na/P ratio thereof is essentially 5/3, and which is characterized by but a single crystalline phase and a characteristic X-ray diffraction pattern.