摘要:
The present invention relates to a priming or body paint having active anti-corrosive and surface cleaning effect containing binding material, pigment and optionally solvent, filler and/or additives, characterized in that said pigment, optionally in addition to other known pigments, comprises:(a) 30-70% parts by weight, preferably 40-55% by weight of alumina hydrate (Al/OH/.sub.3),(b) 20-55% by weight of at least of one of atoxic oxides, hydroxides, oxide hydroxides, carbonates or phosphates of amphoteric elements or metals of variable valency possessing less valency than the maximum, in case of aluminum the oxide or hydroxide thereof,(c) 0-50% by weight, preferably 2-15% by weight of calcium and/or magnesium carbonate,and the grain size thereof is
摘要:
An air-jet mill provided with pregrinding chambers and inner sizer suitable for fine grinding (below 10 .mu.), for cryogenic grinding and also for surface treatment during grinding of hard, elastic and/or thermoplastic materials.During operation there are no moving components to be exposed to heavy wear, and an inner sizer, forming an integral part of the grinding space, uses the energy left after grinding in the system to enable a sharp sizing or separation of fine fractions.
摘要:
An apparatus for separating a slurry into phases containing larger and smaller grains has an upright tank in which a plurality of downwardly extending inlet pipes open at their lower ends between outlets for the coarse and fine phases located at the bottom and top of the tank, respectively. At the lower end of each inlet pipe, an upwardly widening frustoconical cup is provided with a bottom confronting the open end of the inlet pipe to deflect the slurry upwardly and outwardly. Within the cup swirl vanes impart a swirl to the slurry.
摘要:
A method of and apparatus for the mixing of a slurry in a tank having a conical bottom along the axis of the tank, and air-lift pipe is provided which is supplied at its lower end with compressed air to induce an upward flow of the slurry and air mixture through the pipe during start up of a mixing operation. Thus an injection is cut off when steady state is reached and air is injected at an upper level in the pipe located in the upper third of the length thereof but below the upper eighth for continuing mixing operation.
摘要:
The invention relates to a method of burning, calcining or sintering fine-grain material in which the burnt material separated from the gas flow is supplied to a residence container from which a part of the material is returned to the burning zone and the remainder of the material is supplied to the cooling zone. Such a method is distinguished by a low heat and energy requirement and by a simple construction of the apparatus and permits ideal adaptation of the burning conditions to the particular material.
摘要:
The invention relates to a new method of reducing the organic substance content of alum earth production cycle performed according to the Bayer technology. By the method of the invention the majority of the organic substances present in the circulating lye can be removed easily and with only slight losses in sodium content.According to the invention one proceeds so that soda present in the hydrate wash and/or in the soda salt solution is caustified with lime, the solution is evaporated to reach a total sodium oxide concentration of 200 to 400 g/l, the precipitated solid is separated and removed from the system, and the liquid is recycled.
摘要:
The invention relates to a process for preparing alumina being suitable for layer chromatography.The alumina suitable for layer chromatography is prepared in accordance with the invention in such a manner that an aluminium trinydroxyde containing 34 to 37% by weight of bayerite, 3 to 5% by weight of pseudoboehmite and 60 to 62% by weight of amorphous aluminium trihydroxide is heated at 300.degree. C. to 400.degree. C. for 2 to 4 hours.The activated alumina thus produced is snow-white, has a large specific surface and its average grain size is within the range between 8 and 20 .mu.m.The product complies with the requirements of layer chromatographical technique.
摘要:
According to the invention, the grains of the hydrate slurry are separated by sedimentation where the dispersed bubbles of air are removed in course of the presizing, then a supplementary sizing is carried out. Preferably, a liquid free from hydrate grains is fed in to stream against the sinking grains. This liquid is advantageously the spent liquor of the hydrate filter. The apparatus according to the invention consists of a container with conical bottom, a feeding device, a slurry outlet stub and an overflow channel. The inlet stubs of the feeding device, however, are placed off-center and every stub is connected with a presizing equipment. This equipment is composed of a bundle of pipes and/or a pack of plates which are slop placed to geometrical axis: At the upper part of the presizing equipment there is a foam overflow apparatus. The bottom of each presizing equipment is connected with a common cone-frustum type deflector casing. The casing is concentric with the container. There is ring shape gap between the upper edge of the deflector casing and the cylinder jacket of the container. Under the deflector casing there is an upwards convex control cone. The control cone is vertically adjustable and concentric with the deflector casing.
摘要:
The invention relates to a process for the reduction of sodium hydroxide losses of the Bayer-cycle by modified causticization of red mud which comprisessubjecting an optionally previously concentrated red mud slurry led off from the red mud washing line by ramification and containing a liquid phase which has a concentration of 5-40 g. caustic Na.sub.2 0/1. caustification by adjusting the lime content expressed as CaO through addition of lime or lime milk to 1-3.2 moles per mole Al.sub.2 O.sub.3, preferably to 2-2.5 moles per mole Al.sub.2 O.sub.3, related to the total Al.sub.2 O.sub.3 content of the slurry;stirring the slurry for 0.3-5 hours at a temperature of 70.degree.-110.degree. C., preferably at 80.degree.-100.degree. C.;adding to the slurry 3-4 moles, preferably 3.2-3.4 moles, of soda related to 1 mole of the originally dissolved Al.sub.2 O.sub.3, and continuing the stirring for 1-4 hours at 80.degree.-100.degree. C., preferably at a temperature of 90.degree.-95.degree. C.;if necessary causticizing the excess of soda by adding lime or lime milk by methods known per se;if desired concentrating the slurry thus obtained and re-introducing the liquid phase thereof to the red mud washing unit which corresponds to the sodium hydroxide content thereof;and re-entering the slurry to the red mud washing line.The advantages of the process of the present invention are as follows: the sodium hydroxide losses of different origin of Bayer-type alumina production are recovered by a single operation step, the process is simple, requires no expensive equipment and is economical.
摘要翻译:本发明涉及通过红泥的改性苛化来降低拜耳 - 循环的氢氧化钠损失的方法,该方法包括将由红泥浆清洗线引出的任选预先浓缩的红泥浆经分散和含有液相 浓度为5-40g。 苛性钠Na20 / 1。 通过将石灰或石灰乳添加为1-3.2摩尔/摩尔Al 2 O 3,优选为2-2.5摩尔/摩尔Al 2 O 3,通过调整CaO表示的石灰含量与浆料的总Al 2 O 3含量相关; 在70-110℃,优选在80℃-100℃下搅拌该浆料0.3-5小时。 向浆料中加入3-4摩尔,优选3.2-3.4摩尔与1摩尔原始溶解的Al 2 O 3有关的苏打,并在80℃-100℃下,优选在 90°-95℃。 如果需要,通过本身已知的方法加入石灰或石灰乳来苛化苏打水; 如果需要浓缩由此获得的浆料并将其液相再引入对应于其氢氧化钠含量的红泥洗涤单元; 并将浆料重新进入红泥清洗线。 本发明方法的优点如下:通过单一操作步骤回收拜耳式氧化铝生产不同来源的氢氧化钠损失,工艺简单,不需要昂贵的设备,而且经济。
摘要:
The invention relates to plant operations for increasing the cycle times of heat exchangers by the digestion of the aluminium oxide content of a slurry according to the Bayer technology, said slurry consisting of bauxite and sodium aluminate liquor, using an equipment in which the material is heated stepwise and in more parallel material streams, then the material streams are combined and further heated, or combined and kept at the same temperature, or after combination further heated and kept at the same temperature, characterized in that a part of the parallel material streams is slurry, another part of same is aqueous sodium hydroxide solution, preferably sodium aluminate liquor containing sodium hydroxide, or water, and the parallel material streams are exchanged in the heat exchangers in a cyclical manner.