Vanadium pentoxide products are more and more widely used, the market is expanding, and the sales price is rising rapidly. Vanadium pentoxide roasting rotary kiln process is mainly divided into wet vanadium extraction method and fire vanadium extraction method.
Wet vanadium extraction process is also called acidification vanadium extraction technology. It has strong selectivity for ore and large acid consumption in production. 15 ~ 25 tons of sulfuric acid are required for 100 tons of ore. during liquid treatment, the liquid needs to be adjusted to neutral, the alkali consumption is also high, the ton cost of intermediate raw materials is too high, and the waste residue stacking causes a certain amount of environmental pollution. Fire vanadium extraction method is to roast the ore in a rotary kiln and then extract vanadium by leaching. The roasting method is different from that of additives.
Flat kiln roasting method
Flat kiln roasting is a classical roasting method. Through practice, the biggest defect is that the conversion rate is unstable, because the rising speed of air flow is different, the conversion rate error is large in the four seasons of the year, and there are errors in the whole day. This roasting method is to prepare the calorific value of ore material in advance, and control the change of air flow rising speed by adjusting the chimney damper. This adjustment method is difficult to find the best point, so the roasting conversion rate is between 40 ~ 50%.
Multi chamber furnace roasting method
Sichuan Panzhihua Iron and Steel Co., Ltd. was the first to use multi chamber furnace roasting method to extract vanadium in China. The roasting temperature of roasting vanadium slag in high temperature zone is 720 ~ 800 ℃. In 2006, Chenxi giant Vanadium Industry Co., Ltd. also chose this roasting method, and the use effect of the two units was not ideal. The main reason is that the optimal roasting temperature band in the high temperature section of vanadium bearing coal mine is relatively narrow, only the error fluctuation of 10 ~ 20 ℃, and the residence time of ore in the high temperature section is not well controlled. Because vanadium is a continuous oxidation and conversion process in roasting, the residence time at the optimal temperature point should be controlled at 5 ~ 6 hours in order to achieve the highest conversion rate. This roasting method is to prepare the calorific value in advance and adjust the temperature through the amount of air blown in. The material is a process of continuous heat consumption from top to bottom. It is not feasible to stay at a certain temperature point for 5 ~ 6 hours. This furnace type needs to be improved for the roasting of vanadium bearing coal mines.
Fluidized bed furnace roasting method
At present, fluidized bed furnace is used to extract vanadium from vanadium bearing stone coal mines. The success is only in the step of ore decarburization, and its conversion rate is only less than 10%. So far, there is no case that the conversion rate is more than 40%. Although there are many patent skills about the excellent effect of fluidized bed furnace roasting vanadium bearing stone coal mine, they are only words, which are rarely used in production practice and are very dangerous. The difficulty of roasting vanadium bearing stone coal mine in fluidized bed furnace is that the residence time of ore in the furnace is too short. To extend the residence time, only the volume of fluidized bed furnace can be expanded infinitely, which has high cost and great danger. Another defect of fluidized bed roaster is insufficient contact between ore and additives, which can not reach the full load conversion rate and poor economy.
Rotary kiln roasting method
The rotary kiln roasting method is used to extract vanadium from vanadium pentoxide. Sichuan Panzhihua Iron and steel company was the first in China to roast vanadium slag. The high temperature section of roasting is 720 ~ 800 ℃, a certain amount of sodium carbonate is added to vanadium slag, a long flame incinerator is selected, the length of high temperature section is about 20m, and the vanadium conversion rate is more than 90%. The roasting principle is to burn vanadium slag into melt under the effect of sodium carbonate to convert vanadium into sodium vanadate. Vanadium slag does not need a long time in the furnace. First, the vanadium content of vanadium slag is generally about 20%, and the ratio of additives to vanadium content is small. The vanadium content of vanadium bearing stone coal mine is generally about 1%. If it is added according to 12 ~ 15% of ore content, the cost is too high. Second, some ores are not necessarily suitable for adding sodium carbonate. In 2000, Jishou Building Materials Chemical General plant used the vanadium ore of the Autonomous Prefecture and the rotary kiln originally burning vulcanization for trial combustion for two months, but the results were unsuccessful. After practice, the following conclusion was reached: in order to achieve the best conversion rate of the ore, the residence time of the ore at about 930 ℃ in the high temperature section should be maintained at 5 ~ 6 hours, and the minimum high temperature point of the rotary kiln should not be lower than 1100 ℃, The melting point of the ore does not exceed 1000 ℃, so the optimal roasting temperature required for ore conversion limits the normal incineration of the rotary kiln.
From the analysis of the above roasting methods, it can be seen from the analysis of vanadium pentoxide roasting process at this stage that the roasting of vanadium pentoxide in rotary kiln is a relatively advanced and feasible technology, which should be vigorously popularized and applied. Jiangsu Pengfei group has successfully developed a vanadium pentoxide roasting rotary kiln to realize the industrial production of vanadium pentoxide product preparation and promote the technical progress of the industry.
Main products of Jiangsu Pengfei Group Co., Ltd:
Building material scope: complete technology and equipment cement, lime, high phosphorus soil, aluminum vanadium soil, etc.
Metallurgy: laterite nickel ore roasting kiln, lithium ore roasting kiln, gold ore smelting kiln, iron chromium reduction kiln, copper mine shaft furnace, steel pellet, magnetization roasting rotary kiln, large ore mill, vertical coal mill, etc;
Chemical industry: calcium carbonate, titanium dioxide, vanadium pentoxide rotary kiln, zinc oxide rotary kiln, alumina complete set technology and equipment, composite powder complete set technology and equipment, nitriding furnace, coal efficient clean quality improvement kiln, coal to oil, coal clean dry distillation technology and equipment, oil sand oil shale oil extraction technology and equipment;
Environmental protection: solid waste, hazardous waste, sludge disposal kiln, cement kiln collaborative waste disposal technology and equipment;
Vanadium pentoxide, alias: alum anhydride; Vanadium (acid) anhydride; Alum pentoxide; Alum oxide; Vanadium oxide; Anhydrous vanadic acid; Vanadium pentoxide; Vanadium oxide (V)
English name:Vanadium pentoxide
English alias:C.I. 77938; Vanadium pentoxide; Anhydride vanadique; anhydridevanadique; anhydridevanadique(french); divanadiumpentoxide; divanandiumpentoxide; KM vanadium pentoxide; Rcra waste number P120; rcrawastenumberp120
Appearance and properties of vanadium pentoxide: orange yellow, brick red, red brown crystalline powder or gray black flake. Slightly soluble in water, insoluble in ethanol, soluble in strong acid and alkali. Significant volatilization above 700 ℃. It is decomposed into oxygen and vanadium tetroxide at 700 ~ 1125 ℃, which makes it a catalyst for many organic and inorganic reactions. As a strong oxidant, it is easy to be reduced to various low-cost oxides. Slightly soluble in water, easy to form a stable colloidal solution. It is very soluble in alkali and can form vanadate (VO3) under weakly alkaline conditions. Soluble in strong acid (generally soluble at pH = 2) does not generate vanadate ions, but generates oxyvanadium ions (VO2) in the same valence state. It is a toxic substance, and the maximum allowable amount in the air is less than 0.5mg/m. Fire and explosion hazard: This product is non combustible and highly toxic. Harmful to respiratory system and skin. Acute poisoning: it can cause irritation of nose, pharynx and lungs. The contact person has burning eyes, tears, pharyngeal itching, dry cough, chest tightness, general discomfort, fatigue and other manifestations, and in severe cases, bronchitis or bronchopneumonia. High concentration skin contact can cause dermatitis and severe itching. Long term exposure can cause chronic poisoning such as chronic bronchitis, kidney damage and visual impairment. It is formed by the thermal decomposition of ammonium metavanadate or the hydrolysis of vanadium chloride. Depending on the preparation method and conditions, vanadium pentoxide can be yellow, orange, brick red or brown.
