Activated clay is a clay (mainly bentonite) as raw material, the inorganic acid, followed by water rinsing, drying adsorbent made of, look for the milky white powder, odorless, tasteless, non-toxic, strong adsorption, can adsorb colored material, organic matter. Easy to absorb moisture in the air, place too long will reduce the adsorption properties. However, heating above to 300 ℃ began to lose water of crystallization, the structure changes, effects of fading effect. Activated clay is insoluble in water, organic solvents and oils, almost completely soluble in hot caustic soda and hydrochloric acid, the relative density of 2.3-2.5, in water and oil swelling minima.
Activated clay China manufacturer about 40, annual output of about 420000 tons. Device for producing ability is 50000 t/a. Activated clay production mainly concentrated in the northeast, North China, East China, production accounted for over 70% of the country.
In the past people only know of bentonite used as activated clay raw material, actually otherwise, mineral soil with clay properties can be used as the raw material of activated clay. Hunan recently made by sepiolite activated clay, Zhejiang also found that b axis disordered kaolinite can also produce activated clay, Shandong successfully developed with water purifying agent residue as raw material of activated clay. Thus, active clay raw materials more widely. But the activated clay we usually refers to the activated clay with bentonite as raw material.
Bentonite ore grinding to a certain size, can thoroughly and acid activated bentonite mining ground water, high, soft without drying, using direct high-speed beating or wet ball milling, low power consumption.
The deep excavation of the bentonite, as hard as a stone, not dispersed in water, wet beating or cost is much higher than that of wet milling, drying and Raymond mill. The water in the < 20% conditions, to focus on the improvement of drying and milling equipment. Raw material moisture activated clay is less than 15% will be able to use. Adsorption of water only removed 5% of the milling process. The hot flue gases into the Raymond mill, the production cost is much lower than the wet mill.
Manufacturing method of activated clay
Activated clay production process of bentonite as raw material are all wet, dry, semi wet, vapor phase method, calcination etc.. The conventional wet is bentonite, sulfuric acid, water after mixing in the case of mixing heated to 100 ℃, the activation of a period of time after washing, drying, crushing to obtain the product. Disadvantages of this method is the largest consumption of acid, resulting in washing water consumption, serious environmental pollution, high cost. Dry the traditional production process is a small amount of sulfuric acid and water and bentonite mixture and stir well, for a period of time, then drying, grinding to obtain the product. Although this method reduces the consumption of acid, no waste water discharge, the pollution of the environment, but the quality of the products is low, which greatly limits its use. The production process and semi wet is a small amount of sulfuric acid and water and bentonite mixture and stir well, activated under certain temperature (placed) for a period of time, then adding acid and water and then a second step activation. The production technology of semi wet method can solve some problems of the wet and dry, simple process, low cost, high product quality. Generally speaking, the production technology of semi wet than the traditional process of acid consumption is reduced by 1 / 2-2 / 3, water consumption is reduced by 1 / 2-2 / 3, less waste water, a treatment that is no environmental pollution, low cost, under the same conditions, the quality of the products increased by 30% compared with the traditional method for decoloring capacity. Vapor phase technique in pressure thermal vapor to water, acids, soil and dry mix, between static by vapor phase, liquid phase, solid phase was acidified reacted furiously to form semi dry granular acidification, a kind of new technologies by rinsing processes for preparation of activated clay. The technical advantages of the existing legal system of dry and wet clay and calcination method of activated white clay production technology as a whole, has a good practical value, provides a new technology for activated clay produced in china. The technology and traditional wet preparation of activated clay process has the following advantages: compared with acid and water consumption were reduced by about 50%, the production cycle is shortened 1 / 2-1 / 3; light pollution, and easy to control; covers an area of small, high utilization rate of equipment, less investment, quick effect, and in close connection with the existing wet process process and equipment. According to different processes, activated clay can be aluminum, silicon and aluminum sulfate white sodium sulfate, gypsum etc..
China bentonite Professional Committee of the expert group to Kong Bingyan on activated clay production process and equipment optimization optimization scheme, this scheme satisfies the quality of produced competitive products; investment; mechanical equipment operation and repair cost is low; environmental protection. In short production to lower cost.
The production process of activated clay has three problems to be solved: (1) there are certain selectivity to the original bentonite, not all of the different types of bentonite can produce efficient the decolouring ratio ≥ 90%, or some type of bentonite could produce ordinary activated bleaching earths rate greater than 80% – 85% or semi activated clay. Activity index is still not up to H (high activity of activated clay) on the activity of requirements. So the range of its use are subject to some limitations. (2) treatment of acidic wastewater, the lime dosage is too large. (3) oil absorption rate. The decolouring capacity of heavy oil 2% – 5%. The oil was decolorized with clay, inevitably entrained oil, entrainment is activated clay was 20% – 50%, thereby increasing the coke consumption and cost. At present, a few enterprises by leaching is separated from the active waste clay in oil, but after the separation of the oil from clay, color is black, not decolouring good color. Therefore, domestic oil bleaching department wants to use oil absorption of activated clay small.
Application of activated clay
In the range of application, active clay than the surface area, the adsorption capacity, the decolorizing efficiency is high, and the activity degree is low, do not react chemically with the grease and other chemical substances. For the filtration rate of decolorization of liquid quickly, the residual liquid rate is low, such as edible oil, sugar decolorization decolorization. Edible oil bleaching products used for the decolorization of all kinds of vegetable oil, animal oil and mineral oil, such as soybean oil, rapeseed oil, peanut oil, cottonseed oil, sunflower oil, palm oil, etc.. Sugar decoloring agent products with rich majorite purification refined sugar, its colour and lustre, reducing sugar content, pH, ion content, thionyl chloride ion content, protein content, sugar boiling temperature and calcium and magnesium ions content reached the current standard, save the decolorization treatment costs about 60%. Environmental odor absorbing agent has good adsorption odor, odor can eliminate the refrigerator, pet bedroom, toilet and other places. After bleaching liquid is transparent and clear, stable quality, no smell. After using the product, after proper treatment can be used for the two time, it will not cause environmental pollution. Also can be used for moisture desiccant, internal medicine alkali antidote, vitamin A, B adsorption agent, lubricating oil contact contact agent, the gasoline vapor refining agent, as well as the raw material in the temperature of polymerization catalyst, high temperature polymerization agent and manufacturing of particulate clay. In addition, active clay can also be used for carbonless copy paper chromogenic agent.
Activated clay is another important use is the preparation of particulate clay.
Particulate clay is the activated clay as the main raw materials by chemical processing and become, the appearance of unshaped granular activated clay, it has higher specific surface area, has a very high adsorption capacity, widely used in petrochemical industry, aviation kerosene refining, aromatics extraction, mineral oil, animal and vegetable oil, wax and organic liquid decoloration refining, but also for refined oil, base oil, diesel oil, residual olefins, glial, Li Qing, and other impurities removing basic nitrogen compounds.
Clay particles can also be used as a moisture desiccant, internal medicine alkali antidote, vitamin A, B adsorption agent, lubricating oil contact contact agent, the gasoline vapor refining agent, can also be used as a temperature of polymerization catalyst, high temperature polymerization agent.
At present, non-toxic, no entrainment, oil absorption rate is small, can be used for edible oil decoloration refining and not in the petroleum catalysis reaction medium discoloration caused by particulate clay is hot demand.
At present, China clay particles mainly Ling’an Fulong adsorbent factory several manufacturers in the production, mainly non water resistant clay particles, decolorizing capacity, good activity, can basically meet the domestic needs of aromatic industries.
Used for clay particles and petrochemical industry aromatic stock must be activated clay produced by traditional process, dry process production or use attapulgite compound cannot meet the requirements of production.