In the past, people only know using bentonite as raw material of activated clay, actually otherwise, with characteristics of clay mineral can be used as a raw material of activated clay soil, such as montmorillonite clay, montmorillonite clay, sepiolite clay, attapulgite clay, etc.
Kaolinite clay or kaolin clay (kaolin), is a family of kaolinite mineral as the main composition, texture, pure fine clay, appearance is white, such as shallow ash is lubricious, containing impurities was yellow, grey, black, etc.Dense block or loose soil, with a feeling of slightness, hardness less than fingernail.Weight: 2.4-2.6, water absorption after drying.Refractoriness of up to 1770-1790 ℃.Low plasticity, small adhesion, good insulation and chemical stability.
Pure kaolin calcined with a white color of 80%-90%.Montmorillonite clay, also known as bentonite, bentonite and porphyry, is a kind of fine clay with montmorillonite as the main mineral composition.The appearance is generally white, pink, light gray, light yellow, when contaminated by impurity, can be green, purple and other darker colors.The loose earth has a dull luster, and the dense lump has a waxy luster.Hardness 1-2, soft.Block or earthy, slippery feeling.The proportion of 2-3.After absorbing the volume expansion, the maximum amount of water is 8-15 times its volume.High plasticity and good adhesion, suspension and gelation in aqueous solution, and the characteristics of cation exchange.Sepiolite clay is a kind of clay which is mainly composed of sepiolite.The appearance is yellow brown, dark gray, gray and other colors, soil mass, soft and light, hardness 1-2, weight 2.4-2.65, has the viscosity and plasticity, the hand touch has the slippery feeling.After adding water, it can be changed into a paste. After drying, hammer marks can be left by hammering.Attapulgite clay is a kind of clay that is mainly composed of attapulgite. The appearance is the same as that of - clay, especially similar to montmorillonite clay, and they are often symbiotic.Its field identification mark is the appearance of soil, gray, gray, duck egg blue, the soil is delicate, has the slippery feeling, the moisture is sticky and malleable, dry after the light, the shrinkage.Throw it into the water, hiss, and break into pieces, but not swell.The performance of attapulgite clay is the same as that of sepiolite clay, with thermal stability, salt resistance, adsorption and high decolorization ability.In recent years, hunan province has become active white soil with sea foam, and zhejiang has found that the b-axis disordered kaolin can also be used as active clay. Shandong has successfully developed the raw materials for the active clay with the residue of water purifier.The raw materials for active clay are more extensive.But what we usually call reactive white earth is the active white soil made of bentonite?
The activated clay can be made from the activated clay of sea bubble.Selection is water selection, liquid solid ratio is 5 ~ 10.Water concentration after the suspension of 0.5% plus 0.5% of sulfuric acid or hydrochloric acid, boiling for 30 min, then filtering, washing, drying, grinding for products, namely decoloring rate reached to 93%, more than the requirement of national standard decoloring rate 90%.The clay of attapulgite is the king of thousands of soil, and it is said that the active clay of attapulgite (acid-free active white clay) has the characteristics of high decoloration rate and no residual acid.Bentonite is the active white clay processing and production of bentonite as raw materials. The methods of processing and producing bentonite are fully wet, dry, semi-wet, vapor phase, calcining and so on.
All traditional wet method is a mixture of bentonite, sulfuric acid, water under the condition of the stir heated to 100 ℃ after activation for a period of time after washing, drying, crushing a quick product.The main disadvantage of this method is that the consumption of acid is large, which leads to the large amount of washing water, serious environmental pollution and high cost.The steps are: beneficiation;The original soil pulping, purification and discharge of gravel and water;Adding acid and water, and in 80 ~ 100 ℃ under the activation of the 10 to 30 min, at the same time to 1000 r/min stirring;Filtrate, filtrate circulation to the pulp purification step, filter residue to the next step;Drying and grinding;Finished product testing and packaging.The traditional whole dry process is to mix a small amount of sulfuric acid and water with the bentonite mixture and then stir it thoroughly for a period of time and then dry and break the finished product.Although this method reduces the use of acid and waste water and other environmental pollution, its product quality is low, which greatly limits its use.The steps are: beneficiation;Adding acid and water to extrude normal temperature and solid phase activation;Dry crushing;Finished product testing and packaging.The semi-wet process is to mix a small amount of sulfuric acid and water with the bentonite to stir well enough to activate (place) at a certain temperature for a period of time, then add acid and water to the second step to activate.The steps are: beneficiation;Adding acid and water to extrude normal temperature and solid phase activation;Adding acid and water activation;Rinse;Filter;Drying and grinding;Finished product testing and packaging.The semi-wet process has solved the problems of the whole wet method and the whole dry method, the process is simple, the cost is low, the product quality is high.
In general, a half wet production process than the traditional process of acid consumption reduced by half to two-thirds (1/2 ~ 2/3), water consumption and lower 1/2 ~ 2/3, less waste water, a little processing, no environmental pollution, low cost, in the same situation, product quality decoloring force about 30% than that of the traditional methods.Vapor phase method technology is under a pressure hot vapor to water, acid and earth half dry mixture, mix well particle state under the static by vapor phase, liquid phase and solid phase of fierce between half dry granular acidification acidification reaction, after rinsing processes such as the preparation of activated clay is a new technology.The technology of the existing wet clay of legal system and dry and calcination method production technology of activated clay method sets the integration of the advantages of technology, has a wide practical value, for clay production in China provides a kind of new technology.The technology is compared with the traditional wet preparation process with the following advantages:
The amount of acid and water consumption were reduced by 50%, and the production cycle was shortened by 1/2 ~ 1/3.The pollution is light and easy to govern;It has a small footprint, high utilization rate, little investment, quick effect and close connection with the existing wet process process and equipment.According to the process, the active white soil can be combined with aluminum sulfate, sodium silicalite and gypsum.
(1) of the original soil of bentonite has certain selectivity, not for all different types of bentonite can produce the decolorization rate of 90% or more efficient activated clay, which other types of bentonite can only produce the decolorization rate of 80-85% or more ordinary activated clay or half efficient activated clay.The activity index is still less than H type (high activity active white soil).So its use is limited.
(2) the treatment of acidic wastewater is too large.
(3) high oil absorption rate.The amount of active clay decolorization is 2% to 5% of the oil weight.Using white soil to decolorize oil, it is inevitable to carry oil, and the amount of entrainment is 20% to 50% of the active white soil, thus increasing the consumption and cost.At present, a few enterprises adopt the leaching method to separate the oil from the active waste white soil, but the oil products after separation are black and cannot be discolored due to the role of white soil.Therefore, the domestic oil decolorization department hopes to absorb the small active white soil.The active clay has a large surface area, strong adsorption capacity and high decolorization efficiency.Low activity, no chemical reaction with oil and other chemicals;It is used for liquid decoloration filtration rate and low residual liquid rate, such as oil decolorization and sugar decoloring.After decolorizing, the liquid is clear and clear, the quality is stable, no smell, no color, no acid;After using the product, through appropriate processing can undertake secondary use, not cause environmental pollution, etc. Series of products advantages and are widely used in the adsorbent, clay grain, no carbon carbon paper with chromogenic agent.
Level 1, edible oil decoloring agent products are widely applied in all kinds of vegetable oil, animal oil and mineral oil decolorization, such as soybean oil, rapeseed oil, peanut oil, cottonseed oil, sunflower oil, palm oil, coconut oil, castor oil, tea oil, corn germ oil and fine bran oil, sesame oil, tung oil, safflower oil, etc.
Level 2, sugar decolorizing decolorizing products rich in magnesium aluminum silicate purification product of sugar, its colour and lustre, reducing sugar content, PH value, sulfite ion content, chloride ion content, protein content, temperature and sugar content of calcium and magnesium ions achieves the current industry standards, such as saving the decolorization processing costs by about 60%.After decoloring, the filter cake can be used as mixed feed, reducing environmental pollution and realizing comprehensive utilization.
3. The environmental deodorant class products have good adsorption odor function, which can eliminate the smell of refrigerators, pet bedrooms, toilets and other places.
(2) granular white soil.
The price of bentonite raw materials is about 250 yuan/ton, and the domestic market price of ordinary active white clay is about 1200 yuan to 1500/ ton.
According to the scale estimation of 10,000 tons/year active white soil, the equipment and infrastructure investment is about RMB 300-4 million, the cost is 600-700 yuan/ton, the annual output value is about 14 million yuan, and the profit tax is 6 million yuan.If supporting production of white carbon black, 4A molecular sieve and other benefits higher.Bentonite is our country the advantage of resources and reserves in the world's first, but the development and utilization of a late start, deep processing of backward technology, poor product quality, production scale is small, the domestic oil decoloring departments with the high quality activated clay is imported from abroad.The production capacity of active white soil in the United States has reached 4 million tons/year, while our country is only about 200,000 tons/year.According to statistics, the demand of active clay in China has increased by 7-8% annually in recent years.Through historical analysis of the domestic market, in oil refining is a large market, according to industry experts predict that China's annual output of various vegetable oils is about 8 million tons, 500-6 million tons of oil imports, the refined oil accounted for half of the total, about 6.5 million tons.Therefore, the production of efficient active white clay market has broad prospects.