Evaluation Of Active Clay Quality Indicators

- Feb 05, 2018 -

The use of manufacturers, the main problems are the following.

(1) The decolorization of lubricants, the amount of active clay, manufacturers want to use a good bleaching effect and the amount of less products, it also reduces the amount of waste oil absorption.

(2) The decolorization rate of activated clay tested by the Ministry of Chemical Industry is very high, but in the production and use, the decoloring effect is not satisfactory.

(3) for salad oil production, with some activated clay bleaching, the salad oil to bring a lot of smell, affecting the taste of salad oil.

(4) waste soil treatment is worth discussing. As the refinery waste oil contains residual oil, so the waste disposal to other users to extract residual oil, oil companies will waste residue dry oil, waste soil no longer use. The key to solving these problems is to strengthen the research on activation mechanism and pollution control.


1. Evaluation of active clay quality indicators.


At present, the indicators of active clay quality are mainly activity, decolorization rate, bleaching power, free acid, specific surface area and so on. Activity of activated clay is replaced with sodium acetate solution of hydrogen ions in the sample to phenolphthalein as an indicator titrated with sodium hydroxide standard titration to 1000g sample consumption of sodium hydroxide solution [c (NaOH) = 1. 000 mol / L] (mL). The decolorization rate is a technical index for evaluating the decoloration performance of activated clay on petrochemical products. It is a certain sample of kerosene asphalt solution decolorization, decolorization solution before the absorbance E0 and the decolorization solution after the absorbance E1 and the difference between the ratio of E0, known as the decolorization rate of the sample, the higher the decolorization rate, indicating that the activity The better the decolorization performance of clay. Decoloration rate as a percentage, namely: decolorization rate of the sample = (E0-E1) / E0 × 100%.


The bleaching power is a technical index to evaluate the decolorizing performance of the activated clay on the grease products. Under the same test conditions, select a standard soil with moderate bleaching power, and decolorize the same vegetable oil medium with the sample. When the decolorizing effect is the same, take the ratio of the standard soil sample amount W1 to the sample sample amount W2, and multiply To the standard soil decolorization force is the decolorization force of the sample, namely: sample decolorization = decolorization strength standard soil × W1 / W2. Free acid is leached from the sample residual acid in water, with phenolphthalein as an indicator, titration with sodium hydroxide standard solution, 1.000mol / L sodium hydroxide standard solution 1 .00mL with 0.049g of sulfuric acid mass expressed in grams per gram The sample contains a percentage equivalent to the mass of sulfuric acid to indicate the size of the free acid. The smaller the free acid, the less waste acid content, the more thoroughly washed. The specific surface area is the surface area per unit mass of the sample, in m2 / g. Large surface area has a higher adsorption capacity [. For the activity of the clay product decolorization rate, activity, free acid, China's Ministry of Chemical Industry 1994 -02 -09 industry standard HG / T2569 -94 approved this standard.


For the bleaching power, the Ministry of Chemical Industry's industry standards are not required, but the enterprise standard in Zhejiang Province ≥ 110. However, foreign countries do not take decolorization rate and bleaching power as the standard to measure the decolorization effect, but rather strengthen the study of activation mechanism with specific surface area. Only by grasping the theoretical basis, to change the performance of the product can be done easily. At present, the decolorization rate, bleaching power and activity are the main indexes to test the product quality. The three indexes are high, which means the product quality is high, but these three indexes do not reach the maximum under the same process conditions, which requires changing the process Conditions, respectively, so that they reach the maximum, to change the process conditions, it is necessary to do a thorough study of the activation mechanism, and only grasp the mechanism to understand the regularity of things will guide us to improve product quality in order to enable us to affect product quality The various process parameters to adjust, developed a customer satisfaction products. At present, the activity of the products used in the petrochemical industry is above 220, the decolorization rate is up to 98%, while the bleaching power of the products used for decolorization of edible oil is generally over 110, the quality is not high. Generally believed that the activity is greater than 220, the decolorization rate of more than 98%, especially the bleaching power higher than 200, should belong to high-quality activated clay. However, the possibility that the same product has the maximum of the three indexes at the same time is very small because the raw material of bentonite ore varies greatly due to the composition of the raw ore, which requires us to develop a series of products for different purposes according to the needs of users, for example , Petrochemical companies require more than 98% of the decolorization rate, the activity of 220 or more, then under the conditions of maintaining high decoloration rate, change the process conditions, improve product activity, and not to consider the product decolorization; According to the requirements of oil companies, we can Developed high decolorizing products, without considering its decolorization rate and activity.


Strengthen the treatment of waste acid research. At present the treatment of waste acid mainly circulating method and alkali neutralization. Circulation method is the activated clay used in the production process of washing water and reaction liquid used for the activation of bentonite and product rinsing to improve the utilization of acid and reduce waste emissions. Alkali neutralization method is to add liquid ammonia, ammonium salt or lime and other alkaline substances in the acidic waste liquid. The above methods can not meet the requirements of wastewater discharge, which is a national problem. It has been reported that silica is added to spent acid to produce silica similar to silica and white substances, which are used as reinforcing agents, fillers, lubricants and the like for plastic products. It is also reported that Mizusawa of Japan produces in waste liquid Gypsum, polyaluminum, polyferric sulfate and white carbon, which is a revelation for our research.


To consider the impact of each of the factors on the quality of activated clay. Although the process of producing activated clay is not complicated, there are many factors affecting the product quality. Besides the main acid concentration, activation temperature and activation time, there are other raw material quality, drying method, feeding order, liquid to solid ratio, soaking Time, stirring speed, washing method, etc., these parameters affect the activation effect. In the experiment, we found that although the acid concentration, activation temperature and activation time were fixed, the factors such as the purity of the raw material, liquid-solid ratio, washing method and other factors all affected the quality of the products. Therefore, these secondary factors should also be considered in the study. Expand the application of activated clay. At present, the active clay is mainly used in the oil refining industry and the oil industry. Although the usage of white clay in these two industries is increasing, the manufacturers and production scale of white clay are also increasing. The market price of clay is decreasing. The price in 1999 was 1200 yuan / t, the current price of 800 ~ 900 yuan / t. Therefore, it is necessary to develop new products and expand their applications in the fields of food industry, sulfur production, forest and water resources protection, petroleum industry, beverage and sugar industry, chemical industry, environmental protection, paper industry and detergents to maintain their activity The vitality of clay.


Improve the process conditions, the active clay for finishing. At the Seventh National Non-metallic Mine Processing and Utilization Technology Exchange Conference, the concepts of "deep processing" and "finishing" were put forward. The deep-processing products are new products with higher technological content, while finishing is the concept of the old products in all aspects Perfect, the product is more refined and more detailed. There is no market in the short term for high-tech processing of products. However, the long-term consideration of science and technology can not be ignored. At the same time, we must not abandon the market of old products, and refine the old products and improve the quality of products Market Competitiveness.


Improve detection methods. The current testing standards are mainly based on the People's Republic of China Chemical Industry Standard (HG / T 2569 -94) and Geological Publishing House Rock and Mineral Analysis Volume I (Third Edition), and each company has its own standards, but most are based on industry Standards and development. The existing problems are: the Ministry of Chemical Industry standard test activated clay decolorization rate is very high, but in production use, the decolorization is not satisfactory. The test of decolorization also has the same problem. Other test indicators are more or less flawed. Therefore, improving the test method or innovative test methods to illustrate the quality of the product is necessary, and now abroad have adopted the specific surface area as a clay target, which requires our study and reference.


Strengthen the cooperation with the active clay production, use and ore mining enterprises. Although not many enterprises in this survey, but representative, combined with the problems found in laboratory work, provides us with information on the direction of our future work. Strengthening its cooperation with us will enable us to keep abreast of problems in production and use so that we can further improve product performance. Cooperate with the ore mining enterprises so that the raw ore can be rationally exploited, the content of montmorillonite in the raw ore can be raised, and the added value of the bentonite can be increased. Work with businesses to get research out of the lab and better integrate with production to bring research to market. Strengthen information exchange and collect. Understand the latest trends in the development of active clay and clay applications, timely adjustment of work direction and work train of thought. This work can be mainly done from the following aspects: Professional journals, newspapers, a variety of non-metallic mineral processing technology exchange, and production and use of extensive contact factory. At present, there are many manufacturers and research institutes for the production of clay in the whole country.


All in all, activated clay has broad application prospects. With the increase of the output of petrochemical products and grease products, the amount of activated clay is also increasing. And the application fields of clay are expanding. The emphasis should be on the research of activation mechanism and environmental pollution control, improvement Testing methods, to prepare high-quality and efficient finishing products. Used as reinforcements, fillers, lubricants and the like for plastic products. It is also reported that Mizusawa of Japan produced gypsum, polyaluminum, polyferric sulfate and white carbon in the waste liquid, which is an inspiration for our research .

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