The method of purification of solid materials from contaminants

 

(57) Abstract:

The invention relates to chemical cleaning methods of solid materials and is designed for cleaning soils from zagryaznyavshie substances, mainly of petroleum products. For cleaning a contaminated solid material is carried out by crushing hard material, mixing the pulverized material with the reagent solution, stirring the mixture, settling and separation into liquid and solid fractions. As the reagent is used an aqueous solution of water glass concentration of 0.5 - 2.0 vol.% when a volume ratio of the solid material and the reagent solution 1 :(1 - 3). Next, the mixture is stirred for 5 to 15 min, defend 5 to 15 minutes and after separation of the solids washed with water 3 to 4 times. The advantages of this method are the possibility of cleaning without water heating, and the use of liquid glass - substance inorganic nature, environmentally friendly, fire and explosion safe, having a more effective cleaning action compared with other alkaline reagents associated with the presence in its composition of the silicate anions, which are hydrolyzed in aqueous solutions and is able to absorb its pollution. 5 table.

the s, for example, soil from harmful substances, mainly from petroleum products.

Contamination of soils by products of industrial activity is a major environmental problem. Example of the negative impact on the environment is to penetrate into the soil of various substances, including petroleum products, on the territories of the locomotive-and-car-repair plants, depots, refineries, factories that produce grease, warehouses, fuel and lubricants, etc., the Presence of large amounts of contaminated soils necessitates the application of different methods of removal of harmful substances.

Known "Method of installation and emulsifying agent for the Department of materials containing harmful substances" (see list of sources of information used for the examination at the end of the descriptions, I).

According to a known method, for microdispersed emulsification of harmful substances contaminated material is mixed with at least one emulsifying agent, if necessary, with water, and then the emulsion with the addition of water is separated from the material. As the emulsifier used substance, soderjashie salt, for example, the alkali metal salt of one of these sulfates.

In the specified method for cleaning soil from pollution mixtures are used, the components of which are organic compounds, which is very complex in composition and unsafe in the environmental aspect. The description says that fine emulsified particles are well accepted by microorganisms and thereby become harmless. However, there are no data on the residual content in the purified material components emulsifying substances, and the complete lack of them seems doubtful. The described technology is carried out by heating, which raises the cost of cleanup.

Known also Improved method of removing harmful substances from soil (II), mainly oil and its derivatives, using aqueous extractants.

According to the method for extracting impurities used extractant containing pyrophosphate or sodium oxalate concentration of 0.1-1.0% . The contaminated soil isolate using watertight bulkheads, and the extractant pipes injected into the soil. The volume of extractant 50-100 l/m2soils in the day. Then carry out the removal of the extractant by pumping. In the other is in the lower layers of the isolated area, and then is pumped in the form of an extract. The choice of method depends on the type remove harmful substances.

This method of removing harmful substances from the soil requires equipment for injection and pumping solution, pipes, partitions to isolate the contaminated sites, etc. All this significantly increases the cost of treatment. In addition, a very large flow of extractant for soil treatment. In the description of the patent as an example, the results from tillage low pollution degree 1 g/kg of soil (0.1%), so the question arises about the lack of efficiency of this method when a large source of contamination of the soil.

Closest to the claimed object to the technical essence is, in our opinion, the Method of removing contaminants from solid materials" [III], according to which the cleaned material is crushed to particle size of less than 15 cm and mixed with agent-purifier containing a hydroxide of alkali or alkaline earth metal, alcohol and liquid sulfoxide catalyst. After stirring dirty light fraction is separated by sedimentation or centrifugation from less contaminated fraction at the bottom. The bottom fraction is cleaned to the desired level by rinsing the fir pollutants, such as polychlorobiphenyl. Petroleum products are to dehalogenation pollutants and bad are removed from the soil by this method, which was tested by us in practice. According to our data, the degree of purification of soil from petroleum products by this method is not more than 42% with the initial contamination of soil by oil - 10,63% (see tab. 5).

In the description of the patent there is no information about the residual content in the purified material components of the reaction mixture (hydroxide of an alkali metal, sulfoxide, organic alcohol), although at least the latter two of which are environmentally unsafe.

The aim of the invention is to increase the degree of purification of solid materials using cheap and non-toxic reagents.

To achieve this in fashion treatment of solid materials from contaminants, mainly petroleum products, including crushing of the material, mixing the pulverized material with the reagent solution, stirring the mixture and separation of the fractions according to the invention as a reagent is used an aqueous solution of water glass concentration of 0.5 to 2.0 volume% at a volume ratio of the solid material and the reagent solution 1:provide it with water 3-4 times.

Liquid glass is an aqueous solution of alkali metal silicates with the General formula A2OmSiO2where A = Na, K or Li; m - siliceous module (from 1.5 to 3.5 for sodium liquid glass and up to 4.0-4.5 for potassium). It is a thick liquid yellow or gray color density of 1.36-1.50 g/cm3. Due to the alkaline nature of the liquid glass neftemashvnedrenie Malaysia, emulsified and transferred to the surface of the particles in the volume of the aqueous phase. We found that the highest degree of purification from oil products is achieved by using a reagent containing liquid glass 0.5 to 2.0 volume percent, and the optimum content of the liquid glass is 1.0 volume percent. At this concentration, the efficiency of removal of contaminants from the soil and reaches a maximum of 97%.

A great advantage of the proposed method is the ability to clean without water heating, which gives some economic benefits, although in principle the processing of contaminated material can be carried out at elevated temperatures of water.

Liquid glass is a substance inorganic nature, environmentally friendly, fire and explosion safe and relatively cheap. It is more effective is s, which is hydrolyzed in aqueous solutions and is able to absorb its pollution.

The method is as follows.

Oil-contaminated solid material, for example, the soil is subjected to crushing into pieces no larger than 15 cm, and then placed in a reactor and filled with an aqueous solution of water glass concentration of 0.5 to 2.0 volume percent (see table. 1). The ratio of the volume of the soil solution is 1 : (1-3) (see tab. 2). Next, the mixture is stirred for a time that you want to remove from the surface of the particles, pollutants, namely, within 5-15 minutes. When mixing time is less than 5 minutes, the degree of purification is insufficient, and more than 15 minutes does not increase the treatment efficiency (see tab.3). After this, the solution rest for 5-15 minutes in the same mixing device (see tab.3). Defending the need for separation of the phases: solid, water with dissolved pollutants and organic in the form of petroleum products, pop up to the surface. After settling water and the organic phase separated from the solid. Aqueous solution with Neftegazodobycha comes to cleaning, mixing device is supplied water for washing Tiesto leaching depends on the degree of contamination of the material. Washing exercise 3-4 times, resulting in the soil, cleaned from oil.

Examples of the method

Example 1.

Samples of soil contaminated with petroleum products were subjected to grinding to obtain a fraction with sizes not exceeding 15 see Further, these samples were filled with aqueous solutions of water glass concentration 0,1%, 0,5%, 0,8%, 1,0%, 1,5%, 2,0%, 2,3%, 2,5% the volume ratio of the volume of the soil-solution 1 : 1. Then the mixture was stirred for 10 minutes at a rotation speed of mixing device 10 Rev/sec, defended within 10 minutes, after which the liquid fraction was decanted for further processing, and solid 3 times washed with water, each time a new batch.

The cleaning results are presented in table. 1.

Example 2.

The soil samples were processed according to the method described in example 1, a solution of liquid glass, with a concentration of 1% by volume, and processing was carried out at volumetric ratios of the soil-solution: 1 : 0,5; 1 : 1; 1 : 1,5; 1 : 2; 1 : 3; 1 : 4.

The cleaning results are presented in table. 2.

Example 3.

Soil samples taken from the oil content of 7.95% by weight was treated according to the method described in prices the mixture was subjected to stirring for 1, 5, 7, 10, 15, 25 minutes and subsequent sedimentation during 3, 5, 7, 10, 15, 25 minutes.

The cleaning results are presented in table.3.

Example 4.

The soil samples were processed according to the method described in examples 1-3, except that after separation of the solid fraction was washed with water followed by determination of oil and the degree of purification of the soil.

The results are shown in table. 4.

According to the research results, presented in table. 1 - 4, we can conclude that for cleaning soils from petroleum products is the most appropriate method of soil treatment with an aqueous solution of liquid glass concentrations of 0.5 to 2.0 volume% at a volume ratio of solid material and a solution of 1 : (1-3). The optimal values for the concentration of liquid glass is its content is 1 % by volume, and volume ratio of the solid material and the solution is 1 : 1.

Mixing and settling of the mixture should be within 5-15 minutes, and the best time is 10 minutes for both processes. After separation of the solid fraction to ensure the greatest efficiency of cleaning the soil should be washed with water 3 to 4 times.

Us what gentami, including in the manner stated in the description of the U.S. patent N 5228921 (prototype).

The results are shown in table. 5.

According to the table. 5 comparison of different methods of treatment shows the highest efficiency declare our method, because the degree of purification of the soil by this method is at least 95 %. This technology allows you to process a wide range of temperatures from water solutions +5oC to+ 80oC.

Previously used known chemical reagents, as a rule, are artificially synthesized complex organic compounds, such as alkylbenzenesulfonate, alkyl sulphates, alkylalkoxysilane, ethoxylated alcohols, ethoxylated alkyl phenols, etc., Use them when cleaning leads to the fact that in the purified material reaches a certain amount of these compounds. Their Biodegradability is difficult and takes a long time for complete digestion. On the contrary, trace amounts of liquid glass remaining after treatment of the soil, do not cause damage to the environment due to the wide distribution in nature of the components included in the composition of the liquid glass (sodium cations and silicate anions). By offering the glass compared to synthetic organic compounds.

Sources of information used in the preliminary assessment:

I. Application Germany N 3815309; A1 M CL A 62 D 3/00, B 09 B 3/00 C 02 F 3/34, C 02 F 3/12 II B 01 D 17/025, B 01 F 17/00, 17/42, 17/04" published 17.11.88,

II. German patent N 3738264 C1 M CL4A 62 D 3/00, B 01 D 1/02 published 30.03.89,

III. U.S. patent N 5228921 M CL4B 08 B 3/08; B 08 B 7/00 published 20.07.1993, (prototype)

The method of purification of solid materials from contaminants, mainly petroleum products, including crushing of the material, mixing the pulverized material with the reagent solution, stirring the mixture and separation of fractions, characterized in that the reagent is used as an aqueous solution of water glass concentration of 0.5 - 2.0 vol.% when a volume ratio of the solid material and the reagent solution 1 : 1 - 3, then the mixture is stirred for 5 to 15 min, defend 5 to 15 minutes and after separation of the solids washed with water 3 to 4 times.

 

Same patents:

The invention relates to a system of managed floating suction device for collecting a lower density fluid, floating on the surface of another liquid, mostly water

The invention relates to the field of ecology, and is intended to combat pollution by oil, oil products, cyclic and aromatic hydrocarbons, toluene, benzene, etc

The invention relates to a means of combating pollution by oil and soil, etc

The invention relates to a means of combating pollution by oil and soil, soils, etc

The invention relates to the protection of the environment and can be used for liquidation of consequences of emergency oil and oil products moving on the water surface streams

Oil trap pivovarova // 2121035
The invention relates to devices mechanical cleaning methods drains from oil pollution

Oil fence // 2119007

Oil fence // 2119006

The invention relates to devices for separation of oil from oily snow mass, sludge and solids

The invention relates to the oil industry and is intended to suppress the activity of sulfate reducing and heterotrophic bacteria, as well as to combat corrosion problems in systems of production, transportation and storage of oil
The invention relates to the protection of the environment and can be used for cleaning contaminated surfaces riparian zones of small streams, in particular can be used to clean the shores and waters polluted streams and small rivers
The invention relates to a method of cleaning sand from oil spills and can be used in the oil industry and when cleaning the sand of the coastal zone, the contaminated oil in transport accidents and oil tools
The invention relates to chemical treatment of hollow reservoirs and tanks

The invention relates to the creation of fatty cleansing compositions and method of removing contaminants from a substrate, such as printed circuit Board, using a cleansing composition

The invention relates to a power system and can be used for maintenance and repair of heating systems in residential buildings and industrial premises

The invention relates to a method of cleaning surfaces by removing particles from surfaces of articles
Up!