Method for preparing mineral compound fertilizer by sintering rubber sludge

Abstract

The invention discloses a method for preparing a mineral compound fertilizer by sintering rubber sludge, which is characterized by comprising the following steps: naturally air-drying the rubber sludge until the water content is 10-12%, grinding and screening to obtain rubber sludge powder, uniformly mixing the rubber sludge powder, silicon dioxide, potassium carbonate and magnesium oxide, calcining at 800-1000 DEG C, cooling and crushing to obtain the mineral compound fertilizer. Belongs to the technical field of agricultural fertilizer preparation. A reasonable way of turning harm into good and turning waste into wealth is provided for sludge treatment of a sewage treatment plant in the rubber production industry at present, the rubber sludge raw material source is wide, the mineral compound fertilizer preparation process is simple, the application range is wide, the green and environment-friendly concept is met, and a good way is opened up for resource recycling.

Description

Technical Field

[0001] The invention belongs to the technical field of agricultural fertilizer preparation, and in particular relates to a method for preparing mineral compound fertilizer by sintering rubber sludge. Background Art

[0002] Fertilizer, as an important foundation of my country's agricultural production, can provide plants with one or more essential nutrients, and can effectively control and improve soil properties, thereby greatly increasing soil fertility. my country is a large agricultural country with a large demand for fertilizers. However, the current fertilizer production capacity is insufficient, and more than 20 billion yuan is needed to import fertilizers every year. Due to the shortage of fertilizers, their prices remain high, which increases the burden on agriculture. Although the use of inorganic fertilizers can make crops grow well and produce high yields in the short term, for a long time, the one-sided pursuit of high yields in agriculture and over-reliance on the input of fertilizers and pesticides have led to hardening of cultivated land and poor water retention capacity, and cultivated land has gradually lost its value for cultivation. At the same time, the output and quality of agricultural products have also declined seriously, which has posed a threat to my country's food production security, agricultural product quality safety, and agricultural ecological environment safety.

[0003] According to the fertilizer classification principle in my country, fertilizers can be subdivided into quick-acting fertilizers, slow / controlled-release fertilizers, coated fertilizers, and stable fertilizers according to fertilizer efficiency. Compared with quick-acting fertilizers, slow-release fertilizers can effectively prevent excessive salt from harming the root system of crops due to the rapid release of nutrients to the roots. At the same time, its nutrient utilization rate is high and the damage to the environment is small. Among the slow-release fertilizers, there are mineral slow-release fertilizers synthesized by artificial high-temperature calcination, that is, mineral compound fertilizers. Its main active ingredient is minerals, which not only have a long fertilizer effect, but also can effectively improve problems such as soil compaction.

[0004] High temperature sintering is a method of combining several substances in the presence of flux under high temperature conditions to generate new substances. The earliest research in this area was published by Tokunaga TK in 1991. Tokunaga used fly ash as raw material, added KOH and Mg(OH)2 (or dolomite) as potassium and magnesium sources, and prepared mineral compound potash fertilizers with K2MgSiO4 and K2AlFe2Si2O8 as the main phases. High temperature calcined mineral compound potash fertilizers are mainly K2O-MgO-SiO2 mineral slow-release fertilizers, which were first proposed by Yamada K. in 1994. Later, Mangrich A used limestone and Brazilian oil shale as magnesium and silicon sources, added K2CO3 for activation, and used high-temperature calcination to prepare K2MgSi3O8 mineral compound potassium fertilizer at 900°C. The dissolution ratio of K2O in the mineral compound fertilizer was 30.3% in 0.5 mol / L HCl, 23.2% in 0.1 mol / L lemon water, and 6.9% in water. E. Pranoto et al. mixed mineral compound fertilizer with chemical fertilizers such as urea, which significantly increased the yield of tea compared with single urea.

[0005] The composition of rubber sludge is similar to that of soil. It mainly contains a large amount of metal minerals, with a content of more than 70%, and the remaining components are organic matter. Among them, aluminum, iron, calcium, magnesium, and potassium are the main metal components in sludge. Its mineral composition is complex. The analysis of its chemical composition shows that the content of aluminum oxide and iron oxide is generally around 30%.

[0006] Since the phosphorus content in rubber sludge generally exceeds the standard, it has hardly been used at present, which will not only have a significant impact on the ecological environment, but also seriously restrict the sustainable development of the natural rubber industry. After reviewing the literature, it is found that there are currently almost no researchers and institutions that have conducted research on the utilization of rubber sludge. Summary of the invention

[0007] In order to fill the gap in the application research on the recycling of rubber sludge in the current natural rubber processing process, overcome the pollution caused by rubber sludge to the environment, and at the same time utilize it as a resource, the present invention provides a method for preparing mineral compound fertilizer by sintering rubber sludge with activating agents potassium carbonate and magnesium oxide. The method effectively utilizes rubber sludge, realizes the recycling of resources, meets the requirements of green environmental protection, has low investment in the preparation process, has great industrial value, and can effectively avoid polluting the environment.

[0008] The method for preparing mineral compound fertilizer by sintering rubber sludge is as follows: the rubber sludge is naturally air-dried to a moisture content of 10% to 12%, and the rubber sludge powder is obtained after grinding and screening; 5 to 10 parts of rubber sludge powder, 2.7 to 4.2 parts of silicon dioxide, 0.5 to 1 part of potassium carbonate, and 6.1 to 8.7 parts of magnesium oxide are uniformly mixed according to the following weight parts, calcined at 800 to 1000° C. for 0.5 to 2 hours, and the mineral compound fertilizer is obtained after cooling and crushing.

[0009] The present invention uses rubber sludge as the main raw material, and generates mineral compound fertilizer with K2MgSi3O8 as the main component under high temperature conditions by adding activating agents such as potassium carbonate, magnesium oxide and silicon dioxide, which can provide plants with elements necessary for plant growth such as K, Mg and Si.

[0010] The advantages of the present invention are as follows: the present invention fills the blank of the application research on the recycling and utilization of rubber sludge in the current natural rubber processing process, overcomes the pollution caused by rubber sludge to the environment, and at the same time utilizes it as a resource. The method of the present invention effectively utilizes rubber sludge, realizes the recycling and utilization of resources, meets the requirements of green environmental protection, has low investment in the preparation process, has great industrial value, and can effectively avoid polluting the environment.

[0011] Using sludge to produce mineral compound fertilizer will inevitably be an ecologically beneficial production model. It can not only reduce the production cost of organic fertilizer, but also reasonably treat and dispose of organic waste. It is one of the ways to turn organic waste into treasure, thereby synergistically promoting the sustainable and healthy development of industry and agriculture. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 XRD patterns of mineral compound fertilizers at different calcination temperatures. DETAILED DESCRIPTION

[0013] The present invention is further described in detail below in conjunction with embodiments, but the protection scope of the present invention is not limited to the described contents, and the present invention is not limited in any way. Any changes or substitutions made based on the teachings of the present invention belong to the protection scope of the present invention.

[0014] The rubber sludge in the following examples is a byproduct of the sewage treatment stage of Xishuangbanna Jingyang Co., Ltd. of Yunnan Natural Rubber Industry Group, and its main chemical components and contents are shown in Table 1; Table 1 Chemical composition of rubber sludge

[0015] Embodiment 1: (1) Disperse the rubber sludge into uniform blocks, place it in a ventilated and cool place to dry naturally for one week, control the moisture content of the rubber sludge to 10%-12%, grind it to pass through a 40-mesh steel sieve, and collect the sieve to obtain the rubber sludge powder; (2) Mix 10 g of rubber sludge powder, 3.96 g of silicon dioxide, 0.84 g of magnesium oxide, and 6.97 g of potassium carbonate; (3) The mixture of step (2) was placed in a muffle furnace, calcined at 800° C. for 1 hour, cooled, ground and pulverized to obtain a rubber sludge mineral compound fertilizer. The chemical composition of the rubber sludge mineral compound fertilizer is shown in Table 2. The rubber sludge mineral compound fertilizer was tested for the dissolution index of the fertilizer active ingredients and the slow-release performance of the mineral compound fertilizer according to the standard of the People's Republic of China GB / T 23348-2009. The results are shown in Table 3, with the serial number being 1.

[0016] Embodiment 2: The preparation of the rubber sludge mineral compound fertilizer in this embodiment is the same as that in Example 1, except that it is calcined at 850° C. The chemical composition of the rubber sludge mineral compound fertilizer is shown in Table 2. The rubber sludge mineral compound fertilizer is tested for the dissolution index of the fertilizer active ingredients and the slow-release performance of the mineral compound fertilizer according to the People's Republic of China standard GB / T 23348-2009. The results are shown in Table 3, with the serial number being 2.

[0017] Embodiment 3: The preparation of the rubber sludge mineral compound fertilizer in this embodiment is the same as that in Example 1, except that it is calcined at 900° C. The chemical composition of the rubber sludge mineral compound fertilizer is shown in Table 2. The rubber sludge mineral compound fertilizer is tested for the dissolution index of the fertilizer active ingredients and the slow-release performance of the mineral compound fertilizer according to the standard of the People's Republic of China GB / T 23348-2009. The results are shown in Table 3, with the serial number being 3.

[0018] Embodiment 4: The preparation of the rubber sludge mineral compound fertilizer in this embodiment is the same as that in Example 1, except that it is calcined at 950° C. The chemical composition of the rubber sludge mineral compound fertilizer is shown in Table 2. The rubber sludge mineral compound fertilizer is tested for the dissolution index of the fertilizer active ingredients and the slow-release performance of the mineral compound fertilizer according to the standard of the People's Republic of China GB / T 23348-2009. The results are shown in Table 3, with the serial number being 4.

[0019] Embodiment 5: The preparation of the rubber sludge mineral compound fertilizer in this embodiment is the same as that in Example 1, except that it is calcined at 1000° C. The chemical composition of the rubber sludge mineral compound fertilizer is shown in Table 2. The rubber sludge mineral compound fertilizer is tested for the dissolution index of the fertilizer active ingredients and the slow-release performance of the mineral compound fertilizer according to the standard of the People's Republic of China GB / T 23348-2009. The results are shown in Table 3, with the serial number being 5.

[0020] Calcination at 800-1000℃ can make the mineral compound fertilizer achieve the best cost performance. The XRD results of mineral compound fertilizers prepared at different temperatures are as follows: Figure 1 As shown in the figure, it can be seen that the content of mineral compound fertilizer is related to the calcination temperature. The diffraction peaks of the main phase K2MgSi3O8 exist in the samples at 5 calcination temperatures. There are 3 main diffraction peaks at 2θ= 20°, 28° and 33°. When calcined at 850℃ and 950℃, K2MgSi3O8 has 3 weak diffraction peaks at 2θ= 40°, 43° and 21°, respectively. This is consistent with the standard data card PDF#10-0030. The diffraction peak of SiO2 appears when calcined at 800℃ and 950℃, and KAlSiO4 has weak diffraction peaks when calcined at 800℃ and 850℃, which gradually disappears with the increase of calcination temperature ( Figure 1 ).

[0021] Table 2 Chemical composition of mineral compound fertilizer K2MgSi3O8

[0022] Table 3 Dissolution components of mineral compound fertilizer K2MgSi3O8

[0023] From Table 2, it can be seen that the K2O content of rubber sludge mineral compound fertilizer is about 33%, the SiO2 content is (10.7~23.9%), and the MgO content is (5.3~10.2%). In addition to K, Mg and Si, the rubber sludge mineral compound fertilizer also contains considerable Fe2O3 and a small amount of CaO, which is beneficial to the growth of crops. Compared with rubber sludge raw materials, rubber sludge compound fertilizer can increase the K2O and MgO content and improve the utilization rate of rubber sludge in the fertilizer direction.

[0024] The results in Table 3 show that there is no significant difference in the dissolution components of the prepared rubber sludge mineral compound fertilizer in 0.5mol / L HCl and 20g / L citric acid solutions. The dissolution components of K2O and MgO are basically about 20% and 3%, respectively, and the dissolution amount of SiO2 is 6~10%. It can be seen from the above table that the rubber sludge mineral compound fertilizer with K2MgSi3O8 as the main phase has good potential as an agricultural mineral slow-release fertilizer.

Claims

1. A method for preparing mineral compound fertilizer by sintering rubber sludge, characterized in that: The rubber sludge is naturally air-dried to a moisture content of 10% to 12%, and then ground and sieved to obtain rubber sludge powder. The rubber sludge powder, silicon dioxide, potassium carbonate and magnesium oxide are evenly mixed, calcined at 800 to 1000°C, and then cooled and crushed to obtain mineral compound fertilizer.

2. The method for preparing mineral compound fertilizer by sintering rubber sludge according to claim 1, characterized in that: Mix 5-10 parts of rubber sludge powder, 2.7-4.2 parts of silicon dioxide, 0.5-1 part of potassium carbonate, and 6.1-8.7 parts of magnesium oxide according to the following weight parts.

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