A production process of salt without adding anticaking agent

Abstract

The present invention belongs to the field of salt production, and specifically discloses a salt production process without adding anti-caking agents. The present invention controls the temperature and humidity balance of salt before packaging, thereby delaying or changing the formation of crystal bridges between salt crystals, so that the packaged salt can maintain its dynamic balance of moisture adsorption and desorption for a long time, achieving the effect of not agglomerating for a long time. The method does not require substantial improvements to the existing brine purification and salt-making processes, does not change the current salt particle size, does not change the storage conditions after packaging, can achieve continuous production while meeting the demand of not containing anti-caking agents, and is of great significance to enriching the types of salt and improving the quality.

Description

Technical Field

[0001] The invention relates to the field of salt production, and in particular to a production process of salt without adding an anti-caking agent. Background Art

[0002] Salt is an irreplaceable necessity in people's lives and plays an important role in adjusting human functions and maintaining human health. The main component of salt is small cubic particles of sodium chloride. During storage, sodium chloride particles can easily absorb moisture from the environment or attract each other and solidify, turning from loose particles into hard blocks, which seriously affects the storage, transportation and use of salt by consumers.

[0003] In order to solve the problem of salt agglomeration, manufacturers generally add anti-caking agents such as potassium ferrocyanide or ammonium ferric citrate during the production process of salt to prevent salt from agglomerating and keep it loose or free flowing. At present, the safety of various anti-caking agents added to salt has gradually attracted people's attention. Whether anti-caking agents are safe and whether they have any impact on the human body has also caused widespread discussion in society. With the continuous enhancement of consumers' awareness of food safety and the improvement of scientific and healthy concepts, people's calls for green, additive-free, and pure natural salt are getting higher and higher. In order to meet the requirements of consumers, our salt-making industry urgently needs to develop additive-free green refined food salt.

[0004] Most of the non-lumping salt sold on the market is sea salt and lake salt, which are large in size. In actual testing, some products still contain potassium ferrocyanide. Sea salt and lake salt have many impurities that are difficult to remove, and are not as pure as well salt.

[0005] The Chinese invention patent application with publication number CN111892067 B discloses a method for preparing salt brine and large-particle high-calcium salt. In the patent, large-particle high-calcium salt without anti-caking agent can be produced by crystallizing sodium chloride and calcium chloride, and 87% of the particle size is between 0.15-0.85mm. However, this particle size belongs to the conventional particle size of refined edible salt. The "GB / T5461-2016 Edible Salt" standard stipulates that 0.15mm-0.85mm is a small particle size. At this particle size, it is difficult to maintain a non-caking state without adding an anti-caking agent.

[0006] The Chinese invention patent application with publication number CN114573004A discloses a production process for small-grained salt without additives. The process is a conventional process for making salt, the only difference being that the pH value of the finished salt is adjusted to 7.5-8.5, and the ton bag is first packaged and placed for 2-3 days before being transported and packaged by a bucket elevator. However, the process described therein is not beneficial for the preparation of salt without adding anti-caking agents. At the same time, the ton bag is first placed for 2-3 days before being packaged by a bucket elevator, and the production efficiency is low, and continuous production cannot be achieved. Combined with its overall process, it is difficult to ensure that the salt does not clump for a long time without adding an anti-caking agent.

[0007] At present, many methods for preparing salt without anticaking agent mainly increase the particle size of salt or add substances to promote the change of salt crystal form and particle size. It is difficult to keep salt in a non-caking state for a long time at a conventional particle size. The present invention mainly controls the temperature and humidity of salt during packaging to achieve dynamic balance, does not require major changes to the existing process, does not change the particle size and existing storage conditions (moisture-proof, etc.), and can achieve the anti-caking effect after packaging. Summary of the invention

[0008] In order to solve the above technical problems, the present invention provides a production process for salt without adding anti-caking agents. The method adopts a series of measures to control the temperature and humidity balance of salt during packaging, thereby delaying or changing the formation of crystal bridges between salt crystals, so that the packaged salt can maintain its dynamic balance of moisture adsorption and desorption for a long time, achieving the effect of not agglomerating for a long time. This method does not require substantial improvements to the existing brine purification and salt-making processes, does not change the current salt particle size, does not change the storage conditions after packaging (moisture-proof, etc.), can achieve continuous production while meeting the demand of not containing anti-caking agents, and is of great significance to enriching the types of salt and improving the quality. Existing anti-solidification technology does not provide inspiration. It specifically includes the following steps:

[0009] Step 1: Feed the brine refined salt into the fluidized bed, and discharge it after passing through the hot bed and the cold bed;

[0010] Step 2: convey the salt to the silo via a belt. During the belt conveying process, a temperature and humidity control machine is installed at a specific position, and a vibration device is included in the belt conveying process; specifically, the temperature and humidity control machine is set at 6 fixed points during the belt conveying, and each point is 7m apart. The temperature and humidity of the salt under the drying bed are gradient controlled, and the temperature before entering the silo is less than 35°C, and the relative humidity of the air between the salt particles is 65%-75% (i.e. the temperature and humidity requirements during packaging);

[0011] Step 3: A cooling fan is installed at the silo port and a vibrating hammer is installed outside the silo;

[0012] Step 4: Unpacking and packaging (at this time, the temperature of the salt packed into the bag is lower than 35°C, and the relative humidity of the air between the salt particles is between 65% and 75%). After the finished salt is packaged, it is transported by belt.

[0013] Furthermore, in step 1, the brine refined salt is obtained by a known process, such as collecting raw brine, mining it by water-soluble method, and transporting the dissolved brine to the purification workshop through a pipeline; purifying the raw brine by lime flue gas method, adjusting the pH value, and removing high-content calcium and magnesium ions; retaining the obtained refined brine for standby use; evaporating and crystallizing the refined brine, and efficiently evaporating it through an evaporator to obtain salt slurry; passing the obtained salt slurry through a thickener, and then dehydrating it to obtain refined wet salt. Reference may be made to the processes such as CN202211662043.7, CN201710878563.4, and CN202011352999.8, and the process of brine refined salt is not particularly limited;

[0014] Furthermore, in step 1, the temperature of the hot air of the hot bed is 140° C., the temperature of the hot bed salt is 100° C., the material is discharged through the fluidized bed, the discharge temperature is controlled at 45-50° C., and the moisture content is controlled at 0.06g / 100g-0.08g / 100g;

[0015] Furthermore, the role of gradient control is to better ensure that the temperature and humidity of the salt are controlled within the established parameters during the production process. For example, 6 points are set, 1 to 6, and the temperature settings are 42±2℃, 40±2℃, 38±2℃, 36±2℃, 34±2℃, and 32±2℃ respectively.

[0016] Furthermore, in step 2, the belt transport process contains a vibration device, and the frequency is set at 900-960Hz;

[0017] Furthermore, in step 2, the salt flow rate in front of the feed bin is 100-120 kg / min, and a pneumatic vibration hammer is installed outside the feed bin, which strikes every 30 seconds with an impact force of 20-25 kg·m / s;

[0018] In step 2 of the present invention, the temperature and moisture content of the drying bed discharge are controlled, so as to facilitate cooling and dehumidifying in subsequent steps, and promote the dynamic balance of temperature and humidity of the salt. The purpose of reducing caking is achieved by controlling the temperature and humidity in different processes. By installing a temperature and humidity control machine at six positions on the belt, the temperature of the salt after the drying bed is reduced, and the hardening of the salt can be effectively alleviated by controlling the temperature and humidity of the salt. Vibration is increased during the belt transmission process, and the vibration frequency is controlled at 900-960Hz to ensure that the salt can bump up and down during the transmission process, maintain fluidity, and accelerate the expansion of moisture and temperature to prevent the salt from hardening due to the large difference in temperature and humidity between the surface of the salt and the lower layer.

[0019] The present invention adopts the above series of measures to control the temperature and humidity balance of the salt before packaging, that is, the relative humidity of the air between the salt particles is 65%-75%, and the temperature during packaging is controlled to be less than 35°C, thereby delaying or changing the formation of crystal bridges between crystals, so that the packaged salt can maintain its dynamic balance of moisture adsorption and desorption, and the final finished salt maintains good fluidity within 6 months.

[0020] Beneficial effects of the present invention:

[0021] 1. In the continuous production process, by adding temperature and humidity control at key points, the salt is prompted to reach a dynamic balance of temperature and humidity before packaging, making it difficult for crystal bridges to form, and ensuring that the salt will not clump for a long time after packaging without adding anti-caking agents;

[0022] 2. This process does not change the crystal form and grain size of the salt, nor does it change the storage conditions after packaging. It only makes minor changes to the existing salt production process, which can ensure continuous production without reducing the efficiency of the existing production process.

[0023] 3. The process flow of the present invention is simple, the production process is safe and reliable, the production efficiency is high, and the energy consumption is low. It provides a new idea for the preparation of green anti-caking agent-free salt, which is in line with the expectations of consumers and the national policies and guidelines on green and healthy products. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The diagram is a graph showing the agglomeration of packaged salt in each embodiment after being placed for 6 months.

[0025] Figure 2 This is the moisture loss of salt in Example 1 when it is packaged in closed bags made of different materials and placed for 20 days. DETAILED DESCRIPTION

[0026] In order to facilitate understanding of the present invention, the present invention will be described more fully below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0027] The preparation of brine refined salt is as follows:

[0028] Step 1: Collect the raw brine, mine it using the water-soluble method, and transport the dissolved brine to the purification workshop through pipelines;

[0029] Step 2: Purify the raw brine using the lime flue gas method, adjust the pH value, and remove high-content calcium and magnesium ions; retain the resulting refined brine for later use;

[0030] Step 3: Evaporating and crystallizing the refined brine, and efficiently evaporating it through multiple evaporation tanks to obtain salt slurry;

[0031] Step 4: The salt slurry is passed through a thickener and then centrifuged for dehydration to obtain refined wet salt. The obtained brine refined salt enters the following packaging process.

[0032] Example 1

[0033] A production process of salt without adding anticaking agent, comprising the following steps:

[0034] Step 1: Feed the brine refined salt into the fluidized bed, and discharge it after passing through the hot bed and the cold bed. The discharge temperature is controlled at 46°C and the moisture content is controlled at 0.07g / 100g;

[0035] Step 2: Convey to the silo via belt. During the belt conveying process, a temperature and humidity control machine is installed at a specific position. The temperature and humidity control machine is set at 6 fixed points, each 7m apart, to control the temperature and humidity of the salt under the drying bed. The temperature before entering the silo is 34°C, and the relative humidity between the salt particles is 66%. The belt conveying process contains a vibration device, and the frequency is set at 920Hz;

[0036] Step 3: A cooling fan is installed in the silo, a vibrating hammer is installed outside the silo, a temperature monitoring device is installed at the silo discharge port, the salt flow rate in front of the feed silo is 110kg / min, and a pneumatic hammer is installed outside the silo, which strikes every 30s with an impact force of 22kg·m / s;

[0037] Step 4: Unloading, the finished salt is packaged and transported by belt.

[0038] The salt obtained through this step was subjected to a series of characterizations, mainly testing the solidification of the salt at 0 days, 3 days, 7 days, 15 days, 1 month, 3 months and 6 months. No obvious agglomeration was found. The specific results are shown in Table 1.

[0039] Example 2

[0040] A production process of salt without adding anticaking agent, comprising the following steps:

[0041] Step 1: The brine refined salt is fed into the fluidized bed and discharged after passing through the hot bed and the cold bed. The discharge temperature is controlled at 47°C and the moisture content is controlled at 0.08g / 100g.

[0042] Step 2: Convey to the silo via belt. During the belt conveying process, a temperature and humidity control machine is installed at a specific position. The temperature and humidity control machine is set at 6 fixed points, each 7m apart, to control the temperature and humidity of the salt under the drying bed. The temperature drops to 35°C before entering the silo, and the relative humidity between the salt particles is 75%. The belt conveying process contains a vibration device, and the frequency is set at 920Hz;

[0043] Step 3: A cooling fan is installed in the silo, a vibrating hammer is installed outside the silo, a temperature monitoring device is installed at the silo discharge port, the salt flow rate in front of the feed silo is 110kg / min, and a pneumatic hammer is installed outside the silo, which strikes every 30s with an impact force of 22kg·m / s;

[0044] Step 4: Unloading, the finished salt is packaged and transported by belt.

[0045] The salt obtained through this step was subjected to a series of characterizations, mainly testing the solidification of the salt at 0 days, 3 days, 7 days, 15 days, 1 month, 3 months and 6 months. No obvious agglomeration was found. The specific results are shown in Table 1.

[0046] Example 3

[0047] A production process of salt without adding anticaking agent, comprising the following steps:

[0048] Step 1: The brine refined salt is fed into the fluidized bed and discharged after passing through the hot bed and the cold bed. The discharge temperature is controlled at 47°C and the moisture content is controlled at 0.06g / 100g.

[0049] Step 2: Convey to the silo via belt. During the belt conveying process, a temperature and humidity control machine is installed at a specific position. The temperature and humidity control machine is set at 6 fixed points, each 7m apart, to control the temperature and humidity of the salt under the drying bed. The temperature drops to 31°C before entering the silo, and the relative humidity between the salt particles is 68%. The belt conveying process contains a vibration device, and the frequency is set at 920Hz;

[0050] Step 3: A cooling fan is installed in the silo, a vibrating hammer is installed outside the silo, a temperature monitoring device is installed at the silo discharge port, the salt flow rate in front of the silo is 105kg / min, and a pneumatic hammer is installed outside the silo, which strikes every 30s with an impact force of 23kg·m / s;

[0051] Step 4: Unloading, the finished salt is packaged and transported by belt.

[0052] The salt obtained through this step was subjected to a series of characterizations, mainly testing the solidification of the salt at 0 days, 3 days, 7 days, 15 days, 1 month, 3 months and 6 months. No obvious agglomeration was found. The specific results are shown in Table 1.

[0053] Example 4

[0054] A production process of salt without adding anticaking agent, comprising the following steps:

[0055] Step 1: The brine refined salt is fed into the fluidized bed and discharged after passing through the hot bed and the cold bed. The discharge temperature is controlled at 46°C and the moisture content is controlled at 0.06g / 100g.

[0056] Step 2: Convey to the silo via belt. During the belt conveying process, a temperature and humidity control machine is installed at a specific position. The temperature and humidity control machine is set at 6 fixed points, each 7m apart, to control the temperature and humidity of the salt under the drying bed. The temperature drops to 33°C before entering the silo, and the relative humidity between the salt particles is 73%. The belt conveying process contains a vibration device, and the frequency is set at 920Hz;

[0057] Step 3: A cooling fan is installed in the silo, a vibrating hammer is installed outside the silo, a temperature monitoring device is installed at the silo discharge port, the salt flow rate in front of the silo is 105kg / min, and a pneumatic hammer is installed outside the silo, which strikes every 30s with an impact force of 23kg·m / s;

[0058] Step 4: Unloading, the finished salt is packaged and transported by belt.

[0059] The salt obtained through this step was subjected to a series of characterizations, mainly testing the solidification of the salt at 0 days, 3 days, 7 days, 15 days, 1 month, 3 months and 6 months. No obvious agglomeration was found. The specific results are shown in Table 1.

[0060] Comparative Example 1

[0061] The main difference of Comparative Example 1 is that the temperature in step 2 is not controlled to be less than 35°C.

[0062] Step 1: The brine refined salt is fed into the fluidized bed and discharged after passing through the hot bed and the cold bed. The discharge temperature is controlled at 46°C and the moisture content is controlled at 0.07g / 100g.

[0063] Step 2: The salt is transported to the silo via a belt, and the temperature and humidity of the salt under the drying bed are controlled. The temperature before entering the silo is 37°C, and the relative humidity between the salt particles is 66%. The belt transport contains a vibration device, and the frequency is set at 920Hz;

[0064] Step 3: A cooling fan is installed in the silo, a vibrating hammer is installed outside the silo, a temperature monitoring device is installed at the silo discharge port, the salt flow rate in front of the feed silo is 110kg / min, and a pneumatic hammer is installed outside the silo, which strikes every 30s with an impact force of 22kg·m / s;

[0065] Step 4: Unloading, the finished salt is packaged and transported by belt.

[0066] The salt obtained through this step was subjected to a series of characterizations, mainly testing the solidification of the salt at 0 days, 3 days, 7 days, 15 days, 1 month, 3 months and 6 months. Agglomeration was found, and the specific results are shown in Table 1.

[0067] Comparative Example 2

[0068] The main difference of Comparative Example 2 is that the temperature in step 2 is not controlled to be less than 35°C.

[0069] Step 1: The brine refined salt is fed into the fluidized bed and discharged after passing through the hot bed and the cold bed. The discharge temperature is controlled at 50°C and the moisture content is controlled at 0.08g / 100g;

[0070] Step 2: The salt is transported to the silo via a belt, and the temperature and humidity of the salt under the drying bed are controlled. The temperature drops to 39°C before entering the silo, and the relative humidity between the salt particles is 72%. The belt transport process contains a vibration device, and the frequency is set at 920Hz;

[0071] Step 3: A cooling fan is installed in the silo, a vibrating hammer is installed outside the silo, a temperature monitoring device is installed at the silo discharge port, the salt flow rate in front of the feed silo is 110kg / min, and a pneumatic hammer is installed outside the silo, which strikes every 30s with an impact force of 22kg·m / s;

[0072] Step 4: Unloading, the finished salt is packaged and transported by belt.

[0073] The salt obtained through this step was subjected to a series of characterizations, mainly testing the solidification of the salt at 0 days, 3 days, 7 days, 15 days, 1 month, 3 months and 6 months. Agglomeration was found, and the specific results are shown in Table 1.

[0074] Comparative Example 3

[0075] The main difference of Comparative Example 3 is that the relative humidity of the gaps between the salt particles in step 2 is not controlled to 65%-75%.

[0076] Step 1: The brine refined salt is fed into the fluidized bed and discharged after passing through the hot bed and the cold bed. The discharge temperature is controlled at 45°C and the moisture content is controlled at 0.07g / 100g.

[0077] Step 2: The salt is transported to the silo via a belt, and the temperature and humidity of the salt under the drying bed are controlled. The temperature drops to 33°C before entering the silo, and the relative humidity between the salt particles is 62%. The belt transport process contains a vibration device, and the frequency is set at 920Hz;

[0078] Step 3: A cooling fan is installed in the silo, a vibrating hammer is installed outside the silo, a temperature monitoring device is installed at the silo discharge port, the salt flow rate in front of the feed silo is 110kg / min, and a pneumatic hammer is installed outside the silo, which strikes every 30s with an impact force of 22kg·m / s;

[0079] Step 4: Unloading, the finished salt is packaged and transported by belt.

[0080] The salt obtained through this step was subjected to a series of characterizations, mainly testing the solidification of the salt at 0 days, 3 days, 7 days, 15 days, 1 month, 3 months and 6 months. Agglomeration was found, and the specific results are shown in Table 1.

[0081] Comparative Example 4

[0082] The main difference of Comparative Example 4 is that the relative humidity of the gaps between the salt particles in step 2 is not controlled to 65%-75%.

[0083] Step 1: The brine refined salt is fed into the fluidized bed and discharged after passing through the hot bed and the cold bed. The discharge temperature is controlled at 46°C and the moisture content is controlled at 0.06g / 100g.

[0084] Step 2: The salt is transported to the silo via a belt, and the temperature and humidity of the salt under the drying bed are controlled. The temperature drops to 34°C before entering the silo, and the relative humidity between the salt particles is 79%. The belt transport process contains a vibration device, and the frequency is set at 920Hz;

[0085] Step 3: A cooling fan is installed in the silo, a vibrating hammer is installed outside the silo, a temperature monitoring device is installed at the silo discharge port, the salt flow rate in front of the feed silo is 110kg / min, and a pneumatic hammer is installed outside the silo, which strikes every 30s with an impact force of 22kg·m / s;

[0086] Step 4: Unloading, the finished salt is packaged and transported by belt.

[0087] The salt obtained through this step was subjected to a series of characterizations, mainly testing the solidification of the salt at 0 days, 3 days, 7 days, 15 days, 1 month, 3 months and 6 months. Agglomeration was found, and the specific results are shown in Table 1.

[0088] Comparative Example 5

[0089] The main difference of Comparative Example 5 is that the relative humidity of the gaps between the salt particles in step 2 is not controlled to 65%-75%.

[0090] Step 1: The brine refined salt is fed into the fluidized bed and discharged after passing through the hot bed and the cold bed. The discharge temperature is controlled at 47°C and the moisture content is controlled at 0.06g / 100g.

[0091] Step 2: The salt is transported to the silo via a belt, and the temperature and humidity of the salt under the drying bed are controlled. The temperature drops to 39°C before entering the silo, and the relative humidity between the salt particles is 61%. The belt transport process contains a vibration device, and the frequency is set at 920Hz;

[0092] Step 3: A cooling fan is installed in the silo, a vibrating hammer is installed outside the silo, a temperature monitoring device is installed at the silo discharge port, the salt flow rate in front of the feed silo is 110kg / min, and a pneumatic hammer is installed outside the silo, which strikes every 30s with an impact force of 22kg·m / s;

[0093] Step 4: Unloading, the finished salt is packaged and transported by belt.

[0094] The salt obtained through this step was subjected to a series of characterizations, mainly testing the solidification of the salt at 0 days, 3 days, 7 days, 15 days, 1 month, 3 months and 6 months. Agglomeration was found, and the specific results are shown in Table 1.

[0095] Comparative Example 6

[0096] The main difference of Comparative Example 6 is that the temperature in step 2 is not controlled to be less than 35° C., and the relative humidity of the gap between the salt particles is not controlled to be 65%-75%.

[0097] Step 1: The brine refined salt is fed into the fluidized bed and discharged after passing through the hot bed and the cold bed. The discharge temperature is controlled at 50°C and the moisture content is controlled at 0.08g / 100g;

[0098] Step 2: The salt is transported to the silo via a belt, and the temperature and humidity of the salt under the drying bed are controlled. The temperature drops to 41°C before entering the silo, and the relative humidity between the salt particles is 78%. The belt transport process contains a vibration device, and the frequency is set at 920Hz;

[0099] Step 3: A cooling fan is installed in the silo, a vibrating hammer is installed outside the silo, a temperature monitoring device is installed at the silo discharge port, the salt flow rate in front of the feed silo is 110kg / min, and a pneumatic hammer is installed outside the silo, which strikes every 30s with an impact force of 22kg·m / s;

[0100] Step 4: Unloading, the finished salt is packaged and transported by belt.

[0101] The salt obtained through this step was subjected to a series of characterizations, mainly testing the solidification of the salt at 0 days, 3 days, 7 days, 15 days, 1 month, 3 months and 6 months. Agglomeration was found, and the specific results are shown in Table 1.

[0102] Comparative Example 7

[0103] The production is carried out according to the normal salt production process, and the specific steps include:

[0104] Step 1: Collect the raw brine, mine it using the water-soluble method, and transport the dissolved brine to the purification workshop through pipelines;

[0105] Step 2: Purify the raw brine using the lime flue gas method, adjust the pH value, and remove high-content calcium and magnesium ions; retain the resulting refined brine for later use;

[0106] Step 3: Evaporating and crystallizing the refined brine, and efficiently evaporating it through multiple evaporation tanks to obtain salt slurry;

[0107] Step 4: The obtained salt slurry is passed through a thickener and then centrifuged for dehydration to obtain refined wet salt.

[0108] Step 5: Drying: Input into fluidized bed, and unload onto belt after drying;

[0109] Step 6: Transport to the silo via belt;

[0110] Step 7: The products are packaged by automated packaging machines and stored in warehouses.

[0111] Comparative Example 8

[0112] According to the steps of Example 1, the vibration device in the belt conveying process is eliminated. Other operating conditions are the same as those of Example 1.

[0113] Step 1: Feed the brine refined salt into the fluidized bed, and discharge it after passing through the hot bed and the cold bed. The discharge temperature is controlled at 46°C and the moisture content is controlled at 0.07g / 100g;

[0114] Step 2: Convey to the silo via a belt. During the belt conveying process, a temperature and humidity control machine is installed at a specific position. The temperature and humidity control machine is set at 6 fixed points, each 7m apart. The temperature and humidity of the salt under the drying bed are gradient controlled. The temperature before entering the silo is 34°C, and the relative humidity between the salt particles is 66%.

[0115] Step 3: A cooling fan is installed in the silo, a vibrating hammer is installed outside the silo, a temperature monitoring device is installed at the silo discharge port, the salt flow rate in front of the feed silo is 110kg / min, and a pneumatic hammer is installed outside the silo, which strikes every 30s with an impact force of 22kg·m / s;

[0116] Step 4: Unloading, the finished salt is packaged and transported by belt.

[0117] The salt obtained through this step was subjected to a series of characterizations, mainly testing the solidification of the salt at 0 days, 3 days, 7 days, 15 days, 1 month, 3 months and 6 months. No obvious agglomeration was found. The specific results are shown in Table 1.

[0118] Comparative Example 8 shows that the salt has slight caking in 3 days and obvious caking after storage for 1 month. Although the temperature and humidity of the salt are controlled, static transportation is not conducive to the rapid diffusion of water in the salt in a short time, reducing the temperature difference between salt layers, reducing the initial consolidation of the salt, and maintaining fluidity, thereby causing initial hardening and affecting the anti-caking effect.

[0119] The salt obtained through this step was subjected to a series of characterizations, mainly testing the solidification of the salt at 0 days, 3 days, 7 days, 15 days, 1 month, 3 months and 6 months. The agglomeration of the salt was serious. The specific results are shown in Table 1.

[0120] Table 1 Solidification of 2kg packaged salt in different days

[0121] Day 0 3 days 7 days 15 days 1 month 3 months 6 months Example 1 No caking No caking No caking No caking No caking No caking No caking Example 2 No caking No caking No caking No caking No caking No caking Slightly caking Example 3 No caking No caking No caking No caking No caking No caking No caking Example 4 No caking No caking No caking No caking No caking No caking Slightly caking Comparative Example 1 No caking Slightly caking Slightly caking Obvious caking Severe caking Severe caking Severe caking Comparative Example 2 No caking Slightly caking Obvious caking Obvious caking Severe caking Severe caking Severe caking Comparative Example 3 No caking Slightly caking Slightly caking Obvious caking Severe caking Severe caking Severe caking Comparative Example 4 No caking Slightly caking Obvious caking Obvious caking Severe caking Severe caking Severe caking Comparative Example 5 Slightly caking Obvious caking Obvious caking Obvious caking Severe caking Severe caking Severe caking Comparative Example 6 Slightly caking Obvious caking Obvious caking Obvious caking Severe caking Severe caking Severe caking Comparative Example 7 Slightly caking Obvious caking Severe caking Severe caking Severe caking Severe caking Severe caking Comparative Example 8 No caking Slightly caking Slightly caking Slightly caking Obvious caking Obvious caking Severe caking

[0122] Agglomeration strength test

[0123] The agglomeration strength was tested using a thrust meter using a circular probe with a surface area of ​​(the contact surface area is 176.625mm 2 ) Press the agglomerate part and record the peak value of the instrument during the sample crushing process. (Slight agglomeration: agglomeration strength is 0-15N; obvious agglomeration: agglomeration strength is 15-30N; severe agglomeration: agglomeration strength>30N)

[0124] Table 2 2kg packaged salt agglomeration strength test data

[0125]

[0126] Example 1 The moisture loss of salt packaged in closed bags made of different materials after being placed for 20 days is compared, see Table 3.

[0127] Table 3

[0128]

[0129]

[0130] Experiments have shown that the moisture content of packaged salt changes very little with the temperature and humidity of the environment and can be ignored.

Claims

1. A production process for salt without adding anticaking agent, characterized in that: The process is suitable for packaging salt below 2kg and includes the following steps: Step 1: feed the salt obtained by refining brine into the fluidized bed, and discharge the salt after passing through the hot bed and the cold bed. The discharge temperature is controlled at 45-50°C; the moisture content of the discharge is controlled at 0.06 g / 100g-0.08 g / 100g; Step 2: The salt is transported to the packaging silo via a belt conveyor. A temperature and humidity control machine is installed during the belt conveyor to ensure that the temperature before entering the silo is less than 35°C and the relative humidity of the air between the salt particles is 65%-75%. A vibration device is installed during the belt conveyor. The frequency of the vibration device is set at 900-960Hz. Step 3: A cooling fan is installed at the silo port, and a vibrating hammer is installed outside the silo; the salt flow rate in front of the silo is 100-120kg / min, and a pneumatic hammer is installed outside the silo, which strikes every 30s with an impact force of 20-25kg·m / s; Step 4: Unloading, the finished salt is packaged and transported by belt.

2. The production process of anticaking agent-free salt according to claim 1, characterized in that: For the belt transport described in step 2, temperature and humidity control machines are set at 6 fixed points, with each point spaced 7m apart, to perform gradient control on the temperature and humidity of the salt under the drying bed.

Images