Sodium carbonate: 
sodium carbonate, vulgar NaCO, is a salt, sodium carbonate Appearance is a white powder and fine-grained crystal, miso. Its aqueous solution is alkaline and has certain corrosive properties. It can neutralize with acid to form corresponding salt and release carbon dioxide. Sodium carbonate is extremely hygroscopic, easily deliquescent in humid air, slowly absorbs carbon dioxide and water, and partially turns into sodium bicarbonate, so packaging must be Strict, responsible for moisture absorption and agglomeration 
sodium carbonate classification: 
According to Uses, it is divided into industrial grade sodium carbonate and food grade sodium carbonate. According to the bulk density, it is divided into light sodium carbonate (500-600kg/m 3 ) and heavy sodium carbonate (1000 -1200kg/m3), according to the production process is divided into trona, ammonia-alkali method, combined alkali method, ammonium sulfide is divided into common alkali and low-salt alkali. 
1, according to Uses classification: industrial grade sodium carbonate and food grade sodium carbonate, 
2, according to different bulk density, industrial grade sodium carbonate is divided into light sodium carbonate and heavy sodium carbonate. 
3. According to the different sulfide content, it is divided into common alkali and low salt alkali. 
In "Industrial Sodium Carbonate Standard / GB-210.1-2004", ordinary base, low-salt base (by dry mass of NaCl mass fraction) /% are less than or equal to 0.70 and 0.30, respectively. 
4, the production process: ammonia, alkali, trona 
, product packaging 
1, light sodium carbonate is generally 25kg, 40kg, 50kg (alkali method Chinese packaging, is a special case, the same light sodium carbonate, ammonia-alkali method Usually 40kg, the combined alkali method is usually 50kg) 750kg (also counted as tons), and the heavy sodium carbonate is generally 25kg 50kg or ton.
2 domestic sales are generally Chinese packaging. With a company logo and the like. English packaging generally needs to be coordinated. Some manufacturers only have Chinese packaging. Some manufacturers have company logos on English packaging, such as Lianyungang Soda Plant, Tianjin Soda Plant, Junhua, Shuanghuan, Tangshan Sanyou, Haitian, etc. There are also no English packaging. For example, Haihua, there are also Chinese and English control packaging such as double ring 
3, the packaging is generally plastic outer packaging, Haihua old factory is double-layer packaging. The new factory is a single-layer packaging (because the new factory is fully automated mechanical operation, the machine can not complete the bagging work), Haitian sodium carbonate is a single-layer packaging 
, the product packaging amount of 
light alkali: no tray, small cabinet 21 tons / 525bags, 40kg; 420bags, 50kg; 1000kg ton bags, 20 tons for small cabinets, 15 tons for 750kg tons, 
18 tons for trays (18kg for 40kg or 25kg), very small for export, small packets of carbonic acid The maximum packing amount of sodium was confirmed (sodium carbonate for ammonia-alkali method, 21.5 tons for 25kg, 21.52 tons for 40kg), sodium carbonate, light sodium carbonate, 1 train car, 60-65 tons of 
heavy alkali: no tray , small cabinet 25 tons / 500bags, 50kg (for domestic sales, Haihua 50kg installed 26 tons 1000kg with 28 tons: Lianyungang soda plant 50kg installed 29 tons, small cabinet loaded 25 tons) 1000kg tons of bags, small cabinets 25 tons, Tray 22 tons. Exports are rarely used. 
Tankers can hold light sodium carbonate 70/m3. 1 cubic meter of 0.6 tons, the whole canned 40 tons, can not ensure the number of canned 
products HS code 2836200000 
special note: sodium carbonate export tax rebate nine points, do not need to do commodity inspection 
five, the use of products and description of 
sodium carbonate is important One of the chemical raw materials, widely used in light industry and daily necessities, building materials, chemical industry, food industry, metallurgy, textile, petroleum, national defense, medicine and other fields. In industrial alkali, it is mainly light industry, building materials, chemical industry, accounting for about 2/3. Secondly, other industries such as metallurgy, textile, petroleum, national defense, medicine, etc.
1 The glass industry is the largest consumer of sodium carbonate, which consumes 0.2t of sodium carbonate per ton of glass. 
Mainly used for float glass, tube glass bulb, optical glass, etc. Sodium carbonate provides Na ions in the glass batch, acts as a clarifying agent to eliminate bubbles in the glass, and is thermally decomposed in the kiln to release CO2 gas to agitate the glass container! 
2 can also be used in other departments such as chemical metallurgy. 
Industrial sodium carbonate will volatilize when it encounters high temperature to produce gas. It can stir the metal liquid and use the shell to effectively desulfurize with metallurgical calcium oxide. Use heavy sodium carbonate technology to reduce alkali dust flying, reduce raw material consumption, improve working conditions, improve product quality, reduce the erosive effect of alkali powder on refractory materials, and extend the service life of kiln. 
3 as buffer and neutralizer , dough improver, can be used in pastry and pasta products, according to the needs of production 
, there will be microbes forming acid in the process of baking, the dough will become sour after the start, must be neutralized with alkali to make delicious pasta 
4 as a detergent Used in wool rinsing, bath salts and pharmaceuticals, alkaline agents in tanning. 
The sodium carbonate solution is alkaline during the hydrolysis period, and the alkali solution can be saponified with the oil to form a high-grade fatty acid sodium soluble in water. 
5 Sodium 
carbonate sodium carbonate for drilling can reduce the fluid loss of the new slurry, viscosity, The shearing force is increased, but the excessive amount of sodium carbonate will cause the clay particles to coagulate, which will damage the performance of the drilling fluid. The appropriate dosage should be determined by the pulping experiment. Also. When the cement plug or drilling fluid is subjected to calcium intrusion, adding appropriate amount of sodium carbonate to precipitate Ca2+ into CaCO can also make the drilling fluid performance better. 
6 Color TV special reagent (less 
used now) 7 Used in the pharmaceutical industry as an acid-solving agent. Osmotic laxative. 
8 anhydrous sodium carbonate is used for electrical and electrochemical degreasing, electroless copper plating, aluminum corrosion, electropolishing of chlorine and alloy, chemical oxidation of aluminum, sealing after phosphating, rust prevention between processes, electrolytic chrome removal Coating and chrome-removing oxide film, etc., also used in pre-plated copper, plated, and plated steel alloy electrolytes. 
9 printing and dyeing industry used as water softener
10 The tanning industry is used for degreasing raw material skin, neutralizing chrome tanning and increasing the alkalinity of chrome tanning liquid. 
11 light sodium carbonate can be used as a filler for rubber using 
12 water treatment, softening water with lime sodium carbonate method, lime is generally used to remove carbonate hardness in water, sodium carbonate is used to remove non-carbonate hardness 
13 using practical carbonic acid Sodium production of hydroxymethyl cellulose 
14 by-product sodium carbonate for the production of sodium 
silicate Sodium silicate sodium silicate, petroleum silica (quartz sand), sodium carbonate, (or soil alkali) eutectic 
15 cement mortar in the melting kiln The main role of adding sodium carbonate is drought, and it is also to stimulate the mixed material slag. Otherwise it will cause the late strength of the mortar to be low! 
16 sodium carbonate is used to produce sodium fluoride crystals 
. The process of producing sodium fluoride by sodium carbonate has the advantages of easy availability of raw materials, short process flow, low investment, no waste, and low corrosiveness to equipment. 
17 Supplementary edible alkali Uses: 1  water (jian) water, also known as alkaline water, also known as edible water, is a compound food additive, is a material in the food process, drowning is a traditional accessory for Cantonese-style cakes. This material is often added to the preparation of the dough for the mooncake dough. 2 According to the national standard of moon cake, the production of Cantonese-style moon cake will use drowning water. This is the characteristic method of Cantonese-style moon cake. 3 It is made up of potassium carbonate and sodium carbonate as the main components, supplemented by carbonate or polymerized phosphate. The basic compound 
18 sodium carbonate is used as a papermaking 
machine in the process of pulping. In the chemical pulping process, sodium sulphate is used as a buffering agent to slowly dissolve lignin, thereby dispersing cellulose into pulping and papermaking. Is to separate the cellulose and lignin in the wood, lignin is a phenylmethane structure, the structure is complex and stable, not easy to decompose, under alkaline conditions can make lignin into a methylene fluorene structure, while producing a conjugated double The key facilitates the next step of lignin removal (dissolving lignin). 
19 sodium carbonate is used to make burning materials
The burnt material refers to a rock powder containing silicate mixed with sodium carbonate, added with a pigment, and heated and melted. A glassy object that condenses after cooling, similar to glass but with a lower melting point and less transparency (some opaque) used to make utensils or handicrafts. 
6. Performing quality standards for 
industrial sodium carbonate. Sodium carbonate national standard 210.1-2004 class II standard, product quality has reached the international advanced level.

    VII. Quality shelf life 
Food grade sodium carbonate 180 days 
Light sodium carbonate 2 years 
supplement: Screen residue is a noun for measuring particles such as 200 mesh sieve, sieve one powder, 20% below sieve, 80% above sieve, then we will It is said that 80% of the powder is the residue of the sieve. It is said that it is the thing on the sieve. 
Eight, ph value 
Light sodium carbonate 11.6 
Heavy sodium carbonate 12-14 
9. Introduction of the production process 
The sodium carbonate process is mainly divided into the natural alkali method and Synthetic method, and the synthesis method is divided into ammonia-alkali method and combined alkali method. 
China's sodium carbonate technology is mature, and it is one of the few countries in the world with three kinds of processes. In addition to this, there is Japan's new Asahi Law, Russia's nepheline alkali method and so on. 
1 trona 
At present, only a few countries such as the United States, China, Turkey and Kenya are found in the world. Among them, the Green River trona mine in the United States is the most famous. The trona deposit in the Green River area has 42 ore layers containing sodium sesquicarbonate. Even if all the alkali plants in the world are shut down, the US trona is also available for 1300 years of sodium carbonate in the world. The trona mine in Tongbai County, Henan Province, has a total reserve of 150 million tons and a prospective reserve of 3-5 billion tons, accounting for 80% of the country's trona reserves and ranking second in the world. Inner Mongolia Yihua Group has established a natural alkali-based chemical park in Tongbai. Its high-quality low-salt heavy sodium carbonate design has an annual output of 1 million tons. The 
trona process mainly has three kinds of 
a-half-alkali process 
ore mining-dissolving- Clarification to remove impurities - circulating mother liquor - three-effect vacuum crystallization - 240 degrees calcination 
b brine carbonization process 
natural brine - carbonization tower carbonization to heavy alkali - drying - calcination to crude alkali - bleaching-calcination with sodium nitrate at 155 degrees, calcination with carbon dioxide Self-supplied power plant provides 
c-water alkali process
Ore mining - crushed to below 7 cm - 200 degrees for 30 minutes - crude alkali - dissolution, clarification - three-effect vacuum crystallization - 240 degrees calcination 
2 ammonia-alkali production process introduction: 
ammonia-alkali method enables production to achieve continuity, salt The utilization rate is improved and the product quality is pure. Therefore, the product is called sodium carbonate. It is made of salt, limestone (calcined to produce quicklime and carbon dioxide), ammonia as raw material to prepare sodium carbonate, and 
then ammonia gas is introduced into saturated brine. It becomes ammonia brine, and carbon dioxide is introduced to form a sodium bicarbonate precipitate and a ammonium chloride solution having a small solubility. The chemical reaction principle is 
NaCl + NH3 + H2O + CO2 = NaHCO ↓ + NH4CI NaHCO microcrystals 
which are filtered and washed, and calcined by heating to obtain a sodium carbonate product. 2 NaHCO=Na2CO3+H2O+CO2↑ Carbon dioxide gas can be recycled for recycling. The ammonium chloride-containing filtrate is mixed with lime milk {Ca(OH)2}, and the released ammonia gas can be recycled and recycled. 
CaO+H2O=Ca(OH)2, 2NH4CI+Ca(OH)2=CaCI2+2NH3↑+2H2O 
3 combined alkali method The production process 
is a method of combining the two processes of ammonia alkali method and synthetic ammonia method to produce both sodium carbonate and ammonium chloride products. He retained the advantages of the ammonia-alkali method, eliminating its shortcomings, and increasing the utilization rate of salt by 96%. The raw materials were salt, ammonia and carbon dioxide – the exhaust gas from the synthesis of ammonia gas to produce hydrogen gas. The principle of chemical reaction is C+H2O=CO+H2,      
CO+H2O=CO2+H2 
combined alkali method includes two processes
The first process is the same as the ammonia-alkali method. The ammonia gas is introduced into the saturated brine, and the carbon dioxide is passed into the carbon dioxide to form a sodium hydrogencarbonate precipitate. After filtration, the NaHCO microcrystals are obtained, and the sodium carbonate product is obtained by calcination, and the filtrate is chlorine-containing. A solution of ammonium and sodium chloride, the second process is to crystallize ammonium chloride crystals from a solution containing ammonium chloride and sodium chloride, and to add fine powdered sodium chloride to the filtrate under low temperature conditions. And the ammonia gas is introduced, the ammonium chloride can be precipitated separately, and the ammonium chloride product is obtained by washing and drying by filtration. At this time, the solution obtained by filtering out the precipitation of ammonium chloride has been substantially saturated with sodium chloride, and can be recycled by using a combined alkali method and an ammonia-based method. The biggest advantage is that the utilization rate of salt is increased to more than 96%, the same salt is used to produce more sodium carbonate than the ammonia-based method, and it comprehensively utilizes the carbon dioxide of the ammonia plant and the chloride ion of the alkali plant. Production of two valuable products - sodium carbonate and ammonium chloride, the carbon dioxide of the ammonia plant is converted into the main raw material of the alkali plant to produce sodium carbonate, thus saving the limestone used in the alkali plant to produce carbon dioxide. The amount of chlorine used in the alkali plant is replaced by the chlorine component of the alkali plant, which is the useless component of the alkali plant. Therefore, it is no longer possible to produce calcium chloride which is not useful and has a relatively difficult to handle. Reduced environmental pollution. And greatly reduce the cost of sodium carbonate and nitrogen fertilizer, fully embodies the superiority of large-scale joint production. Advantages 
and Disadvantages of Two Production Processes 
Advantages of Preparation of Sodium Carbonate by Ammonia-Based Process 
1 Raw Material: Preparation of Sodium Carbonate by Ammonia-Based Method Wide source of raw materials 
2 Purity: Sodium carbonate prepared by ammonia-based method, high purity of product 
3 Production capacity:: Sodium carbonate prepared by ammonia-alkali method can be continuously produced and has strong production capacity. 
Disadvantages: Low NaCl utilization rate 
requires abundant raw salt. , limestone, coal, water and other resources supply, and to discharge a large amount of waste residue waste liquid 
combined with the advantages of alkali method 
1 utilization: high utilization of raw materials, both the production of sodium carbonate and the production of the same amount of ammonium chloride 
2 production input costs : The production process does not require the use of limestone or coke, which can effectively reduce the investment in production costs.
3 equipment input cost: the sodium carbonate part does not need to use the cumbersome equipment such as the ammonia tower ashing machine, which not only reduces the process steps, but also reduces the equipment input cost. 
4 Environmental protection: the combined alkali method basically closes the circulation, and the small amount discharges the waste liquid. There will not be a large amount of waste liquid waste discharged, which can be produced in the in-situ soda plant, which is more conducive to sales. 
Disadvantages 
Co-production of ammonium chloride is easily restricted by agricultural development and compound fertilizer industry. 
10. Sodium carbonate test method 
1 Sodium carbonate plant is generally calculated by dry basis. Method, but many companies use the wet basis measurement method, dry basis measurement method (ammonia alkali method) sodium carbonate content can reach 99.3-99.4 wet base and dry basis measurement method can differ by a few percentage points 
2 sodium carbonate is generally divided into superior products And first-class products. The content of superior products is 99.2, and the content of first-class products is 99.8.