Some standard content:
Chemical Industry Standard of the People's Republic of China
Industrial Basic Zinc Carbonate
1 Subject Content and Scope of Application
HG/T 2523-93
This standard specifies the technical requirements, test methods, inspection rules, as well as marking, packaging, transportation and storage of industrial basic zinc carbonate. This standard applies to industrial basic zinc carbonate produced by zinc sulfate method and alkaline leaching method. This product is mainly used as a raw material for catalysts and desulfurizers, and is also used as an activator for rubber and latex, etc. Molecular formula: ZnCO, 2Zn(OH)2·H,O
Relative molecular mass: 342.23 (according to the international relative atomic mass in 1989) 2 Reference standards
Chemical reagents-Preparation of standard solutions for titration analysis (volumetric analysis) GB/T 601
GB/T 602
GB/T603
Chemical reagents-Preparation of standard solutions for determination of impurities Preparation of preparations and products used in chemical reagent test methods Methods for expressing and determining limit values GB 1250
GB/T 6284
GB/T 6678
GB/T 6682
General method for determination of moisture content in chemical products-Gravimetric method
General rules for sampling of chemical products
Specifications and test methods for water used in analytical laboratoriesGB8946Plastic woven bags
3 Technical requirements
3.1 Appearance: white powder.
3.2 Industrial basic zinc carbonate shall meet the requirements of the following table: Approved by the Ministry of Chemical Industry of the People's Republic of China on September 8, 1993 514
Implementation on July 1, 1994
Main content (as Zn) (as dry basis)
Loss on ignition
Heavy metal (as Pb) content
Sulfate (as SO,) content
Fineness (through 75μm sieve)
Cadmium (Cd) content
HG/T2523-93
Superior product
25.0~28.0
Note: If the user has special requirements for fineness index, it can be negotiated with the manufacturer. 4 Test method
First-class product
25.0～30.0
Qualified product
25.0~~32.0
The reagents and water used in this standard, unless otherwise specified, refer to analytical pure reagents and grade 3 water specified in GB/T6682. The standard titration solutions, impurity standard solutions, preparations and products used in the test, unless otherwise specified, are prepared in accordance with the provisions of GB/T601, GB/T602 and GB/T603. 4.1 Determination of main content
4.1.1 Summary of method
Dissolve the sample with hydrochloric acid, add a masking agent to mask the interfering ions, and titrate with disodium ethylenediaminetetraacetic acid standard titration solution in acetic acid-sodium acetate buffer solution of pH 5~6, using xylenol orange as the indicator solution. 4.1.2 Reagents and materials
4.1.2.1 Ascorbic acid;
4.1.2.2 Hydrochloric acid (GB/T622) solution: 1+1;4.1.2.3 Ammonia (GB/T631) solution: 2+3;4.1.2.4 Sodium fluoride (GB/T1264) solution: 200g/L, stored in a plastic bottle,4.1.2.5 Sodium thiosulfate (GB/T637) solution: 100g/L;4.1.2.6 Acetic acid-sodium acetate buffer solution: pH=5.5. Dissolve 150g sodium acetate (GB/T694) in water, add 50mL glacial acetic acid (GB/T676), dilute to 1000mL with water, and shake well. Disodium ethylenediaminetetraacetate (EDTA) (GB/T1401) standard titration solution: c(CrHrO.N,Na2) about 0.05mol/L; 4.1.2.7
4.1.2.8 p-Nitrophenol indicator solution: 1g/L; xylenol orange indicator solution: 2 g/L.
4.1.2.9
4.1.3 Analysis steps
Weigh about 2g of the sample that has been dried to constant weight at 105110℃ in advance, accurate to 0.0002g, place it in a 400mL tall beaker, add a small amount of water to moisten it, and dissolve it with hydrochloric acid solution. Transfer it to a 250mL volumetric flask, add water to dilute to the scale, and shake well. Use a pipette to transfer 25mL of the test solution and place it in a 250mL conical flask. Add 70mL water, 0.1g ascorbic acid, and 2 drops of p-nitrophenol indicator solution. Adjust to yellow with ammonia solution, and then adjust to colorless with hydrochloric acid solution. Add 20mL acetic acid-sodium acetate buffer solution, 5mL sodium fluoride solution, and 5mL sodium thiosulfate solution, and shake well. Add 5 drops of xylenol orange indicator solution, and titrate with disodium ethylenediaminetetraacetic acid standard titration solution until the solution changes from purple-red to bright yellow, which is the end point.
Perform a blank test at the same time.
4.1.4 Expression of analysis results
HG/T2523--93
The main content (in terms of Zn) X expressed in mass percentage is calculated according to formula (1): (V - V.): c× 0.065 39 >
65.39 X (V - V.) - c
Wherein: c--—actual concentration of EDTA standard titration solution, mol/L; 100
V--The volume of EDTA standard titration solution consumed by titrating the test solution, mL; V,——-The volume of EDTA standard titration solution consumed by titrating the blank, mL; -The mass of the sample, g;
0.06539——-The mass of zinc in grams equivalent to 1.00ml EDTA standard titration solution [c (Ci.Hl.OgN,Naz) = 1.000mol/1.
4.1.5 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result, and the absolute difference between the two parallel determination results shall not exceed 0.2%. 4.2 Determination of loss on ignition
4.2.1 Summary of method
The sample is pyrolyzed into zinc oxide at 650±50℃, and the loss on ignition is measured. 4.2.2 Instruments and equipment
4.2.2.1 Porcelain: 30mL.
4.2.3 Analysis steps
Weigh about 3g of sample, accurate to 0.0002g, place in porcelain that has been calcined to constant weight at 65050℃, and calcine to constant weight at 650±50℃.
4.2.4 Expression of analysis results
The ignition loss X expressed as mass percentage is calculated according to formula (2): Xz=m=㎡ ×100
Where: m2-
The mass of the sample and the crucible, g:
-The mass of the residue and the crucible, g;
-The mass of the sample, g.
4.2.5 Permissible difference
Take the arithmetic mean of the parallel determination results as the determination result. The absolute difference between the two parallel determination results shall not exceed 0.1%. 4.3 Determination of heavy metal content
4.3.1 Summary of the method
Dissolve the sample with hydrochloric acid and adjust to weak alkalinity with ammonia water. Use CN- to mask zinc. Heavy metal ions react with the newly prepared sodium sulfide solution to form colored sulfide precipitation, which is visually compared with the standard colorimetric solution. 4.3.2 Reagents and materials
4.3.2.1 Hydrochloric acid (GB/T622) solution: 1+1; 4.3.2.2 Ammonia (GB/T631) solution: 2+3; 4.3.2.3 Potassium cyanide (GB/T1271) solution: 200g/L, 4.3.2.4 Sodium sulfide (HG3-905) solution: 100g/L, prepared before use; 4.3.2.5 Lead standard solution: 1mL contains 0.01mgPb. After preparation according to GB/T603, take 10mL with a pipette, place in a 100mL volumetric flask, dilute with water to the mark, and shake to hook. This solution is prepared just before use.
4.3.3 Analysis steps
HG/T 2523-93
Weigh 1.00±0.01 of the sample and moisten with a small amount of water. Dissolve with hydrochloric acid solution. Transfer to a 100ml volumetric flask and shake well. Take 10ml with a pipette, place in a 50mlL colorimetric tube, and neutralize with ammonia solution until slightly turbid. Add 5mL potassium cyanide solution, 1ml sodium sulfide solution, add water to the mark, and shake to hook. Place in a dark place for 10min, and the color should not be darker than the standard colorimetric solution. Preparation of standard colorimetric solution: Use a pipette to transfer 4.00mL (for superior products) and 5.00mL (for first-class products and qualified products) of lead standard solution into a 50mL colorimetric tube, add water to 10mL, and treat it in the same way as the test solution. 4.4 Determination of moisture content
4.4.1 Summary of the method
Article 2 of GB/T6284.
4.4.2 Instruments and equipment
4.4.2.1 Weighing bottle: $50mm×30mm. 4.4.3 Analysis steps
Weigh about 3g of sample, accurate to 0.0002g, and proceed according to Article 5 of GB/T6284. 4.4.4 Expression of analysis results
The moisture content X expressed as mass percentage is calculated according to formula (3): X. =
Where: m.—mass of sample and weighing bottle, g; mass of sample and weighing bottle after drying, g
m——mass of sample, g.
4.4.5 Allowable difference
Take the arithmetic mean of the parallel determination results as the determination result, and the absolute difference between the two parallel determination results shall not exceed 0.1%. 4.5 Determination of sulfate content
4.5.1 Summary of method
Under acidic conditions, barium fluoride is added to form a white precipitate with sulfate ions in the test solution. Turbidimetric analysis with barium sulfate standard turbidimetric solution.
4.5.2 Reagents and materials
4. 5.2. 1 95% ethanol (GB/T 671); 4.5.2.2 Hydrochloric acid (GB/T622) solution: 1+1; 4.5.2.3 Barium fluoride (GB/T652) solution: 100g/L; 4.5.2.4 Sulfate standard solution: 1mL contains 0.1mgSO4. 4.5.3 Analysis steps
Weigh 0.50±0.01g of sample and place it in a 100mL beaker. Moisten it with a small amount of water and dissolve it with hydrochloric acid solution. Boil for 3min and cool it. Transfer it to a 100mL volumetric flask (filter if necessary). Dilute it to the mark with water and shake it. Use a pipette to transfer 10mL of the test solution and place it in a 50ml colorimetric tube. Add water to about 25mL. Add 5mL ethanol, 2mL barium chloride solution, add water to the scale, and shake well. Let stand for 10 minutes. The turbidity should not be deeper than the standard turbidity solution.
Preparation of standard turbidity solution: Use a pipette to take 3.00mL (for superior products) and 4.00mL (for first-class products) of sulfate standard solution, and treat it in the same way as the test solution.
4.6 Determination of fineness
4.6.1 Reagents and materials
4. 6. 1. 1 95% ethanol (GB/T 679). 4.6.2 Instruments and equipment
4.6.2.1 Test sieve (GB6003): Φ75×25/0.075mm517
4.6.2.2 Large-character sheep-hair brush.
4.6.3 Analysis steps
HG/T 2523-93
Weigh about 10g of sample, accurate to 0.01g, and place it in a test sieve that has been dried to constant weight at 105-110℃ in advance. Fill a 1000ml beaker with tap water and slowly immerse the test sieve in the water. After the sample is moistened, use a large-character sheep hair brush with a tip of about 1/3 of the tip to gently brush it at a speed of two times per second. After brushing for 20 times, lift the test sieve out of the water. Change the water every two times until the beaker is clear and free of sample. Use a distilled water flow of 300-400mL/min to flush the sample on the brush into the sieve and rinse the sieve for 30s. Then, rinse it once with 10mL of ethanol. Dry the test sieve at 105-110℃ to constant weight. 4.6.4 Expression of analysis results
Fineness X expressed as mass percentage is calculated according to formula (4): m2
Wherein: ml—mass of test sieve, g;
m2—mass of test sieve and sieve residue, g; m—mass of sample, g;
X, moisture content measured according to 4.4.
4.6.5 Allowable difference
100 -- X..
The arithmetic mean of the parallel determination results is taken as the determination result, and the absolute difference between the two parallel determination results shall not exceed 0.2%. 4.7 Determination of pot content
4.7.1 Summary of method
The content of the element in the sample is determined by measuring the absorbance of the atomic vapor generated by the test solution and the standard solution to the radiation of the specific absorption wavelength of the cadmium element.
4.7.2 Reagents and materials
4.7.2.1 Hydrochloric acid (GB/T622) solution: 1+1;4.7.2.2 Nitric acid (GB/T626) solution: 1+1;4.7.2.3 Standard solution: 1mL contains 0.02000mgCd. Weigh 0.1000g high-purity cadmium powder, place it in a 150mL beaker, add 20mL nitric acid solution, heat to dissolve, and evaporate until there is no NO. Cool. Transfer to a 1000mL volumetric flask, dilute to the mark with water, and shake.
Use a pipette to transfer 20mL of this standard solution, place it in a 100mL volumetric flask, dilute to the mark with water, and shake well. Prepare this dilute solution before use.
4.7.3 Instruments and equipment
4.7.3.1 Atomic absorption spectrophotometer;
4.7.3.2 Cadmium hollow cathode lamp;
4.7.3.3 Flame: acetylene-air.
4.7.4 Analysis steps
4.7.4.1 Drawing of working curvewwW.bzxz.Net
In 5 100mL volumetric flasks, add 0 (reagent blank solution), 1.00, 2.00, 3.00, 4.00mL cadmium standard solution, add 10mL hydrochloric acid solution, dilute to the scale with water, and shake well. Use an atomic absorption spectrophotometer to measure the absorbance at 228.8nm with water as the reference. Subtract the absorbance of the reagent blank solution from the absorbance of each standard reference solution, and draw a working curve with the cadmium mass concentration as the horizontal axis and the corresponding absorbance as the vertical axis. 4.7.4.2 Determination
Weigh about 0.5g of sample, accurate to 0.0002g, place in a 150mL beaker, moisten with a small amount of water, add nitric acid solution to dissolve, heat and evaporate until no NO,. Cool. Transfer to a 100mL volumetric flask, add 10mL hydrochloric acid solution, dilute to scale with water, and shake well. Use an atomic absorption spectrophotometer to measure the absorbance at 228.8nm with water as reference. Find the cadmium mass concentration from the working curve. 4.7.5 Expression of analysis results
The cadmium (Cd) content X expressed as a mass percentage is calculated according to formula (5): X, = e × 100 × 10 × 100 =
Where: β is the cadmium mass concentration of the test solution obtained from the working curve, mg/mL; m is the mass of the sample, g.
4.7.6 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result, and the absolute difference between the two parallel determination results shall not exceed 0.02%. 5 Inspection rules
5.1 The seven index items specified in this standard, namely, main content, loss on ignition, heavy metal content, moisture, sulfate content, fineness, and cadmium content, are type inspection items. Among them, six index items, namely, main content, loss on ignition, heavy metal content, moisture, sulfate content, and fineness, are factory inspection items. Under normal production conditions, type inspection shall be carried out at least once every six months. 5.2 Industrial basic zinc carbonate shall be inspected by the quality supervision and inspection department of the manufacturer in accordance with the provisions of this standard. The manufacturer shall ensure that all products shipped out of the factory meet the requirements of this standard. Each batch of products shipped out of the factory shall be accompanied by a quality certificate. The content includes: manufacturer name, product name, grade, net weight, batch number or production date, proof that the product quality meets this standard and the number of this standard. 5.3 The user has the right to inspect and accept the industrial basic zinc carbonate received in accordance with the provisions of this standard. The inspection and acceptance shall be carried out within one month from the date of arrival of the goods.
5.4 Each batch of products shall not exceed 15t.
5.5 Determine the number of sampling units in accordance with the provisions of Article 6.6 of GB/T6678. When sampling, insert the sampler from the central vertical line of the packaging bag to 3/4 of the depth of the material layer to collect samples. After mixing the collected samples, reduce them to about 500g according to the quartering method, and pack them in two clean and dry wide-mouth bottles with stoppers and seal them. A label is attached to the bottle, indicating: manufacturer name, product name, batch number, sampling date and name of the sampler. One bottle is used for inspection and the other is kept for three months for reference.
5.6 If one of the test results does not meet the requirements of this standard, re-sample from twice the amount of packaging for verification. If even one of the test results does not meet the requirements of this standard, the entire batch of products cannot be accepted. 5.7 When the supply and demand parties have objections to the product quality, they shall be handled in accordance with the provisions of the "Interim Measures for National Product Quality Arbitration Inspection". 5.8 The rounded value comparison method specified in GB1250 shall be used to determine whether the test results meet the standards. 6 Marking, packaging, transportation, storage
6.1 The packaging bag of industrial basic zinc carbonate should have firm and clear markings, including: manufacturer name, product name, trademark, grade, net weight, batch number or production date and this standard number. 6.2 Industrial basic zinc carbonate is double-layer packaged. The inner packaging is a polyethylene plastic film bag with dimensions of 1050mm×570mm and a thickness of 0.08mm; the outer packaging is a plastic woven bag with a specification size of 900mmX550mm. Its performance and inspection methods should comply with the provisions of GB8946B. The net weight of each bag of this product is 25kg. 6.3 Packaging of industrial basic zinc carbonate. The inner bag is tied with vinyl rope or other ropes of equivalent quality, or sealed with other equivalent methods; the outer bag is folded at a distance of not less than 30mm from the edge of the bag, and the mouth is sewn with vinyl thread or other threads of equivalent quality at a distance of not less than 15mm from the edge of the bag. The stitch length is 7~12mm, the stitches are neat and the stitch length is uniform. There is no leakage or skipping. 6.4 Industrial basic zinc carbonate should be covered during transportation to prevent rain and moisture. 6.5 Industrial basic zinc carbonate should be stored in a cool and dry place to prevent rain and moisture. Prevent sunlight and heat. 519
HG/T2523--93
Appendix A
Treatment of cyanide waste liquid
(Supplement)
In order to prevent the pollution of cyanide waste liquid, the cyanide waste liquid after each analysis should be treated before discharge. A1 Method Summary
Under alkaline conditions, hypochlorite is used as an oxidant to oxidize and decompose cyanide ions into non-toxic nitrogen and carbon dioxide. 2CN- + 5CIO-+ H,O = N2 + → 2CO,+ + 20H*+ 5C-A2 Operation steps
Collect the waste liquid in a 500mL beaker, place it in a fume hood, add 25g bleaching powder, stir it thoroughly, and discharge it after 12h. The reagents used in the above operations are all industrial grade. Additional remarks:
This standard was proposed by the Science and Technology Department of the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of Tianjin Chemical Research Institute of the Ministry of Chemical Industry. This standard was drafted by Tianjin Chemical Research Institute, Lianyungang Haibin Chemical Plant, Jiangsu Province, and Shanghai Jinghua Chemical Plant. The main drafters of this standard are Wang Qi, Liu Changyu, Liu Xinyuan, Cai Zhilan, Sun Lijun, and Teng Shilan. This standard refers to the US military specification MIL-Z-12061B (1983) "Technical Grade Basic Zinc Carbonate". 520
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