A method for reducing lead content in tin protochloride

A technology of stannous chloride and lead content, which is applied in the field of lead removal and can solve problems such as excessive lead content

Active Publication Date: 2015-11-11
GUANGXI HUAXI GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the high lead content in the raw material stannous chloride, the lead content in the product exceeds the standard.
How to reduce the lead content in stannous chloride has become a difficult problem in the field of stannous pyrophosphate production. At present, there is no report on how to reduce the lead content of high-lead stannous chloride in raw materials for the production of low-lead stannous pyrophosphate.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Put 200kg, 250kg, 300kg of stannous chloride (Pb%=0.014%) in 2m 3 Add 500L of deionized water to the reaction kettle, stir, and after it is completely dissolved, add 20kg of sodium hydroxide, adjust the pH of the solution to 8, continue to raise the temperature of the solution to 60°C, and press barium chloride After the mass ratio of lead ion in stannous chloride is 20:1, add 25kg of barium chloride solution dropwise, add 25 times of sodium carbonate solution, stir for 1h under this condition, and then centrifuge the stannous chloride solution Produced barium carbonate white precipitation, obtains transparent raw material low-lead stannous chloride solution, stand-by. The stannous chloride after deleading is reacted with pyrophosphate to obtain stannous pyrophosphate products, and the above stannous chloride is used in different mass concentrations to obtain lead contents of 0.0035%, 0.0039% and 0.0041% in the products respectively.

Embodiment 2

[0020] Put 200kg of stannous chloride (Pb%=0.014%) into 2m 3 Add 500L of deionized water to the reaction kettle, stir, and after it is completely dissolved, add 20kg of sodium hydroxide, adjust the pH of the solution to 8, continue to raise the temperature of the solution to 60°C, and press barium chloride After the mass ratio of lead ion in stannous chloride is 30:1, add 37.5kg of barium chloride solution dropwise, add 25 times of sodium carbonate solution, stir for 1h under this condition, and centrifuge the stannous chloride solution The white precipitate of barium carbonate produced by separation was obtained to obtain the transparent raw material low-lead stannous chloride, which was set aside. The stannous chloride after deleading is reacted with pyrophosphate to obtain stannous pyrophosphate product, and the lead content in the product reaches 0.0030%.

Embodiment 3

[0022] Put 200kg of stannous chloride (Pb%=0.014%) into 2m 3 Add 500L of deionized water to the reaction kettle, stir, and after it is completely dissolved, add 20kg of sodium hydroxide, adjust the pH of the solution to 8, continue to raise the temperature of the solution to 65°C, keep stirring, press barium chloride After the mass ratio of lead ion in stannous chloride is 40:1, add 50kg of barium chloride solution dropwise, add 25 times of sodium carbonate solution, stir for 1h under this condition, and then centrifuge the stannous chloride solution Produced barium carbonate white precipitate, obtains transparent raw material low-lead stannous chloride solution, stand-by. The stannous chloride after deleading is reacted with pyrophosphate to obtain stannous pyrophosphate product, and the lead content in the product reaches 0.0035%.

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PUM

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Abstract

The invention discloses a method for reducing lead content in stannous chloride. The method comprises the following steps of (1) dissolution: dissolving stannous chloride in water and preparing into a stannous chloride solution; (2) adjustment of a pH value: adjusting a pH value of the stannous chloride solution to 8-9 with an alkaline solution and heating to a temperature of 60-80 DEG C with stirring; (3) lead removal: dropwise adding a certain amount of a barium chloride-sodium carbonate solution into the stannous chloride solution with the pH value adjusted, controlling a reaction end point to a natural pH value, wherein a ratio of the amount of barium chloride to that of lead ions in stannous chloride is 20-60:1; and a ratio of the amount of substance of sodium carbonate to that of barium and lead ions is 13:12; and (4) solid-liquid separation: separating the stannous chloride solution with the lead removed by centrifugation and removing the precipitate. Lead content of high lead stannous chloride is reduced to below 0.005% through a barium carbonate co-precipitation method, thereby producing low lead stannous pyrophosphate. The lead content of the product can reach an industrial standard.

Description

technical field [0001] The invention belongs to the field of lead removal, in particular to a method for reducing lead content in stannous chloride. Background technique [0002] Stannous pyrophosphate (Sn 2 P 2 o 7 ) has a wide range of uses, and can be used for tin plating of cyanide-free electroplating, fillers for toothpaste, dyeing in the printing and dyeing industry, refined pottery in the ceramic industry, and improvement of paint performance in the paint industry. Especially in the field of toothpaste fillers, the control of lead content is very strict, and the industry standard controls the lead content in stannous pyrophosphate to be below 0.005%. The current production method of stannous pyrophosphate is mainly prepared by reacting stannous chloride with pyrophosphate. However, due to the high lead content in the raw material tin protochloride, the lead content in the product exceeds the standard. How to reduce the lead content in tin protochloride has become...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01G19/06
Inventor 杨育兵王运龙叶有明阮桦吴伯增农永萍张诚廖珍旭陈进中伍祥武荣桂能
Owner GUANGXI HUAXI GRP CO LTD
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