阅读说明：本技术 一种医用氯化钠的精制提纯方法 (Refining and purifying method of medical sodium chloride ) 是由 艾隆英 刘彦波 杨权杰 于 2021-09-24 设计创作，主要内容包括：本发明公开了一种医用氯化钠的精制提纯方法。首先将天然盐溶解于纯净水中,然后采用超滤或微滤过滤,去除溶液中的大分子有机物、胶体和微粒,再采用两级纳滤膜设备滤液进行处理,两级纳滤膜设备连用,能够有效去除溶液中的硫酸根,将纳滤膜设备渗透液泵入外循环蒸发器,过程中采用蒸汽加热,蒸汽压力控制在0.05-0.2Mpa,过程中,纳滤膜设备渗透液由不饱和变为饱和,氯化钠结晶析出,氯化钠析出的同时进一步提纯,最后过滤,干燥,包装。整个工艺将超滤/微滤和纳滤膜设备结合,完全采用膜法工艺处理,工艺简单、出水水质稳定、容易控制和实现自动化,最后精制得到的氯化钠杂质含量低,完全达到医用的指标。(The invention discloses a refining and purifying method of medical sodium chloride. Firstly, natural salt is dissolved in purified water, then ultrafiltration or microfiltration is adopted to remove macromolecular organic matters, colloids and particles in the solution, then two-stage nanofiltration membrane equipment filtrate is adopted to treat, two-stage nanofiltration membrane equipment is used together to effectively remove sulfate radicals in the solution, nanofiltration membrane equipment permeate is pumped into an external circulation evaporator, steam heating is adopted in the process, the steam pressure is controlled to be 0.05-0.2Mpa, in the process, the nanofiltration membrane equipment permeate is changed from unsaturated state to saturated state, sodium chloride is crystallized and separated out, the sodium chloride is further purified while being separated out, and finally, filtration, drying and packaging are carried out. The whole process combines ultrafiltration/microfiltration and nanofiltration membrane equipment, completely adopts membrane process treatment, has simple process, stable effluent quality, easy control and automation realization, and finally obtains sodium chloride with low impurity content by refining, which completely reaches medical index.)

1. A refining and purifying method of medical sodium chloride is characterized by comprising the following steps:

dissolving natural salt in purified water to obtain a salt solution containing impurities, wherein the solution contains metal ion elements such as magnesium ions and calcium ions and also contains sulfate ions;

step two, ultrafiltration or microfiltration is adopted for the salt solution to remove macromolecular organic matters, colloids and particles in the solution;

step three, two stages of nanofiltration membrane equipment are adopted to treat the solution obtained in the step two, and the two stages of nanofiltration membrane equipment are used together, so that sulfate radicals in the solution can be effectively removed;

pumping the nanofiltration membrane equipment penetrating fluid into an external circulation evaporator, heating by adopting steam in the process, controlling the steam pressure to be 0.05-0.2Mpa, changing the nanofiltration membrane equipment penetrating fluid from unsaturated state to saturated state in the process, crystallizing and separating out sodium chloride, and further purifying while separating out the sodium chloride;

dissolving the salt in the third step, putting the salt into a filter tank, filtering by adopting a traditional microfiltration or ultrafiltration separation process, and intercepting sodium chloride crystals;

and step six, drying the salt discharged from the filter in a drying bed, packaging according to the pharmaceutical grade after full drying, wherein the product can reach the standard of pharmaceutical grade for sodium chloride for injection, and preparing saline with different concentrations for hospital patients according to actual requirements.

2. The refining and purifying method of medical sodium chloride as claimed in claim 1, wherein the recovery rate of the first stage nanofiltration can reach 90%, the penetrating fluid of the first stage nanofiltration is used as the inlet water of the second stage nanofiltration, the recovery rate of the second stage nanofiltration can reach 95%, and the total recovery rate can reach 85.5%.

3. The method for refining and purifying medical sodium chloride as claimed in claim 2, wherein in the step two and the step four, the filtering membrane is polysulfone, polyethersulfone or polyvinylidene fluoride, the feeding pressure is less than 10bar, the pore diameter of the membrane is 0.001-0.1 μm, and the cut-off molecular weight is 1000-30000 Da.

Technical Field

The invention relates to the technical field of sodium chloride purification, in particular to a refining and purifying method of medical sodium chloride.

Background

The sodium chloride injection is mainly used for treating: water loss due to various causes, including hypotonic, isotonic, and hypertonic water loss; hypertonic nonketotic diabetic coma, use isotonic or hypotonic sodium chloride can correct the state of water loss and isotonic; low chloride metabolic alkalosis. The sodium chloride injection is a traditional medicine generally adopted clinically in the medical field in all countries in the world at present, when a patient uses the sodium chloride injection, the sodium chloride injection directly enters a blood circulation system through intramuscular injection, and because natural salt sodium chloride contains a plurality of harmful impurities, if the harmful impurities are not removed, the natural salt sodium chloride enters blood, a plurality of complications can be caused, and the body of the patient is damaged. The traditional natural salt purification process comprises the steps of firstly dissolving natural salt, then adding barium chloride for sedimentation to remove sulfate ions, then adding sodium carbonate for sedimentation to remove introduced barium ions, then filtering supernate through an ultrafiltration or microfiltration membrane system, and finally dissolving, filtering, drying and packaging salt obtained by twice recrystallization. The disadvantages of this process are: 1. the barium chloride and the sodium carbonate are added, a feeding tank is needed, the occupied area is large, and the operation is complex; 2. the reagents barium chloride and sodium carbonate are required to be added twice, and the barium chloride has toxicity and can increase the cost of the reagents; 3. the sulfate radical is removed by a precipitation method, so that the removal rate of the sulfate radical is not high, and the sulfate radical cannot be completely removed; 4. the distillation is carried out twice, the distillation temperature needs 130 ℃, and high energy consumption is needed, so that the cost is increased; 5. during the crystallization process, sodium sulfate and some substances with similar solubility, such as metal cations, exist in crystals and cannot be removed.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and seek to design a preparation method of medical-grade sodium chloride.

In order to achieve the purpose, the invention adopts the following technical scheme:

a refining and purifying method of medical sodium chloride comprises the following steps:

dissolving natural salt in purified water to obtain a salt solution containing impurities, wherein the solution contains metal ion elements such as magnesium ions and calcium ions and also contains sulfate ions;

step two, ultrafiltration or microfiltration is adopted for the salt solution to remove macromolecular organic matters, colloids and particles in the solution;

step three, separating the solution obtained in the step two by adopting two stages of nanofiltration membrane equipment, wherein the two stages of nanofiltration membrane equipment are used together, so that sulfate radicals in the solution can be effectively removed;

pumping the nanofiltration membrane equipment penetrating fluid into an external circulation evaporator, heating by adopting steam in the process, controlling the steam pressure to be 0.05-0.2Mpa, changing the nanofiltration membrane equipment penetrating fluid from unsaturated state to saturated state in the process, crystallizing and separating out sodium chloride, and further purifying while separating out the sodium chloride;

dissolving the salt in the third step, putting the salt into a filter tank, filtering by adopting a traditional microfiltration or ultrafiltration separation process, and intercepting sodium chloride crystals;

and step six, drying the salt discharged from the filter in a drying bed, packaging according to the pharmaceutical grade after full drying, wherein the product can reach the standard of pharmaceutical grade for sodium chloride for injection, and preparing saline with different concentrations for hospital patients according to actual requirements.

Furthermore, the recovery rate of the first-stage nanofiltration can reach 90%, penetrating fluid of the first-stage nanofiltration is used as inlet water of the second-stage nanofiltration, the recovery rate of the second-stage nanofiltration can reach 95%, and the total recovery rate can reach 85.5%.

Further, in the step two and the step four, the filtering membrane is polysulfone, polyethersulfone or polyvinylidene fluoride, the water feeding pressure is less than 10bar, the membrane aperture is 0.001-0.1 μm, and the cut-off molecular weight is 1000-30000 Da.

Compared with the prior art, the invention has the following beneficial effects: 1. the whole process combines ultrafiltration/microfiltration and nanofiltration membrane equipment, completely adopts membrane process treatment, and has the advantages of simple process, stable effluent quality, easy control and realization of automation; 2. the use of chemical agents is reduced, and a large amount of solid waste is avoided; 3. the impurity content of the sodium chloride obtained by refining is low, and the sodium chloride completely reaches the medical index.

The specific implementation mode is as follows:

the invention is further illustrated by the following specific examples.

Example 1

A purification process of sodium chloride for injection specifically comprises the following steps:

adding natural salt into purified water, heating and stirring to fully dissolve the natural salt into a salt solution of 300g/L, wherein the solution contains calcium, magnesium, iron and some heavy metal elements as well as sodium sulfate, pre-filtering the solution by adopting a microfiltration or ultrafiltration system, wherein a used filtering membrane is polysulfone, polyether sulfone or polyvinylidene fluoride, the water feeding pressure is less than 10bar, the recovery rate of the solution is higher than 99%, micro-particles with the particle size of 0.01-0.1 mu m can be filtered, the intercepted molecular weight is 1000-30000Da, the solution is used for removing suspended matters in the solution, the turbidity of the filtered solution is less than 0.5NT, and the scaling of a nanofiltration membrane in the subsequent process can be greatly reduced;

and step two, filtering the solution by a multi-stage nanofiltration membrane device, wherein the multi-stage nanofiltration membrane device comprises a first stage nanofiltration membrane device and a second stage nanofiltration membrane device, the first stage nanofiltration membrane device is composed of a plurality of standard unit modules connected in series, the feed water pressure of the feed water is 25-30bar, the feed water enters a standard unit chamber when the temperature is room temperature, water and sodium chloride pass through the nanofiltration membrane to generate a permeate flow with relatively low feed water impurities, multivalent metal cations and sulfate radicals are intercepted by the nanofiltration membrane, or the multivalent metal cations and sulfate radicals are intercepted by the nanofiltration membrane or are rejected due to an electrostatic rejection mechanism, the surface layer of the nanofiltration membrane has charges, or positive or negative, which depend on the pH value condition of the mixed solution, when the solution containing metal ions flows through the surface of the nanofiltration membrane, the solution has certain net charges, and therefore, the membrane is allowed to intercept ionic metal impurities in the solution. The interception of the nanofiltration membrane on metal ions means that the metal ions are not allowed to pass through, and a intercepted water flow with higher content of metal impurities is formed, and is called as a concentrated solution. The recovery rate of the first-stage nanofiltration membrane equipment is 90%, the rejection rate of sulfate radicals can reach 98%, the rejection rate of other metal elements can reach more than 90%, namely, 0.1 cubic meter of intercepted water flow can be generated for every 1 cubic meter of inlet water. The second stage nanofiltration membrane equipment is similar to the first stage nanofiltration membrane equipment and consists of a plurality of connected standard unit chambers, but the second stage nanofiltration membrane equipment unit is smaller than the first stage nanofiltration membrane equipment unit, the second stage nanofiltration membrane equipment further processes the permeate flow sent by the first stage nanofiltration membrane equipment to further reduce the amount of impurities in the solution so as to improve the purity of salt, the multistage nanofiltration membrane equipment consists of nanofiltration modules with commercial standard sizes (such as 4 inches or 8 inches), and the nanofiltration membranes are nanofiltration membranes with stable interception and flux, and have the selectivity of more than 98 percent and the flux performance of more than 1L/m 2-hr-bar. The recovery rate of the multi-stage nanofiltration membrane equipment to water is 80-85%, the sulfate concentration in 80-85% penetrating fluid is less than 2ppm, only trace metal impurities suitable for recycling or reusing are generated in concentrated solution, and the solution is neutral and pollution-free and can be directly discharged into the nature; or directly recycled to the process operation for reuse without any chemical treatment, such as: returning to the water inlet loop of the first-stage nanofiltration membrane equipment after filtration, and enabling concentrated solution after being intercepted by the multistage nanofiltration membrane equipment to contain high-concentration sodium chloride and a large amount of metal impurities and sulfate radicals to enter the first stage for re-separation.

Evaporating and crystallizing penetrating fluid obtained by the multi-stage nanofiltration membrane equipment, wherein the penetrating fluid of the nanofiltration membrane equipment contains high-concentration sodium chloride, sodium chloride larger than 300g/L, sulfate radicals smaller than 2ppm and trace content of other metal cations, and evaporating and crystallizing in a steam tower at the temperature of larger than 100 ℃ to further improve the purity of the sodium chloride;

and step four, filtering the crystallized crystals by adopting a microfiltration or ultrafiltration system, wherein the used filtering membrane is polysulfone, polyether sulfone or polyvinylidene fluoride, the water feeding pressure is less than 10bar, the recovery rate of the solution is higher than 99 percent, and relatively pure sodium chloride particles can be obtained. And then, feeding the filtered granular salt into a drying tower at 100 ℃ for drying to obtain a relatively pure sodium chloride product, wherein the purified sodium chloride meets the standard of sodium chloride (for injection) in Chinese pharmacopoeia.

It should be understood that the above-described examples of the present invention are illustrative only for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. It will be appreciated by those skilled in the art that changes in these forms and modifications may be made without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims.