Ten Historical Events Affecting the Development of Chemistry

1. The starting point of human civilization-the use of fire

Millions of years ago, human beings lived a very simple primitive life, living by hunting and eating raw meat and wild fruits. According to archaeologists' research, at least 500,000 years ago, we can find evidence that humans used fire, that is, charred animal bones were found in the place where Peking man lived in Zhoukoudian, Beijing. With fire, primitive people bid farewell to the life of eating and drinking blood. After eating cooked food, people's health level has improved, their intelligence has developed and their viability has improved. Later, people learned to make a fire by friction and drill wood to make a fire, so that the fire can be carried with them. Therefore, people are no longer the watchmen of the fire, but the fire-makers who can control the fire. Fire is a weapon used by human beings to invent tools and create wealth. Taking advantage of this characteristic, fire can produce various chemical reactions, thus starting ceramics, metallurgy, brewing and other processes, and entering the vast world of production and life.

2. A long history of pottery making technology.

It is difficult to prove when pottery came into being. There are different opinions about the origin of pottery. Some people speculate that the most primitive container of human life is made of branches. In order to make it fireproof and dense, a layer of clay is usually coated on the inside and outside of the container. In the process of use, these containers occasionally catch fire, and all the branches in them are burned out, but the clay will not catch fire, not only remains, but also becomes harder and better than before. This accident gave people great inspiration. Later, people simply stopped using branches as skeletons and began to consciously mash clay, mix it with water, knead it into a very soft degree, shape it into various shapes, dry it in the sun, and finally burn it on a bonfire to make original pottery. About 1 10,000 years ago, kilns for firing pottery began to appear in China, becoming the first country to produce pottery. The invention and manufacturing technology of pottery is a major breakthrough. Pottery-making process has changed the properties of clay, resulting in a series of chemical changes in the composition of clay, such as silica, alumina, calcium carbonate (gài) and magnesium oxide (měi), which makes pottery have excellent waterproof and durable properties. Therefore, pottery has not only new technical significance but also new economic significance. It adds cooking methods for people to handle food, and tools such as ceramic spinning wheels, ceramic knives and ceramic rollers also play an important role in production. At the same time, ceramic containers can make grain and water easy to store. Therefore, pottery has quickly become a necessity for human life and production, especially for people who have settled down to engage in agricultural production.

3. The rise of metallurgical chemistry

In the late Neolithic period, people began to use metal instead of stone tools to make tools. The most used is copper. However, this natural resource is limited after all, so metallurgy of smelting metal from ore came into being. Copper ore was first smelted. About 3800 BC, Iran began to mix copper ore (malachite) with charcoal, and after heating, copper was obtained. Pure copper is soft, and the quality of tools and weapons made of it is not good enough. On this basis, after improvement, bronzes appeared. By 3000 ~ 2500 BC, in addition to copper, tin (xρ) and lead (qiān) were also smelted. Adding tin to pure copper can reduce the melting point of copper to about 800℃, so it is easier to cast. The alloy of copper and tin is called bronze (sometimes containing lead), which has high hardness and is suitable for manufacturing production tools. The weapons made of bronze are hard and sharp, and the production tools made of bronze are far better than copper. There are also bronze coins cast in bronze. China has made great achievements in casting bronzes, such as the "Simuwu" Ding in the early Yin Dynasty. It is a ritual vessel and the largest bronze unearthed in the world. Another example is the chime in the Warring States period, which is a great creation in ancient music. Therefore, the appearance of bronzes promoted the development of agriculture, weapons, finance and art at that time, and pushed social civilization forward a step. China, Egypt and India were the first countries in the world to make and use iron. In the late Spring and Autumn Period (6th century BC), China made pig iron for casting. At the earliest time, charcoal was used to make iron, and carbon monoxide produced by incomplete combustion of charcoal reduced iron oxide in iron ore to metallic iron. Iron is widely used to make plowshares, iron tools (a weeding tool), shovels and other agricultural tools, iron pans and other utensils, and of course it is also used to make weapons. It was not until the 8th century BC to the 7th century BC that Europe and other countries successively entered the Iron Age. Because iron is harder than bronze and the raw materials for ironmaking are far richer than copper, iron has replaced bronze in most places.

4. China's great contributions-gunpowder and papermaking.

Black powder is one of the four great inventions in ancient China. Why is it called "black powder"? This should also start with the raw materials it uses. The three raw materials of gunpowder are sulfur, mirabilite (xiāo) and charcoal. Charcoal is black, so gunpowder is black, which is called black gunpowder. The nature of gunpowder is easy to catch fire, so it can be associated with fire, but how to understand the word "medicine"? It turns out that sulfur and saltpeter were both medicines for treating diseases in ancient times. So black powder can be understood as black medicine that will catch fire. The invention of gunpowder was related to alchemy in the Western Han Dynasty in China. The purpose of alchemy is to seek the medicine of immortality. The raw materials of an alchemist include sulfur and saltpeter. The method of alchemy is to put sulfur and saltpeter into an alchemy furnace and extract them with fire for a long time. In the process of repeated alchemy, there have been fires and explosions again and again. After many experiments, the method of making gunpowder was finally found. Black powder broke away from alchemy after its invention and has been used in the military. Ancient people fought with swords and guns at close range and bows and arrows at a long distance. With black powder, since the Song Dynasty, various new weapons have appeared, such as gunpowder packs fired with bows. There are two kinds of gunpowder packages: fireballs and fire thistles. Fire is used to ignite the gunpowder line, throw the gunpowder package out and kill each other by burning and exploding. Around the 8th century AD, China's alchemy spread to Arabia, and the preparation method of gunpowder also spread to the past, and later spread to Europe. In this way, China's gunpowder became the "ancestor" of modern explosives. This is one of China's great inventions. Paper is a tool for human beings to preserve knowledge and spread culture, and it is a great contribution of the Chinese nation to human civilization. Before paper made of plant fibers was used, the main methods of spreading characters in ancient China were: engraving on Oracle Bone Inscriptions (tortoise shell, ox bone), the so-called Oracle Bone Inscriptions; Oracle bones were limited in number, and were later carved on bamboo slips or wooden slips. But the number of bamboo slips used in Confucius' The Analects of Confucius can be imagined. In addition, silk woven from silk (bó) can also be used for writing, but it is difficult to produce silk in large quantities. Finally, paper made of plant fibers came into being and has been passed down to this day. 1957 In May, archaeologists in China discovered some beige ancient papers in the ancient tomb of Ba (bà) Bridge in Anxian County, Shaanxi Province. It has been identified that this paper is mainly made of hemp fiber, and its age will not be later than that of Emperor Wu of Han Dynasty (65438 BC+056 ~ 87 BC). It is the earliest plant fiber paper in the world. When it comes to the invention of paper, people will think of Cai Lun. He was a constant attendant during the reign of Emperor Wu of the Han Dynasty. Seeing that the bamboo slips used for writing at that time were too heavy, he summarized the experience of predecessors in papermaking, and led craftsmen to use bark, hemp heads, rags and broken fishing nets as raw materials, first cut them into pieces or cut them off, soaked them in water for a long time, then pounded them into pulp, and then spread them on mats to dry them to make paper. It is light and thin, suitable for writing, and very popular. Papermaking is an extremely complicated chemical process and the product of the wisdom of the working people. In fact, there was paper before Cai Lun, so Cai Lun can only be regarded as an improver of papermaking technology.

5. Alchemy and Alchemy

When the feudal society developed to a certain stage, the productivity was greatly improved, and the ruling class demanded more and more material enjoyment, so emperors and nobles naturally had two extravagant hopes: first, they hoped to master more wealth for themselves to enjoy; Second, when they have great wealth, they always want to enjoy it forever. Therefore, there is a desire to live forever. For example, after Qin Shihuang unified China, he couldn't wait to seek the elixir of life. Not only did Xu Fu and others go out to sea to look for it, but he also called a large group of alchemists (alchemists) to refine cinnabar-Dan medicine for him day and night. The alchemist wants to turn some stones into gold (that is, to make gold and silver artificially). They believe that base metals such as copper, lead, tin and iron can be transformed into precious metals such as gold and silver in some way. For example, Greek alchemists melted copper, lead, tin and iron into alloys and then soaked them in calcium polysulfide solution. As a result, a layer of tin sulfide was formed on the surface of the alloy, which resembled gold in color (now golden tin sulfide is called gold powder, which can be used as the gold coating of ancient buildings). At this point, alchemists subjectively believe that "gold" has been refined. In fact, this method of judging material changes only from the surface color and not from the essence is self-deception. They never achieved the goal of "turning the stone into gold". Although the pious alchemists and alchemists did not achieve their goals, their efforts were not completely in vain. They spent many years in a humble "chemical laboratory" shrouded in poisonous gas and smoke, and should be said to be the first batch of "chemists" who devoted themselves to exploring the mysteries of chemical science. They have accumulated rich experience and failed lessons for the establishment of chemistry discipline, and even summarized some laws of chemical reaction. For example, Ge Hong, an alchemist in China, put forward from the practice of alchemy: "Cinnabar (mercury sulfide) will be burned into mercury, and after accumulation (sulfur and mercury are put together), it will also be turned into cinnabar." This is a summary of the law of chemical change, that is, "substances can be transformed into each other by artificial methods." An alchemist and an alchemist are doing these primitive chemical experiments day and night. They certainly need a lot of experimental instruments, so they invented the still, melting furnace, heating pot, beaker and filtering device. They also produced many chemicals, useful alloys or drugs to treat diseases according to the needs at that time, many of which are acids, bases and salts commonly used today. In order to record the method and process of the experiment, they also created many technical terms and wrote many works. It is these theories, chemical experimental methods, chemical instruments, alchemy and alchemy works that started the science of chemistry. It can be seen from these historical facts that alchemists and alchemists have made great contributions to the rise and development of chemistry. Future generations must not ridicule them for their "pursuit of immortality, turning stone into gold", but should respect them as pioneers in developing chemical science. Therefore, in English, the terms chemist and alchemist are very similar, and their real meaning is "chemistry comes from alchemy".

Second, the establishment of modern chemical theory-exploring the material structure

The world is made of matter, but what is matter made of? Xi Bochang (about 1 140 BC) was the first person who tried to answer this question. He believes: "It is easy to have Tai Chi, easy to have two instruments, two instruments give birth to four elephants, and four elephants give birth to gossip." Explain the composition of matter with yin-yang gossip. About BC 1400, western natural philosophy put forward the idea of material structure. Thales of Greece believed that water was the mother of all things; Hercules thinks that everything is made of fire; Aristotle took four kinds of "primitiveness" as the most primitive nature when he demonstrated the material structure in the book "Occurrence and Destruction". They are hot and cold, dry and wet. When they were in two combination, they formed four "elements" of fire, air, water and earth, and then formed various substances. None of the above arguments touches on the essence of material structure. In the history of chemical development, it was Boyle in England who gave a clear definition of elements for the first time. He pointed out: "Elements are the basis of matter, which can combine with other elements to form compounds. However, if the element is separated from the compound, it can't be decomposed into something simpler than it. " Boyle also argued that chemistry should not be regarded as an empirical skill in making metals and drugs, but as a science. Therefore, Boyle is regarded as the person who established chemistry as a science. Man's understanding of the structure of matter is endless, and matter is made up of elements. So, what are elements made of? 1803, the atomic theory founded by British chemist Dalton further solved this problem. There are three main contents in atomism: 1. All elements are composed of particles that cannot be divided and destroyed. These particles are called atoms. 2. Atoms of the same element have the same properties and masses, but atoms of different elements have different properties and masses; 3. A certain number of two different elements combine to form a compound. Atomic theory has successfully explained many chemical phenomena. Then the Italian chemist avogadro put forward the molecular theory in 18 1 1, which further supplemented and developed Dalton's atomism. He believes that many substances often exist in the form of molecules rather than atoms. For example, oxygen is an oxygen molecule composed of two oxygen atoms, while compounds are actually molecules. Since then, chemistry has turned from macro to micro, making chemical research based on atomic and molecular levels.

Third, the rise of modern chemistry.

At the end of 19, three major discoveries appeared in physics, namely X-ray, radioactivity and electron. These new discoveries have violently impacted Dalton's thought about the indivisibility of atoms, thus opening the door to the internal structure of atoms and nuclei and revealing the deeper mysteries of the micro-world. After introducing physical theories such as thermodynamics into chemistry, we can use the concepts of chemical equilibrium and reaction speed to judge the direction and conditions of substance transformation in chemical reactions, thus establishing physical chemistry and theoretically raising chemistry to a new level. Based on the establishment of quantum mechanics, the theory of chemical bond (binding force between atoms in a molecule) makes people further understand the relationship between molecular structure and properties, greatly promotes the connection between chemistry and materials science, and provides a theoretical basis for the development of materials science. The relationship between chemistry and society is also increasingly close. Chemists observe and think about social problems from the viewpoint of chemistry, and use chemical knowledge to analyze and solve social problems, such as energy crisis, food problems, environmental pollution and so on. The intersection and infiltration of chemistry and other disciplines have produced many marginal disciplines, such as biochemistry, geochemistry, cosmochemistry, marine chemistry, atmospheric chemistry and so on. , make biology, electronics, aerospace, laser, geology, ocean and other technologies develop rapidly. Chemistry has also provided countless material guarantees for human beings' food, clothing, housing and transportation, and made due contributions to improving people's lives and improving human health. With the rise of modern chemistry, chemistry has developed from inorganic chemistry and organic chemistry into a multidisciplinary science, and a chemical discipline with inorganic chemistry, organic chemistry, analytical chemistry, physical chemistry and polymer chemistry as sub-disciplines has been established. Chemist, a "molecular architect", will create today's mansion and tomorrow's world for all mankind with fickle hands.

6. Safe explosives benefit mankind-Nobel invents safe explosives.

"Boom .." There was a loud noise, and the earth and rocks fell everywhere. This is a scene that we can often see from the screen and the screen. Nowadays, powerful explosives are indispensable pioneers in large-scale engineering construction such as mining and road construction. But at the beginning, how did humans find and tame this "friend" with infinite strength and bad temper? It's a long story As we all know, the black rocket is one of the four great inventions in ancient China. About 13 ~ 14 century, it spread to European countries through Arab countries in Central Asia. Europeans learned to use gunpowder and popularized it. They not only created guns fired with gunpowder, but also developed production with gunpowder. /kloc-in the 0/7th century, with the deepening of the industrial revolution, many countries urgently demanded the development of mining industry, accelerated the mining speed, and needed more powerful explosives. However, the traditional black powder is not fully burned and its explosive power is not strong, so it is urgent to find a powerful new explosive. 1847, the Italian Sobolero invented a high explosive called nitroglycerin, which was much more powerful than black powder. But it is very easy to explode, and it is very dangerous to manufacture, store and transport. People can't control it, so it is difficult to apply it to practice. In order to tame this fierce "wild horse", many people took great pains, but failed; But it was the Swedish warrior alfred nobel who finally surrendered and rode this wild horse and produced high-efficiency and safe explosives.

Nobel's father is a mechanic and has no higher education, but he likes chemical experiments very much and develops explosives whenever he has time. Under the influence of his father, Nobel Junior was also keen on improving the research of explosives. But his parents disapprove, because it is too dangerous to make explosives. His father wants him to be a mechanic honestly. But Nobel firmly believes that improving explosives will create great wealth for mankind. Parents were moved by the strong will of persistent pursuit and had to acquiesce. From then on, the father and son stood in the same trench and struggled side by side to overcome scientific difficulties. At the beginning of 1862, Nobel began to study the manufacture of controllable high explosives with nitroglycerin. Nitroglycerin, he thought, is a liquid and difficult to control. If mixed with solid black powder, isn't it easy to store and control? He added 10% nitroglycerin to the black powder, and the explosive power of the mixed explosive was greatly enhanced. However, he soon discovered that explosives could not be stored for a long time. After a few hours, nitroglycerin was completely absorbed by the pores of the powder, the combustion speed slowed down, and the explosive power was greatly weakened, which was of no practical value.

In order to develop a controllable and efficient explosive, Nobel made bold experiments and careful observation day and night. In the past, people detonated black powder by igniting the fuse, but this method could not detonate nitroglycerin. Nitroglycerin is not easy to explode according to human requirements, but it is easy to explode by itself. What an unruly guy!

1In the early summer of 862, Nobel designed an important surprise test to detonate nitroglycerin: put nitroglycerin in a small glass tube into a metal tube filled with black powder, put a fuse on it, and plug the metal nozzle tightly; Light the fuse and throw the metal pipe into the deep ditch. Suddenly, there was a bang and a violent explosion, which showed that the nitroglycerin inside had completely exploded. Nobel realized that a small amount of black powder exploded in a sealed container, which could completely explode the separated nitroglycerin.

The following autumn, Nobel established his first laboratory in Helenbo, Stockholm, specializing in the research and manufacture of nitroglycerin. At first, he used black powder as the initiator, but the effect was not very satisfactory. Later, he used mercury fulminate as a detonating tube (now called a detonator) and successfully detonated nitroglycerin. In 1864, he obtained a patent for this invention. He finally invented a practical nitroglycerin explosive.

The joy of initial success has not passed yet, followed by a heavy blow. 1On September 3rd, 864, in order to further improve the performance of detonators and make more efficient explosives, they conducted new tests. Only heard a loud noise, the laboratory was sent to the sky, and the ground was blown out of a big hole. When people came from the ruins to rescue Nobel, the bloody Nobel kept saying, "The experiment was successful, my experiment was successful!" " "Yes, the power of the new explosives is enormous, but the losses are also heavy: his laboratory was completely destroyed, Nobel's younger brother Amy was killed, his father was seriously injured and disabled, and his brother and himself were also injured. After the accident, the neighbors were so frightened that the authorities banned them from producing or testing explosives in the city. As a result, Nobel can only move the equipment to the gondola in Lake Mara, 3 kilometers away. But this did not shake Nobel's determination to make new explosives. After many twists and turns, the first nitroglycerin factory in the world was finally approved by the government. In March 1865, it was built in Winterwegen.

The explosives produced by Nobel Company are very popular in the mining industry. In addition to Sweden, patents have also been obtained in Britain, France, Germany and the United States. However, the performance of new explosives is still not stable enough, and accidents often occur in transportation: an American train exploded due to bumps on the way and turned into a pile of scrap iron; The seagoing ship "Europa" encountered a strong wind in the Atlantic Ocean, and its hull tilted, causing nitroglycerin to explode and the ship sank. A series of accidents aroused people's doubts about nitroglycerin, and some countries even ordered an embargo. Faced with this difficult situation, many people advised Nobel not to engage in dangerous explosion experiments again, but Nobel vowed not to stop until he reached his goal. What he considered was to make nitroglycerin explosive very safe without weakening its explosive power.

Nobel made a series of experiments in succession, hoping to adsorb nitroglycerin with some porous substances, such as charcoal powder, sawdust and cement, so as to reduce the risk of explosion, but the results were not satisfactory. Once the nitroglycerin tank on the transport vehicle was accidentally broken, nitroglycerin flowed out and mixed with diatomite as a shock-proof filler next to it, but nothing happened. This gave Nobel a great inspiration. After repeated experiments, he finally made a solid explosive with diatomite absorbing three parts of nitroglycerin. This kind of explosive is very safe to transport and use, and it is a Nobel safe explosive. In order to dispel people's doubts about safe explosives,1on July 4, 867, Nobel made an open comparative experiment. He put a box of safe explosives on a pile of lit firewood, and the explosives did not explode; Then a box of safety explosives was dropped from a 20-meter-high cliff, but it still didn't explode; Finally, the caves and iron drums were filled with safe explosives and detonated with detonators, all of which exploded successfully! The "Wild Horse" finally put on the halter, and the explosives were no longer daunting.

Nobel made persistent efforts and continued to improve his explosives. He dissolved one part of collodion (nitrocellulose with low nitrogen content) in nine parts of nitroglycerin, and obtained a gel with stronger explosive force-fried gel, 1887. He added a small amount of camphor to nitroglycerin and collodion, and invented smokeless gunpowder with strong explosive power and less smoke. Until today, gunpowder commonly used in military production still belongs to this type. In the rumbling explosion, Nobel's career developed rapidly. His factories are all over Europe and America, and the sales of new explosives have soared. His invention greatly promoted the construction of roads and ironware, and contributed to the excavation of tunnels and the exploitation of mineral deposits; But his explosives also deepened the disaster and pain of the war and made him very sad. In order to benefit mankind,1October 29th, 1895, 165438+ He wrote a famous will in Paris, and set up a scientific research institution with a part of the huge wealth accumulated in his life as a fund, with five prizes of physics, chemistry, physiology (or medicine), literature and peace.

7. Initiate a new era of soda production industry-Hou invented the combined soda production method.

In the chemical industry, soda ash is an important chemical raw material, the chemical name is also called "sodium carbonate", which is a white powder. Don't underestimate it, it is of great use! Use it when making soap, glass and paper; Used when spinning and weaving; It is also indispensable in the process of ironmaking and steelmaking. You can also use it to make many chemical products! It was born in a chemical plant and produced by the combined alkali production method. This method was initiated by Hou, a pioneer of chemical industry in China, so it is also called "Hou Shi soda process". So under what circumstances did Hou study the alkali-making method, and how did he establish Hou's alkali-making method? Things have to start from the17th century. At that time, people knew that soda ash was used in the production of glass, paper and soap, but at that time, alkali was extracted from plant ash and salt lake water, and people didn't know that it could be produced from factories. Later, a French doctor, Lu Lanhua, spent four years creating a method of making soda ash at 179 1. Since then, the factory can continuously produce soda ash, which met the needs of industrial production at that time. Unfortunately, this method is not perfect, and there are still many shortcomings, such as high temperature in the production process, high labor intensity of workers, high coal consumption and low product quality, so many people want to improve it. 1862, the Belgian chemist Sulvi proposed a method of making alkali with salt, limestone and ammonia as the main raw materials, which was called "ammonia alkali method" or "Sulvi alkali method". Because of its high output, good quality, low cost and continuous production, this method quickly replaced Lubran's method. But this method is strictly controlled by the manufacturer, and it is not allowed to leak out at all, and it is not allowed to be known by others. At the beginning of the 20th century, China also needed soda ash for industrial production at that time, but it could not produce it by itself and had to rely on imports. During the First World War, the output of soda ash was greatly reduced and the traffic was blocked. A British soda ash manufacturing company took the opportunity to raise the price of soda ash and even refused to supply it to China, which led to the closure and bankruptcy of China soda ash factory. At that time, China students studying in the United States studied hard and got excellent results. He studied chemical engineering in the United States for 8 years and obtained a doctorate 192 1. When he heard that foreign car capitalists were so stuck around the necks of China people, his lungs would explode. He vowed to return to China after finishing his studies, and use what he learned to serve the motherland and revitalize China's national industry. 192 1 year 10 and then returned to China. He is the chief engineer of Ren Yongli Alkali Industry Company, and his task is to create the first alkali plant in China. At that time, if alkali was to be produced, it could only be produced by Sulvi's alkali production method.

The principle is simple, but it is difficult to do. Due to the technical blockade, Hou can only rely on his own continuous research, experiment and exploration. After a long period of hard work, we finally designed the process and installed the equipment, and then started the trial production. Who knows, I met with difficulties from the beginning. One day, just after the trial operation, the high ammonia distillation tower suddenly shook badly and made a loud noise. Everyone was so scared that Hou immediately stopped. Upon inspection, all pipes were blocked by white sediment. What shall we do? At first he stabbed him with a big iron drill, and he was so tired that he was sweating all over, but it didn't help. Later, he came up with a way to add dry alkali to let the sediment fall slowly, and finally turned the corner. There are many faults like this, and he eliminates them one by one every time. After several years' efforts, the first soda ash plant in China was officially put into operation on August 3rd. 1924. The workers came to the workshop early that day to witness the birth of the first batch of soda ash in China. A few hours later, I don't know who shouted "come out!" " "Everyone's eyes looked at the alkali mouth together. Huh? How did it come out as red and white alkali? It should be white by rights! Everyone's heart is cold. At this time, the equipment was carefully inspected, and the original soda came out with rust, which made the product turn red. We all breathed a sigh of relief when the reason was found. Later, they improved the equipment and finally made a pure white product. Looking at the glistening soda ash, Hou smiled. He smiled so comfortably that years of hard work were not in vain. He finally explored the mystery of Sulvi's soda production process and realized his oath to serve the motherland.

1937, Japanese imperialism launched a war of aggression against China. They took a fancy to the ammonium sulfate plant in Nanjing and wanted to buy Hou, but Hou flatly refused. In order not to damage the factory, he decided to move the factory to Sichuan and build a new chemical plant in western Sichuan, Li Yong. The main raw material for alkali production is a vegetable basin, that is, sodium chloride, while the salt in Sichuan is well salt, which needs to be hoisted out from a deep well with a bamboo tube. Because the concentration is thin, it must be concentrated to become raw materials, so the cost of salt is high. In addition, the fatal disadvantage of Sulvi alkali method is that the utilization rate of salt is not high, that is to say, 30% of salt is wasted, so the cost is high, so Hou decided not to use Sulvi alkali method and found a new way out. Firstly, he analyzed the shortcomings of Sulvi soda process, and found that the main reason was that half of the raw materials were useless, and only sodium in salt and carbonate in lime were used to produce soda ash. The other half of chlorine in salt combines with calcium in lime to form calcium chloride, which is not used. So how can we turn the other half of the ingredients into treasure? He thought and thought and designed many schemes, but they were all overturned. Later, he finally thought of whether Sulvi's alkali-making method and synthetic ammonia method could be combined into one, that is, ammonia and carbon dioxide used for alkali-making were directly provided by synthetic ammonia plant, and ammonium chloride in filtrate was precipitated by adding salt water. This kind of ammonium chloride can be used as both chemical raw material and chemical fertilizer, which can greatly improve the utilization rate of salt and save a lot of equipment, such as lime kiln, ash bucket and ammonia distillation tower. With this idea, success depends on practice. So he successfully led the technicians and started the experiment. L times, 2 times, 10 times, 100 times ... more than 500 experiments were conducted and more than 2,000 samples were analyzed. The experiment was successful and the idea became a reality.

This new method of alkali production is named "combined alkali production method", which increases the utilization rate of salt from 70% to 96% at once. In addition, calcium chloride, a waste that pollutes the environment, has become a useful chemical fertilizer for crops-ammonium chloride, and it can also reduce 1/3 equipment, so its superiority greatly exceeds that of Sulvi soda production method, thus creating a new era of soda production industry in the world.