Old K says every week – talking about things in the petrochemical design industry. Post 38: Looking back on the past – Qinghai Potash Fertilizer

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Old K writes every week – Talks about things in the petrochemical engineering design industry, Post 38: Looking back on the past – Potash in Qinghai. Potash helps plants carry out photosynthesis, promotes the synthesis of plant proteins, and makes the plant’s branches and leaves stronger and thicker； It can also enhance the plant’s stress resistance, such as resistance to diseases, cold, drought, lodging, and salinity, thereby improving the quality of the plants and increasing their ability to absorb nitrogen. Potassium fertilizers mainly include potassium chloride and potassium sulfate. The production and consumption of potassium chloride far exceed those of potassium sulfate. Potassium sulfate is particularly suitable for chloride-sensitive and potassium-loving cash crops, such as tobacco, grapes, sugar beets, tea plants, potatoes, flax, and various fruit trees. Our country suffers from a severe potassium shortage; it is necessary to import large amounts of potash fertilizer from countries such as Russia and Canada every year, with several million tons still needing to be imported each year. China’s potassium resources are concentrated in the Chaharhan Salt Lake in the Qaidam Basin of Qinghai and Lop Nur in Xinjiang; the potassium resources in the Chaharhan Salt Lake are in the form of potassium chloride, while those in Lop Nur are in the form of potassium sulfate. Before the large-scale extraction of potash in Qinghai and Xinjiang, potash production in China was limited to a few seawater potash extraction plants in coastal areas, on a very small scale. The extraction of potash fertilizer in Qinghai began in the 1950s, and large-scale industrial production was not achieved until the 1980s; the current annual production volume of potassium chloride is around 5 million tons ； The extraction of potassium fertilizers in Lop Nur, Xinjiang, started relatively late; large-scale production was only achieved at the end of the 1990s, with the current output amounting to about 2 million tons of potassium sulfate per year. **Great emphasis was placed on the development of Qinghai’s salt lake resources; at that time, the Qinghai Salt Lake Research Institute was established in Xining. The Ministry of Chemical Industry assigned the task of designing potassium fertilizers to the Lianyungang Chemical Mine Design and Research Institute under the Ministry (now Zhonglan Lianhai Engineering Company) and the Changsha Chemical Mine Design and Research Institute. The pioneers in the field of potassium fertilizers dedicated their youth to advancing China’s potassium fertilizer industry under extremely difficult conditions. I was fortunate enough to be involved in the Qinghai Potash Project for some time; in total, I spent about 5 months on site at the salt lake. Qinghai Chaharhan Salt Lake is about 750 kilometers away from Xining, and about 50 kilometers away from Golmud. Gelemu is an important city that connects Qinghai and Tibet; it is locally known as the \"little \". At that time, its population was only in the hundreds of thousands, and it served as a settlement for gold miners. It had a fairly complete range of service facilities, and men who were away from home for long periods of time were prone to committing moral offenses there. Although the Chaharhan Salt Lake is only a few dozen kilometers away from Golmud, there is no fresh water beneath the salt lake, while Golmud has an abundance of fresh water underground. Upon arriving at the salt lake, it felt quite novel. The roads were made of salt – fresh water was sprinkled on the salt-covered surface, and then a roller was used to flatten it, resulting in roads that were fairly smooth, though very hard. If you pee on the ground, a small deep hole appears there. Due to the high altitude, it hardly ever rains throughout the year, resulting in a very dry climate that easily causes cracks in the lips and heels. Therefore, before business trips, it is necessary to get some crack-preventing ointment from the office clinic to take with one. Due to low air pressure, climbing stairs makes one out of breath ； Due to the low air pressure, water boils at around 90 degrees, so a pressure cooker is needed to cook rice; otherwise, it won’t be fully cooked. There are two types of distribution for the potassium-rich brine resources in salt lakes: one is the brine found on the surface of the salt lakes, and the other is underground brine. This brine forms as a result of snowmelt from mountains seeping into the ground, where it dissolves solid minerals to create brine. Brine mainly contains magnesium chloride, sodium chloride, potassium chloride, and small amounts of trace elements such as lithium (in order of decreasing concentration). The extraction process of potassium chloride is as follows: Brine is left to crystallize under sunlight in sodium salt ponds in salt fields to produce sodium chloride; it is then left to crystallize under sunlight in carnallite ponds to produce carnallite (KCl·MgCl2·6H2O). The carnallite is transported to a processing plant, where it is mixed with fresh water but not completely dissolved. Chemicals are added to float out potassium chloride, which is then washed and filtered before being dried to yield powdered potassium chloride product. Later, a crystallization process using brine was developed, yielding granular potassium chloride products that contain no additives and can be used for industrial purposes. The main by-products in the potassium chloride production process are mother liquor (rich in magnesium chloride) and sodium chloride; due to transportation costs, magnesium chloride and sodium chloride were rarely utilized at that time. Over the past decade or so, Qinghai Potash Fertilizer Factory has increased its investment; while expanding the production capacity of potassium chloride, it has also established new projects for producing caustic soda, soda ash, polyvinyl chloride, polypropylene, metallic magnesium, and lithium carbonate. Due to reckless investment, the company accumulated heavy debts, its stocks were delisted, and it faced severe difficulties; it was only saved from bankruptcy thanks to the intervention of local authorities and relevant departments. Qinghai potash fertilizer has played a vital role in addressing China’s shortage of potassium resources. It is hoped that those working in the potash fertilizer industry today will carry forward the spirit of hard work demonstrated by those who worked in this field before, and improve potash fertilizer production even further. Tip: You can enter “Lao K’s Weekly Thoughts – Talks on Matters in the Petrochemical Design Industry” into the website’s search engine to view previous posts