A new phenomenon occurred in phosph-chemical industries recently, the output of wet method phosphoric acid (PA for short) boosted and is largely used to produce phosphate products. Some enterprises put wet method PA apparatus into use one after another, and promote producing phosphate salts from wet method PA. After Guizhou Hongfu Industry Group’s application of purification process in wet method PA, it shocked the PA market with low prices. The nonstop increase of wet method PA amount leads some one to propose the idea that wet method PA will take place of furnace method and become the mainstream of phosph-chemical in China. The author has been caring about this phenomenon. After investigating and studying in many aspects, the author holds the opinion that furnace method PA will remain the mainstream in Chinese phosph-chemical.

As is known to all, in conventional wet method PA process, product is obtained by rock phosphorus reacting with inorganic acid, and then separating the sedimentation materials. The advantage in this method is low cost, resulting in low PA market prices. However, PA from this method holds disadvantages of to much foreign substances. As a result of the low quality, it is used in fertilizer industries only. Production process of furnace method is to combust yellow phosphorus and then reacts with water, getting PA of tech grade or food grade. Production cost of furnace method PA is higher but with good quality and less foreign substances. Therefore, its price is somewhat higher than wet method PA. Wet method PA process has been improved recently. Taking Guizhou Hongfu Industry Group as a representative, she has put new refining wet method process PA production lines into use. In contrast to conventional process, this method has improved PA quality, reduced foreign substances largely. And PA produced from this refining wet method is accepted by some enterprises and begin to be used to produce technical grade phosphate. Yellow phosphorus, raw material of furnace method is commonly considered to be of high pollution, high energy consumption and resources consumption, and is strict in production process. With the fierce market competition, wet method refining PA with low cost is accepted by customers and develops very fast. Causing disputes within phosph-chemical industry. Some even claim that wet method PA will substitute furnace method in the future and become the mainstream.

1. Recent situation of Chinese phosph-chemical.

The author has been engaging in phosph-chemical work for two decades, and pays attention to every movement in the industry. As to the new phenomenon, after practicing, contrasting and repeatedly proofing, the author discovers that yellow phosphorus and PA produced from yellow phosphorus cause less pollution and consumes less energy compared to wet method. Moreover, PA from furnace method is applied in industries with high science and technology content. It is a raw material of food grade, medicine grade and other refine phosphate products and closely linked to human lives. Its advantage could not be replaced by wet method PA. Therefore, yellow phosphorus and its acid cannot be simply defined as high pollution and energy consumption products. It’s boldly forecasted that yellow phosphorus and its acid will remain the mainstream in Chinese phosph-chemical industry now and for a long time in the future.

1.1 Energy consumed in production of yellow phosphorus is electricity. The price of electricity increases as a result of national restriction on electricity since 2003. This leads to the boost in price of yellow phosphorus cost. Electricity restriction policy causes insufficient production of yellow phosphorus, resulting in colossal profits with the price boosting from 7,000 to 20,000 RMB/ton between 2003 and 2006. Yellow phosphorus enterprises got large amount of fund and established many new factories enticed by the colossal profits. Yellow phosphorus output began to increase after 2006. This lead to the phenomenon of supply over requirement, and provided an opportunity for the production of furnace method PA. This paved a way for the raw materials. Price of yellow phosphorus began to reduce between 2006 and 2007, and came back to normal profit with present price being around 11,000, a little higher than 7,000 earlier.

1.2 With the continuous increase of international oil prices, developed countries have started to research and develop new energies leading by the US. Bio-diesel oil and low cost alcohol have been developed at present, and used by large amount. These energies have partially substituted petroleum. Bio-diesel oil and alcohol are refined from crops and plants. Crops and plants need a lot of phosphate fertilizers during growing up. Therefore, the widely application of new energies will bring up the development of phosphate fertilizer industry, causing increases of its prices. This brings up the development of wet method PA which is the raw material of phosphate fertilizers indirectly. And its price will go up accordingly, getting close to the price of furnace method PA. This will certainly make room for furnace method PA price.

1.3 Under traditional conception, yellow phosphorus is defined as a product with high pollution, high energy consumption, and consumes resources. Towards this traditional conception, we do not recognize it by its appearance, but have new acknowledgement and new definition.

1.3.1High pollution

It has always been regarded that yellow phosphorus and its PA are highly pollutive products. The result turn out to be quite the opposite after practicing and proofing. First of all, the convert rate of phosphorus element is over 99% in the process of turning rock phosphorus into yellow phosphorus, with all kinds of poisonous substances converted or reduced when heated at high temperature. Meanwhile, the recovery rate of phosphorus element is up to 99% during the process of producing furnace method PA from yellow phosphorus. Phosphorus lost is very low, taking only 1%. All kinds of microelement contents are reduced to below innocuity and nontoxic standards. Second, little waste residue is generated in the process of producing PA from yellow phosphorus, only large amount of granulating slag is generated sometimes when producing yellow phosphorus from rock phosphorus. Phosphorus residue can be used to produce building materials and siliceous fertilizer after being recycled. Cement cost can be reduced by producing with phosphorus residue, and this can bring good profits to cement factories. Pollution is controlled in production areas and basically no pollution transfer exists in producing yellow phosphorus and its PA. Third, all process water in production process can be reused. The goal of no waste water discharge is achieved. Plenty of heat energy is generated so investment on heat energy equipment can be reduced. Waste gas generated in production process can be used as energy resource and raw material to produce formic acid. Waste gas contains only 50 ppm phosphorus, so it causes little pollution to the atmosphere.

By comparison, phosphorus convert rate is only 90%, the other 10% gets lost during production of wet method PA. What is more, quite a lot of poisonous substances exist in waste residue and are difficult to be treated. At the same time, wet method PA production generates a lot of waste water. The water is acidic and has high fluoride content. Large amount of waste gas is generated which contains toxic substances. In addition, the inorganic acid used in wet method production is sulfuric acid, raw material of which contains many injurious substances. This is to import pollution resources into China as sulphur is mainly obtained by importing. This virtually enlarges pollution in our country, and makes it more difficult to treat. Wet method PA is not high in purity and contains a lot of foreign and toxic substances. These foreign and toxic substances are difficult to be treat and will cause second pollution when the acid is applied to produce other products.

By comparing these two methods, yellow phosphorus and its PA basically causes no waste water, gas or residue, making it better than wet method PA. It can be concluded hereby that, yellow phosphorus and its PA causes lower pollution in producing PA.

1.3.2 High consumption of energy.

The production process of yellow phosphorus and its PA does consume large quantities of energy, but we think it worthwhile as it brings us products with high quality. We can not define yellow phosphorus and PA as products with high pollution, high energy consumption and consumption of resources. We should also consider their advantages, for example, whether the product contains high science and technology, whether the technology is mature and whether the product is unable to be substituted, etc. Production process of furnace method PA has a long history. The process is mature in our country with high product concentration, few foreign substances especially fluoride and heavy metal and others. All kinds of fine phosphate and organic phosphorus product with high quality and high standard can be produced from this method. A technical standard that wet method PA cannot achieve. With economical development, people have been paying much attention to health and environmental protection problems, and quality requirement on all kinds of products will be higher and higher. From the view that people oriented, people foremost, standards for all kinds of phosph-chemical products will gradually get higher. A lot of toxic substances exist in wet method PA, among which fluoride and arsenic content could not be reduced to any lower. Wet method PA will directly do harm to human being's health if applied in food, medicine or high end industries. At the same time, we must give up some traditional views and ways of working. For example, feeding stuff grade phosph-chemical products use wet method PA as raw materials for lower costs. Harmful substances in wet method PA will transfer into human bodies via food chains, threading people’s health. Health is closely related to our future, with the burden heavy and the road ahead long. Therefore, we should promote using high quality and harmless raw materials, PA products from yellow phosphorus. And we should claim for green food and green environment. Under the precondition of people oriented, people foremost, wet method PA can still not substitute the high quality position of furnace method acid despite of its relatively lower costs.

1.3.3 Consumption of resources

We regard the production process of yellow phosphorus and its acid as the most resource saving method in phosph-chemical industries. Phosphorus recycle rate in furnace method PA production is as high as 98%, but only 85~90% for wet method. In the production of 1 ton PA, furnace method consumes 10~20% less resources than wet method. The value and recycle rate are high in the byproducts of yellow phosphorus and PA. Very little waste water, gas or residue is generated, if any. For example, waste water can be recycled and reused, so no discharge is possible. Carbon monoxide in the waste gas can be collected and used to produce formic acid, sodium formate, calcium formate and others. End gas amount from 1 ton yellow phosphorus is about 2,700 to 3,000 M3, among which CO takes 85~90%, with heat value equivalent to 5,500~6,500 M3 city gas. Thus making yellow phosphorus end gas a vary good heat resource and synthetic gas raw material. Many factories have used yellow phosphorus end gas as fuel in our country at present, used for baking ores, silicate rocks or to produce heat for hot polycondensation of sodium tripolyphosphate and sodium hexametaphosphate. There is a large space for omprehensive utilization of yellow phosphorus end gas, only need to purify with suitable method. There are complete sets of yellow phosphorus end gas purify technology in China at present, with treated gas contains up to 95% CO. Content of phosphorus, sulfur, arsenic and fluoride meets standards, and completely meets the demand of raw material in chemical synthetics. It is another outstanding characteristic and advantage of yellow phosphorus and its acid by applying advanced production technology, converting waste into resources and turning resources consumption into saving.

Production and consumption of furnace method PA takes large proportions. Using yellow phosphorus to produce PA takes about 70%. Most factories take process of yellow phosphorus--furnace method PA--sodium tripolyphosphate or sodium hexametaphosphate.Requirement on many phosph-chemical products is relatively high, especially for food grade or above. The products must use yellow phosphorus as raw material, such as electronic grade PA, HPA, organic phosphorus, phosphorus trichloride, high purity phosphate salts, etc. According to statistics, about 90% furnace PA is used to prepare fine phosphate salts. Technology content and attaching value are very large in the fashioning and deep processing with yellow phosphorus and furnace PA as raw materials, it has large development prospect.

It can be summed up that yellow phosphorus and its PA are no longer production methods with high pollution, high energy consumption and resources consumption as conventionally defined. On the contrary, the production process causes lower pollution, and is the most resources saving method in phosph-chemical industry. Moreover, its advantages of high product quality and reusable resources cannot be replaced by wet method PA. With the continual increasing price of wet method PA, the acid is doomed to be unable to become the mainstream in phosph-chemical in China. It is furnace method PA that is the mainstream of phosph-chemical industries in China.

2. Status quo of phosph-chemical in the world.

The current integrative yellow phosphorus furnace method route in China is more advantageous in costs than wet method route in Europe. Phosph-chemical products from developed countries will gradually retreat from international market. With the growing up of phosph-chemical in China, the production process becomes more and more mature. What is more, requirements on fine phosphate salts increase day by day in international market. The products will get close to high technology, fine and top. And requirement on furnace method PA from our country will continue to increase. It is indicated that, fine phosphate salts in China keeps increasing fast in recent years. It is considered by experts that there is large development potential in the future, especially the five additives.

Chinese fine phosph-chemical causes transfer in global capacity with its integrative advantages. The occupancy proportion in global phosph-chemical market by China will continue to increase in the future. Market prospect of furnace method PA is good. Practice will proof that furnace method PA will remain the mainstream in Chinese phosph-chemical industry.

Written in Nanning, China, Oct. 2007